1
|
Huo R, Armstrong AJ, Nelmes GR, Lawes DJ, Edwards AJ, McMullin CL, Hicks J. Stabilisation of the [SiH 6] 2- Anion within a Supramolecular Assembly. Chemistry 2024; 30:e202400662. [PMID: 38376067 DOI: 10.1002/chem.202400662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 02/21/2024]
Abstract
The hypercoordinate [SiH6]2- anion is not stable in solution. Here, we report the room temperature, solution stable molecular [SiH6]2- complex, [{KCa(NON)(OEt2)}2][SiH6] (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethyl-xanthene)), where the [SiH6]2- anion is stabilised within a supramolecular assembly that mimics the solid-state environment of the anion in the lattice of K2SiH6. Solution-state reactivity of the complex towards carbon monoxide, benzaldehyde, azobenzene and acetonitrile is reported, yielding a range of reduction and C-C coupled products.
Collapse
Affiliation(s)
- Ryan Huo
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Alicia J Armstrong
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Gareth R Nelmes
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Douglas J Lawes
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Claire L McMullin
- Department of Chemistry, University of Bath Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| |
Collapse
|
2
|
Edwards AJ, King MF, López-García M, Peckham D, Noakes CJ. Assessing the effects of transient weather conditions on airborne transmission risk in naturally ventilated hospitals. J Hosp Infect 2024; 148:1-10. [PMID: 38447806 DOI: 10.1016/j.jhin.2024.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Many UK hospitals rely heavily on natural ventilation as their main source of airflow in patient wards. This method of ventilation can have cost and energy benefits, but it may lead to unpredictable flow patterns between indoor spaces, potentially leading to the unexpected transport of infectious material to other connecting zones. However, the effects of weather conditions on airborne transmission are often overlooked. METHODS A multi-zone CONTAM model of a naturally ventilated hospital respiratory ward, incorporating time-varying weather, was proposed. Coupling this with an airborne infection model, this study assessed the variable risk in interconnected spaces, focusing particularly on occupancy, disease and ventilation scenarios based on a UK respiratory ward. RESULTS The results suggest that natural ventilation with varying weather conditions can cause irregularities in the ventilation rates and interzonal flow rates of connected zones, leading to infrequent but high peaks in the concentration of airborne pathogens in particular rooms. This transient behaviour increases the risk of airborne infection, particularly through movement of pathogens between rooms, and highlights that large outbreaks may be more likely under certain conditions. This study demonstrated how ventilation rates achieved by natural ventilation are likely to fall below the recommended guidance, and that the implementation of supplemental mechanical ventilation can increase ventilation rates and reduce the variability in infection risks. CONCLUSION This model emphasizes the need for consideration of transient external conditions when assessing the risk of transmission of airborne infection in indoor environments.
Collapse
Affiliation(s)
- A J Edwards
- EPSRC Centre for Doctoral Training in Fluid Dynamics, University of Leeds, Leeds, UK.
| | - M-F King
- School of Civil Engineering, University of Leeds, Leeds, UK
| | | | - D Peckham
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - C J Noakes
- School of Civil Engineering, University of Leeds, Leeds, UK
| |
Collapse
|
3
|
Thomas SP, Singh A, Grosjean A, Alhameedi K, Grønbech TBE, Piltz R, Edwards AJ, Iversen BB. The Ambiguous Origin of Thermochromism in Molecular Crystals of Dichalcogenides: Chalcogen Bonds versus Dynamic Se-Se/Te-Te Bonds. Angew Chem Int Ed Engl 2023; 62:e202311044. [PMID: 37718313 DOI: 10.1002/anie.202311044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/15/2023] [Accepted: 09/15/2023] [Indexed: 09/19/2023]
Abstract
We report thermochromism in crystals of diphenyl diselenide (dpdSe) and diphenyl ditelluride (dpdTe), which is at variance with the commonly known mechanisms of thermochromism in molecular crystals. Variable temperature neutron diffraction studies indicated no conformational change, tautomerization or phase transition between 100 K and 295 K. High-pressure crystallography studies indicated no associated piezochromism in dpdSe and dpdTe crystals. The evolution of the crystal structures and their electronic band structure with pressure and temperature reveal the contributions of intramolecular and intermolecular factors towards the origin of thermochromism-especially the intermolecular Se⋅⋅⋅Se and Te⋅⋅⋅Te chalcogen bonds and torsional modes of vibrations around the dynamic Se-Se and Te-Te bonds. Further, a co-crystal of dpdSe with iodine (dpdSe-I2 ) and an alloy crystal of dpdSe and dpdTe implied a predominantly intramolecular origin of the observed thermochromism associated with vibronic coupling.
Collapse
Affiliation(s)
- Sajesh P Thomas
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, 110016, India
- Department of Chemistry and iNano, Aarhus University, Langelandsgade 140, Aarhus, 8000, Denmark
| | - Ashi Singh
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Arnaud Grosjean
- School of Molecular Sciences, University of Western Australia, Perth, WA 6009, Australia
- National Synchrotron Radiation Research Center, Hsinchu 30076 (Taiwan)
| | - Khidhir Alhameedi
- School of Molecular Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Thomas Bjørn E Grønbech
- Department of Chemistry and iNano, Aarhus University, Langelandsgade 140, Aarhus, 8000, Denmark
| | - Ross Piltz
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, NSW 2234, Australia
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, NSW 2234, Australia
| | - Bo B Iversen
- Department of Chemistry and iNano, Aarhus University, Langelandsgade 140, Aarhus, 8000, Denmark
| |
Collapse
|
4
|
Mullassery S, Yuvaraj K, Dange D, Jones DDL, Del Rosal I, Piltz RO, Edwards AJ, Maron L, Jones C. Magnesium(I) Reduction of Aluminum(III) Hydride Complexes: Generation of Mixed Valence Aluminum (AlI/Al0) Hydride Cluster Compounds, [Al6H8(NR3)2{Mg(β-diketiminate)}4]. Angew Chem Int Ed Engl 2023:e202305582. [PMID: 37236910 DOI: 10.1002/anie.202305582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 05/28/2023]
Abstract
Reduction of a range of amido- and aryloxy-aluminum dihydride complexes, e.g. [AlH2(NR3){N(SiMe3)2}] (NR3 = NMe3 or N-methylpiperidine (NMP)), with β-diketiminato dimagnesium(I) reagents, [{(ArNacnac)Mg}2] (ArNacnac = [HC(MeCNAr)2]-, Ar = mesityl (Mes) or 2,6-xylyl (Xyl)), have afforded deep red mixed valence aluminum hydride cluster compounds, [Al6H8(NR3)2{Mg(ArNacnac)}4], which have an average Al oxidation state of +0.66, the lowest for any well-defined aluminum hydride compound. In the solid-state, the clusters are shown to have distorted octahedral Al6 cores, having zero-valent Al axial sites and mono-valent AlH2- equatorial units. Several novel by-products were isolated from the reactions that gave the clusters, including the Mg-Al bonded magnesio-aluminate complexes, [(ArNacnac)(Me3N)Mg-Al(μ-H)3[{Mg(ArNacnac)}2(μ-H)]]. Computational analyses of one aluminum hydride cluster revealed its Al6 core to be electronically delocalized, and to possess one unoccupied, and six occupied, skeletal molecular orbitals.
Collapse
Affiliation(s)
| | - K Yuvaraj
- Monash University, Chemistry, AUSTRALIA
| | | | | | - Iker Del Rosal
- Paul Sabatier University: Universite Toulouse III Paul Sabatier, Chemistry, FRANCE
| | - Ross O Piltz
- ANSTO: Australian Nuclear Science and Technology Organisation, Neutron Diffraction, AUSTRALIA
| | - Alison J Edwards
- ANSTO: Australian Nuclear Science and Technology Organisation, Neutron Diffraction, AUSTRALIA
| | - Laurent Maron
- University of Toulouse 3: Universite Toulouse III Paul Sabatier, Chemistry, FRANCE
| | - Cameron Jones
- Monash University, School of Chemistry, Box 23, 3800, Victoria, AUSTRALIA
| |
Collapse
|
5
|
Andralojc LE, Kim DH, Edwards AJ. Diagnostic accuracy of a decision-support software for the detection of intracranial large-vessel occlusion in CT angiography. Clin Radiol 2023; 78:e313-e318. [PMID: 36754714 DOI: 10.1016/j.crad.2022.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 10/05/2022] [Accepted: 10/15/2022] [Indexed: 01/13/2023]
Abstract
AIM To investigate the real-world clinical performance of the decision-support software "e-CTA" (e-Stroke Suite, Brainomix Limited, Oxford UK) for the detection of acute intracranial large-vessel occlusion (LVO) on computed tomography (CT) angiography at a UK district general hospital. MATERIALS AND METHODS The retrospective study included 300 consecutive CT angiograms of the head and neck performed between 8 March 2021 and 20 May 2021. e-CTA findings were recorded and compared with the radiologist report. Cases in which there was disagreement between e-CTA and the radiologist were reviewed by a sub-specialist vascular radiologist as the reference standard. RESULTS The incidence of intracranial LVO was 7%. e-CTA correctly identified 18 of 21 intracranial proximal LVOs (86%). There were 34 false positives. The sensitivity was 0.86 (95% confidence interval [CI], 0.64-0.97), with specificity of 0.88 (95% CI, 0.83-0.91). The positive predictive value was 0.35 (95% CI, 0.27-0.43). The negative predictive value was 0.99 (95% CI, 0.96-1.00). CONCLUSION Sensitivity, specificity, and negative predictive values were similar to those reported in the literature (Seker et al., Int J Stroke. 2021; 17:77-82); however, the positive predictive value for e-CTA was significantly lower. In practice, this meant that over half of all reported occlusions by the software were false positives. Radiologists should be aware of these metrics in order to assign appropriate weight to software findings when formulating a report. Differences in population demographics, scanners, CT protocols, and incidence are all factors potentially influencing software accuracy. Local validation testing may help provide accuracy metrics more relevant to individual institutions.
