1
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Yuan D, Goodfellow AS, Kasten K, Duan Z, Kang T, Cordes DB, McKay AP, Bühl M, Boyce GR, Smith AD. Understanding divergent substrate stereoselectivity in the isothiourea-catalysed conjugate addition of cyclic α-substituted β-ketoesters to α,β-unsaturated aryl esters. Chem Sci 2023; 14:14146-14156. [PMID: 38098722 PMCID: PMC10717594 DOI: 10.1039/d3sc05470e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023] Open
Abstract
The development of enantioselective synthetic methods capable of generating vicinal stereogenic centres, where one is tetrasubstituted (such as either an all-carbon quaternary centre or where one or more substituents are heteroatoms), is a recognised synthetic challenge. Herein, the enantioselective conjugate addition of a range of carbo- and heterocyclic α-substituted β-ketoesters to α,β-unsaturated aryl esters using the isothiourea HyperBTM as a Lewis base catalyst is demonstrated. Notably, divergent diastereoselectivity is observed through the use of either cyclopentanone-derived or indanone-derived substituted β-ketoesters with both generating the desired stereodefined products with high selectivity (>95 : 5 dr, up to 99 : 1 er). The scope and limitations of these processes are demonstrated, alongside application on gram scale. The origin of the divergent substrate selectivity has been probed through the use of DFT-analysis, with preferential orientation driven by dual stabilising CH⋯O interactions. The importance of solvation with strongly polar transition-states is highlighted and the SMD solvation model is demonstrated to capture solvation effects reliably.
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Affiliation(s)
- Ding Yuan
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
- School of Biological and Chemical Engineering, Panzhihua University Panzhihua 617000 China
| | - Alister S Goodfellow
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Kevin Kasten
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Zhuan Duan
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Tengfei Kang
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - David B Cordes
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Aidan P McKay
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Michael Bühl
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
| | - Gregory R Boyce
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
- Department of Chemistry and Physics, Florida Gulf Coast University Fort Myers Florida 33965 USA
- Department of Chemistry and Biochemistry, East Stroudsburg University East Stroudsburg Pennsylvania 18301 USA
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews St Andrews Fife KY16 9ST UK
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2
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Fusco E, Ashbrook SE, Bühl M. 13C pNMR shifts of MOFs based on Cu(II)-paddlewheel dimers - DFT predictions for spin-1/2 defects. Phys Chem Chem Phys 2023; 25:31898-31906. [PMID: 37971425 DOI: 10.1039/d3cp04618d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
We present DFT predictions (CAM-B3LYP/II level) for the paramagnetic Nuclear Magnetic Resonance (pNMR) spectra of small molecular models based on the Cu(II)-paddlewheel dimer motif that is present in metal-organic frameworks (MOFs, notably the HKUST and STAM families). We explore potential point defects with spin-1/2 discovered through electron paramagnetic resonance (EPR) experiments. We consider defects through substitution of one Cu(II) centre in the dimer with protons, or through one-electron reduction, affording a mixed-valence dimer. While most of the defects have predicted pNMR shifts at room temperature in the range of those for the non-defective MOFs, their detection and assignment should be possible based on their distinct temperature dependence.
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Affiliation(s)
- Edoardo Fusco
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews, Fife KY16 9ST, UK.
| | - Sharon E Ashbrook
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews, Fife KY16 9ST, UK.
| | - Michael Bühl
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews, Fife KY16 9ST, UK.
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3
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Tarcza AE, Slawin AMZ, Carpenter-Warren CL, Bühl M, Kilian P, Chalmers BA. Constrained Phosphine Chalcogenide Selenoethers Supported by peri-Substitution. Molecules 2023; 28:7297. [PMID: 37959719 PMCID: PMC10650533 DOI: 10.3390/molecules28217297] [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: 10/09/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
A series of phosphorus and selenium peri-substituted acenaphthene species with the phosphino group oxidized by O, S, and Se has been isolated and fully characterized, including by single-crystal X-ray diffraction. The P(V) and Se(II) systems showed fluxional behavior in solution due to the presence of two major rotamers, as evidenced with solution NMR spectroscopy. Using Variable-Temperature NMR (VT NMR) and supported by DFT (Density Functional Theory) calculations and solid-state NMR, the major rotamers in the solid and in solution were identified. All compounds showed a loss of the through-space JPSe coupling observed in the unoxidized P(III) and Se(II) systems due to the sequestration of the lone pair of the phosphine, which has been previously identified as the major contributor to the coupling pathway.
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Affiliation(s)
| | | | | | | | | | - Brian A. Chalmers
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
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4
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Zhang L, Christie FA, Tarcza AE, Lancaster HG, Taylor LJ, Bühl M, Malkina OL, Woollins JD, Carpenter-Warren CL, Cordes DB, Slawin AMZ, Chalmers BA, Kilian P. Phosphine and Selenoether peri-Substituted Acenaphthenes and Their Transition-Metal Complexes: Structural and NMR Investigations. Inorg Chem 2023; 62:16084-16100. [PMID: 37722079 PMCID: PMC10548420 DOI: 10.1021/acs.inorgchem.3c02255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Indexed: 09/20/2023]
Abstract
A series of peri-substituted acenaphthene-based phosphine selenoether bidentate ligands Acenap(iPr2P)(SeAr) (L1-L4, Acenap = acenaphthene-5,6-diyl, Ar = Ph, mesityl, 2,4,6-trisopropylphenyl and supermesityl) were prepared. The rigid acenaphthene framework induces a forced overlap of the phosphine and selenoether lone pairs, resulting in a large magnitude of through-space 4JPSe coupling, ranging from 452 to 545 Hz. These rigid ligands L1-L4 were used to prepare a series of selected late d-block metals, mercury, and borane complexes, which were characterized, including by multinuclear NMR and single-crystal X-ray diffraction. The Lewis acidic motifs (BH3, Mo(CO)4, Ag+, PdCl2, PtCl2, and HgCl2) bridge the two donor atoms (P and Se) in all but one case in the solid-state structures. Where the bridging motif contained NMR-active nuclei (11B, 107Ag, 109Ag, 195Pt, and 199Hg), JPM and JSeM couplings are observed directly, in addition to the altered JPSe in the respective NMR spectra. The solution NMR data are correlated with single-crystal diffraction data, and in the case of mercury(II) complexes, they are also correlated with the solid-state NMR data and coupling deformation density calculations. The latter indicate that the through-space interaction dominates in free L1, while in the L1HgCl2 complex, the main coupling pathway is via the metal atom and not through the carbon framework of the acenaphthene ring system.
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Affiliation(s)
- Lutao Zhang
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
- Institute
of Wolfberry Science, Ningxia Academy of Agriculture and Forestry
Sciences, Yinchuan 750002, China
| | - Francesca A. Christie
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Anna E. Tarcza
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Helena G. Lancaster
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Laurence J. Taylor
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Michael Bühl
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Olga L. Malkina
- Institute
of Inorganic Chemistry, Slovak Academy of Sciences, Bratislava 84 536, Slovakia
| | - J. Derek Woollins
- Department
of Chemistry, Khalifa University, Abu Dhabi 127788, United Arab Emirates
| | | | - David B. Cordes
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Alexandra M. Z. Slawin
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Brian A. Chalmers
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
| | - Petr Kilian
- EaStChem
School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Fife, U.K.
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5
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Owen AE, Preiss A, McLuskie A, Gao C, Peters G, Bühl M, Kumar A. Correction to "Manganese Catalyzed Dehydrogenative Synthesis of Urea Derivatives and Polyureas". ACS Catal 2023; 13:10796-10797. [PMID: 37614523 PMCID: PMC10442911 DOI: 10.1021/acscatal.3c02871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 08/25/2023]
Abstract
[This corrects the article DOI: 10.1021/acscatal.2c00850.].
