1
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Jay RM, Coates MR, Zhao H, Winghart MO, Han P, Wang RP, Harich J, Banerjee A, Wikmark H, Fondell M, Nibbering ETJ, Odelius M, Huse N, Wernet P. Photochemical Formation and Electronic Structure of an Alkane σ-Complex from Time-Resolved Optical and X-ray Absorption Spectroscopy. J Am Chem Soc 2024; 146:14000-14011. [PMID: 38713061 PMCID: PMC11117182 DOI: 10.1021/jacs.4c02077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/08/2024]
Abstract
C-H bond activation reactions with transition metals typically proceed via the formation of alkane σ-complexes, where an alkane C-H σ-bond binds to the metal. Due to the weak nature of metal-alkane bonds, σ-complexes are challenging to characterize experimentally. Here, we establish the complete pathways of photochemical formation of the model σ-complex Cr(CO)5-alkane from Cr(CO)6 in octane solution and characterize the nature of its metal-ligand bonding interactions. Using femtosecond optical absorption spectroscopy, we find photoinduced CO dissociation from Cr(CO)6 to occur within the 100 fs time resolution of the experiment. Rapid geminate recombination by a fraction of molecules is found to occur with a time constant of 150 fs. The formation of bare Cr(CO)5 in its singlet ground state is followed by complexation of an octane molecule from solution with a time constant of 8.2 ps. Picosecond X-ray absorption spectroscopy at the Cr L-edge and O K-edge provides unique information on the electronic structure of the Cr(CO)5-alkane σ-complex from both the metal and ligand perspectives. Based on clear experimental observables, we find substantial destabilization of the lowest unoccupied molecular orbital upon coordination of the C-H bond to the undercoordinated Cr center in the Cr(CO)5-alkane σ-complex, and we define this as a general, orbital-based descriptor of the metal-alkane bond. Our study demonstrates the value of combining optical and X-ray spectroscopic methods as complementary tools to study the stability and reactivity of alkane σ-complexes in their role as the decisive intermediates in C-H bond activation reactions.
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Affiliation(s)
- Raphael M. Jay
- Department
of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Michael R. Coates
- Department
of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden
| | - Huan Zhao
- Center
for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Marc-Oliver Winghart
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Peng Han
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Ru-Pan Wang
- Center
for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Jessica Harich
- Center
for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Ambar Banerjee
- Department
of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Hampus Wikmark
- Department
of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - Mattis Fondell
- Institute
for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH, 12489 Berlin, Germany
| | - Erik T. J. Nibbering
- Max
Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, 12489 Berlin, Germany
| | - Michael Odelius
- Department
of Physics, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden
| | - Nils Huse
- Center
for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Philippe Wernet
- Department
of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
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2
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Dias HVR, Parasar D, Yakovenko AA, Stephens PW, Muñoz-Castro Á, Vanga M, Mykhailiuk P, Slobodyanyuk E. In situ studies of reversible solid-gas reactions of ethylene responsive silver pyrazolates. Chem Sci 2024; 15:2019-2025. [PMID: 38332831 PMCID: PMC10848740 DOI: 10.1039/d3sc04182d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/28/2023] [Indexed: 02/10/2024] Open
Abstract
Solid-gas reactions and in situ powder X-ray diffraction investigations of trinuclear silver complexes {[3,4,5-(CF3)3Pz]Ag}3 and {[4-Br-3,5-(CF3)2Pz]Ag}3 supported by highly fluorinated pyrazolates reveal that they undergo intricate ethylene-triggered structural transformations in the solid-state producing dinuclear silver-ethylene adducts. Despite the complexity, the chemistry is reversible producing precursor trimers with the loss of ethylene. Less reactive {[3,5-(CF3)2Pz]Ag}3 under ethylene pressure and low-temperature conditions stops at an unusual silver-ethylene complex in the trinuclear state, which could serve as a model for intermediates likely present in more common trimer-dimer reorganizations described above. Complete structural data of three novel silver-ethylene complexes are presented together with a thorough computational analysis of the mechanism.
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Affiliation(s)
- H V Rasika Dias
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019 USA
| | - Devaborniny Parasar
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019 USA
| | - Andrey A Yakovenko
- X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory Argonne Illinois 60439 USA
| | - Peter W Stephens
- Department of Physics and Astronomy, Stony Brook University Stony Brook NY 11794-3800 USA
| | - Álvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián Bellavista 7 Santiago 8420524 Chile
| | - Mukundam Vanga
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019 USA
| | - Pavel Mykhailiuk
- Enamine Ltd. Winston Churchill Street 78 02094 Kyiv Ukraine
- Taras Shevchenko National University of Kyiv, Faculty of Chemistry Volodymyrska 60 01601 Kyiv Ukraine
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3
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Goodall JC, Sajjad MA, Thompson EA, Page SJ, Kerrigan AM, Jenkins HT, Lynam JM, Macgregor SA, Weller AS. In crystallo lattice adaptivity triggered by solid-gas reactions of cationic group 7 pincer complexes. Chem Commun (Camb) 2023; 59:10749-10752. [PMID: 37602809 PMCID: PMC10484290 DOI: 10.1039/d3cc03201a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 08/02/2023] [Indexed: 08/22/2023]
Abstract
The group 7 complexes [M(κ3-2,6-(R2PO)2C5H3N)(CO)2L][BArF4] [M = Mn, R = iPr, L = THF; M = Re, R = tBu, L = vacant site] undergo in crystallo solid-gas reactivity with CO to form the products of THF substitution or CO addition respectively. There is a large, local, adaptive change of [BArF4] anions for M = Mn, whereas for M = Re the changes are smaller and also remote to the site of reactivity.
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Affiliation(s)
- Joe C Goodall
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - M Arif Sajjad
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | | | - Samuel J Page
- Department of Chemistry, University of Durham, Durham, DH1 3LE, UK
| | - Adam M Kerrigan
- The York-JEOL Nanocentre, University of York, Heslington, York, YO10 5BR, UK
| | - Huw T Jenkins
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Jason M Lynam
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Andrew S Weller
- Department of Chemistry, University of York, York, YO10 5DD, UK
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4
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Sajjad MA, Macgregor SA, Weller AS. A comparison of non-covalent interactions in the crystal structures of two σ-alkane complexes of Rh exhibiting contrasting stabilities in the solid state. Faraday Discuss 2023; 244:222-240. [PMID: 37096331 DOI: 10.1039/d3fd00009e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Non-covalent interactions surrounding the cationic Rh σ-alkane complexes within the crystal structures of [(Cy2PCH2CH2PCy2)Rh(NBA)][BArF4], [1-NBA][BArF4] (NBA = norbornane, C7H12; ArF = 3,5-(CF3)2C6H3), and [1-propane][BArF4] are analysed using Quantum Theory of Atoms in Molecules (QTAIM) and Independent Gradient Model approaches, the latter under a Hirshfeld partitioning scheme (IGMH). In both structures the cations reside in an octahedral array of [BArF4]- anions within which the [1-NBA]+ cation system exhibits a greater number of C-H⋯F contacts to the anions. QTAIM and IGMH analyses indicate these include the strongest individual atom-atom non-covalent interactions between the cation and the anion in these systems. The IGMH approach highlights the directionality of these C-H⋯F contacts that contrasts with the more diffuse C-H⋯π interactions. The accumulative effects of the latter lead to a more significant stabilizing contribution. IGMH %δGatom plots provide a particularly useful visual tool to identify key interactions and highlight the importance of a -{C3H6}- propylene moiety that is present within both the propane and NBA ligands (the latter as a truncated -{C3H4}- unit) and the cyclohexyl rings of the phosphine substituents. The potential for this to act as a privileged motif that confers stability on the crystal structures of σ-alkane complexes in the solid-state is discussed. The greater number of C-H⋯F inter-ion interactions in the [1-NBA][BArF4] system, coupled with more significant C-H⋯π interactions are all consistent with greater non-covalent stabilisation around the [1-NBA]+ cation. This is also supported by larger computed δGatom indices as a measure of cation-anion non-covalent interaction energy.