Collapse
Affiliation(s)
- L E Andralojc
- The Department of Clinical Imaging, Royal Cornwall Hospitals NHS Trust, Truro, Cornwall, TR1 3LJ, UK
| | - D H Kim
- The Department of Clinical Imaging, Royal Cornwall Hospitals NHS Trust, Truro, Cornwall, TR1 3LJ, UK.
| | - A J Edwards
- The Department of Clinical Imaging, Royal Cornwall Hospitals NHS Trust, Truro, Cornwall, TR1 3LJ, UK
| |
Collapse
|
6
|
McMullen JS, Huo R, Vasko P, Edwards AJ, Hicks J. Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers. Angew Chem Int Ed Engl 2023; 62:e202215218. [PMID: 36344462 PMCID: PMC10100151 DOI: 10.1002/anie.202215218] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Indexed: 11/09/2022]
Abstract
The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be "terminal", but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.
Collapse
Affiliation(s)
- Jacob S McMullen
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Ryan Huo
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Petra Vasko
- Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P.O. Box 55, 00014, Helsinki, Finland
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| |
Collapse
|
7
|
McMullen JS, Huo R, Vasko P, Edwards AJ, Hicks J. Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202215218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jacob S. McMullen
- Australian National University Research School of Chemistry 2601 Acton AUSTRALIA
| | - Ryan Huo
- Australian National University Research School of Chemistry 2601 Acton AUSTRALIA
| | - Petra Vasko
- University of Helsinki - Kumpula Campus: Helsingin Yliopisto - Kumpulan Kampus Department of Chemistry Helsinki FINLAND
| | - Alison J. Edwards
- Australian Nuclear Science and Technology Organisation - Lucas Heights Campus: Australian Nuclear Science and Technology Organisation Australian Centre for Neutron Scattering 2234 Sydney AUSTRALIA
| | - Jamie Hicks
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| |
Collapse
|
8
|
Garçon M, Phanopoulos A, Sackman GA, Richardson C, White AJP, Cooper RI, Edwards AJ, Crimmin MR. The Continuum Between Hexagonal Planar and Trigonal Planar Geometries. Angew Chem Int Ed Engl 2022; 61:e202211948. [PMID: 36094744 PMCID: PMC9828084 DOI: 10.1002/anie.202211948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Indexed: 01/12/2023]
Abstract
New heterometallic hydride complexes that involve the addition of {Mg-H} and {Zn-H} bonds to group 10 transition metals (Pd, Pt) are reported. The side-on coordination of a single {Mg-H} to Pd forms a well-defined σ-complex. In contrast, addition of three {Mg-H} or {Zn-H} bonds to Pd or Pt results in the formation of planar complexes with subtly different geometries. We compare their structures through experiment (X-ray diffraction, neutron diffraction, multinuclear NMR), computational methods (DFT, QTAIM, NCIPlot), and theoretical analysis (MO diagram, Walsh diagram). These species can be described as snapshots along a continuum of bonding between ideal trigonal planar and hexagonal planar geometries.
Collapse
Affiliation(s)
- Martí Garçon
- Department of ChemistryMolecular Sciences Research HubImperial College London82 Wood Lane, Shepherds BushLondonW12 0BZUK
| | - Andreas Phanopoulos
- Department of ChemistryMolecular Sciences Research HubImperial College London82 Wood Lane, Shepherds BushLondonW12 0BZUK
| | - George A. Sackman
- Chemical CrystallographyChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK,Australian Centre for Neutron Scattering, ANSTONew Illawarra RoadLucas HeightsNSW, 2234Australia
| | - Christopher Richardson
- School of Chemistry and Molecular BioscienceUniversity of WollongongWollongongNSW 2522Australia
| | - Andrew J. P. White
- Department of ChemistryMolecular Sciences Research HubImperial College London82 Wood Lane, Shepherds BushLondonW12 0BZUK
| | - Richard I. Cooper
- Chemical CrystallographyChemistry Research Laboratory12 Mansfield RoadOxfordOX1 3TAUK
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering, ANSTONew Illawarra RoadLucas HeightsNSW, 2234Australia
| | - Mark R. Crimmin
- Department of ChemistryMolecular Sciences Research HubImperial College London82 Wood Lane, Shepherds BushLondonW12 0BZUK
| |
Collapse
|
9
|
Richardson GM, Howarth J, Evans MJ, Edwards AJ, Cameron SA, Anker MD. Reactivity of a β-diketiminate ytterbium(II) hydride with cyclopentadiene derivatives. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2130277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Georgia M. Richardson
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Jesse Howarth
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Matthew J. Evans
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Alison J. Edwards
- Australian Nuclear Science and Technology Organisation, Australian Centre for Neutron Scattering, Sydney, Australia
| | - Scott A. Cameron
- Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, New Zealand
| | - Mathew David Anker
- School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| |
Collapse
|
10
|
Duvinage D, Puylaert P, Wieduwilt EK, Malaspina LA, Edwards AJ, Lork E, Mebs S, Hupf E, Grabowsky S, Beckmann J. Nickel and Palladium Complexes of a PP(O)P Pincer Ligand Based upon a peri-Substituted Acenaphthyl Scaffold and a Secondary Phosphine Oxide. Inorg Chem 2022; 61:8406-8418. [PMID: 35609007 DOI: 10.1021/acs.inorgchem.1c03266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A PP(O)P pincer ligand based upon a peri-substituted acenaphthyl (Ace) scaffold and a secondary phosphine oxide, (5-Ph2P-Ace-6-)2P(O)H, was prepared and fully characterized including a neutron diffraction study. The reaction with [Ni(H2O)6]Cl2 and PdCl2 produced ionic metal(II) complexes [κ3-P,P',P''((5-Ph2P-Ace-6-)2P(OH))MCl]Cl, which upon addition of Et3N gave rise to zwitterionic metal(II) complexes κ3-P,P',P''((5-Ph2P-Ace-6-)2P(O))MCl (M = Ni, Pd). The reaction with Ni(COD)2 (COD = cyclooctadiene) provided the η3-cyclooctenyl Ni(II) complex κ3-P,P',P''((5-Ph2P-Ace-6-)2P(O))Ni(η3-C8H13). A detailed complementary bonding analysis of the P-H, P-O, and P-M interactions was carried out (M = Ni, Pd).
Collapse
Affiliation(s)
- Daniel Duvinage
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany
| | - Pim Puylaert
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany
| | - Erna K Wieduwilt
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany.,CNRS, Laboratoire de Physique et Chimie Theoriques (LPCT), Université de Lorraine, 1 Boulevard Arago, 57078 Metz, France
| | - Lorraine A Malaspina
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany.,Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Alison J Edwards
- Australian Nuclear Science and Technology Organisation, Australian Centre for Neutron Scattering, New Illawarra Road, Lucas Heights, Sydney 2234, Australia
| | - Enno Lork
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany
| | - Stefan Mebs
- Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Emanuel Hupf
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany
| | - Simon Grabowsky
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany.,Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Jens Beckmann
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 3 & 7, 28359 Bremen, Germany
| |
Collapse
|
11
|
Paparo A, Matthews AJR, Smith CD, Edwards AJ, Yuvaraj K, Jones C. N-Heterocyclic carbene, carbodiphosphorane and diphosphine adducts of beryllium dihalides: synthesis, characterisation and reduction studies. Dalton Trans 2021; 50:7604-7609. [PMID: 33988210 DOI: 10.1039/d1dt01393a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reaction of several N-heterocyclic carbenes, a carbodiphosphorane, and bis(diphenylphosphino)ethane (DPPE) with [BeX2(OEt2)2] (X = Br or I) have yielded a variety of beryllium dihalide adduct complexes, all of which were crystallographically characterised. Attempts to reduce the compounds to low oxidation state beryllium complexes using a variety of reducing agents have been carried out, but were of limited success. However, reaction of [(IPr)BeBr2] (IPr = :C{(DipNCH)2}; Dip = 2,6-diisopropylphenyl) with the aluminium(i) heterocycle, [:Al(DipNacnac)] (DipNacnac = [HC(MeCNDip)2]-) afforded the adduct complex, [{(IPr)(Br)Be(μ-H)}2], while reduction of [(IPr)BeBr2] with potassium naphthalenide gave the beryllium naphthalenediyl complex, [(IPr)Be(C10H8)]. Furthermore, reaction of [{(DPPE)BeI2}∞], with [:Al(DipNacnac)] led to insertion of the Al centre of the heterocycle into a Be-I bond, and formation of a rare example of an Al-Be bonded complex, [(DPPE)(i)Be-Al(i)(DipNacnac)].
Collapse
Affiliation(s)
- Albert Paparo
- School of Chemistry, PO Box 23, Monash University, VIC 3800, Australia.
| | | | - Cory D Smith
- School of Chemistry, PO Box 23, Monash University, VIC 3800, Australia.