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6
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Brodie CN, Owen AE, Kolb JS, Bühl M, Kumar A. Synthesis of Polyethyleneimines from the Manganese Catalyzed Coupling of Ethylene Glycol and Ethylenediamine. Angew Chem Int Ed Engl 2023:e202306655. [PMID: 37195140 DOI: 10.1002/anie.202306655] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/18/2023]
Abstract
Polyethyleneimines find many applications in products such as detergents, adhesives, cosmetics, and for processes such as tissue culture, gene therapy, and CO2 capture. The current state-of-the-art technology for the production of the branched polyethyleneimines involves aziridine feedstock which is a highly toxic, volatile and mutagenic chemical and raises significant concern to human health and environment. We report here a novel method for the synthesis of branched polyethyleneimines from ethylene glycol and ethylenediamine feedstock which are much safer, environmentally benign, commercially available and potentially renewable feedstock. The polymerisation reaction is catalysed by a complex of an earth-abundant metal, manganese and liberates H2O as the only by-product. Our mechanistic studies using a combination of DFT computation and experiment suggest that the reaction proceeds by the formation and subsequent hydrogenation of imine intermediates.
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Affiliation(s)
| | | | | | - Michael Bühl
- University of St Andrews, Chemistry, UNITED KINGDOM
| | - Amit Kumar
- Saint Andrews University, Chemistry, North Haugh, KY169ST, St. Andrews, UNITED KINGDOM
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7
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Zhang X, Barrow J, van Mourik T, Bühl M. Towards Computational Modeling of Ligand Binding to the ILPR G-Quadruplex. Molecules 2023; 28:molecules28083447. [PMID: 37110681 PMCID: PMC10145587 DOI: 10.3390/molecules28083447] [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: 02/23/2023] [Revised: 03/31/2023] [Accepted: 04/02/2023] [Indexed: 04/29/2023] Open
Abstract
Using a combination of unconstrained and constrained molecular dynamics simulations, we have evaluated the binding affinities between two porphyrin derivatives (TMPyP4 and TEGPy) and the G-quadruplex (G4) of a DNA fragment modeling the insulin-linked polymorphic region (ILPR). Refining a well-established potential of mean force (PMF) approach to selections of constraints based on root-mean-square fluctuations results in an excellent agreement between the calculated and observed absolute free binding energy of TMPyP4. The binding affinity of IPLR-G4 toward TEGPy is predicted to be higher than that toward TMPyP4 by 2.5 kcal/mol, which can be traced back to stabilization provided by the polyether side chains of TMPyP4 that can nestle into the grooves of the quadruplex and form hydrogen bonds through the ether oxygen atoms. Because our refined methodology can be applied to large ligands with high flexibility, the present research opens an avenue for further ligand design in this important area.
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Affiliation(s)
- Xiaotong Zhang
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - John Barrow
- School of Medicine, Medical Sciences and Nutrition, Institute of Education in Healthcare and Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Tanja van Mourik
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Michael Bühl
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
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8
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Oates CL, Goodfellow AS, Bühl M, Clarke ML. Rational Design of a Facially Coordinating P,N,N Ligand for Manganese-Catalysed Enantioselective Hydrogenation of Cyclic Ketones. Angew Chem Int Ed Engl 2023; 62:e202212479. [PMID: 36341982 PMCID: PMC10107995 DOI: 10.1002/anie.202212479] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [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: 08/24/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
DFT calculations on the full catalytic cycle for manganese catalysed enantioselective hydrogenation of a selection of ketones have been carried out at the PBE0-D3PCM //RI-BP86PCM level. Mn complexes of an enantiomerically pure chiral P,N,N ligand have been found to be most reactive when adopting a facial coordination mode. The use of a new ligand with an ortho-substituted dimethylamino-pyridine motif has been calculated to completely transform the levels of enantioselectivity possible for the hydrogenation of cyclic ketones relative to the first-generation Mn catalysts. In silico evaluation of substrates has been used to identify those likely to be reduced with high enantiomer ratios (er), and others that would exhibit less selectivity; good agreements were then found in experiments. Various cyclic ketones and some acetophenone derivatives were hydrogenated with er's up to 99 : 1.
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Affiliation(s)
- Conor L. Oates
- EaStCHEM School of ChemistryUniversity of St AndrewsPurdie BuildingNorth HaughSt Andrews, KY16 9STUK
| | - Alister S. Goodfellow
- EaStCHEM School of ChemistryUniversity of St AndrewsPurdie BuildingNorth HaughSt Andrews, KY16 9STUK
| | - Michael Bühl
- EaStCHEM School of ChemistryUniversity of St AndrewsPurdie BuildingNorth HaughSt Andrews, KY16 9STUK
| | - Matthew L. Clarke
- EaStCHEM School of ChemistryUniversity of St AndrewsPurdie BuildingNorth HaughSt Andrews, KY16 9STUK
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9
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Xu M, Liu C, Naden AB, Früchtl H, Bühl M, Irvine JTS. Electrochemical Activation Applied to Perovskite Titanate Fibers to Yield Supported Alloy Nanoparticles for Electrocatalytic Application. Small 2023; 19:e2204682. [PMID: 36372544 DOI: 10.1002/smll.202204682] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Active bi-metallic nanoparticles are of key importance in catalysis and renewable energy. Here, the in situ formation of bi-metallic nanoparticles is investigated by exsolution on 200 nm diameter perovskite fibers. The B-site co-doped perovskite fibers display a high degree of exsolution, decorated with NiCo or Ni3 Fe bi-metallic nanoparticles with average diameter about 29 and 35 nm, respectively. The perovskite fibers are utilized as cathode materials in pure CO2 electrolysis cells due to their redox stability in the CO/CO2 atmosphere. After in situ electrochemical switching, the nanoparticles exsolved from the perovskite fiber demonstrate an enhanced performance in pure CO2 electrolysis. At 900 °C, the current density of solid oxide electrolysis cell (SOEC) with 200 µm YSZ electrolyte supported NiFe doped perovskite fiber anode reaches 0.75 Acm-2 at 1.6 V superior to the NiCo doped perovskite fiber anode (about 1.5 times) in pure CO2 . According to DFT calculations (PBE-D3 level) the superior CO2 conversion on NiFe compared to NiCo bi-metallic species is related to an enhanced driving force for C-O cleavage under formation of CO chemisorbed on the nanoparticle and a reduced binding energy of CO required to release this product.
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Affiliation(s)
- Min Xu
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Chencheng Liu
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Aaron B Naden
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Herbert Früchtl
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - Michael Bühl
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
| | - John T S Irvine
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK
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10
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O'Hagan D, Fang Z, Yu C, Bühl M. Does perdeuteration increase the polarity of Janus face cycloalkanes? Helv Chim Acta 2022. [DOI: 10.1002/hlca.202200177] [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: 12/23/2022]
Affiliation(s)
- David O'Hagan
- University of St Andrews Department of Chemistry North Haugh KY16 9ST St. Andrews UNITED KINGDOM
| | - Zeguo Fang
- Hubei University of Technology Chemistry UNITED KINGDOM
| | - Cihang Yu
- St Andrews University Chemistry UNITED KINGDOM
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11
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Oates CL, Goodfellow AS, Bühl M, Clarke ML. Rational Design of a Facially Coordinating P,N,N Ligand for Manganese‐Catalysed Enantioselective Hydrogenation of Cyclic Ketones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202212479] [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)
- Conor L. Oates
- University of St Andrews School of Chemistry UNITED KINGDOM
| | | | - Michael Bühl
- University of St Andrews School of Chemistry UNITED KINGDOM
| | - Matthew L. Clarke
- University of St Andrews School of Chemistry Purdie Building, School of Chemistry,School of Chemistry,University of St AndrewsNorth Haugh KY16 9ST St Andrews UNITED KINGDOM
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12
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Shrimpton-Phoenix E, Mitchell J, Bühl M. Computational Insights into the Catalytic Mechanism of Is‐PETase: An Enzyme Capable of degrading poly(ethylene) terephthalate. Chemistry 2022; 28:e202201728. [PMID: 36112344 PMCID: PMC10091965 DOI: 10.1002/chem.202201728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Indexed: 11/11/2022]
Abstract
Is-PETase has become an enzyme of significant interest due to its ability to catalyse the degradation of polyethylene terephthalate (PET) at mesophilic temperatures. We performed hybrid quantum mechanics and molecular mechanics (QM/MM) at the DSD-PBEP86-D3/ma-def2-TZVP/CHARMM27//rev-PBE-D3/dev2-SVP/CHARMM level to calculate the energy profile for the degradation of a suitable PET model by this enzyme. Very low overall barriers are computed for serine protease-type hydrolysis steps (as low as 34.1 kJ mol-1 ). Spontaneous deprotonation of the final product, terephthalic acid, with a high computed driving force indicates that product release could be rate limiting.