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Affiliation(s)
- M Arif Sajjad
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Andrew S Weller
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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5
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Jay RM, Banerjee A, Leitner T, Wang RP, Harich J, Stefanuik R, Wikmark H, Coates MR, Beale EV, Kabanova V, Kahraman A, Wach A, Ozerov D, Arrell C, Johnson PJM, Borca CN, Cirelli C, Bacellar C, Milne C, Huse N, Smolentsev G, Huthwelker T, Odelius M, Wernet P. Tracking C-H activation with orbital resolution. Science 2023; 380:955-960. [PMID: 37262165 DOI: 10.1126/science.adf8042] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023]
Abstract
Transition metal reactivity toward carbon-hydrogen (C-H) bonds hinges on the interplay of electron donation and withdrawal at the metal center. Manipulating this reactivity in a controlled way is difficult because the hypothesized metal-alkane charge-transfer interactions are challenging to access experimentally. Using time-resolved x-ray spectroscopy, we track the charge-transfer interactions during C-H activation of octane by a cyclopentadienyl rhodium carbonyl complex. Changes in oxidation state as well as valence-orbital energies and character emerge in the data on a femtosecond to nanosecond timescale. The x-ray spectroscopic signatures reflect how alkane-to-metal donation determines metal-alkane complex stability and how metal-to-alkane back-donation facilitates C-H bond cleavage by oxidative addition. The ability to dissect charge-transfer interactions on an orbital level provides opportunities for manipulating C-H reactivity at transition metals.
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Affiliation(s)
- Raphael M Jay
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Ambar Banerjee
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Torsten Leitner
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Ru-Pan Wang
- Center for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Jessica Harich
- Center for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | - Robert Stefanuik
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Hampus Wikmark
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
| | - Michael R Coates
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Emma V Beale
- Paul-Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | | | | | - Anna Wach
- Paul-Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Dmitry Ozerov
- Paul-Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | | | | | | | | | | | | | - Nils Huse
- Center for Free-Electron Laser Science, Department of Physics, University of Hamburg, 22761 Hamburg, Germany
| | | | | | - Michael Odelius
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Philippe Wernet
- Department of Physics and Astronomy, Uppsala University, 751 20 Uppsala, Sweden
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6
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Abstract
The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial intermediates in the activation of the strong C-H σ-bonds found in alkanes. Methane, the simplest alkane, binds even more weakly than larger alkanes. Here we report an example of a long-lived methane complex formed by directly binding methane as an incoming ligand to a reactive organometallic complex. Photo-ejection of carbon monoxide from a cationic osmium-carbonyl complex dissolved in an inert hydrofluorocarbon solvent saturated with methane at -90 °C affords an osmium(II) complex, [η5-CpOs(CO)2(CH4)]+, containing methane bound to the metal centre. Nuclear magnetic resonance (NMR) spectroscopy confirms the identity of the σ-methane complex and shows that the four protons of the metal-bound methane are in rapid exchange with each other. The methane ligand has a characteristically shielded 1H NMR resonance (δ -2.16), and the highly shielded carbon resonance (δ -56.3) shows coupling to the four attached protons (1JC-H = 127 Hz). The methane complex has an effective half-life of about 13 hours at -90 °C.
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7
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Doyle LR, Galpin MR, Furfari SK, Tegner BE, Martínez-Martínez AJ, Whitwood AC, Hicks SA, Lloyd-Jones GC, Macgregor SA, Weller AS. Inverse Isotope Effects in Single-Crystal to Single-Crystal Reactivity and the Isolation of a Rhodium Cyclooctane σ-Alkane Complex. Organometallics 2022; 41:284-292. [PMID: 35273423 PMCID: PMC8900153 DOI: 10.1021/acs.organomet.1c00639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 12/15/2022]
Abstract
![]()
The
sequential solid/gas single-crystal to single-crystal reaction
of [Rh(Cy2P(CH2)3PCy2)(COD)][BArF4] (COD = cyclooctadiene) with H2 or
D2 was followed in situ by solid-state 31P{1H} NMR spectroscopy (SSNMR) and ex situ by solution quenching
and GC-MS. This was quantified using a two-step Johnson–Mehl–Avrami–Kologoromov
(JMAK) model that revealed an inverse isotope effect for the second
addition of H2, that forms a σ-alkane complex [Rh(Cy2P(CH2)3PCy2)(COA)][BArF4]. Using D2, a temporal window is determined
in which a structural solution for this σ-alkane complex is
possible, which reveals an η2,η2-binding mode to the Rh(I) center, as supported by periodic density
functional theory (DFT) calculations. Extensive H/D exchange occurs
during the addition of D2, as promoted by the solid-state
microenvironment.
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Affiliation(s)
- Laurence R. Doyle
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Martin R. Galpin
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
| | - Samantha K. Furfari
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Bengt E. Tegner
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, United Kingdom
| | | | - Adrian C. Whitwood
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Scott A. Hicks
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Guy C. Lloyd-Jones
- Department of Chemistry, University of Edinburgh, Edinburgh, Scotland EH9 3FJ, United Kingdom
| | - Stuart A. Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, Scotland EH14 4AS, United Kingdom
| | - Andrew S. Weller
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
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8
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Perutz RN, Sabo‐Etienne S, Weller AS. Metathesis by Partner Interchange in σ-Bond Ligands: Expanding Applications of the σ-CAM Mechanism. Angew Chem Int Ed Engl 2022; 61:e202111462. [PMID: 34694734 PMCID: PMC9299125 DOI: 10.1002/anie.202111462] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 12/13/2022]
Abstract
In 2007 two of us defined the σ-Complex Assisted Metathesis mechanism (Perutz and Sabo-Etienne, Angew. Chem. Int. Ed. 2007, 46, 2578-2592), that is, the σ-CAM concept. This new approach to reaction mechanisms brought together metathesis reactions involving the formation of a variety of metal-element bonds through partner-interchange of σ-bond complexes. The key concept that defines a σ-CAM process is a single transition state for metathesis that is connected by two intermediates that are σ-bond complexes while the oxidation state of the metal remains constant in precursor, intermediates and product. This mechanism is appropriate in situations where σ-bond complexes have been isolated or computed as well-defined minima. Unlike several other mechanisms, it does not define the nature of the transition state. In this review, we highlight advances in the characterization and dynamic rearrangements of σ-bond complexes, most notably alkane and zincane complexes, but also different geometries of silane and borane complexes. We set out a selection of catalytic and stoichiometric examples of the σ-CAM mechanism that are supported by strong experimental and/or computational evidence. We then draw on these examples to demonstrate that the scope of the σ-CAM mechanism has expanded to classes of reaction not envisaged in 2007 (additional σ-bond ligands, agostic complexes, sp2 -carbon, surfaces). Finally, we provide a critical comparison to alternative mechanisms for metathesis of metal-element bonds.