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - K Yuvaraj
- School of Chemistry, PO Box 23, Monash University, VIC 3800, Australia.
| | - Cameron Jones
- School of Chemistry, PO Box 23, Monash University, VIC 3800, Australia.
| |
Collapse
|
12
|
Abstract
A series of neutral magnesium and calcium complexes bearing an extremely bulky diamido ligand have been synthesised and crystallographically characterised. A number of these complexes feature rare group 2 metalaromatic interactions, such as the η6-coordination of benzene and 'agostic-like' C-H coordination, the latter previously unseen in neutral Mg and Ca complexes.
Collapse
Affiliation(s)
- Jacob S McMullen
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales 2234, Australia
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, ACT 2601, Australia.
| |
Collapse
|
13
|
Desai N, Edwards AJ, Ernest TB, Tuleu C, Orlu M. 'Big Data' informed drug development: a case for acceptability. Drug Discov Today 2020; 26:865-869. [PMID: 33358700 DOI: 10.1016/j.drudis.2020.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/26/2020] [Accepted: 12/16/2020] [Indexed: 01/12/2023]
Abstract
Data, which help inform various stages of drug product development, are increasingly being collected using newer, more novel platforms, such as mobile applications, and analysed computationally as much larger 'Big Data' data sets, revealing patterns relating to human behaviour and interactions. Medicine acceptability gauges the ability and willingness of patients to take their dosage forms. It has become a crucial human component of drug product design. Vouching for the age appropriateness of medicinal products, acceptability related data are now expected by regulatory bodies. Shifting from traditional paper-based to electronic data-gathering platforms will allow the pharmaceutical industry to collect real-world, real-time, clinically relevant data, capable of informing current and future drug product development, reducing time and cost, and setting foundations for patient-centric drug product design.
Collapse
Affiliation(s)
- Neel Desai
- Department of Pharmaceutics, UCL School of Pharmacy, University College London, London, WC1N 1AX, UK.
| | - A J Edwards
- GlaxoSmithKline, David Jack Centre, Park Road, Ware, SG12 0DP, UK
| | - T B Ernest
- GlaxoSmithKline, David Jack Centre, Park Road, Ware, SG12 0DP, UK
| | - C Tuleu
- Department of Pharmaceutics, UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - M Orlu
- Department of Pharmaceutics, UCL School of Pharmacy, University College London, London, WC1N 1AX, UK
| |
Collapse
|
14
|
Pal R, Jelsch C, Malaspina LA, Edwards AJ, Murshed MM, Grabowsky S. syn and anti polymorphs of 2,6-dimethoxy benzoic acid and its molecular and ionic cocrystals: Structural analysis and energetic perspective. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128721] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
15
|
Chen R, Qin G, Li S, Edwards AJ, Piltz RO, Del Rosal I, Maron L, Cui D, Cheng J. Molecular Thorium Trihydrido Clusters Stabilized by Cyclopentadienyl Ligands. Angew Chem Int Ed Engl 2020; 59:11250-11255. [DOI: 10.1002/anie.202002303] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/22/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Runhai Chen
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Guorui Qin
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Shihui Li
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organization New IIIawarra Road Lucas Heights NSW 2234 Australia
| | - Ross O. Piltz
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organization New IIIawarra Road Lucas Heights NSW 2234 Australia
| | - Iker Del Rosal
- LPCNO, CNRS & INSA UPS Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Laurent Maron
- LPCNO, CNRS & INSA UPS Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Dongmei Cui
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- University of Science and Technology of China Hefei Anhui 230039 China
| | - Jianhua Cheng
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- University of Science and Technology of China Hefei Anhui 230039 China
| |
Collapse
|
16
|
Chen R, Qin G, Li S, Edwards AJ, Piltz RO, Del Rosal I, Maron L, Cui D, Cheng J. Molecular Thorium Trihydrido Clusters Stabilized by Cyclopentadienyl Ligands. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Runhai Chen
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Guorui Qin
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Shihui Li
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organization New IIIawarra Road Lucas Heights NSW 2234 Australia
| | - Ross O. Piltz
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organization New IIIawarra Road Lucas Heights NSW 2234 Australia
| | - Iker Del Rosal
- LPCNO, CNRS & INSA UPS Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Laurent Maron
- LPCNO, CNRS & INSA UPS Université de Toulouse 135 Avenue de Rangueil 31077 Toulouse France
| | - Dongmei Cui
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- University of Science and Technology of China Hefei Anhui 230039 China
| | - Jianhua Cheng
- State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences No. 5625, Renmin Street Changchun 130022 China
- University of Science and Technology of China Hefei Anhui 230039 China
| |
Collapse
|
17
|
Mezera MA, Li W, Edwards AJ, Koch DJ, Beard AD, Wiltbank MC. Identification of stable genes in the corpus luteum of lactating Holstein cows in pregnancy and luteolysis: Implications for selection of reverse-transcription quantitative PCR reference genes. J Dairy Sci 2020; 103:4846-4857. [PMID: 32229123 DOI: 10.3168/jds.2019-17526] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/10/2020] [Indexed: 12/20/2022]
Abstract
In lactating dairy cattle, the corpus luteum (CL) is a dynamic endocrine tissue vital for pregnancy maintenance, fertility, and cyclicity. Understanding processes underlying luteal physiology is therefore necessary to increase reproductive efficiency in cattle. A common technique for investigating luteal physiology is reverse-transcription quantitative PCR (RT-qPCR), a valuable tool for quantifying gene expression. However, reference-gene-based RT-qPCR quantification methods require utilization of stably expressed genes to accurately assess mRNA expression. Historically, selection of reference genes in cattle has relied on subjective selection of a small pool of reference genes, many of which may have significant expression variation among different tissues or physiologic states. This is particularly concerning in dynamic tissues such as the CL, with its capacity for rapid physiologic changes during luteolysis, and likely in the less characterized period of CL maintenance during pregnancy. Thus, there is a clear need to identify reference genes well suited for the bovine CL over a wide range of physiological states. Whole-transcriptome RNA sequencing stands as an effective method to identify new reference genes by enabling the assessment of the expression profile of the entire pool of mRNA transcripts. We report the identification of 13 novel putative reference genes using RNA sequencing in the bovine CL throughout early pregnancy and luteolysis: RPL4, UQCRFS1, COX4I1, RPS4X, SSR3, CST3, ZNF266, CDC42, CD63, HIF1A, YWHAE, EIF3E, and PPIB. Independent RT-qPCR analyses were conducted confirming expression stability in another set of CL tissues from pregnancy and regression, with analyses performed for 3 groups of samples: (1) all samples, (2) samples from pregnancy alone, and (3) samples throughout the process of CL regression. Seven genes were found to be more stable in all states than 2 traditional reference genes (ACTB and GAPDH): RPS4X, COX4I1, PPIB, SSR3, RPL4, YWHAE, and CDC42. When CL tissues from pregnant animals alone were analyzed, CST3, HIF1A, and CD63 were also identified as more stable than ACTB and GAPDH. Identification of these new reference genes will aid in accurate normalization of RT-qPCR results, contributing to proper interpretation of gene expression relevant to luteal physiology. Furthermore, our analysis sheds light on the effects of luteolysis and pregnancy on the stability of gene expression in the bovine CL.
Collapse
Affiliation(s)
- M A Mezera
- Department of Dairy Science, University of Wisconsin, Madison 53706; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison 53706
| | - W Li
- USDA Dairy Forage Research Center, Madison, WI 53706.
| | - A J Edwards
- USDA Dairy Forage Research Center, Madison, WI 53706
| | - D J Koch
- USDA Dairy Forage Research Center, Madison, WI 53706
| | - A D Beard
- Department of Dairy Science, University of Wisconsin, Madison 53706; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison 53706
| | - M C Wiltbank
- Department of Dairy Science, University of Wisconsin, Madison 53706
| |
Collapse
|
18
|
Malaspina LA, Hoser AA, Edwards AJ, Woińska M, Turner MJ, Price JR, Sugimoto K, Nishibori E, Bürgi HB, Jayatilaka D, Grabowsky S. Hydrogen atoms in bridging positions from quantum crystallographic refinements: influence of hydrogen atom displacement parameters on geometry and electron density. CrystEngComm 2020. [DOI: 10.1039/d0ce00378f] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen atom positions can be obtained accurately from X-ray diffraction data of hydrogen maleate salts via Hirshfeld atom refinement.
Collapse
|
19
|
Hupf E, Malaspina LA, Holsten S, Kleemiss F, Edwards AJ, Price JR, Kozich V, Heyne K, Mebs S, Grabowsky S, Beckmann J. Proximity Enforced Agostic Interactions Involving Closed-Shell Coinage Metal Ions. Inorg Chem 2019; 58:16372-16378. [PMID: 31747261 DOI: 10.1021/acs.inorgchem.9b01845] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A proximity enforcing diarylsilane ligand is reported, which gives rise to unusual Si-H···M interactions with the d10 metal ions Cu+ and Ag+ upon complexation. These interactions are studied in detail both experimentally and computationally and can be classified to be weakly agostic in nature for the Si-H···Cu interaction. The Si-H···Ag interaction has more signatures of an electrostatic contact.