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Affiliation(s)
| | - John Mitchell
- University of St Andrews School of Chemistry UNITED KINGDOM
| | - Michael Bühl
- University of St. Andrews School of Chemistry North Haugh KY16 9ST St. Andrews UNITED KINGDOM
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13
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Wu J, Young CM, Watts AA, Slawin AMZ, Boyce GR, Bühl M, Smith AD. Isothiourea-Catalyzed Enantioselective Michael Addition of Malonates to α,β-Unsaturated Aryl Esters. Org Lett 2022; 24:4040-4045. [PMID: 35652512 PMCID: PMC9278409 DOI: 10.1021/acs.orglett.2c01486] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [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] [Indexed: 12/23/2022]
Abstract
An enantioselective Michael addition of malonates to α,β-unsaturated para-nitrophenyl esters was achieved using the Lewis basic isothiourea HyperBTM, giving excellent levels of product enantioselectivity (up to >99:1 enantiomeric ratio) in good yields and with complete regioselectivity (>20:1 regioselectivity ratio) in the presence of alternative (phenyl ketone and ethyl ester) Michael acceptors. Density functional theory calculations indicate that N-acylation is rate-limiting. This constitutes a rare example of a highly enantioselective addition of simple, readily available malonates to α,β-unsaturated esters.
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Affiliation(s)
- Jiufeng Wu
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Amy A Watts
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Gregory R Boyce
- Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, Florida 33965, United States
| | - Michael Bühl
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
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14
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Owen AE, Preiss A, McLuskie A, Gao C, Peters G, Bühl M, Kumar A. Manganese-Catalyzed Dehydrogenative Synthesis of Urea Derivatives and Polyureas. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00850] [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: 11/30/2022]
Affiliation(s)
| | - Annika Preiss
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
| | - Angus McLuskie
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
| | - Chang Gao
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
| | - Gavin Peters
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
| | - Amit Kumar
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY169ST, U.K
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15
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Abstract
![]()
We
report a computational study of the little-studied neutral bisulfite,
bisulfate, dihydro-phosphite, and dihydro-phosphate radicals (HSOx•, H2POx•, x =
3,4), calling special attention to their various tautomeric structures
together with pKa values estimated from
the Gibbs free energies of their dissociations (at the G4 and CAM-B3LYP
levels of density functional theory). The energetics of microhydration
clusters with up to four water molecules for the S-based species and
up to eight water molecules for the P-based species were investigated.
The number of microhydrating water molecules needed to induce spontaneous
de-protonation is found to correlate the acid strength of each radical.
According to the computed Gibbs free reaction and activation energies,
S- and P-centered radicals preferentially add to the double bond of
propene (a lipid model), whereas the O-centered radical tautomers
prefer H-abstraction. The likely downstream reactions of these radicals
in biological media are discussed.
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Affiliation(s)
- Michael Bühl
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K
| | - Tallulah Hutson
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K
| | - Alice Missio
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K
| | - John C Walton
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, U.K
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16
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Delarmelina M, Carneiro JWDM, Catlow CRA, Bühl M. Design of CO2 hydrogenation catalysts based on phosphane/borane frustrated Lewis pairs and xanthene-derived scaffolds. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2021.106385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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17
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Ke Z, Dawson DM, Ashbrook SE, Bühl M. Origin of the Temperature Dependence of 13C pNMR Shifts for Copper Paddlewheel MOFs. Chem Sci 2022; 13:2674-2685. [PMID: 35340852 PMCID: PMC8890090 DOI: 10.1039/d1sc07138f] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/02/2022] [Indexed: 11/21/2022] Open
Abstract
An efficient protocol for the calculation of 13C pNMR shifts in metal-organic frameworks based on Cu(II) paddlewheel dimers is proposed, which involves simplified structural models, optimised using GFN2-xTB for the...
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Affiliation(s)
- Zhipeng Ke
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
| | - Michael Bühl
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews St Andrews KY16 9ST UK
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18
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Minova IB, Bühl M, Matam SK, Catlow CRA, Frogley MD, Cinque G, Wright PA, Howe RF. Carbene-like reactivity of methoxy groups in a single crystal SAPO-34 MTO catalyst. Catal Sci Technol 2022. [DOI: 10.1039/d1cy02361f] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In situ synchrotron infrared microspectroscopy on single crystals of SAPO-34 reveals that a carbene insertion mechanism is responsible for the first carbon–carbon bond formation from surface methoxy groups.
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Affiliation(s)
- Ivalina B. Minova
- EastCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
| | - Michael Bühl
- EastCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
| | - Santhosh K. Matam
- UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Oxford, OX11 0FA, UK
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
| | - C. Richard A. Catlow
- UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Oxford, OX11 0FA, UK
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK
- Department of Chemistry, University College London, London WC1E 6BT, UK
| | - Mark D. Frogley
- MIRIAM beamline B22, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Gianfelice Cinque
- MIRIAM beamline B22, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Paul A. Wright
- EastCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
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19
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Schattenberg CJ, Lehmann M, Bühl M, Kaupp M. Systematic Evaluation of Modern Density Functional Methods for the Computation of NMR Shifts of 3d Transition-Metal Nuclei. J Chem Theory Comput 2021; 18:273-292. [PMID: 34968062 DOI: 10.1021/acs.jctc.1c00964] [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: 11/30/2022]
Abstract
A wide range of density functionals from all rungs of Jacob's ladder have been evaluated systematically for a set of experimental 3d transition-metal NMR shifts of 70 complexes encompassing 12 × 49Ti, 10 × 51V, 10 × 53Cr, 11 × 55Mn, 9 × 57Fe, 9 × 59Co, and 9 × 61Ni shift values, as well as a diverse range of electronic structure characteristics. The overall 39 functionals evaluated include one LDA, eight GGAs, seven meta-GGAs (including their current-density-functional─CDFT─versions), nine global hybrids, four range-separated hybrids, eight local hybrids, and two double hybrids, and we also include Hartree-Fock and MP2 calculations. While recent evaluations of the same functionals for a very large coupled-cluster-based benchmark of main-group shieldings and shifts achieved in some cases aggregate percentage mean absolute errors clearly below 2%, the best results for the present 3d-nuclei set are in the range between 4 and 5%. Strikingly, the overall best-performing functionals are the recently implemented CDFT versions of two meta-GGAs, namely cM06-L (4.0%) and cVSXC (4.3%), followed by cLH14t-calPBE (4.9%), B3LYP (5.0%), and cLH07t-SVWN (5.1%), i.e., the previously best-performing global hybrid and two local hybrids. A number of further functionals achieve aggregate deviations in the range 5-6%. Range-separated hybrids offer no particular advantage over global hybrids. Due to the overall poor performance of Hartree-Fock theory for all systems except the titanium complexes, MP2 and double-hybrid functionals are unsuitable for these 3d-nucleus shifts and provide large errors. Global hybrid functionals with larger EXX admixtures, such as BHLYP or M06-2X, also perform poorly, and some other highly parametrized global hybrids also are unsuitable. For many functionals depending on local kinetic energy τ, their CDFT variants perform much better than their "non-CDFT" versions. This holds notably also for the above-mentioned M06-L and VSXC, while the effect is small for τ-dependent local hybrids and can even be somewhat detrimental to the agreement with experiment for a few other cases. The separation between well-performing and more poorly performing functionals is mainly determined by their results for the most critical nuclei 55Mn, 57Fe, and 59Co. Here either moderate exact-exchange admixtures or CDFT versions of meta-GGAs are beneficial for the accuracy. The overall deviations of the better-performing global or local hybrids are then typically dominated by the 53Cr shifts, where triplet instabilities appear to disfavor exact-exchange admixture. Further detailed analyses help to pinpoint specific nuclei and specific types of complexes that are challenges for a given functional.