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Affiliation(s)
| | - Sylviane Sabo‐Etienne
- CNRSLCC (Laboratoire de Chimie de Coordination)205 route de Narbonne, BP 44099F-31077Toulouse Cedex 4France
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9
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Perutz RN, Sabo‐Etienne S, Weller AS. Metathesis by Partner Interchange in σ‐Bond Ligands: Expanding Applications of the σ‐CAM Mechanism. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202111462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Sylviane Sabo‐Etienne
- CNRS LCC (Laboratoire de Chimie de Coordination) 205 route de Narbonne, BP 44099 F-31077 Toulouse Cedex 4 France
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10
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Abstract
X-ray crystallography is an invaluable tool in design and development of organometallic catalysis, but application typically requires species to display sufficiently high solution concentrations and lifetimes for single crystalline samples to be obtained. In crystallo organometallic chemistry relies on chemical reactions that proceed within the single-crystal environment to access crystalline samples of reactive organometallic fragments that are unavailable by alternate means. This highlight describes approaches to in crystallo organometallic chemistry including (a) solid-gas reactions between transition metal complexes in molecular crystals and diffusing small molecules, (b) reactions of organometallic complexes within the extended lattices of metal-organic frameworks (MOFs), and (c) intracrystalline photochemical transformations to generate reactive organometallic fragments. Application of these methods has enabled characterization of catalytically important transient species, including σ-alkane adducts of transition metals, metal alkyl intermediates implicated in metal-catalyzed carbonylations, and reactive M-L multiply bonded species involved in C-H functionalization chemistry. Opportunities and challenges for in crystallo organometallic chemistry are discussed.
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Affiliation(s)
- Kaleb A Reid
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA.
| | - David C Powers
- Department of Chemistry, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA.
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11
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Bukvic A, Burnage AL, Tizzard GJ, Martínez-Martínez AJ, McKay AI, Rees NH, Tegner BE, Krämer T, Fish H, Warren MR, Coles SJ, Macgregor SA, Weller AS. A Series of Crystallographically Characterized Linear and Branched σ-Alkane Complexes of Rhodium: From Propane to 3-Methylpentane. J Am Chem Soc 2021; 143:5106-5120. [PMID: 33769815 PMCID: PMC8154534 DOI: 10.1021/jacs.1c00738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Indexed: 12/12/2022]
Abstract
Using solid-state molecular organometallic (SMOM) techniques, in particular solid/gas single-crystal to single-crystal reactivity, a series of σ-alkane complexes of the general formula [Rh(Cy2PCH2CH2PCy2)(ηn:ηm-alkane)][BArF4] have been prepared (alkane = propane, 2-methylbutane, hexane, 3-methylpentane; ArF = 3,5-(CF3)2C6H3). These new complexes have been characterized using single crystal X-ray diffraction, solid-state NMR spectroscopy and DFT computational techniques and present a variety of Rh(I)···H-C binding motifs at the metal coordination site: 1,2-η2:η2 (2-methylbutane), 1,3-η2:η2 (propane), 2,4-η2:η2 (hexane), and 1,4-η1:η2 (3-methylpentane). For the linear alkanes propane and hexane, some additional Rh(I)···H-C interactions with the geminal C-H bonds are also evident. The stability of these complexes with respect to alkane loss in the solid state varies with the identity of the alkane: from propane that decomposes rapidly at 295 K to 2-methylbutane that is stable and instead undergoes an acceptorless dehydrogenation to form a bound alkene complex. In each case the alkane sits in a binding pocket defined by the {Rh(Cy2PCH2CH2PCy2)}+ fragment and the surrounding array of [BArF4]- anions. For the propane complex, a small alkane binding energy, driven in part by a lack of stabilizing short contacts with the surrounding anions, correlates with the fleeting stability of this species. 2-Methylbutane forms more short contacts within the binding pocket, and as a result the complex is considerably more stable. However, the complex of the larger 3-methylpentane ligand shows lower stability. Empirically, there therefore appears to be an optimal fit between the size and shape of the alkane and overall stability. Such observations are related to guest/host interactions in solution supramolecular chemistry and the holistic role of 1°, 2°, and 3° environments in metalloenzymes.
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Affiliation(s)
- Alexander
J. Bukvic
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K.
- Department
of Chemistry, Chemistry Research Laboratories, University of Oxford, Oxford OX1 3TA, U.K.
| | - Arron L. Burnage
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS. U.K.
| | - Graham J. Tizzard
- UK
National Crystallography Service, University
of Southampton, Highfield, Southampton SO17 1BJ, U.K.
| | | | - Alasdair I. McKay
- Department
of Chemistry, Chemistry Research Laboratories, University of Oxford, Oxford OX1 3TA, U.K.
| | - Nicholas H. Rees
- Department
of Chemistry, Chemistry Research Laboratories, University of Oxford, Oxford OX1 3TA, U.K.
| | - Bengt E. Tegner
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS. U.K.
| | - Tobias Krämer
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS. U.K.
| | - Heather Fish
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K.
| | - Mark R. Warren
- Diamond
Light Source Ltd., Diamond House,
Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Simon J. Coles
- UK
National Crystallography Service, University
of Southampton, Highfield, Southampton SO17 1BJ, U.K.
| | - Stuart A. Macgregor
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS. U.K.
| | - Andrew S. Weller
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K.
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12
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Johnson A, Royle CG, Brodie CN, Martínez-Martínez AJ, Duckett SB, Weller AS. η 2-Alkene Complexes of [Rh(PONOP- iPr)(L)] + Cations (L = COD, NBD, Ethene). Intramolecular Alkene-Assisted Hydrogenation and Dihydrogen Complex [Rh(PONOP- iPr)(η-H 2)] . Inorg Chem 2021; 60:13903-13912. [PMID: 33570930 PMCID: PMC8456414 DOI: 10.1021/acs.inorgchem.0c03687] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Rhodium-alkene complexes of the pincer ligand κ3-C5H3N-2,6-(OPiPr2)2 (PONOP-iPr) have been prepared and structurally characterized: [Rh(PONOP-iPr)(η2-alkene)][BArF4] [alkene = cyclooctadiene (COD), norbornadiene (NBD), ethene; ArF = 3,5-(CF3)2C6H3]. Only one of these, alkene = COD, undergoes a reaction with H2 (1 bar), to form [Rh(PONOP-iPr)(η2-COE)][BArF4] (COE = cyclooctene), while the others show no significant reactivity. This COE complex does not undergo further hydrogenation. This difference in reactivity between COD and the other alkenes is proposed to be due to intramolecular alkene-assisted reductive elimination in the COD complex, in which the η2-bound diene can engage in bonding with its additional alkene unit. H/D exchange experiments on the ethene complex show that reductive elimination from a reversibly formed alkyl hydride intermediate is likely rate-limiting and with a high barrier. The proposed final product of alkene hydrogenation would be the dihydrogen complex [Rh(PONOP-iPr)(η2-H2)][BArF4], which has been independently synthesized and undergoes exchange with free H2 on the NMR time scale, as well as with D2 to form free HD. When the H2 addition to [Rh(PONOP-iPr)(η2-ethene)][BArF4] is interrogated using pH2 at higher pressure (3 bar), this produces the dihydrogen complex as a transient product, for which enhancements in the 1H NMR signal for the bound H2 ligand, as well as that for free H2, are observed. This is a unique example of the partially negative line-shape effect, with the enhanced signals that are observed for the dihydrogen complex being explained by the exchange processes already noted.