Collapse
Affiliation(s)
- Emanuel Hupf
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany.,Department of Chemistry , University of Alberta , 11227 Saskatchewan Dr. , Edmonton , Alberta T6G 2G2 , Canada
| | - Lorraine A Malaspina
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany
| | - Sebastian Holsten
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany
| | - Florian Kleemiss
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany.,Departement für Chemie und Biochemie , Universität Bern , Freiestrasse 3 , 3012 Bern , Switzerland
| | - Alison J Edwards
- Australian Centre for Neutron Scattering , ANSTO , New Illawarra Road , Lucas Heights , NSW 2234 , Australia
| | - Jason R Price
- MX Beamlines, Australian Synchrotron , ANSTO , 800 Blackburn Road , Clayton , Victoria 3168 , Australia
| | - Valeri Kozich
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Karsten Heyne
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Stefan Mebs
- Institut für Experimentalphysik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Simon Grabowsky
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany.,Departement für Chemie und Biochemie , Universität Bern , Freiestrasse 3 , 3012 Bern , Switzerland
| | - Jens Beckmann
- Institut für Anorganische Chemie und Kristallographie , Universität Bremen , Leobener Straße 3 & 7 , 28359 Bremen , Germany
| |
Collapse
|
20
|
Sarkar S, Thomas SP, Potnuru LR, Edwards AJ, Grosjean A, Ramanathan KV, Guru Row TN. Experimental Insights into the Electronic Nature, Spectral Features, and Role of Entropy in Short CH 3···CH 3 Hydrophobic Interactions. J Phys Chem Lett 2019; 10:7224-7229. [PMID: 31696712 DOI: 10.1021/acs.jpclett.9b02734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hydrophobic interactions are often explored in solution-state aggregation of molecules. However, an experimental electron density description about these interactions is still lacking. Here, we report a systematic study on the electronic nature of methyl···methyl hydrophobic interactions in a series of multicomponent crystals of biologically active molecules. Charge density models based on high-resolution X-ray diffraction allow the visualization of subtle details of electron density features in the interaction region. Our study classifies these interactions as atypical group···group interactions in contrast to σ-hole interactions, which are stabilized by the minimized electrostatic repulsion and maximized dispersion forces. For the first time, we quantified the solid-state entropic contribution from the torsional mode of the methyl groups in stabilizing these interactions by thermal motion analysis based on neutron diffraction as well as variable-temperature crystallography. The carbon atoms in methyl···methyl interactions show a unique upfield chemical shift in the 13C solid-state NMR signal.
Collapse
Affiliation(s)
- Sounak Sarkar
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore - 560012 , India
| | - Sajesh P Thomas
- Department of Chemistry and iNano , Langelandsgade 140 , Aarhus 8000 , Denmark
| | | | - Alison J Edwards
- Australian Nuclear Science and Technology Organisation (ANSTO) , Lucas Heights , Sydney , NSW 2232 , Australia
| | - Arnaud Grosjean
- School of Molecular Sciences , The University of Western Australia , Perth 6009 , Australia
| | | | - T N Guru Row
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore - 560012 , India
| |
Collapse
|
21
|
Malaspina LA, Wieduwilt EK, Bergmann J, Kleemiss F, Meyer B, Ruiz-López MF, Pal R, Hupf E, Beckmann J, Piltz RO, Edwards AJ, Grabowsky S, Genoni A. Fast and Accurate Quantum Crystallography: From Small to Large, from Light to Heavy. J Phys Chem Lett 2019; 10:6973-6982. [PMID: 31633355 DOI: 10.1021/acs.jpclett.9b02646] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The coupling of the crystallographic refinement technique Hirshfeld atom refinement (HAR) with the recently constructed libraries of extremely localized molecular orbitals (ELMOs) gives rise to the new quantum-crystallographic method HAR-ELMO. This method is significantly faster than HAR but as accurate and precise, especially concerning the free refinement of hydrogen atoms from X-ray diffraction data, so that the first fully quantum-crystallographic refinement of a protein is presented here. However, the promise of HAR-ELMO exceeds large molecules and protein crystallography. In fact, it also renders possible electron-density investigations of heavy elements in small molecules and facilitates the detection and isolation of systematic errors from physical effects.
Collapse
Affiliation(s)
- Lorraine A Malaspina
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
| | - Erna K Wieduwilt
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
- Université de Lorraine , CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT) , 1 Boulevard Arago , 57078 Metz , France
| | - Justin Bergmann
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
| | - Florian Kleemiss
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
- Departement für Chemie und Biochemie , Universität Bern , Freiestrasse 3 , 3012 Bern , Switzerland
| | - Benjamin Meyer
- Université de Lorraine , CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT) , 1 Boulevard Arago , 57078 Metz , France
| | - Manuel F Ruiz-López
- Université de Lorraine , CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT) , 1 Boulevard Arago , 57078 Metz , France
| | - Rumpa Pal
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
| | - Emanuel Hupf
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
| | - Jens Beckmann
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
| | - Ross O Piltz
- Australian Nuclear Science and Technology Organisation , Australian Centre for Neutron Scattering , New Illawarra Road , Lucas Heights , NSW 2234 , Australia
| | - Alison J Edwards
- Australian Nuclear Science and Technology Organisation , Australian Centre for Neutron Scattering , New Illawarra Road , Lucas Heights , NSW 2234 , Australia
| | - Simon Grabowsky
- Institut für Anorganische Chemie und Kristallographie, Fachbereich 2 - Biologie/Chemie , Universität Bremen , Leobener Straße 3 und 7 , 28359 Bremen , Germany
- Departement für Chemie und Biochemie , Universität Bern , Freiestrasse 3 , 3012 Bern , Switzerland
| | - Alessandro Genoni
- Université de Lorraine , CNRS, Laboratoire de Physique et Chimie Théoriques (LPCT) , 1 Boulevard Arago , 57078 Metz , France
| |
Collapse
|
22
|
Hooper TN, Lau S, Chen W, Brown RK, Garçon M, Luong K, Barrow NS, Tatton AS, Sackman GA, Richardson C, White AJP, Cooper RI, Edwards AJ, Casely IJ, Crimmin MR. The partial dehydrogenation of aluminium dihydrides. Chem Sci 2019; 10:8083-8093. [PMID: 31762968 PMCID: PMC6855256 DOI: 10.1039/c9sc02750e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/12/2019] [Indexed: 11/21/2022] Open
Abstract
The reactions of a series of β-diketiminate stabilised aluminium dihydrides with ruthenium bis(phosphine), palladium bis(phosphine) and palladium cyclopentadienyl complexes is reported.
The reactions of a series of β-diketiminate stabilised aluminium dihydrides with ruthenium bis(phosphine), palladium bis(phosphine) and palladium cyclopentadienyl complexes is reported. In the case of ruthenium, alane coordination occurs with no evidence for hydrogen loss resulting in the formation of ruthenium complexes with a pseudo–octahedral geometry and cis-relation of phosphine ligands. These new ruthenium complexes have been characterised by multinuclear and variable temperature NMR spectroscopy, IR spectroscopy and single crystal X-ray diffraction. In the case of palladium, a series of structural snapshots of alane dehydrogenation have been isolated and crystallographically characterised. Variation of the palladium precursor and ligand on aluminium allows kinetic control over reactivity and isolation of intermetallic complexes that contain new Pd–Al and Pd–Pd interactions. These complexes differ by the ratio of H : Al (2 : 1, 1.5 : 1 and 1 : 1) with lower hydride content species forming with dihydrogen loss. A combination of X-ray and neutron diffraction studies have been used to interrogate the structures and provide confidence in the assignment of the number and position of hydride ligands. 27Al MAS NMR spectroscopy and calculations (DFT, QTAIM) have been used to gain an understanding of the dehydrogenation processes. The latter provide evidence for dehydrogenation being accompanied by metal–metal bond formation and an increased negative charge on Al due to the covalency of the new metal–metal bonds. To the best of our knowledge, we present the first structural information for intermediate species in alane dehydrogenation including a rare neutron diffraction study of a palladium–aluminium hydride complex. Furthermore, as part of these studies we have obtained the first SS 27Al NMR data on an aluminium(i) complex. Our findings are relevant to hydrogen storage, materials chemistry and catalysis.
Collapse
Affiliation(s)
- Thomas N Hooper
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Samantha Lau
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Wenyi Chen
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Ryan K Brown
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Martí Garçon
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Karen Luong
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Nathan S Barrow
- Johnson Matthey Technology Centre , Blounts Court, Sonning Common , Reading , RG4 9NH , UK
| | - Andrew S Tatton
- Department of Materials , University of Oxford , OX1 3PH , UK
| | - George A Sackman
- Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Australia.,Chemical Crystallography , Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK
| | | | - Andrew J P White
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| | - Richard I Cooper
- Chemical Crystallography , Department of Chemistry , University of Oxford , 12 Mansfield Road , Oxford , OX1 3TA , UK
| | - Alison J Edwards
- Australian Centre for Neutron Scattering , Australian Nuclear Science and Technology Organisation , Australia
| | - Ian J Casely
- Johnson Matthey Technology Centre , Blounts Court, Sonning Common , Reading , RG4 9NH , UK
| | - Mark R Crimmin
- Department of Chemistry , Molecular Sciences Research Hub , Imperial College London , 80 Wood Lane, Shepherds Bush , London , W12 0BZ , UK .
| |
Collapse
|
23
|
Thomas SP, Grosjean A, Flematti GR, Karton A, Sobolev AN, Edwards AJ, Piltz RO, Iversen BB, Koutsantonis GA, Spackman MA. Investigation of an Unusual Crystal Habit of Hydrochlorothiazide Reveals Large Polar Enantiopure Domains and a Possible Crystal Nucleation Mechanism. Angew Chem Int Ed Engl 2019; 58:10255-10259. [PMID: 31136063 DOI: 10.1002/anie.201905085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Indexed: 11/09/2022]
Abstract
The observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro-XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit-cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit.