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Affiliation(s)
- Caspar Jonas Schattenberg
- Institut für Chemie, Theoretische Chemie/Quantenchemie Sekretariat C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623, Berlin, Germany
| | - Morten Lehmann
- Institut für Chemie, Theoretische Chemie/Quantenchemie Sekretariat C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623, Berlin, Germany
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St Andrews KY16 9ST, Fife, U.K
| | - Martin Kaupp
- Institut für Chemie, Theoretische Chemie/Quantenchemie Sekretariat C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623, Berlin, Germany
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20
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Chalmers BA, Somisara DMUK, Surgenor BA, Athukorala Arachchige KS, Woollins JD, Bühl M, Slawin AMZ, Kilian P. Synthetic and Structural Study of peri-Substituted Phosphine-Arsines. Molecules 2021; 26:7222. [PMID: 34885804 PMCID: PMC8658757 DOI: 10.3390/molecules26237222] [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] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022] Open
Abstract
A series of phosphorus-arsenic peri-substituted acenaphthene species have been isolated and fully characterised, including single crystal X-ray diffraction. Reactions of EBr3 (E = P, As) with iPr2PAcenapLi (Acenap = acenaphthene-5,6-diyl) afforded the thermally stable peri-substitution supported donor-acceptor complexes, iPr2PAcenapEBr23 and 4. Both complexes show a strong P→E dative interaction, as observed by X-ray crystallography and 31P NMR spectroscopy. DFT calculations indicated the unusual As∙∙∙As contact (3.50 Å) observed in the solid state structure of 4 results from dispersion forces rather than metallic interactions. Incorporation of the excess AsBr3 in the crystal structure of 3 promotes the formation of the ion separated species [iPr2PAcenapAsBr]+Br- 5. A decomposition product 6 containing the rare [As6Br8]2- heterocubane dianion was isolated and characterised crystallographically. The reaction between iPr2PAcenapLi and EtAsI2 afforded tertiary arsine (BrAcenap)2AsEt 7, which was subsequently lithiated and reacted with PhPCl2 and Ph2PCl to afford cyclic PhP(Acenap)2AsEt 8 and acyclic EtAs(AcenapPPh2)2 9.
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Affiliation(s)
- Brian A. Chalmers
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
| | - D. M. Upulani K. Somisara
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
| | | | | | - J. Derek Woollins
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
- Department of Chemistry, Khalifa University, Abu Dhabi 127788, United Arab Emirates
| | - Michael Bühl
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
| | - Alexandra M. Z. Slawin
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
| | - Petr Kilian
- EaStChem School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK; (B.A.C.); (D.M.U.K.S.); (J.D.W.); (M.B.); (A.M.Z.S.)
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21
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Fuentes JA, Janka ME, Rodgers J, Fontenot KJ, Bühl M, Slawin AMZ, Clarke ML. Effect of Ligand Backbone on the Selectivity and Stability of Rhodium Hydroformylation Catalysts Derived from Phospholane-Phosphites. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- José A. Fuentes
- EaStCHEM School of Chemistry, University of St Andrews, Purdie Building, North Haugh, St Andrews KY16 9ST, United Kingdom
| | - Mesfin E. Janka
- Eastman Chemical Company, 200 South Wilcox Drive, Kingsport, Tennessee 37660, United States
| | - Jody Rodgers
- Eastman Chemical Company, 200 South Wilcox Drive, Kingsport, Tennessee 37660, United States
| | - Kevin J. Fontenot
- Eastman Chemical Company, 200 South Wilcox Drive, Kingsport, Tennessee 37660, United States
| | - Michael Bühl
- EaStCHEM School of Chemistry, University of St Andrews, Purdie Building, North Haugh, St Andrews KY16 9ST, United Kingdom
| | - Alexandra M. Z. Slawin
- EaStCHEM School of Chemistry, University of St Andrews, Purdie Building, North Haugh, St Andrews KY16 9ST, United Kingdom
| | - Matthew L. Clarke
- EaStCHEM School of Chemistry, University of St Andrews, Purdie Building, North Haugh, St Andrews KY16 9ST, United Kingdom
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22
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Abstract
This perspective highlights the computational modelling of alkene and alkyne alkoxycarbonylation at palladium catalysts. We cover studies on Pd-catalysed alkoxycarbonylation of alkenes with bidentate diphosphine ligands, which reveal a hydride pathway is operating with an intermolecular alcoholysis step, where explicit solvation is mandatory to estimate the overall barriers correctly and model alcoholysis/copolymerisation selectivities. Subsequently, we discuss Pd-catalysed alkyne alkoxycarbonylation with P,N-chelating ligands, where an in situ base mechanism is operating involving ketene-type intermediates. We also discuss catalyst poisoning due to allene and designing a potential new catalyst tolerant towards allene poisoning.
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Affiliation(s)
- Shahbaz Ahmad
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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23
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McGeachie LJR, Bühl M, Cordes DB, Slawin AMZ, Woollins JD. Bridging (Thionylimido)metal Complexes. Inorg Chem 2021; 60:8423-8427. [PMID: 34043915 DOI: 10.1021/acs.inorgchem.1c00725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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
We report the first examples of the thionylimido ligand acting as a μ2-bridging ligand between two transition-metal centers; using Cp2Ti(NSO)2, we describe bi- and tetrametallic systems.
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Affiliation(s)
- Liam J R McGeachie
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Michael Bühl
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom
| | - David B Cordes
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M Z Slawin
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom
| | - J Derek Woollins
- EaStCHEM School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom.,Department of Chemistry, Khalifa University, Abu Dhabi, United Arab Emirates
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24
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Gallarati S, Dingwall P, Fuentes JA, Bühl M, Clarke ML. Understanding Catalyst Structure–Selectivity Relationships in Pd-Catalyzed Enantioselective Methoxycarbonylation of Styrene. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00613] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Simone Gallarati
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, KY16 9ST, U.K
| | - Paul Dingwall
- School of Chemistry and Chemical Engineering, Queen’s University Belfast, Belfast, BT9 5AG, U.K
| | - José A. Fuentes
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, KY16 9ST, U.K
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, KY16 9ST, U.K
| | - Matthew L. Clarke
- School of Chemistry, University of St. Andrews, North Haugh, St. Andrews, KY16 9ST, U.K
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25
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Chabbra S, Smith DM, Bell NL, Watson AJB, Bühl M, Cole-Hamilton DJ, Bode BE. First experimental evidence for a bis-ethene chromium(I) complex forming from an activated ethene oligomerization catalyst. Sci Adv 2020; 6:6/51/eabd7057. [PMID: 33355141 DOI: 10.1126/sciadv.abd7057] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
A bis-ethene chromium(I) species, which is the postulated key intermediate in the widely accepted metallacyclic mechanism for ethene oligomerization, is experimentally observed. This catalytic transformation is an important commercial route to linear α-olefins (primarily, 1-hexene and 1-octene), which act as comonomers for the production of polyethene. Here, electron paramagnetic resonance studies of a catalytic system based on [Cr(CO)4(PNP)][Al(OC(CF3)3)4] [PNP = Ph2PN(iPr)PPh2] activated with Et6Al2 provide the first unequivocal evidence for a chromium(I) bis-ethene complex. The concentration of this species is enhanced under ethene and isotope labeling studies that confirm its composition as containing [Cr(C2H4)2(CO)2(PNP)]+ These observations open a new route to mechanistic studies of selective ethene oligomerization.
