Unusual Concerted Lewis Acid−Lewis Base Mechanism for Hydrogen Activation by a Phosphine−Borane Compound
- 24 June 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 47 (14), 6212-6219
- https://doi.org/10.1021/ic702489s
Abstract
Density functional theory calculations have been carried out to investigate the possible reaction mechanisms for the reversible dihydrogen activation catalyzed by a phosphine-borane compound, (C6H2Me3)2P(C6F4)B(C6F5)2 (Welch, G. C.; Juan, R. R. S; Masuda, J. D.; Stephan, D. W. Science. 2006, 314, 1124-1126). The present calculations show that an unusual concerted Lewis acid-Lewis base mechanism is more favorable than the proton transfer or hydride transfer mechanisms suggested previously. In the concerted Lewis acid-Lewis base mechanism, the H-H heterolytic cleavage is achieved through the simultaneous electron transfer from the lone-pair orbital of the Lewis base P center to the sigma* orbital of H2 and from the sigma orbital of H2 to the empty orbital of the Lewis acid B center. The solvent is found to dramatically change the potential energy surface. The proposed mechanism can account well for the bimolecular H-D exchange process observed in deuteration experiments and the experimental fact that the H2 activation is reversible at mild conditions.Keywords
This publication has 29 references indexed in Scilit:
- A Dinuclear Ni(µ-H)Ru Complex Derived from H 2Science, 2007
- A Promising Mimic of Hydrogenase ActivityScience, 2007
- Facile Splitting of Hydrogen and Ammonia by Nucleophilic Activation at a Single Carbon CenterScience, 2007
- Breaking the H 2 Marriage and Reuniting the CoupleScience, 2006
- Facile Activation of Dihydrogen by an Unsaturated Heavier Main Group CompoundJournal of the American Chemical Society, 2005
- Catalysis of the electrochemical H evolution by di-iron sub-site modelsCoordination Chemistry Reviews, 2005
- DFT investigations of models related to the active site of [NiFe] and [Fe] hydrogenasesCoordination Chemistry Reviews, 2005
- Asymmetric Catalysis: Science and Opportunities (Nobel Lecture) Copyright© The Nobel Foundation 2002. We thank the Nobel Foundation, Stockholm, for permission to print this lecture.Angewandte Chemie-International Edition, 2002
- Reactions with Molecular Hydrogen in Microorganisms: Evidence for a Purely Organic Hydrogenation CatalystChemical Reviews, 1996
- Characterization of the first examples of isolable molecular hydrogen complexes, M(CO)3(PR3)2(H2) (M = molybdenum or tungsten; R = Cy or isopropyl). Evidence for a side-on bonded dihydrogen ligandJournal of the American Chemical Society, 1984