Collapse
Affiliation(s)
- Sajesh P Thomas
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia.,Department of Chemistry and iNano, Aarhus University, 8000, Aarhus C, Denmark
| | - Arnaud Grosjean
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Gavin R Flematti
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Amir Karton
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Alexandre N Sobolev
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, WA, 6009, Australia
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, NSW, 2234, Australia
| | - Ross O Piltz
- Australian Centre for Neutron Scattering, ANSTO, Lucas Heights, NSW, 2234, Australia
| | - Bo B Iversen
- Center for Materials Crystallography, Department of Chemistry, Aarhus University, 8000, Aarhus C, Denmark
| | - George A Koutsantonis
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| | - Mark A Spackman
- School of Molecular Sciences, University of Western Australia, Perth, WA, 6009, Australia
| |
Collapse
|
24
|
Thomas SP, Grosjean A, Flematti GR, Karton A, Sobolev AN, Edwards AJ, Piltz RO, Iversen BB, Koutsantonis GA, Spackman MA. Investigation of an Unusual Crystal Habit of Hydrochlorothiazide Reveals Large Polar Enantiopure Domains and a Possible Crystal Nucleation Mechanism. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sajesh P. Thomas
- School of Molecular Sciences University of Western Australia Perth WA 6009 Australia
- Department of Chemistry and iNano Aarhus University 8000 Aarhus C Denmark
| | - Arnaud Grosjean
- School of Molecular Sciences University of Western Australia Perth WA 6009 Australia
| | - Gavin R. Flematti
- School of Molecular Sciences University of Western Australia Perth WA 6009 Australia
| | - Amir Karton
- School of Molecular Sciences University of Western Australia Perth WA 6009 Australia
| | - Alexandre N. Sobolev
- Centre for Microscopy, Characterisation and Analysis University of Western Australia Perth WA 6009 Australia
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering ANSTO Lucas Heights NSW 2234 Australia
| | - Ross O. Piltz
- Australian Centre for Neutron Scattering ANSTO Lucas Heights NSW 2234 Australia
| | - Bo B. Iversen
- Center for Materials Crystallography Department of Chemistry Aarhus University 8000 Aarhus C Denmark
| | | | - Mark A. Spackman
- School of Molecular Sciences University of Western Australia Perth WA 6009 Australia
| |
Collapse
|
25
|
Brown BE, Dunne RP, Somerfield PJ, Edwards AJ, Simons WJF, Phongsuwan N, Putchim L, Anderson L, Naeije MC. Long-term impacts of rising sea temperature and sea level on shallow water coral communities over a ~40 year period. Sci Rep 2019; 9:8826. [PMID: 31217535 PMCID: PMC6584745 DOI: 10.1038/s41598-019-45188-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/29/2019] [Indexed: 01/18/2023] Open
Abstract
Effects of combined rising sea temperature and increasing sea level on coral reefs, both factors associated with global warming, have rarely been addressed. In this ~40 y study of shallow reefs in the eastern Indian Ocean, we show that a rising relative sea level, currently estimated at ~11 mm y−1, has not only promoted coral cover but also has potential to limit damaging effects of thermally-induced bleaching. In 2010 the region experienced the most severe bleaching on record with corals subject to sea temperatures of >31 °C for 7 weeks. While the reef flats studied have a common aspect and are dominated by a similar suite of coral species, there was considerable spatial variation in their bleaching response which corresponded with reef-flat depth. Greatest loss of coral cover and community structure disruption occurred on the shallowest reef flats. Damage was less severe on the deepest reef flat where corals were subject to less aerial exposure, rapid flushing and longer submergence in turbid waters. Recovery of the most damaged sites took only ~8 y. While future trajectories of these resilient reefs will depend on sea-level anomalies, and frequency of extreme bleaching the positive role of rising sea level should not be under-estimated.
Collapse
Affiliation(s)
- B E Brown
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK. .,Environmental Research Unit, University of the Highlands and Islands, Castle Street, Thurso, Caithness, KW14 7JD, Scotland, UK.
| | - R P Dunne
- West Briscoe, Baldersdale, Barnard Castle, Co. Durham, DL12 9UP, UK
| | - P J Somerfield
- Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth, PL1 3DH, UK
| | - A J Edwards
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - W J F Simons
- Department of Space Engineering, Delft University of Technology, NL - 2629 HS Delft, Netherlands
| | - N Phongsuwan
- Department of Marine and Coastal Resources, 120 Moo 3, Changwathana Road, Bangkok, 10210, Thailand
| | - L Putchim
- Phuket Marine Biological Center, PO Box 60, Phuket, 8300, Thailand
| | - L Anderson
- Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - M C Naeije
- Department of Space Engineering, Delft University of Technology, NL - 2629 HS Delft, Netherlands
| |
Collapse
|
26
|
Schwamm RJ, Edwards AJ, Fitchett CM, Coles MP. A study of di(amino)stibines with terminal Sb(iii) hydrogen-ligands by X-ray- and neutron-diffraction. Dalton Trans 2019; 48:2953-2958. [PMID: 30741279 DOI: 10.1039/c8dt05113e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The bis(amidodimethyl)disiloxane ligands [O{SiMe2NR}2]2- (R = 2,6-Me2C6H3 (Ar') and 2,6-iPr2C6H3 (Ar), abbreviated [NONR]2-, are a stable support for Sb(iii) complexes of general formula Sb(NONR)X (X = Cl, H). The compounds are monomeric in the solid-state, with bidentate N,N'-coordination of the [NONR]2- and terminal chloride/hydrogen-ligands. Sb(NONAr')H was analyzed by single-crystal neutron diffraction, giving the first accurate parameters for the Sb-H bond to an antimony(iii) centre.
Collapse
Affiliation(s)
- Ryan J Schwamm
- School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
| | | | | | | |
Collapse
|
27
|
Shi MW, Thomas SP, Hathwar VR, Edwards AJ, Piltz RO, Jayatilaka D, Koutsantonis GA, Overgaard J, Nishibori E, Iversen BB, Spackman MA. Measurement of Electric Fields Experienced by Urea Guest Molecules in the 18-Crown-6/Urea (1:5) Host-Guest Complex: An Experimental Reference Point for Electric-Field-Assisted Catalysis. J Am Chem Soc 2019; 141:3965-3976. [PMID: 30761898 DOI: 10.1021/jacs.8b12927] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-resolution synchrotron and neutron single-crystal diffraction data of 18-crown-6/(pentakis)urea measured at 30 K are combined, with the aim of better appreciating the electrostatics associated with intermolecular interactions in condensed matter. With two 18-crown-6 molecules and five different urea molecules in the crystal, this represents the most ambitious combined X-ray/synchrotron and neutron experimental charge density analysis to date on a cocrystal or host-guest system incorporating such a large number of unique molecules. The dipole moments of the five urea guest molecules in the crystal are enhanced considerably compared to values determined for isolated molecules, and 2D maps of the electrostatic potential and electric field show clearly how the urea molecules are oriented with dipole moments aligned along the electric field exerted by their molecular neighbors. Experimental electric fields in the range of 10-19 GV m-1, obtained for the five different urea environments, corroborate independent measurements of electric fields in the active sites of enzymes and provide an important experimental reference point for recent discussions focused on electric-field-assisted catalysis.
Collapse
Affiliation(s)
- Ming W Shi
- School of Molecular Sciences , University of Western Australia , 35 Stirling Highway , Crawley , WA 6009 , Australia
| | - Sajesh P Thomas
- School of Molecular Sciences , University of Western Australia , 35 Stirling Highway , Crawley , WA 6009 , Australia.,Center for Materials Crystallography and Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
| | - Venkatesha R Hathwar
- Center for Materials Crystallography and Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark.,Division of Physics, Faculty of Pure and Applied Sciences , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Alison J Edwards
- Australian Nuclear Science and Technology Organization , Australian Centre for Neutron Scattering , New Illawarra Road , Lucas Heights , New South Wales 2234 , Australia
| | - Ross O Piltz
- Australian Nuclear Science and Technology Organization , Australian Centre for Neutron Scattering , New Illawarra Road , Lucas Heights , New South Wales 2234 , Australia
| | - Dylan Jayatilaka
- School of Molecular Sciences , University of Western Australia , 35 Stirling Highway , Crawley , WA 6009 , Australia
| | - George A Koutsantonis
- School of Molecular Sciences , University of Western Australia , 35 Stirling Highway , Crawley , WA 6009 , Australia
| | - Jacob Overgaard
- Center for Materials Crystallography and Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
| | - Eiji Nishibori
- Division of Physics, Faculty of Pure and Applied Sciences , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8571 , Japan
| | - Bo B Iversen
- Center for Materials Crystallography and Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
| | - Mark A Spackman
- School of Molecular Sciences , University of Western Australia , 35 Stirling Highway , Crawley , WA 6009 , Australia
| |
Collapse
|
28
|
Bonyhady SJ, Collis D, Holzmann N, Edwards AJ, Piltz RO, Frenking G, Stasch A, Jones C. Anion stabilised hypercloso-hexaalane Al 6H 6. Nat Commun 2018; 9:3079. [PMID: 30082681 PMCID: PMC6079018 DOI: 10.1038/s41467-018-05504-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/06/2018] [Indexed: 11/09/2022] Open
Abstract
Boron hydride clusters are an extremely diverse compound class, which are of enormous importance to many areas of chemistry. Despite this, stable aluminium hydride analogues of these species have remained staunchly elusive to synthetic chemists. Here, we report that reductions of an amidinato-aluminium(III) hydride complex with magnesium(I) dimers lead to unprecedented examples of stable aluminium(I) hydride complexes, [(ArNacnac)Mg]2[Al6H6(Fiso)2] (ArNacnac = [HC(MeCNAr)2]-, Ar = C6H2Me3-2,4,6 Mes; C6H3Et2-2,6 Dep or C6H3Me2-2,6 Xyl; Fiso = [HC(NDip)2]-, Dip = C6H3Pri2-2,6), which crystallographic and computational studies show to possess near neutral, octahedral hypercloso-hexaalane, Al6H6, cluster cores. The electronically delocalised skeletal bonding in these species is compared to that in the classical borane, [B6H6]2-. Thus, the chemistry of classical polyhedral boranes is extended to stable aluminium hydride clusters for the first time.