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Affiliation(s)
- S Chabbra
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
- Centre of Magnetic Resonance, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
| | - D M Smith
- Drochaid Research Services, St Andrews, Fife KY16 9ST, Scotland, UK
| | - N L Bell
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
| | - A J B Watson
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
| | - M Bühl
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
- Centre of Magnetic Resonance, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
| | - D J Cole-Hamilton
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
| | - B E Bode
- EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK.
- Centre of Magnetic Resonance, University of St Andrews, St Andrews, Fife KY16 9ST, Scotland, UK
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26
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Yu C, Kütt A, Röschenthaler G, Lebl T, Cordes DB, Slawin AMZ, Bühl M, O'Hagan D. Janus Face All-cis 1,2,4,5-tetrakis(trifluoromethyl)- and All-cis 1,2,3,4,5,6-hexakis(trifluoromethyl)- Cyclohexanes. Angew Chem Int Ed Engl 2020; 59:19905-19909. [PMID: 32691941 PMCID: PMC7693182 DOI: 10.1002/anie.202008662] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Indexed: 02/03/2023]
Abstract
We report the synthesis of all-cis 1,2,4,5-tetrakis (trifluoromethyl)- and all-cis 1,2,3,4,5,6-hexakis (trifluoromethyl)- cyclohexanes by direct hydrogenation of precursor tetrakis- or hexakis- (trifluoromethyl)benzenes. The resultant cyclohexanes have a stereochemistry such that all the CF3 groups are on the same face of the cyclohexyl ring. All-cis 1,2,3,4,5,6-hexakis(trifluoromethyl)cyclohexane is the most sterically demanding of the all-cis hexakis substituted cyclohexanes prepared to date, with a barrier (ΔG) to ring inversion calculated at 27 kcal mol-1 . The X-ray structure of all-cis 1,2,3,4,5,6-hexakis(trifluoromethyl)cyclohexane displays a flattened chair conformation and the electrostatic profile of this compound reveals a large diffuse negative density on the fluorine face and a focused positive density on the hydrogen face. The electropositive hydrogen face can co-ordinate chloride (K≈103 ) and to a lesser extent fluoride and iodide ions. Dehydrofluorination promoted decomposition occurs with fluoride ion acting as a base.
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Affiliation(s)
- Cihang Yu
- School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Agnes Kütt
- Department of Life Sciences and ChemistryJacobs University Bremen, gGmbHP.O. Box 750 56128725BremenGermany
- University of TartuInstitute of ChemistryRavila 14a50411TartuEstonia
| | - Gerd‐Volker Röschenthaler
- Department of Life Sciences and ChemistryJacobs University Bremen, gGmbHP.O. Box 750 56128725BremenGermany
| | - Tomas Lebl
- School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - David B. Cordes
- School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | | | - Michael Bühl
- School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - David O'Hagan
- School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
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27
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Cormanich RA, Zeoly LA, Santos H, Camilo NS, Bühl M, Coelho F. Origin of the Diastereoselectivity of the Heterogeneous Hydrogenation of a Substituted Indolizine. J Org Chem 2020; 85:11541-11548. [PMID: 32786618 PMCID: PMC7498159 DOI: 10.1021/acs.joc.0c01338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Indexed: 11/30/2022]
Abstract
![]()
In this work, the stereoselective
heterogeneous hydrogenation of
a tetrasubstituted indolizine was studied. Partial hydrogenation products
were obtained in three steps from a substituted pyridine-2-carboxaldehyde
prepared from commercial pyridoxine hydrochloride. The hydrogenation
of the indolizine ring was shown to be diastereoselective, forming trans-6b and cis-9. Theoretical calculations (ab initio and DFT) were
used to rationalize the unusual trans stereoselectivity
for 6b, and a keto–enol tautomerism under kinetic
control has been proposed as the source of diastereoselectivity.
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Affiliation(s)
- Rodrigo A Cormanich
- University of Campinas, Institute of Chemistry, Department of Organic Chemistry, PO Box 6154, 13083-970, Campinas, São Paulo, Brazil
| | - Lucas A Zeoly
- University of Campinas, Institute of Chemistry, Department of Organic Chemistry, PO Box 6154, 13083-970, Campinas, São Paulo, Brazil
| | - Hugo Santos
- University of Campinas, Institute of Chemistry, Department of Organic Chemistry, PO Box 6154, 13083-970, Campinas, São Paulo, Brazil
| | - Nilton S Camilo
- University of Campinas, Institute of Chemistry, Department of Organic Chemistry, PO Box 6154, 13083-970, Campinas, São Paulo, Brazil
| | - Michael Bühl
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY169ST, U.K
| | - Fernando Coelho
- University of Campinas, Institute of Chemistry, Department of Organic Chemistry, PO Box 6154, 13083-970, Campinas, São Paulo, Brazil
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28
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Yu C, Kütt A, Röschenthaler G, Lebl T, Cordes DB, Slawin AMZ, Bühl M, O'Hagan D. Janus Face All‐
cis
1,2,4,5‐tetrakis(trifluoromethyl)‐ and All‐
cis
1,2,3,4,5,6‐hexakis(trifluoromethyl)‐ Cyclohexanes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Cihang Yu
- School of Chemistry University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Agnes Kütt
- Department of Life Sciences and Chemistry Jacobs University Bremen, gGmbH P.O. Box 750 561 28725 Bremen Germany
- University of Tartu Institute of Chemistry Ravila 14a 50411 Tartu Estonia
| | - Gerd‐Volker Röschenthaler
- Department of Life Sciences and Chemistry Jacobs University Bremen, gGmbH P.O. Box 750 561 28725 Bremen Germany
| | - Tomas Lebl
- School of Chemistry University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - David B. Cordes
- School of Chemistry University of St Andrews North Haugh St Andrews KY16 9ST UK
| | | | - Michael Bühl
- School of Chemistry University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - David O'Hagan
- School of Chemistry University of St Andrews North Haugh St Andrews KY16 9ST UK
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29
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Yao Z, Buck M, Bühl M. Density Functional Theory Study of Pd Aggregation on a Pyridine-Terminated Self-Assembled Monolayer. Chemistry 2020; 26:10555-10563. [PMID: 32428284 PMCID: PMC7497155 DOI: 10.1002/chem.202001242] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/13/2020] [Indexed: 11/08/2022]
Abstract
By using density functional theory calculations, the initial steps towards Pd metal cluster formation on a pyridine-terminated self-assembled monolayer (SAM) consisting of 3-(4-(pyridine-4-yl)phenyl)propane-1-thiol on an Au(1 1 1) surface are investigated. Theoretical modelling allows the investigation of structural details of the SAM surface and the metal/SAM interface at the atomic level, which is essential for elucidating the nature of Pd-SAM and Pd-Pd interactions at the liquid/solid interface and gaining insight into the mechanism of metal nucleation in the initial stage of electrodeposition. The structural flexibility of SAM molecules was studied first and the most stable conformation was identified, planar molecules in a herringbone packing, as the model for Pd adsorption. Two binding sites are found for Pd atoms on the pyridine end group of the SAM. The strong interaction between Pd atoms and pyridines illustrates the importance of SAM functionalisation in the metal nucleation process. Consistent with an energetic driving force of approximately -0.3 eV per Pd atom towards Pd aggregation suggested by static calculations, a spontaneous Pd dimerisation is observed in ab initio molecular dynamic studies of the system. Nudged elastic band calculations suggest a potential route with a low energy barrier of 0.10 eV for the Pd atom diffusion and then dimerisation on top of the SAM layer.