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Affiliation(s)
- Alice Johnson
- Chemical Research Laboratories, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Cameron G Royle
- Chemical Research Laboratories, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.,Department of Chemistry, University of York, York YO10 5DD, U.K
| | - Claire N Brodie
- Department of Chemistry, University of York, York YO10 5DD, U.K
| | | | - Simon B Duckett
- Department of Chemistry, University of York, York YO10 5DD, U.K
| | - Andrew S Weller
- Department of Chemistry, University of York, York YO10 5DD, U.K
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13
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Furfari SK, Tegner BE, Burnage AL, Doyle LR, Bukvic AJ, Macgregor SA, Weller AS. Selectivity of Rh⋅⋅⋅H-C Binding in a σ-Alkane Complex Controlled by the Secondary Microenvironment in the Solid State. Chemistry 2021; 27:3177-3183. [PMID: 33112000 PMCID: PMC7898853 DOI: 10.1002/chem.202004585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/27/2020] [Indexed: 12/13/2022]
Abstract
Single-crystal to single-crystal solid-state molecular organometallic (SMOM) techniques are used for the synthesis and structural characterization of the σ-alkane complex [Rh(tBu2 PCH2 CH2 CH2 PtBu2 )(η2 ,η2 -C7 H12 )][BArF 4 ] (ArF =3,5-(CF3 )2 C6 H3 ), in which the alkane (norbornane) binds through two exo-C-H⋅⋅⋅Rh interactions. In contrast, the bis-cyclohexyl phosphine analogue shows endo-alkane binding. A comparison of the two systems, supported by periodic DFT calculations, NCI plots and Hirshfeld surface analyses, traces this different regioselectivity to subtle changes in the local microenvironment surrounding the alkane ligand. A tertiary periodic structure supporting a secondary microenvironment that controls binding at the metal site has parallels with enzymes. The new σ-alkane complex is also a catalyst for solid/gas 1-butene isomerization, and catalyst resting states are identified for this.
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Affiliation(s)
| | - Bengt E. Tegner
- Institute of Chemical SciencesHeriot-Watt UniversityEdinburghEH14 4ASUK
| | - Arron L. Burnage
- Institute of Chemical SciencesHeriot-Watt UniversityEdinburghEH14 4ASUK
| | | | - Alexander J. Bukvic
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
- Department of ChemistryUniversity of OxfordMansfield RoadOxfordOX1 3TAUK
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14
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Bowden ME, Ginovska B, Jones MO, Karkamkar AJ, Ramirez-Cuesta AJ, Daemen LL, Schenter GK, Miller SA, Repo T, Chernichenko K, Leick N, Martinez MB, Autrey T. Heterolytic Scission of Hydrogen Within a Crystalline Frustrated Lewis Pair. Inorg Chem 2020; 59:15295-15301. [PMID: 33000622 DOI: 10.1021/acs.inorgchem.0c02290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the heterolysis of molecular hydrogen under ambient conditions by the crystalline frustrated Lewis pair (FLP) 1-{2-[bis(pentafluorophenyl)boryl]phenyl}-2,2,6,6-tetramethylpiperidine (KCAT). The gas-solid reaction provides an approach to prepare the solvent-free, polycrystalline ion pair KCATH2 through a single crystal to single crystal transformation. The crystal lattice of KCATH2 increases in size relative to the parent KCAT by approximately 2%. Microscopy was used to follow the transformation of the highly colored red/orange KCAT to the colorless KCATH2 over a period of 2 h at 300 K under a flow of H2 gas. There is no evidence of crystal decrepitation during hydrogen uptake. Inelastic neutron scattering employed over a temperature range from 4-200 K did not provide evidence for the formation of polarized H2 in a precursor complex within the crystal at low temperatures and high pressures. However, at 300 K, the INS spectrum of KCAT transformed to the INS spectrum of KCATH2. Calculations suggest that the driving force is more favorable in the solid state compared to the solution or gas phase, but the addition of H2 into the KCAT crystal is unfavorable. Ab Initio methods were used to calculate the INS spectra of KCAT, KCATH2, and a possible precursor complex of H2 in the pocket between the B and N of crystalline KCAT. Ex-situ NMR showed that the transformation from KCAT to KCATH2 is quantitative and our results suggest that the hydrogen heterolysis process occurs via H2 diffusion into the FLP crystal with a rate-limiting movement of H2 from inactive positions to reactive sites.
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Affiliation(s)
- Mark E Bowden
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
| | - Bojana Ginovska
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
| | - Martin Owen Jones
- ISIS Neutron and Muon Spallation Facility, STFC, RAL, Didcot OX11 0QX, U.K.,St Andrews University, St Andrews, Fife KY16 9AJ, Scotland U.K
| | - Abhijeet J Karkamkar
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
| | - Anibal J Ramirez-Cuesta
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Luke L Daemen
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Gregory K Schenter
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
| | - Seth A Miller
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
| | - Timo Repo
- Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki, Finland
| | | | - Noemi Leick
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80403, United States
| | - Madison B Martinez
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80403, United States
| | - Tom Autrey
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999 Richland, Washington 99352, United States
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15
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Peralta RA, Huxley MT, Evans JD, Fallon T, Cao H, He M, Zhao XS, Agnoli S, Sumby CJ, Doonan CJ. Highly Active Gas Phase Organometallic Catalysis Supported Within Metal-Organic Framework Pores. J Am Chem Soc 2020; 142:13533-13543. [PMID: 32650640 DOI: 10.1021/jacs.0c05286] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Metal-organic frameworks (MOFs) can act as a platform for the heterogenization of molecular catalysts, providing improved stability, allowing easy catalyst recovery and a route toward structural elucidation of the active catalyst. We have developed a MOF, 1, possessing vacant N,N-chelating sites which are accessible via the porous channels that penetrate the structure. In the present work, cationic rhodium(I) norbornadiene (NBD) and bis(ethylene) (ETH) complexes paired with both noncoordinating and coordinating anions have been incorporated into the N,N-chelation sites of 1 via postsynthetic metalation and facile anion exchange. Exploiting the crystallinity of the host framework, the immobilized Rh(I) complexes were structurally characterized using X-ray crystallography. Ethylene hydrogenation catalysis by 1·[Rh(NBD)]X and 1·[Rh(ETH)2]X (X = Cl and BF4) was studied in the gas phase (2 bar, 46 °C) to reveal that 1·[Rh(ETH)2](BF4) was the most active catalyst (TOF = 64 h-1); the NBD materials and the chloride salt were notably less active. On the basis of these observations, the activity of the Rh(I) bis(ethylene) complexes, 1·[Rh(ETH)2]BF4 and 1·[Rh(ETH)2]Cl, in butene isomerization was also studied using gas-phase NMR spectroscopy. Under one bar of butene at 46 °C, 1·[Rh(ETH)2]BF4 rapidly catalyzes the conversion of 1-butene to 2-butene with a TOF averaging 2000 h-1 over five cycles. Notably, the chloride derivative, 1 [Rh(ETH)2]Cl displays negligible activity in comparison. XPS analysis of the postcatalysis sample, supported by DFT calculations, suggest that the catalytic activity is inhibited by the strong interactions between a Rh(III) allyl hydride intermediate and the chloride anion.