Collapse
Affiliation(s)
- Simon J Bonyhady
- School of Chemistry, Monash University, PO Box 23, Clayton, VIC, 3800, Australia
| | - David Collis
- School of Chemistry, Monash University, PO Box 23, Clayton, VIC, 3800, Australia
| | - Nicole Holzmann
- Scientific Computing Department, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, OX11 0QX, UK
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Ross O Piltz
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Gernot Frenking
- Fachbereich Chemie, Philipps-Universität Marburg, 35032, Marburg, Germany.
| | - Andreas Stasch
- School of Chemistry, Monash University, PO Box 23, Clayton, VIC, 3800, Australia.
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, KY16 9ST, St Andrews, UK.
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, Clayton, VIC, 3800, Australia.
| |
Collapse
|
29
|
Li J, Ma HZ, Reid GE, Edwards AJ, Hong Y, White JM, Mulder RJ, O'Hair RAJ. Synthesis and X‐Ray Crystallographic Characterisation of Frustum‐Shaped Ligated [Cu
18
H
16
(DPPE)
6
]
2+
and [Cu
16
H
14
(DPPA)
6
]
2+
Nanoclusters and Studies on Their H
2
Evolution Reactions. Chemistry 2018; 24:2070-2074. [DOI: 10.1002/chem.201705448] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Jiaye Li
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| | - Howard Z. Ma
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| | - Gavin E. Reid
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
- Department of Biochemistry and Molecular Biology University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organisation New Illawarra Road Lucas Heights NSW 2234 Australia
| | - Yuning Hong
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| | - Jonathan M. White
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| | - Roger J. Mulder
- CSIRO Manufacturing Research Way Clayton, Victoria 3168 Australia
| | - Richard A. J. O'Hair
- School of Chemistry and Bio21 Molecular Science, and Biotechnology Institute University of Melbourne 30 Flemington Rd Parkville, Victoria 3010 Australia
| |
Collapse
|
30
|
Obies M, Perkins NR, Arcisauskaite V, Heath GA, Edwards AJ, McGrady JE. Redox-Dependent Metal−Metal Bonding in Trinuclear Metal Chains: Probing the Transition from Covalent Bonding to Exchange Coupling. Chemistry 2017; 24:5309-5318. [DOI: 10.1002/chem.201704727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Mohammed Obies
- Department of Chemistry; University of Oxford; South Parks Road Oxford OX1 3QZ UK
- College of Pharmacy; University of Babylon; Hilla Iraq
| | - Nicholas R. Perkins
- Research School of Chemistry; The Australian National University; Canberra ACT0200 Australia
| | - Vaida Arcisauskaite
- Department of Chemistry; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| | - Graham A. Heath
- Physical, Engineering and Mathematical Sciences; ADFA; Northcott Road Canberra ACT2600 Australia
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering; Australian Nuclear Science and Technology OrganisationNew Illawarra Road; Lucas Heights NSW 2232 Australia
| | - John E. McGrady
- Department of Chemistry; University of Oxford; South Parks Road Oxford OX1 3QZ UK
| |
Collapse
|
31
|
Andrade Malaspina L, Sugimoto K, Edwards AJ, Grabowsky S. Mapping the trajectory of proton transfer via experimental electron density. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317094256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
32
|
Caise A, Abdalla JAB, Tirfoin R, Edwards AJ, Aldridge S. A Gallium Hydride as an Oxidizing Agent: Direct Synthesis of IrVComplexes via Ga−H Bond Activation. Chemistry 2017; 23:16906-16913. [DOI: 10.1002/chem.201704372] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Alexa Caise
- Department of Chemistry; University of Oxford; Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR UK)
| | - Joseph A. B. Abdalla
- Department of Chemistry; University of Oxford; Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR UK)
| | - Rémi Tirfoin
- Department of Chemistry; University of Oxford; Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR UK)
| | - Alison J. Edwards
- Australian Centre for Neutron Scattering; Australian Nuclear Science and Technology Organisation; New Illawarra Road Lucas Heights NSW 2234 Australia
| | - Simon Aldridge
- Department of Chemistry; University of Oxford; Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR UK)
| |
Collapse
|
33
|
Aakeröy CB, Alavi S, Brammer L, Bryce DL, Clark T, Del Bene JE, Edwards AJ, Esterhuysen C, Guru Row TN, Kennepohl P, Legon AC, Lloyd GO, Murray JS, Pennington WT, Politzer P, Riley KE, Rosokha SV, Scheiner S, Tsuzuki S, Vargas-Baca I. Computational approaches and sigma-hole interactions: general discussion. Faraday Discuss 2017; 203:131-163. [PMID: 28960014 DOI: 10.1039/c7fd90061a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
|
34
|
Aakeröy CB, Beer PD, Beyeh NK, Brammer L, Branca M, Bryce DL, Del Bene JE, Edwards AJ, Erdelyi M, Esterhuysen C, Fourmigué M, Kennepohl P, Lee LM, Mosquera MEG, Murray JS, Mustoe CL, Pennington WT, Politzer P, Riley KE, Rosokha SV, Scheiner S, Taylor MS, Tsuzuki S, Vargas-Baca I, Xu Y. The halogen bond in solution: general discussion. Faraday Discuss 2017; 203:347-370. [PMID: 28960018 DOI: 10.1039/c7fd90063e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
35
|
Abdalla JAB, Caise A, Sindlinger CP, Tirfoin R, Thompson AL, Edwards AJ, Aldridge S. Structural snapshots of concerted double E-H bond activation at a transition metal centre. Nat Chem 2017; 9:1256-1262. [PMID: 29168480 DOI: 10.1038/nchem.2792] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 05/04/2017] [Indexed: 11/09/2022]
Abstract
Bond activation at a transition metal centre is a key fundamental step in numerous chemical transformations. The oxidative addition of element-hydrogen bonds, for example, represents a critical step in a range of widely applied catalytic processes. Despite this, experimental studies defining steps along the bond activation pathway are very rare. In this work, we report on fundamental studies defining a new oxidative activation pathway: combined experimental and computational approaches yield structural snapshots of the simultaneous activation of both bonds of a β-diketiminate-stabilized GaH2 unit at a single metal centre. Systematic variation of the supporting phosphine ligands and single crystal X-ray/neutron diffraction are exploited in tandem to allow structural visualization of the activation process, from a η2-H,H σ-complex showing little Ga-H bond activation, through species of intermediate geometry featuring stretched Ga-H and compressed M-H/M-Ga bonds, to a fully activated metal dihydride featuring a neutral (carbene-type) N-heterocyclic GaI ligand.
Collapse
Affiliation(s)
- Joseph A B Abdalla
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Alexa Caise
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Christian P Sindlinger
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Rémi Tirfoin
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Amber L Thompson
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, New South Wales 2234, Australia
| | - Simon Aldridge
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| |
Collapse
|
36
|
Thomas SP, Shi MW, Koutsantonis GA, Jayatilaka D, Edwards AJ, Spackman MA. The Elusive Structural Origin of Plastic Bending in Dimethyl Sulfone Crystals with Quasi‐isotropic Crystal Packing. Angew Chem Int Ed Engl 2017; 56:8468-8472. [DOI: 10.1002/anie.201701972] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 03/28/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Sajesh P. Thomas
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | - Ming W. Shi
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | | | - Dylan Jayatilaka
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | - Alison J. Edwards
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights Sydney NSW 2232 Australia
| | - Mark A. Spackman
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| |
Collapse
|
37
|
Thomas SP, Shi MW, Koutsantonis GA, Jayatilaka D, Edwards AJ, Spackman MA. The Elusive Structural Origin of Plastic Bending in Dimethyl Sulfone Crystals with Quasi‐isotropic Crystal Packing. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701972] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sajesh P. Thomas
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | - Ming W. Shi
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | | | - Dylan Jayatilaka
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| | - Alison J. Edwards
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights Sydney NSW 2232 Australia
| | - Mark A. Spackman
- School of Molecular Sciences The University of Western Australia Perth 6009 Australia
| |
Collapse
|
38
|
Aakeröy CB, Alavi S, Beyeh NK, Brammer L, Branca M, Bryce DL, Christopherson JC, Clark T, Cottrell SJ, Del Bene JE, Dichiarante V, Edwards AJ, Erdelyi M, Esterhuysen C, Fourmigué M, Friščić T, Kennepohl P, Legon AC, Lloyd GO, Murray JS, Mustoe CL, Pennington WT, Rosokha SV, Roy Choudhury A, Scheiner S, Szell PMJ, Taylor MS, Tsuzuki S. Solid-state chemistry and applications: general discussion. Faraday Discuss 2017; 203:459-483. [DOI: 10.1039/c7fd90064c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
39
|
Aakeröy CB, Alavi S, Beer PD, Beyeh NK, Brammer L, Bryce DL, Clark T, Cottrell SJ, Del Bene JE, Edwards AJ, Esterhuysen C, Friščić T, Guru Row TN, Kennepohl P, Lloyd GO, Roy Choudhury A, Scheiner S, Southern SA, Taylor MS, Tsuzuki S, Vargas-Baca I. Beyond the halogen bond: general discussion. Faraday Discuss 2017; 203:227-244. [DOI: 10.1039/c7fd90062g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
40
|
Edwards AJ, Mackenzie CF, Spackman PR, Jayatilaka D, Spackman MA. Intermolecular interactions in molecular crystals: what’s in a name? Faraday Discuss 2017; 203:93-112. [DOI: 10.1039/c7fd00072c] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Structure–property relationships are the key to modern crystal engineering, and for molecular crystals this requires both a thorough understanding of intermolecular interactions, and the subsequent use of this to create solids with desired properties. There has been a rapid increase in publications aimed at furthering this understanding, especially the importance of non-canonical interactions such as halogen, chalcogen, pnicogen, and tetrel bonds. Here we show how all of these interactions – and hydrogen bonds – can be readily understood through their common origin in the redistribution of electron density that results from chemical bonding. This redistribution is directly linked to the molecular electrostatic potential, to qualitative concepts such as electrostatic complementarity, and to the calculation of quantitative intermolecular interaction energies. Visualization of these energies, along with their electrostatic and dispersion components, sheds light on the architecture of molecular crystals, in turn providing a link to actual crystal properties.
