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How Frustrated Lewis Acid/Base Systems Pass through Transition‐State Regions: H 2 Cleavage by [ t Bu 3 P/B(C 6 F 5 ) 3 ]
Author(s) -
Pu Maoping,
Privalov Timofei
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402450
Subject(s) - chemistry , borane , lewis acids and bases , crystallography , stereochemistry , resonance (particle physics) , molecular dynamics , computational chemistry , atomic physics , physics , catalysis , biochemistry
We investigate the transition‐state (TS) region of the potential energy surface (PES) of the reaction t Bu 3 P+H 2 +B(C 6 F 5 ) 3 → t Bu 3 P‐H (+) + (−) HB(C 6 F 5 ) 3 and the dynamics of the TS passage at room temperature. Owing to the conformational inertia of the phosphane⋅⋅⋅borane pocket involving heavy t Bu 3 P and B(C 6 F 5 ) 3 species and features of the PES E (P⋅⋅⋅H, B⋅⋅⋅H | B⋅⋅⋅P) as a function of P⋅⋅⋅H, B⋅⋅⋅H, and B⋅⋅⋅P distances, a typical reactive scenario for this reaction is a trajectory that is trapped in the TS region for a period of time (about 350 fs on average across all calculated trajectories) in a quasi‐bound state (scattering resonance). The relationship between the timescale of the TS passage and the effective conformational inertia of the phosphane⋅⋅⋅borane pocket leads to a prediction that isotopically heavier Lewis base/Lewis acid pairs and normal counterparts could give measurably different reaction rates. Herein, the predicted quasi‐bound state could be verified in molecular collision experiments involving femtosecond spectroscopy.