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Affiliation(s)
- Ricardo A Peralta
- Centre for Advanced Nanomaterials and Department of Chemistry, The University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - Michael T Huxley
- Centre for Advanced Nanomaterials and Department of Chemistry, The University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - Jack D Evans
- Department of Inorganic Chemistry, Technische Universität Dresden, Bergstraße 66, 01062 Dresden, Germany
| | - Thomas Fallon
- Centre for Advanced Nanomaterials and Department of Chemistry, The University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - Haijie Cao
- Institute of Materials for Energy and Environment, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Maoxia He
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Xiu Song Zhao
- Institute of Materials for Energy and Environment, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, PR China.,School of Chemical Engineering, The University of Queensland, St Lucia,Brisbane 4072, Australia
| | - Stefano Agnoli
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Christopher J Sumby
- Centre for Advanced Nanomaterials and Department of Chemistry, The University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - Christian J Doonan
- Centre for Advanced Nanomaterials and Department of Chemistry, The University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
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16
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Reiners M, Baabe D, Münster K, Zaretzke MK, Freytag M, Jones PG, Coppel Y, Bontemps S, Rosal ID, Maron L, Walter MD. NH 3 formation from N 2 and H 2 mediated by molecular tri-iron complexes. Nat Chem 2020; 12:740-746. [PMID: 32601410 DOI: 10.1038/s41557-020-0483-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 05/05/2020] [Indexed: 01/27/2023]
Abstract
Living systems carry out the reduction of N2 to ammonia (NH3) through a series of protonation and electron transfer steps under ambient conditions using the enzyme nitrogenase. In the chemical industry, the Haber-Bosch process hydrogenates N2 but requires high temperatures and pressures. Both processes rely on iron-based catalysts, but molecular iron complexes that promote the formation of NH3 on addition of H2 to N2 have remained difficult to devise. Here, we isolate the tri(iron)bis(nitrido) complex [(Cp'Fe)3(μ3-N)2] (in which Cp' = η5-1,2,4-(Me3C)3C5H2), which is prepared by reduction of [Cp'Fe(μ-I)]2 under an N2 atmosphere and comprises three iron centres bridged by two μ3-nitrido ligands. In solution, this complex reacts with H2 at ambient temperature (22 °C) and low pressure (1 or 4 bar) to form NH3. In the solid state, it is converted into the tri(iron)bis(imido) species, [(Cp'Fe)3(μ3-NH)2], by addition of H2 (10 bar) through an unusual solid-gas, single-crystal-to-single-crystal transformation. In solution, [(Cp'Fe)3(μ3-NH)2] further reacts with H2 or H+ to form NH3.
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Affiliation(s)
- Matthias Reiners
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Dirk Baabe
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Katharina Münster
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Marc-Kevin Zaretzke
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Matthias Freytag
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Peter G Jones
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany
| | - Yannick Coppel
- CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT, Toulouse, France
| | - Sébastien Bontemps
- CNRS, LCC (Laboratoire de Chimie de Coordination), Université de Toulouse, UPS, INPT, Toulouse, France
| | - Iker Del Rosal
- Université de Toulouse, INSA-UPS-LPCNO and CNRS-LPCNO, Toulouse, France
| | - Laurent Maron
- Université de Toulouse, INSA-UPS-LPCNO and CNRS-LPCNO, Toulouse, France
| | - Marc D Walter
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Braunschweig, Germany.
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17
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Wei X, Qin XJ, Jin Q, Yu HF, Ding CF, Khan A, Liu YP, Xia C, Luo XD. Indole alkaloids with self-activated sp2 C H bond from Alstonia scholaris. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.151894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Boyd TM, Tegner BE, Tizzard GJ, Martínez‐Martínez AJ, Neale SE, Hayward MA, Coles SJ, Macgregor SA, Weller AS. A Structurally Characterized Cobalt(I) σ-Alkane Complex. Angew Chem Int Ed Engl 2020; 59:6177-6181. [PMID: 31943626 PMCID: PMC7187152 DOI: 10.1002/anie.201914940] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Indexed: 11/11/2022]
Abstract
A cobalt σ-alkane complex, [Co(Cy2 P(CH2 )4 PCy2 )(norbornane)][BArF 4 ], was synthesized by a single-crystal to single-crystal solid/gas hydrogenation from a norbornadiene precursor, and its structure was determined by X-ray crystallography. Magnetic data show this complex to be a triplet. Periodic DFT and electronic structure analyses revealed weak C-H→Co σ-interactions, augmented by dispersive stabilization between the alkane ligand and the anion microenvironment. The calculations are most consistent with a η1 :η1 -alkane binding mode.
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Affiliation(s)
- Timothy M. Boyd
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | - Bengt E. Tegner
- Institute of Chemical SciencesHeriot-Watt UniversityEdinburghEH14 4ASUK
| | - Graham J. Tizzard
- UK National Crystallography ServiceChemistryFaculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
| | | | - Samuel E. Neale
- Institute of Chemical SciencesHeriot-Watt UniversityEdinburghEH14 4ASUK
| | - Michael A. Hayward
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | - Simon J. Coles
- UK National Crystallography ServiceChemistryFaculty of Engineering and Physical SciencesUniversity of SouthamptonSouthamptonSO17 1BJUK
| | | | - Andrew S. Weller
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
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19
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Young RJ, Huxley MT, Pardo E, Champness NR, Sumby CJ, Doonan CJ. Isolating reactive metal-based species in Metal-Organic Frameworks - viable strategies and opportunities. Chem Sci 2020; 11:4031-4050. [PMID: 34122871 PMCID: PMC8152792 DOI: 10.1039/d0sc00485e] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/19/2020] [Indexed: 02/01/2023] Open
Abstract
Structural insight into reactive species can be achieved via strategies such as matrix isolation in frozen glasses, whereby species are kinetically trapped, or by confinement within the cavities of host molecules. More recently, Metal-Organic Frameworks (MOFs) have been used as molecular scaffolds to isolate reactive metal-based species within their ordered pore networks. These studies have uncovered new reactivity, allowed observation of novel metal-based complexes and clusters, and elucidated the nature of metal-centred reactions responsible for catalysis. This perspective considers strategies by which metal species can be introduced into MOFs and highlights some of the advantages and limitations of each approach. Furthermore, the growing body of work whereby reactive species can be isolated and structurally characterised within a MOF matrix will be reviewed, including discussion of salient examples and the provision of useful guidelines for the design of new systems. Novel approaches that facilitate detailed structural analysis of reactive chemical moieties are of considerable interest as the knowledge garnered underpins our understanding of reactivity and thus guides the synthesis of materials with unprecedented functionality.
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Affiliation(s)
- Rosemary J Young
- Department of Chemistry, Centre for Advanced Nanomaterials, The University of Adelaide Adelaide Australia
- School of Chemistry, The University of Nottingham Nottingham UK
| | - Michael T Huxley
- Department of Chemistry, Centre for Advanced Nanomaterials, The University of Adelaide Adelaide Australia
| | - Emilio Pardo
- Institute of Molecular Science, University of Valencia Valencia Spain
| | | | - Christopher J Sumby
- Department of Chemistry, Centre for Advanced Nanomaterials, The University of Adelaide Adelaide Australia
| | - Christian J Doonan
- Department of Chemistry, Centre for Advanced Nanomaterials, The University of Adelaide Adelaide Australia
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20
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Boyd TM, Tegner BE, Tizzard GJ, Martínez‐Martínez AJ, Neale SE, Hayward MA, Coles SJ, Macgregor SA, Weller AS. A Structurally Characterized Cobalt(I) σ‐Alkane Complex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914940] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Timothy M. Boyd
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
- Department of ChemistryUniversity of York York YO10 5DD UK
| | - Bengt E. Tegner
- Institute of Chemical SciencesHeriot-Watt University Edinburgh EH14 4AS UK
| | - Graham J. Tizzard
- UK National Crystallography ServiceChemistryFaculty of Engineering and Physical SciencesUniversity of Southampton Southampton SO17 1BJ UK
| | | | - Samuel E. Neale
- Institute of Chemical SciencesHeriot-Watt University Edinburgh EH14 4AS UK
| | - Michael A. Hayward
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
| | - Simon J. Coles
- UK National Crystallography ServiceChemistryFaculty of Engineering and Physical SciencesUniversity of Southampton Southampton SO17 1BJ UK
| | | | - Andrew S. Weller
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
- Department of ChemistryUniversity of York York YO10 5DD UK
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21
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Martínez‐Martínez AJ, Rees NH, Weller AS. Reversible Encapsulation of Xenon and CH
2
Cl
2
in a Solid‐State Molecular Organometallic Framework (Guest@SMOM). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Antonio J. Martínez‐Martínez
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
- Current Address: CIQSO-Centre for Research in Sustainable Chemistry and Department of ChemistryUniversity of Huelva Campus El Carmen 21007 Huelva Spain
| | - Nicholas H. Rees
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
| | - Andrew S. Weller
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of Oxford Oxford OX1 3TA UK
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22
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Martínez‐Martínez AJ, Rees NH, Weller AS. Reversible Encapsulation of Xenon and CH 2 Cl 2 in a Solid-State Molecular Organometallic Framework (Guest@SMOM). Angew Chem Int Ed Engl 2019; 58:16873-16877. [PMID: 31539184 PMCID: PMC6899477 DOI: 10.1002/anie.201910539] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Indexed: 12/22/2022]
Abstract
Reversible encapsulation of CH2 Cl2 or Xe in a non-porous solid-state molecular organometallic framework of [Rh(Cy2 PCH2 PCy2 )(NBD)][BArF4 ] occurs in single-crystal to single-crystal transformations. These processes are probed by solid-state NMR spectroscopy, including 129 Xe SSNMR. Non-covalent interactions with the -CF3 groups, and hydrophobic channels formed, of [BArF4 ]- anions are shown to be important, and thus have similarity to the transport of substrates and products to and from the active site in metalloenzymes.