Collapse
Affiliation(s)
- Alison J. Edwards
- Australian Centre for Neutron Scattering
- Australian Nuclear Science and Technology Organization
- Lucas Heights
- Australia
| | | | - Peter R. Spackman
- School of Molecular Sciences
- University of Western Australia
- Perth
- Australia
| | - Dylan Jayatilaka
- School of Molecular Sciences
- University of Western Australia
- Perth
- Australia
| | - Mark A. Spackman
- School of Molecular Sciences
- University of Western Australia
- Perth
- Australia
| |
Collapse
|
41
|
Chadwick FM, Krämer T, Gutmann T, Rees NH, Thompson AL, Edwards AJ, Buntkowsky G, Macgregor SA, Weller AS. Selective C-H Activation at a Molecular Rhodium Sigma-Alkane Complex by Solid/Gas Single-Crystal to Single-Crystal H/D Exchange. J Am Chem Soc 2016; 138:13369-13378. [PMID: 27631345 DOI: 10.1021/jacs.6b07968] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The controlled catalytic functionalization of alkanes via the activation of C-H bonds is a significant challenge. Although C-H activation by transition metal catalysts is often suggested to operate via intermediate σ-alkane complexes, such transient species are difficult to observe due to their instability in solution. This instability may be controlled by use of solid/gas synthetic techniques that enable the isolation of single-crystals of well-defined σ-alkane complexes. Here we show that, using this unique platform, selective alkane C-H activation occurs, as probed by H/D exchange using D2, and that five different isotopomers/isotopologues of the σ-alkane complex result, as characterized by single-crystal neutron diffraction studies for three examples. Low-energy fluxional processes associated with the σ-alkane ligand are identified using variable-temperature X-ray diffraction, solid-state NMR spectroscopy, and periodic DFT calculations. These observations connect σ-alkane complexes with their C-H activated products, and demonstrate that alkane-ligand mobility, and selective C-H activation, are possible when these processes occur in the constrained environment of the solid-state.
Collapse
Affiliation(s)
- F Mark Chadwick
- Department of Chemistry, Mansfield Road, University of Oxford , Oxford OX1 3TA, U.K
| | - Tobias Krämer
- Institute of Chemical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, U.K
| | - Torsten Gutmann
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt , Alarich-Weiss-Strasse 8, D-64287 Darmstadt, Germany
| | - Nicholas H Rees
- Department of Chemistry, Mansfield Road, University of Oxford , Oxford OX1 3TA, U.K
| | - Amber L Thompson
- Department of Chemistry, Mansfield Road, University of Oxford , Oxford OX1 3TA, U.K
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organization , Locked Bag 2001 Kirrawee D.C., New South Wales 2232, Australia
| | - Gerd Buntkowsky
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt , Alarich-Weiss-Strasse 8, D-64287 Darmstadt, Germany
| | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, U.K
| | - Andrew S Weller
- Department of Chemistry, Mansfield Road, University of Oxford , Oxford OX1 3TA, U.K
| |
Collapse
|
42
|
Grabowsky S, Malaspina LA, Woinska M, Nishibori E, Sugimoto K, Edwards AJ, Jayatilaka D. Hydrogen maleate salts: precise and accurate determination of the hydrogen atom position in short hydrogen bonds using X-ray diffraction at extremely low temperatures. Acta Crystallogr A Found Adv 2016. [DOI: 10.1107/s2053273316098685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
|
43
|
Schwamm RJ, Vianello R, Maršavelski A, García MÁ, Claramunt RM, Alkorta I, Saame J, Leito I, Fitchett CM, Edwards AJ, Coles MP. (15)N NMR Spectroscopy, X-ray and Neutron Diffraction, Quantum-Chemical Calculations, and UV/vis-Spectrophotometric Titrations as Complementary Techniques for the Analysis of Pyridine-Supported Bicyclic Guanidine Superbases. J Org Chem 2016; 81:7612-25. [PMID: 27494395 DOI: 10.1021/acs.joc.6b01330] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pyridine substituted with one and two bicyclic guanidine groups has been studied as a potential source of superbases. 2-{hpp}C5H4N (I) and 2,6-{hpp}2C5H3N (II) (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) were protonated using [HNEt3][BPh4] to afford [I-H][BPh4] (1a), [II-H][BPh4] (2), and [II-H2][BPh4]2 (3). Solution-state (1)H and (15)N NMR spectroscopy shows a symmetrical cation in 2, indicating a facile proton-exchange process in solution. Solid-state (15)N NMR data differentiates between the two groups, indicating a mixed guanidine/guanidinium. X-ray diffraction data are consistent with protonation at the imine nitrogen, confirmed for 1a by single-crystal neutron diffraction. The crystal structure of 1a shows association of two [I-H](+) cations within a cage of [BPh4](-) anions. Computational analysis performed in the gas phase and in MeCN solution shows that the free energy barrier to transfer a proton between imino centers in [II-H](+) is 1 order of magnitude lower in MeCN than in the gas phase. The results provide evidence that linking hpp groups with the pyridyl group stabilizes the protonation center, thereby increasing the intrinsic basicity in the gas phase, while the bulk prevents efficient cation solvation, resulting in diminished pKa(MeCN) values. Spectrophotometrically measured pKa values are in excellent agreement with calculated values and confirm that I and II are superbases in solution.
Collapse
Affiliation(s)
- Ryan J Schwamm
- School of Chemical and Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6012, New Zealand
| | - Robert Vianello
- Computational Organic Chemistry and Biochemistry Group, Ruder Bošković Institute , Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Aleksandra Maršavelski
- Computational Organic Chemistry and Biochemistry Group, Ruder Bošković Institute , Bijenička cesta 54, 10000 Zagreb, Croatia
| | - M Ángeles García
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED , Paseo Senda del Rey 9, 28040 Madrid, Spain
| | - Rosa M Claramunt
- Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, UNED , Paseo Senda del Rey 9, 28040 Madrid, Spain
| | - Ibon Alkorta
- Instituto de Química Médica (IQM-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain
| | - Jaan Saame
- Institute of Chemistry, University of Tartu , 14a Ravila Street, 50411, Tartu, Estonia
| | - Ivo Leito
- Institute of Chemistry, University of Tartu , 14a Ravila Street, 50411, Tartu, Estonia
| | | | - Alison J Edwards
- Bragg Institute, Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2234, Australia
| | - Martyn P Coles
- School of Chemical and Physical Sciences, Victoria University of Wellington , P.O. Box 600, Wellington 6012, New Zealand
| |
Collapse
|
44
|
Suh HW, Balcells D, Edwards AJ, Guard LM, Hazari N, Mader EA, Mercado BQ, Repisky M. Understanding the Solution and Solid-State Structures of Pd and Pt PSiP Pincer-Supported Hydrides. Inorg Chem 2015; 54:11411-22. [PMID: 26582548 DOI: 10.1021/acs.inorgchem.5b02073] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The PSiP pincer-supported complex ((Cy)PSiP)PdH [(Cy)PSiP = Si(Me)(2-PCy2-C6H4)2] has been implicated as a crucial intermediate in carboxylation of both allenes and boranes. At this stage, however, there is uncertainty regarding the exact structure of ((Cy)PSiP)PdH, especially in solution. Previously, both a Pd(II) structure with a terminal Pd hydride and a Pd(0) structure featuring an η(2)-silane have been proposed. In this contribution, a range of techniques were used to establish that ((Cy)PSiP)PdH and the related Pt species, ((Cy)PSiP)PtH, are true M(II) hydrides in both the solid state and solution. The single-crystal X-ray structures of ((Cy)PSiP)MH (M = Pd and Pt) and the related species ((iPr)PSiP)PdH [(iPr)PSiP = Si(Me)(2-P(i)Pr2-C6H4)2] are in agreement with the presence of a terminal metal hydride, and the exact geometry of ((Cy)PSiP)PtH was confirmed using neutron diffraction. The (1)H and (29)Si{(1)H}NMR chemical shifts of ((Cy)PSiP)MH (M = Pd and Pt) are consistent with a structure containing a terminal hydride, especially when compared to the chemical shifts of related pincer-supported complexes. In fact, in this work, two general trends relating to the (1)H NMR chemical shifts of group 10 pincer-supported terminal hydrides were elucidated: (i) the hydride shift moves downfield from Ni to Pd to Pt and (ii) the hydride shift moves downfield with more trans-influencing pincer central donors. DFT calculations indicate that structures containing a M(II) hydride are lower in energy than the corresponding η(2)-silane isomers. Furthermore, the calculated NMR chemical shifts of the M(II) hydrides using a relativistic four-component methodology incorporating all significant scalar and spin-orbit corrections are consistent with those observed experimentally. Finally, in situ X-ray absorption spectroscopy (XAS) was used to provide further support that ((Cy)PSiP)MH exist as M(II) hydrides in solution.