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Affiliation(s)
- Zhen Yao
- EaStCHEM School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | - Manfred Buck
- EaStCHEM School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
| | - Michael Bühl
- EaStCHEM School of ChemistryUniversity of St AndrewsNorth HaughSt AndrewsFifeKY16 9STUK
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30
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Affiliation(s)
| | | | - David B. Cordes
- School of Chemistry University of St Andrews KY16 9ST St Andrews U.K
| | - Michael Bühl
- School of Chemistry University of St Andrews KY16 9ST St Andrews U.K
| | - Steven J. Gray
- School of Chemistry University of St Andrews KY16 9ST St Andrews U.K
| | - Guoxiong Hua
- School of Chemistry University of St Andrews KY16 9ST St Andrews U.K
| | | | - J. Derek Woollins
- School of Chemistry University of St Andrews KY16 9ST St Andrews U.K
- Department of Chemistry Khalifa University Abu Dhabi UAE
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31
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Lorusso P, Ahmad S, Brill (née Schmid) K, Cole‐Hamilton DJ, Sieffert N, Bühl M. On the Catalytic Activity of [RuH
2
(PPh
3
)
3
(CO)] (PPh
3
=triphenylphosphine) in Ruthenium‐Catalysed Generation of Hydrogen from Alcohols: a Combined Experimental and DFT study. ChemCatChem 2020. [DOI: 10.1002/cctc.202000159] [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: 11/09/2022]
Affiliation(s)
- Patrizia Lorusso
- EastCHEM School of ChemistryUniversity of St. Andrews North Haugh St. Andrews, Fife KY16 9ST UK
| | - Shahbaz Ahmad
- EastCHEM School of ChemistryUniversity of St. Andrews North Haugh St. Andrews, Fife KY16 9ST UK
| | | | - David J. Cole‐Hamilton
- EastCHEM School of ChemistryUniversity of St. Andrews North Haugh St. Andrews, Fife KY16 9ST UK
| | | | - Michael Bühl
- EastCHEM School of ChemistryUniversity of St. Andrews North Haugh St. Andrews, Fife KY16 9ST UK
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32
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Nejman PS, Curzon TE, Bühl M, McKay D, Woollins JD, Ashbrook SE, Cordes DB, Slawin AMZ, Kilian P. Phosphorus–Bismuth Peri-Substituted Acenaphthenes: A Synthetic, Structural, and Computational Study. Inorg Chem 2020; 59:5616-5625. [DOI: 10.1021/acs.inorgchem.0c00317] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Phillip S. Nejman
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | - Thomasine E. Curzon
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | - Michael Bühl
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | - David McKay
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | - J. Derek Woollins
- Department of Chemistry, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Sharon E. Ashbrook
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | - David B. Cordes
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
| | | | - Petr Kilian
- EaStChem School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 ST, U.K
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33
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Abstract
Structures of aqueous [Be(H2O)4]2+, its outer-sphere and inner-sphere complexes with F-, Cl-, and SO42-, and dinuclear complexes with a [Be2(κ-OH)(κ-SO4)]+ core have been studied through Car-Parrinello molecular dynamics (CPMD) simulations with the BLYP functional. According to constrained CPMD/BLYP simulations and pointwise thermodynamic integration, the free energy of deprotonation of [Be(H2O)4]2+ and its binding free energy with F- are 9.6 and -6.2 kcal/mol, respectively, in good accord with available experimental data. The computed activation barriers for replacing a water ligand in [Be(H2O)4]2+ with F- and SO42-, 10.9 and 13.6 kcal/mol, respectively, are also in good qualitative agreement with available experimental data. These ligand-substitution reactions are indicated to follow associative interchange mechanisms with backside (SN2-like) attack of the anion relative to the aquo ligand it is displacing. Outperforming static density functional theory computations of the salient kinetic and thermodynamic quantities involving simple polarizable continuum solvent models, CPMD simulations are validated as a promising tool for studying the structures and speciation of beryllium complexes in aqueous solution.
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Affiliation(s)
- Onyekachi Raymond
- Chemistry, School of Science , University of Waikato , Private Bag 3105 , Hamilton 3240 , New Zealand.,Institute of Environmental Science and Research (ESR) , P.O. Box 50348 , Porirua 5240 , New Zealand.,EaStCHEM School of Chemistry, North Haugh , University of St Andrews , St Andrews , Fife KY16 9ST , U.K
| | - Michael Bühl
- EaStCHEM School of Chemistry, North Haugh , University of St Andrews , St Andrews , Fife KY16 9ST , U.K
| | - Joseph R Lane
- Chemistry, School of Science , University of Waikato , Private Bag 3105 , Hamilton 3240 , New Zealand
| | - William Henderson
- Chemistry, School of Science , University of Waikato , Private Bag 3105 , Hamilton 3240 , New Zealand
| | - Penelope J Brothers
- School of Chemical Sciences , University of Auckland , Private Bag 92019 , Auckland 1142 , New Zealand
| | - Paul G Plieger
- School of Fundamental Sciences , Massey University , Private Bag 11222 , Palmerston North 4410 , New Zealand
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34
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Delarmelina M, Nicoletti CD, de Moraes MC, Futuro DO, Bühl M, de C da Silva F, Ferreira VF, de M Carneiro JW. α- and β-Lapachone Isomerization in Acidic Media: Insights from Experimental and Implicit/Explicit Solvation Approaches. Chempluschem 2020; 84:52-61. [PMID: 31950738 DOI: 10.1002/cplu.201800485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 09/19/2018] [Revised: 11/01/2018] [Indexed: 11/10/2022]
Abstract
Combined experimental and mixed implicit/explicit solvation approaches were employed to gain insights into the origin of switchable regioselectivity of acid-catalyzed lapachol cyclization and α-/β-lapachone isomerization. It was found that solvating species under distinct experimental conditions stabilized α- and β-lapachone differently, thus altering the identity of the thermodynamic product. The energy profile for lapachol cyclization revealed that this process can occur with low free-energy barriers (lower than 8.0 kcal mol-1 ). For α/β isomerization in a dilute medium, the computed enthalpic barriers are 15.1 kcal mol-1 (α→β) and 14.2 kcal mol-1 (β→α). These barriers are lowered in concentrated medium to 11.5 and 12.6 kcal mol-1 , respectively. Experimental determination of isomers ratio was quantified by HPLC and NMR measurements. These findings provide insights into the chemical behavior of lapachol and lapachone derivatives in more complex environments.
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Affiliation(s)
- Maicon Delarmelina
- Instituto de Química, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24020-141, Brazil
| | - Caroline D Nicoletti
- Faculdade de Farmácia, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24241-002, Brazil
| | - Marcela C de Moraes
- Instituto de Química, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24020-141, Brazil
| | - Debora O Futuro
- Faculdade de Farmácia, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24241-002, Brazil
| | - Michael Bühl
- University of St Andrews, School of Chemistry North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Fernando de C da Silva
- Instituto de Química, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24020-141, Brazil
| | - Vitor F Ferreira
- Instituto de Química, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24020-141, Brazil.,Faculdade de Farmácia, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24241-002, Brazil
| | - José W de M Carneiro
- Instituto de Química, Universidade Federal Fluminense Niterói, Rio de Janeiro, 24020-141, Brazil
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35
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Li C, Dickson R, Rockstroh N, Rabeah J, Cordes DB, Slawin AMZ, Hünemörder P, Spannenberg A, Bühl M, Mejía E, Zysman-Colman E, Kamer PCJ. Ligand electronic fine-tuning and its repercussion on the photocatalytic activity and mechanistic pathways of the copper-photocatalysed aza-Henry reaction. Catal Sci Technol 2020. [DOI: 10.1039/d0cy01221a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Subtle electronic ligand effects have a strong impact on the mechanistic pathway of a photocatalytic coupling reaction.