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Affiliation(s)
- Antonio J. Martínez‐Martínez
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Current Address: CIQSO-Centre for Research in Sustainable Chemistry and Department of ChemistryUniversity of HuelvaCampus El Carmen21007HuelvaSpain
| | - Nicholas H. Rees
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | - Andrew S. Weller
- Chemistry Research LaboratoriesDepartment of ChemistryUniversity of OxfordOxfordOX1 3TAUK
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23
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McKay AI, Bukvic AJ, Tegner BE, Burnage AL, Martı Nez-Martı Nez AJ, Rees NH, Macgregor SA, Weller AS. Room Temperature Acceptorless Alkane Dehydrogenation from Molecular σ-Alkane Complexes. J Am Chem Soc 2019; 141:11700-11712. [PMID: 31246012 PMCID: PMC7007236 DOI: 10.1021/jacs.9b05577] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The non-oxidative catalytic dehydrogenation of light alkanes via C-H activation is a highly endothermic process that generally requires high temperatures and/or a sacrificial hydrogen acceptor to overcome unfavorable thermodynamics. This is complicated by alkanes being such poor ligands, meaning that binding at metal centers prior to C-H activation is disfavored. We demonstrate that by biasing the pre-equilibrium of alkane binding, by using solid-state molecular organometallic chemistry (SMOM-chem), well-defined isobutane and cyclohexane σ-complexes, [Rh(Cy2PCH2CH2PCy2)(η:η-(H3C)CH(CH3)2][BArF4] and [Rh(Cy2PCH2CH2PCy2)(η:η-C6H12)][BArF4] can be prepared by simple hydrogenation in a solid/gas single-crystal to single-crystal transformation of precursor alkene complexes. Solid-gas H/D exchange with D2 occurs at all C-H bonds in both alkane complexes, pointing to a variety of low energy fluxional processes that occur for the bound alkane ligands in the solid-state. These are probed by variable temperature solid-state nuclear magnetic resonance experiments and periodic density functional theory (DFT) calculations. These alkane σ-complexes undergo spontaneous acceptorless dehydrogenation at 298 K to reform the corresponding isobutene and cyclohexadiene complexes, by simple application of vacuum or Ar-flow to remove H2. These processes can be followed temporally, and modeled using classical chemical, or Johnson-Mehl-Avrami-Kologoromov, kinetics. When per-deuteration is coupled with dehydrogenation of cyclohexane to cyclohexadiene, this allows for two successive KIEs to be determined [kH/kD = 3.6(5) and 10.8(6)], showing that the rate-determining steps involve C-H activation. Periodic DFT calculations predict overall barriers of 20.6 and 24.4 kcal/mol for the two dehydrogenation steps, in good agreement with the values determined experimentally. The calculations also identify significant C-H bond elongation in both rate-limiting transition states and suggest that the large kH/kD for the second dehydrogenation results from a pre-equilibrium involving C-H oxidative cleavage and a subsequent rate-limiting β-H transfer step.
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Affiliation(s)
- Alasdair I McKay
- Chemistry Research Laboratories, University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Alexander J Bukvic
- Chemistry Research Laboratories, University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Bengt E Tegner
- Institute of Chemical Sciences, Heriot Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Arron L Burnage
- Institute of Chemical Sciences, Heriot Watt University , Edinburgh EH14 4AS , United Kingdom
| | | | - Nicholas H Rees
- Chemistry Research Laboratories, University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Stuart A Macgregor
- Institute of Chemical Sciences, Heriot Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Andrew S Weller
- Chemistry Research Laboratories, University of Oxford , Oxford OX1 3TA , United Kingdom
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24
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Sun L, An Y, Ma L, Han Y. Single‐Crystalline Organoiridium Complex for Gas‐Triggered Chromogenic Switches and Its Applications on CO Detection and Reversible Scavenging. CHINESE J CHEM 2019. [DOI: 10.1002/cjoc.201900151] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Li‐Ying Sun
- Key Laboratory of Synthetic and Natural Functional Molecule ChemistryCollege of Chemistry and Materials Science, Northwest University Xi'an Shaaxi 710127 China
| | - Yuan‐Yuan An
- Key Laboratory of Synthetic and Natural Functional Molecule ChemistryCollege of Chemistry and Materials Science, Northwest University Xi'an Shaaxi 710127 China
| | - Li‐Li Ma
- Key Laboratory of Synthetic and Natural Functional Molecule ChemistryCollege of Chemistry and Materials Science, Northwest University Xi'an Shaaxi 710127 China
| | - Ying‐Feng Han
- Key Laboratory of Synthetic and Natural Functional Molecule ChemistryCollege of Chemistry and Materials Science, Northwest University Xi'an Shaaxi 710127 China
- State Key Laboratory of Structural ChemistryFujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 350002 China
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25
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Lu Q, Neese F, Bistoni G. London dispersion effects in the coordination and activation of alkanes in σ-complexes: a local energy decomposition study. Phys Chem Chem Phys 2019; 21:11569-11577. [DOI: 10.1039/c9cp01309a] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The coupled-cluster-based local energy decomposition (LED) analysis is used to elucidate the nature of the TM–alkane interaction in alkane σ-complexes.