Collapse
Affiliation(s)
- Hee-Won Suh
- The Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - David Balcells
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Alison J Edwards
- Bragg Institute, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Louise M Guard
- The Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Nilay Hazari
- The Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Elizabeth A Mader
- The Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Brandon Q Mercado
- The Department of Chemistry, Yale University , P.O. Box 208107, New Haven, Connecticut 06520, United States
| | - Michal Repisky
- Centre for Theoretical and Computational Chemistry (CTCC), University of Tromsø-The Arctic University of Norway , N-9037 Tromsø, Norway
| |
Collapse
|
45
|
Ma Y, Klontz KC, DiNovi MJ, Edwards AJ, Hennes RF. Evaluation of the Level of Food Safety Protection Provided by the U.S. Grade "A" Pasteurized Milk Ordinance and Its Associated Cooperative Grade "A" Milk Safety Program. J Food Prot 2015; 78:1428-33. [PMID: 26219354 DOI: 10.4315/0362-028x.jfp-15-078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present study was conducted to evaluate the level of food safety protection provided to consumers of Grade "A" milk and milk products in the United States by the National Conference on Interstate Milk Shipments (NCIMS) Grade "A" Milk Safety Program through its implementation and enforcement of the U.S. Grade "A" Pasteurized Milk Ordinance (PMO). The number of reported illnesses associated with Grade "A" milk and milk products in the United States was obtained from state and federal agencies and published articles. The consumption of Grade "A" milk and milk products in the United States was estimated from food consumption survey data for individuals. The level of food safety protection was measured quantitatively using the metric of annual illness attack rate. During a 15-year period (1999 through 2013), the estimated annual illness attack rate was 0.41 reported illnesses per 1 billion exposures (estimated using person-day intake data) or 0.52 reported illnesses per 1 billion lb (454 million kg) of Grade "A" milk and milk products consumed. Food safety protection provided to consumers of Grade "A" milk and milk products by the NCIMS through its implementation and enforcement of the PMO is important given the common consumption of Grade "A" milk and milk products in the United States.
Collapse
Affiliation(s)
- Yinqing Ma
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA.
| | - Karl C Klontz
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA
| | - Michael J DiNovi
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA
| | - Alison J Edwards
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA
| | - Robert F Hennes
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA
| |
Collapse
|
46
|
Cole JM, Lin TC, Edwards AJ, Piltz RO, Depotter G, Clays K, Lee SC, Kwon OP. Concerted mitigation of O···H and C(π)···H interactions prospects sixfold gain in optical nonlinearity of ionic stilbazolium derivatives. ACS Appl Mater Interfaces 2015; 7:4693-4698. [PMID: 25654641 DOI: 10.1021/am508213c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
DAST (4-dimethylamino-N-methyl-4-stilbazolium tosylate) is the most commercially successful organic nonlinear optical (NLO) material for frequency-doubling, integrated optics, and THz wave applications. Its success is predicated on its high optical nonlinearity with concurrent sufficient thermal stability. Many chemical derivatives of DAST have therefore been developed to optimize their properties; yet, to date, none have surpassed the overall superiority of DAST for NLO photonic applications. This is perhaps because DAST is an ionic salt wherein its NLO-active cation is influenced by multiple types of subtle intermolecular forces that are hard to quantify, thus, making difficult the molecular engineering of better functioning DAST derivatives. Here, we establish a model parameter, ηinter, that isolates the influence of intermolecular interactions on second-order optical nonlinearity in DAST and its derivatives, using second-harmonic generation (SHG) as a qualifier; by systematically mapping intercorrelations of all possible pairs of intermolecular interactions to ηinter, we uncover a relationship between concerted intermolecular interactions and SHG output. This correlation reveals that a sixfold gain in the intrinsic second-order NLO performance of DAST is possible, by eliminating the identified interactions. This prediction offers the first opportunity to systematically design next-generation DAST-based photonic device nanotechnology to realize such a prospect.
Collapse
Affiliation(s)
- Jacqueline M Cole
- Cavendish Laboratory, University of Cambridge , J. J. Thomson Avenue, Cambridge, CB3 0HE, U.K
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Fucke K, McIntyre GJ, Lemée-Cailleau MH, Wilkinson C, Edwards AJ, Howard JAK, Steed JW. Inside Cover: Insights into the Crystallisation Process from Anhydrous, Hydrated and Solvated Crystal Forms of Diatrizoic Acid (Chem. Eur. J. 3/2015). Chemistry 2015. [DOI: 10.1002/chem.201590006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
48
|
Fucke K, McIntyre GJ, Lemée-Cailleau MH, Wilkinson C, Edwards AJ, Howard JAK, Steed JW. Insights into the crystallisation process from anhydrous, hydrated and solvated crystal forms of diatrizoic acid. Chemistry 2015; 21:1036-47. [PMID: 25370384 DOI: 10.1002/chem.201404693] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Indexed: 11/11/2022]
Abstract
Diatrizoic acid (DTA), a clinically used X-ray contrast agent, crystallises in two hydrated, three anhydrous and nine solvated solid forms, all of which have been characterised by X-ray crystallography. Single-crystal neutron structures of DTA dihydrate and monosodium DTA tetrahydrate have been determined. All of the solid-state structures have been analysed using partial atomic charges and hardness algorithm (PACHA) calculations. Even though in general all DTA crystal forms reveal similar intermolecular interactions, the overall crystal packing differs considerably from form to form. The water of the dihydrate is encapsulated between a pair of host molecules, which calculations reveal to be an extraordinarily stable motif. DTA presents functionalities that enable hydrogen and halogen bonding, and whilst an extended hydrogen-bonding network is realised in all crystal forms, halogen bonding is not present in the hydrated crystal forms. This is due to the formation of a hydrogen-bonding network based on individual enclosed water squares, which is not amenable to the concomitant formation of halogen bonds. The main interaction in the solvates involves the carboxylic acid, which corroborates the hypothesis that this strong interaction is the last one to be broken during the crystal desolvation and nucleation process.
Collapse
Affiliation(s)
- Katharina Fucke
- School of Medicine, Pharmacy and Health, Durham University, University Boulevard, Stockton-on-Tees, TS17 6BH (United Kingdom).
| | | | | | | | | | | | | |
Collapse
|
49
|
Yang H, Wang Y, Edwards AJ, Yan J, Zheng N. High-yield synthesis and crystal structure of a green Au30cluster co-capped by thiolate and sulfide. Chem Commun (Camb) 2014; 50:14325-7. [DOI: 10.1039/c4cc01773k] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
50
|
Woińska M, Jayatilaka D, Spackman MA, Edwards AJ, Dominiak PM, Woźniak K, Nishibori E, Sugimoto K, Grabowsky S. Hirshfeld atom refinement for modelling strong hydrogen bonds. Acta Crystallogr A Found Adv 2014; 70:483-98. [PMID: 25176996 DOI: 10.1107/s2053273314012443] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/28/2014] [Indexed: 11/10/2022]
Abstract
High-resolution low-temperature synchrotron X-ray diffraction data of the salt L-phenylalaninium hydrogen maleate are used to test the new automated iterative Hirshfeld atom refinement (HAR) procedure for the modelling of strong hydrogen bonds. The HAR models used present the first examples of Z' > 1 treatments in the framework of wavefunction-based refinement methods. L-Phenylalaninium hydrogen maleate exhibits several hydrogen bonds in its crystal structure, of which the shortest and the most challenging to model is the O-H...O intramolecular hydrogen bond present in the hydrogen maleate anion (O...O distance is about 2.41 Å). In particular, the reconstruction of the electron density in the hydrogen maleate moiety and the determination of hydrogen-atom properties [positions, bond distances and anisotropic displacement parameters (ADPs)] are the focus of the study. For comparison to the HAR results, different spherical (independent atom model, IAM) and aspherical (free multipole model, MM; transferable aspherical atom model, TAAM) X-ray refinement techniques as well as results from a low-temperature neutron-diffraction experiment are employed. Hydrogen-atom ADPs are furthermore compared to those derived from a TLS/rigid-body (SHADE) treatment of the X-ray structures. The reference neutron-diffraction experiment reveals a truly symmetric hydrogen bond in the hydrogen maleate anion. Only with HAR is it possible to freely refine hydrogen-atom positions and ADPs from the X-ray data, which leads to the best electron-density model and the closest agreement with the structural parameters derived from the neutron-diffraction experiment, e.g. the symmetric hydrogen position can be reproduced. The multipole-based refinement techniques (MM and TAAM) yield slightly asymmetric positions, whereas the IAM yields a significantly asymmetric position.
Collapse
Affiliation(s)
- Magdalena Woińska
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Dylan Jayatilaka
- School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - Mark A Spackman
- School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| | - Alison J Edwards
- Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights NSW 2234, Australia
| | - Paulina M Dominiak
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Krzysztof Woźniak
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Eiji Nishibori
- RIKEN RSC-Rigaku Collaboration Center, RIKEN SPring-8 Center, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kunihisa Sugimoto
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Simon Grabowsky
- School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia
| |
Collapse
|