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Affiliation(s)
- Chenfei Li
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
| | - Robert Dickson
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
| | | | - Jabor Rabeah
- Leibniz Institute for Catalysis
- 18059 Rostock
- Germany
| | - David B. Cordes
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
| | - Alexandra M. Z. Slawin
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
| | | | | | - Michael Bühl
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
| | | | - Eli Zysman-Colman
- Organic Semiconductor Centre
- EaStCHEM School of Chemistry
- University of St Andrews
- KY16 9ST St Andrews
- UK
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36
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Abstract
The synthesis and conformation of an all-syn 2,3,4.7.8,9 hexafluoro alkane is explored by X-ray, NMR and DFT.
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Affiliation(s)
- Nawaf Al-Maharik
- EaStCHEM School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
- Department of Chemistry
| | - David B. Cordes
- EaStCHEM School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
| | | | - Michael Bühl
- EaStCHEM School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
| | - David O'Hagan
- EaStCHEM School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
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37
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Ahmad S, Crawford LE, Bühl M. Palladium-catalysed methoxycarbonylation of ethene with bidentate diphosphine ligands: a density functional theory study. Phys Chem Chem Phys 2020; 22:24330-24336. [DOI: 10.1039/d0cp04454g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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
The mechanism and origin of selectivity of Pd-catalysed formation of methyl propionate is elucidated through DFT calculations.
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Affiliation(s)
- Shahbaz Ahmad
- School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
| | | | - Michael Bühl
- School of Chemistry
- University of St. Andrews
- St. Andrews
- UK
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38
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Affiliation(s)
- Peter Portius
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, United Kingdom
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Michael Bühl
- School of Chemistry, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom
| | - Michael W. George
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315100, China
| | - Friedrich-Wilhelm Grevels
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - James J. Turner
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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39
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Ke Z, Jamieson LE, Dawson DM, Ashbrook SE, Bühl M. NMR chemical shifts of urea loaded copper benzoate. A joint solid-state NMR and DFT study. Solid State Nucl Magn Reson 2019; 101:31-37. [PMID: 31082542 DOI: 10.1016/j.ssnmr.2019.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 05/21/2023]
Abstract
We report solid-state 13C NMR spectra of urea-loaded copper benzoate, Cu2(C6H5CO2)4·2(urea), a simplified model for copper paddlewheel-based metal-organic frameworks (MOFs), along with first-principles density functional theory (DFT) computation of the paramagnetic NMR (pNMR) chemical shifts. Assuming a Boltzmann distribution between a diamagnetic open-shell singlet ground state (in a broken-symmetry Kohn-Sham DFT description) and an excited triplet state, the observed δ(13C) values are reproduced reasonably well at the PBE0-⅓/IGLO-II//PBE0-D3/AE1 level. Using the proposed assignments of the signals, the mean absolute deviation between computed and observed 13C chemical shifts is below 30 ppm over a range of more than 1100 ppm.
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Affiliation(s)
- Zhipeng Ke
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Lauren E Jamieson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Daniel M Dawson
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Sharon E Ashbrook
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK.
| | - Michael Bühl
- School of Chemistry, EaStCHEM and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK.
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40
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Ahmad S, Bühl M. Design of a Highly Active Pd Catalyst with P,N Hemilabile Ligands for Alkoxycarbonylation of Alkynes and Allenes: A Density Functional Theory Study. Chemistry 2019; 25:11625-11629. [DOI: 10.1002/chem.201902402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/16/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Shahbaz Ahmad
- EastCHEM School of Chemistry University of St. Andrews North Haugh St. Andrews Fife KY16 9ST United Kingdom
| | - Michael Bühl
- EastCHEM School of Chemistry University of St. Andrews North Haugh St. Andrews Fife KY16 9ST United Kingdom
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41
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Bello D, Rubanu MG, Bandaranayaka N, Götze JP, Bühl M, O'Hagan D. Acetyl Coenzyme A Analogues as Rationally Designed Inhibitors of Citrate Synthase. Chembiochem 2019; 20:1174-1182. [PMID: 30605257 DOI: 10.1002/cbic.201800700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Indexed: 12/14/2022]
Abstract
In this study, we probed the inhibition of pig heart citrate synthase (E.C. 4.1.3.7) by synthesising seven analogues either designed to mimic the proposed enolate intermediate in this enzyme reaction or developed from historical inhibitors. The most potent inhibitor was fluorovinyl thioether 9 (Ki =4.3 μm), in which a fluorine replaces the oxygen atom of the enolate. A comparison of the potency of 9 with that of its non-fluorinated vinyl thioether analogue 10 (Ki =68.3 μm) revealed a clear "fluorine effect" favouring 9 by an order of magnitude. The dethia analogues of 9 and 10 proved to be poor inhibitors. A methyl sulfoxide analogue was a moderate inhibitor (Ki =11.1 μm), thus suggesting hydrogen bonding interactions in the enolate site. Finally, E and Z propenoate thioether isomers were explored as conformationally constrained carboxylates, but these were not inhibitors. All compounds were prepared by the synthesis of the appropriate pantetheinyl diol and then assembly of the coenzyme A structure according to a three-enzyme biotransformation protocol. A quantum mechanical study, modelling both inhibitors 9 and 10 into the active site indicated short CF⋅⋅⋅H contacts of ≈2.0 Å, consistent with fluorine making two stabilising hydrogen bonds, and mimicking an enolate rather than an enol intermediate. Computation also indicated that binding of 9 to citrate synthase increases the basicity of a key aspartic acid carboxylate, which becomes protonated.
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Affiliation(s)
- Davide Bello
- University of St Andrews, School of Chemistry, North Haugh, St. Andrews, KY16 9ST, UK
| | - Maria Grazia Rubanu
- University of St Andrews, School of Chemistry, North Haugh, St. Andrews, KY16 9ST, UK
| | | | - Jan P Götze
- University of St Andrews, School of Chemistry, North Haugh, St. Andrews, KY16 9ST, UK.,Present address: Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, 14495, Berlin, Germany
| | - Michael Bühl
- University of St Andrews, School of Chemistry, North Haugh, St. Andrews, KY16 9ST, UK
| | - David O'Hagan
- University of St Andrews, School of Chemistry, North Haugh, St. Andrews, KY16 9ST, UK
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42
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Ahmad S, Berry EA, Boyle CH, Hudson CG, Ireland OW, Thompson EA, Bühl M. Formation of metallacarboxylic acids through Hieber base reaction. A density functional theory study. J Mol Model 2019; 25:45. [PMID: 30684012 PMCID: PMC6347588 DOI: 10.1007/s00894-018-3915-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 12/19/2018] [Indexed: 11/25/2022]
Abstract
Using density functional theory (B97-D/ECP2/PCM//RI-BP86/ECP1 level), we have studied the effects of ligand variation on OH- uptake by transition-metal carbonyls (Hieber base reaction), i.e., LnM(CO) + OH- → [LnM(CO2H)]-, M = Fe, Ru, Os, L = CO, PMe3, PF3, py, bipy, Cl, H. The viability of this step depends notably on the nature of the co-ligands, and a large span of driving forces is predicted, ranging from ΔG = -144 kJ/mol to +122 kJ/mol. Based on evaluation of atomic charges from natural population analysis, it is the ability of the co-ligands to delocalize the additional negative charge (through their π-acidity) that is the key factor affecting the driving force for OH- uptake. Implications for the design of new catalysts for water gas shift reaction are discussed. Graphical abstract ᅟ.