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Affiliation(s)
- Qing Lu
- Max-Planck-Institut für Kohlenforschung
- Mülheim an der Ruhr
- Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung
- Mülheim an der Ruhr
- Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung
- Mülheim an der Ruhr
- Germany
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26
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The effect of the counteranion on the loss of hydrogen from cationic ruthenium dihydrogen complexes in the solid state. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.09.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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27
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Martínez-Martínez AJ, Tegner BE, McKay AI, Bukvic AJ, Rees NH, Tizzard GJ, Coles SJ, Warren MR, Macgregor SA, Weller AS. Modulation of σ-Alkane Interactions in [Rh(L 2)(alkane)] + Solid-State Molecular Organometallic (SMOM) Systems by Variation of the Chelating Phosphine and Alkane: Access to η 2,η 2-σ-Alkane Rh(I), η 1-σ-Alkane Rh(III) Complexes, and Alkane Encapsulation. J Am Chem Soc 2018; 140:14958-14970. [PMID: 30351014 DOI: 10.1021/jacs.8b09364] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solid/gas single-crystal to single-crystal (SC-SC) hydrogenation of appropriate diene precursors forms the corresponding σ-alkane complexes [Rh(Cy2P(CH2) nPCy2)(L)][BArF4] ( n = 3, 4) and [ RhH(Cy2P(CH2)2( CH)(CH2)2PCy2)(L)][BArF4] ( n = 5, L = norbornane, NBA; cyclooctane, COA). Their structures, as determined by single-crystal X-ray diffraction, have cations exhibiting Rh···H-C σ-interactions which are modulated by both the chelating ligand and the identity of the alkane, while all sit in an octahedral anion microenvironment. These range from chelating η2,η2 Rh···H-C (e.g., [Rh(Cy2P(CH2) nPCy2)(η2η2-NBA)][BArF4], n = 3 and 4), through to more weakly bound η1 Rh···H-C in which C-H activation of the chelate backbone has also occurred (e.g., [ RhH(Cy2P(CH2)2( CH)(CH2)2PCy2)(η1-COA)][BArF4]) and ultimately to systems where the alkane is not ligated with the metal center, but sits encapsulated in the supporting anion microenvironment, [Rh(Cy2P(CH2)3PCy2)][COA⊂BArF4], in which the metal center instead forms two intramolecular agostic η1 Rh···H-C interactions with the phosphine cyclohexyl groups. CH2Cl2 adducts formed by displacement of the η1-alkanes in solution ( n = 5; L = NBA, COA), [ RhH(Cy2P(CH2)2( CH)(CH2)2PCy2)(κ1-ClCH2Cl)][BArF4], are characterized crystallographically. Analyses via periodic DFT, QTAIM, NBO, and NCI calculations, alongside variable temperature solid-state NMR spectroscopy, provide snapshots marking the onset of Rh···alkane interactions along a C-H activation trajectory. These are negligible in [Rh(Cy2P(CH2)3PCy2)][COA⊂BArF4]; in [ RhH(Cy2P(CH2)2( CH)(CH2)2PCy2)(η1-COA)][BArF4], σC-H → Rh σ-donation is supported by Rh → σ*C-H "pregostic" donation, and in [Rh(Cy2P(CH2) nPCy2)(η2η2-NBA)][BArF4] ( n = 2-4), σ-donation dominates, supported by classical Rh(dπ) → σ*C-H π-back-donation. Dispersive interactions with the [BArF4]- anions and Cy substituents further stabilize the alkanes within the binding pocket.
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Affiliation(s)
| | - Bengt E Tegner
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Alasdair I McKay
- Chemistry Research Laboratories , University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Alexander J Bukvic
- Chemistry Research Laboratories , University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Nicholas H Rees
- Chemistry Research Laboratories , University of Oxford , Oxford OX1 3TA , United Kingdom
| | - Graham J Tizzard
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences , University of Southampton , Southampton SO17 1BJ , United Kingdom
| | - Simon J Coles
- UK National Crystallography Service, Chemistry, Faculty of Natural and Environmental Sciences , University of Southampton , Southampton SO17 1BJ , United Kingdom
| | - Mark R Warren
- Harwell Science and Innovation Campus, Diamond Light Source Ltd. , Didcot OX11 0DE , United Kingdom
| | - Stuart A Macgregor
- Institute of Chemical Sciences , Heriot-Watt University , Edinburgh EH14 4AS , United Kingdom
| | - Andrew S Weller
- Chemistry Research Laboratories , University of Oxford , Oxford OX1 3TA , United Kingdom
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28
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Bezzubov SI, Kalle P, Bilyalova AA, Tatarin SV, Dolzhenko VD. Overcoming the Inertness of Iridium(III) in a Facile Single-Crystal to Single-Crystal Reaction of Iodine Vapor with a Cyclometalated Chloride Monomer. Chemistry 2018; 24:12779-12783. [DOI: 10.1002/chem.201801963] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Stanislav I. Bezzubov
- Kurnakov Institute of General and Inorganic Chemistry; Russian Academy of Sciences; Leninskiy pr. 31 Moscow 119991 Russia
| | - Paulina Kalle
- Kurnakov Institute of General and Inorganic Chemistry; Russian Academy of Sciences; Leninskiy pr. 31 Moscow 119991 Russia
| | - Alfiya A. Bilyalova
- Department of Chemistry; Lomonosov Moscow State University; Lenin's hills 1/3 Moscow 119991 Russia
| | - Sergei V. Tatarin
- Department of Chemistry; Lomonosov Moscow State University; Lenin's hills 1/3 Moscow 119991 Russia
| | - Vladimir D. Dolzhenko
- Department of Chemistry; Lomonosov Moscow State University; Lenin's hills 1/3 Moscow 119991 Russia
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29
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McKay AI, Martínez-Martínez AJ, Griffiths HJ, Rees NH, Waters JB, Weller AS, Krämer T, Macgregor SA. Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alasdair I. McKay
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | | | - Hannah J. Griffiths
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Nicholas H. Rees
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Jordan B. Waters
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Andrew S. Weller
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Tobias Krämer
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Stuart A. Macgregor
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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30
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Knighton RC, Emerson‐King J, Rourke JP, Ohlin CA, Chaplin AB. Solution, Solid-State, and Computational Analysis of Agostic Interactions in a Coherent Set of Low-Coordinate Rhodium(III) and Iridium(III) Complexes. Chemistry 2018; 24:4927-4938. [PMID: 29377308 PMCID: PMC5901041 DOI: 10.1002/chem.201705990] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Indexed: 11/16/2022]
Abstract
A homologous family of low-coordinate complexes of the formulation trans-[M(2,2'-biphenyl)(PR3 )2 ][BArF4 ] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT 1 H and 31 P NMR spectroscopy) and solid-state (single crystal X-ray diffraction) data, and analysis in silico (DFT-based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the IrIII compared to RhIII complexes and, with respect to the phosphine ligands, in the order PiBu3 >PCy3 >PiPr3 >PPh3 . In addition to these structure-property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2-difluorobenzene vs. CH2 Cl2 ) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M-H-C distances.
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Affiliation(s)
- Richard C. Knighton
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Jack Emerson‐King
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Jonathan P. Rourke
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - C. André Ohlin
- Department of ChemistryUmeå UniversityLinneausvag 6907 34UmeåSweden
| | - Adrian B. Chaplin
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
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31
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Guan J, Wriglesworth A, Sun XZ, Brothers EN, Zarić SD, Evans ME, Jones WD, Towrie M, Hall MB, George MW. Probing the Carbon-Hydrogen Activation of Alkanes Following Photolysis of Tp'Rh(CNR)(carbodiimide): A Computational and Time-Resolved Infrared Spectroscopic Study. J Am Chem Soc 2018; 140:1842-1854. [PMID: 29290110 DOI: 10.1021/jacs.7b12152] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carbon-hydrogen bond activation of alkanes by Tp'Rh(CNR) (Tp' = Tp = trispyrazolylborate or Tp* = tris(3,5-dimethylpyrazolyl)borate) were followed by time-resolved infrared spectroscopy (TRIR) in the υ(CNR) and υ(B-H) spectral regions on Tp*Rh(CNCH2CMe3), and their reaction mechanisms were modeled by density functional theory (DFT) on TpRh(CNMe). The major intermediate species were: κ3-η1-alkane complex (1); κ2-η2-alkane complex (2); and κ3-alkyl hydride (3). Calculations predict that the barrier between 1 and 2 arises from a triplet-singlet crossing and intermediate 2 proceeds over the rate-determining C-H activation barrier to give the final product 3. The activation lifetimes measured for the Tp*Rh(CNR) and Tp*Rh(CO) fragments with n-heptane and four cycloalkanes (C5H10, C6H12, C7H14, and C8H16) increase with alkanes size and show a dramatic increase between C6H12 and C7H14. A similar step-like behavior was observed previously with CpRh(CO) and Cp*Rh(CO) fragments and is attributed to the wider difference in C-H bonds that appear at C7H14. However, Tp'Rh(CNR) and Tp'Rh(CO) fragments have much longer absolute lifetimes compared to those of CpRh(CO) and Cp*Rh(CO) fragments, because the reduced electron density in dechelated κ2-η2-alkane Tp' complexes stabilizes the d8 Rh(I) in a square-planar geometry and weakens the metal's ability for oxidative addition of the C-H bond. Further, the Tp'Rh(CNR) fragment has significantly slower rates of C-H activation in comparison to the Tp'Rh(CO) fragment for the larger cycloalkanes, because the steric bulk of the neopentyl isocyanide ligand hinders the rechelation in κ2-Tp'Rh(CNR)(cycloalkane) species and results in the C-H activation without the assistance of the rechelation.
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Affiliation(s)
- Jia Guan
- Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States
| | - Alisdair Wriglesworth
- School of Chemistry, University of Nottingham , University Park NG7 2RD, United Kingdom
| | - Xue Zhong Sun
- School of Chemistry, University of Nottingham , University Park NG7 2RD, United Kingdom
| | | | - Snežana D Zarić
- Science Program, Texas A&M University at Qatar , Doha, Qatar.,Department of Chemistry, University of Belgrade , Belgrade, Serbia
| | - Meagan E Evans
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - William D Jones
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory , Chilton, Oxfordshire OX11 0QX, United Kingdom
| | - Michael B Hall
- Department of Chemistry, Texas A&M University , College Station, Texas 77843-3255, United States
| | - Michael W George
- School of Chemistry, University of Nottingham , University Park NG7 2RD, United Kingdom.,Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China , 199 Taikang East Road, Ningbo 315100, China
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Chadwick FM, McKay AI, Martinez-Martinez AJ, Rees NH, Krämer T, Macgregor SA, Weller AS. Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates. Chem Sci 2017; 8:6014-6029. [PMID: 28989631 PMCID: PMC5625289 DOI: 10.1039/c7sc01491k] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/05/2017] [Indexed: 01/24/2023] Open
Abstract
Solid-state molecular organometallic catalysis (SMOM-cat): synthetic routes, unique structural motifs, mobility in the solid-state and very active gas/solid isomerization catalysts.
Single-crystal to single-crystal solid/gas reactivity and catalysis starting from the precursor sigma-alkane complex [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArF4] (NBA = norbornane; ArF = 3,5-(CF3)2C6H3) is reported. By adding ethene, propene and 1-butene to this precursor in solid/gas reactions the resulting alkene complexes [Rh(Cy2PCH2CH2PCy2)(alkene)x][BArF4] are formed. The ethene (x = 2) complex, [Rh(Cy2PCH2CH2PCy2)(ethene)2][BArF4]-Oct, has been characterized in the solid-state (single-crystal X-ray diffraction) and by solution and solid-state NMR spectroscopy. Rapid, low temperature recrystallization using solution methods results in a different crystalline modification, [Rh(Cy2PCH2CH2PCy2)(ethene)2][BArF4]-Hex, that has a hexagonal microporous structure (P6322). The propene complex (x = 1) [Rh(Cy2PCH2CH2PCy2)(propene)][BArF4] is characterized as having a π-bound alkene with a supporting γ-agostic Rh···H3C interaction at low temperature by single-crystal X-ray diffraction, variable temperature solution and solid-state NMR spectroscopy, as well as periodic density functional theory (DFT) calculations. A fluxional process occurs in both the solid-state and solution that is proposed to proceed via a tautomeric allyl-hydride. Gas/solid catalytic isomerization of d3-propene, H2C
Created by potrace 1.16, written by Peter Selinger 2001-2019
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CHCD3, using [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArF4] scrambles the D-label into all possible positions of the propene, as shown by isotopic perturbation of equilibrium measurements for the agostic interaction. Periodic DFT calculations show a low barrier to H/D exchange (10.9 kcal mol–1, PBE-D3 level), and GIPAW chemical shift calculations guide the assignment of the experimental data. When synthesized using solution routes a bis-propene complex, [Rh(Cy2PCH2CH2PCy2)(propene)2][BArF4], is formed. [Rh(Cy2PCH2CH2PCy2)(butene)][BArF4] (x = 1) is characterized as having 2-butene bound as the cis-isomer and a single Rh···H3C agostic interaction. In the solid-state two low-energy fluxional processes are proposed. The first is a simple libration of the 2-butene that exchanges the agostic interaction, and the second is a butene isomerization process that proceeds via an allyl-hydride intermediate with a low computed barrier of 14.5 kcal mol–1. [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArF4] and the polymorphs of [Rh(Cy2PCH2CH2PCy2)(ethene)2][BArF4] are shown to be effective in solid-state molecular organometallic catalysis (SMOM-Cat) for the isomerization of 1-butene to a mixture of cis- and trans-2-butene at 298 K and 1 atm, and studies suggest that catalysis is likely dominated by surface-active species. [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArF4] is also shown to catalyze the transfer dehydrogenation of butane to 2-butene at 298 K using ethene as the sacrificial acceptor.
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Affiliation(s)
- F Mark Chadwick
- Department of Chemistry , Chemistry Research Laboratories , University of Oxford , OX1 3TA , UK .
| | - Alasdair I McKay
- Department of Chemistry , Chemistry Research Laboratories , University of Oxford , OX1 3TA , UK .
| | | | - Nicholas H Rees
- Department of Chemistry , Chemistry Research Laboratories , University of Oxford , OX1 3TA , UK .
| | - Tobias Krämer
- Institute of Chemical Sciences , Heriot Watt University , Edinburgh , EH14 4AS , UK .
| | - Stuart A Macgregor
- Institute of Chemical Sciences , Heriot Watt University , Edinburgh , EH14 4AS , UK .
| | - Andrew S Weller
- Department of Chemistry , Chemistry Research Laboratories , University of Oxford , OX1 3TA , UK .
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Tagne Kuate AC, Lalancette RA, Jäkle F. Planar-chiral ferrocenylphosphine-borane complexes featuring agostic-type B–H⋯E (E = Hg, Sn) interactions. Dalton Trans 2017; 46:6253-6264. [DOI: 10.1039/c6dt04791b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferrocenylphosphine-borane adducts with Lewis acidic organotin and organomercury substituents inortho-position show rare agostic-type B–H⋯E (E = Sn, Hg) interactions that have been studied by single crystal XRD, multinuclear solution NMR, and computational methods.
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Affiliation(s)
- Alain C. Tagne Kuate
- Department of Chemistry
- Rutgers University-Newark
- Newark
- USA
- Department of Chemistry
| | | | - F. Jäkle
- Department of Chemistry
- Rutgers University-Newark
- Newark
- USA
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McKay AI, Krämer T, Rees NH, Thompson AL, Christensen KE, Macgregor SA, Weller AS. Formation of a σ-alkane Complex and a Molecular Rearrangement in the Solid-State: [Rh(Cyp2PCH2CH2PCyp2)(η2:η2-C7H12)][BArF4]. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00645] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alasdair I. McKay
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Tobias Krämer
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Nicholas H. Rees
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Amber L. Thompson
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Stuart A. Macgregor
- Institute
of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Andrew S. Weller
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
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