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Affiliation(s)
- Shahbaz Ahmad
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Elisabeth A. Berry
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Conor H. Boyle
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Christopher G. Hudson
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Oliver W. Ireland
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Emily A. Thompson
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
| | - Michael Bühl
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST UK
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43
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Holroyd LF, Bühl M, Gaigeot MP, van Mourik T. Thermodynamics of 5-Bromouracil Tautomerization From First-Principles Molecular Dynamics Simulations. Quantum Systems in Physics, Chemistry and Biology - Theory, Interpretation, and Results 2019. [DOI: 10.1016/bs.aiq.2018.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Ahmad S, Lockett A, Shuttleworth TA, Miles-Hobbs AM, Pringle PG, Bühl M. Palladium-catalysed alkyne alkoxycarbonylation with P,N-chelating ligands revisited: a density functional theory study. Phys Chem Chem Phys 2019; 21:8543-8552. [PMID: 30957820 DOI: 10.1039/c9cp01471c] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A revised in situ base mechanism of alkyne alkoxycarbonylation via a Pd catalyst with hemilabile P,N-ligands (PyPPh2, Py = 2-pyridyl) has been fully characterised at the B3PW91-D3/PCM level of density functional theory. Key intermediates on this route are acryloyl and η3-propen-1-oyl complexes that readily undergo methanolysis. With two hemilabile P,N-ligands and one or both of them protonated, the overall computed barrier is 16.8 kcal mol-1. This new mechanism is consistent with all of the experimental data relating to substituent effects on relative reaction rates and branched/linear selectivities, including new results on the methoxycarbonylation of phenylacetylene using (4-Me2N-Py)PPh2 and (6-Cl-Py)PPh2 ligands. This ligand is found to decrease catalytic activity over PyPPh2, thus invalidating a formerly characterised in situ base mechanism.
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Affiliation(s)
- Shahbaz Ahmad
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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45
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Guo YY, McNulty JA, Mica NA, Samuel IDW, Slawin AMZ, Bühl M, Lightfoot P. Structure-directing effects in (110)-layered hybrid perovskites containing two distinct organic moieties. Chem Commun (Camb) 2019; 55:9935-9938. [DOI: 10.1039/c9cc04964a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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
The combination of two similar ‘disc-shaped’ organo-cations is shown to template the formation of (110)-cut layered perovskites of stoichiometry AA′BX4.
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Affiliation(s)
- Yuan-Yuan Guo
- School of Chemistry and EaStChem
- University of St Andrews
- St Andrews
- UK
| | - Jason A. McNulty
- School of Chemistry and EaStChem
- University of St Andrews
- St Andrews
- UK
| | - Natalie A. Mica
- Organic Semiconductor Centre
- SUPA
- School of Physics
- University of St Andrews
- St Andrews
| | - Ifor D. W. Samuel
- Organic Semiconductor Centre
- SUPA
- School of Physics
- University of St Andrews
- St Andrews
| | | | - Michael Bühl
- School of Chemistry and EaStChem
- University of St Andrews
- St Andrews
- UK
| | - Philip Lightfoot
- School of Chemistry and EaStChem
- University of St Andrews
- St Andrews
- UK
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46
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Henwood AF, Antón-García D, Morin M, Rota Martir D, Cordes DB, Casey C, Slawin AMZ, Lebl T, Bühl M, Zysman-Colman E. Conjugated, rigidified bibenzimidazole ancillary ligands for enhanced photoluminescence quantum yields of orange/red-emitting iridium(iii) complexes. Dalton Trans 2019; 48:9639-9653. [DOI: 10.1039/c9dt00423h] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A family of six orange/red-emitting cationic iridium complexes were synthesized and their optoelectronic properties comprehensively characterized.
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47
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Sieffert N, Thakkar A, Bühl M. Modelling uranyl chemistry in liquid ammonia from density functional theory. Chem Commun (Camb) 2018; 54:10431-10434. [PMID: 30159574 DOI: 10.1039/c8cc05382k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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
We developed a computationally efficient protocol based on Density Functional Theory (DFT) and a continuum solvation model (CSM) to predict reaction free energies of complexation reactions of uranyl in liquid ammonia. Several functionals have been tested against CCSD(T) and different CSMs have been assessed relative to Car-Parrinello Molecular Dynamics (CPMD) simulations in explicit solvent.
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48
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Liu R, Morris E, Cheng X, Amigues E, Lau K, Kim B, Liu Y, Ke Z, Ashbrook SE, Bühl M, Dawson G. SERS of Trititanate Nanotubes: Selective Enhancement of Catechol Compounds. ChemistrySelect 2018. [DOI: 10.1002/slct.201801781] [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] [Indexed: 11/11/2022]
Affiliation(s)
- Ruochen Liu
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
- Department of Chemistry; University of Liverpool; Crown Street Liverpool
| | - Edmund Morris
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
- Department of Chemistry; University of Liverpool; Crown Street Liverpool
| | - Xiaorong Cheng
- Suzhou Institute of Industrial Technology, Suzhou, PR; China
| | - Eric Amigues
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
| | - Kim Lau
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
| | - Baekman Kim
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
| | - Yuanhang Liu
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
| | - Zhipeng Ke
- School of Chemistry; University of St Andrews
| | | | | | - Graham Dawson
- Department of Chemistry; Xian Jiaotong Liverpool University, Suzhou, PR; China
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Bykova T, Al-Maharik N, Slawin AMZ, Bühl M, Lebl T, O'Hagan D. Benzylic Functionalisation of Phenyl all-cis-2,3,5,6-Tetrafluorocyclohexane Provides Access to New Organofluorine Building Blocks. Chemistry 2018; 24:13290-13296. [PMID: 29882357 DOI: 10.1002/chem.201802166] [Citation(s) in RCA: 9] [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: 05/01/2018] [Revised: 06/04/2018] [Indexed: 11/07/2022]
Abstract
Selectively fluorinated hydrocarbons continue to attract attention for tuning pharmacokinetic properties in agrochemical and pharmaceutical discovery programmes. This study identifies benzylic bromination of phenyl all-cis-2,3,5,6-tetrafluorocyclohexane 2 as a key reaction for accessing building blocks containing the all-cis-2,3,5,6-tetrafluorocyclohexane ring system. These cyclohexanes are of interest as the fluorines are only on one face of the cyclohexane, and this imparts an unusual polar aspect, very different to an otherwise hydrophobic cyclohexane. Ritter type reactions of benzyl bromide 4 with DMF and acetonitrile generated the corresponding benzyl alcohol 6 and benzylacetamide 7 respectively. Benzylacetamide 7 was hydrolysed to benzyl amine 8 and syn-amino-alcohol 9, and separately the phenyl ring was oxidatively cleaved to furnish carboxylic acid acetamide 10, which after hydrolysis gave the tetrafluorocyclohexyl amino acid 11. A trans-halogenation of benzylbromide 4 with AgF2 gave benzyl fluoride 13. Oxidative cleavage of the aryl ring then gave pentafluorocyclohexyl carboxylic acid 14. This carboxylic acid was readily converted to amides 23-26 and the preferred conformations of these α-fluoroamides were explored by DFT, X-ray structure and 1 H-19 F HOESY NMR analysis.
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Affiliation(s)
- Tetiana Bykova
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
| | - Nawaf Al-Maharik
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
- Current address: Alistiqlal University, Jericho, Palestine
| | - Alexandra M Z Slawin
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
| | - Michael Bühl
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
| | - Tomas Lebl
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
| | - David O'Hagan
- School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY15 5EA, UK
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Abstract
The temperature dependence of the low-frequency C-O bands in the IR spectrum of [(η4-norbornadiene)Fe(CO)3], reminiscent of signal coalescence in dynamic NMR, was interpreted by Grevels (in 1987) as chemical exchange due to very fast rotation of the diene group. Since then, there has been both support and objection to this interpretation. We discuss these various claims involving both one- and two-dimensional IR and, largely on the basis of new density functional theory calculations, furnish support for Grevels' original interpretation.
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Affiliation(s)
- James J Turner
- School of Chemistry , University of Nottingham, University Park , Nottingham NG7 2RD , United Kingdom
| | - Michael Bühl
- School of Chemistry , University of St. Andrews , St. Andrews , Fife KY16 9ST , United Kingdom
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