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Analysis of the bonding in XH 3 Cu + (XB, Al, Ga) complexes
Author(s) -
Corral Inés,
Mó Otilia,
Yáñez Manuel
Publication year - 2005
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20827
Subject(s) - antibonding molecular orbital , agostic interaction , chemistry , natural bond orbital , crystallography , atomic orbital , lone pair , density functional theory , molecular orbital , molecular orbital diagram , binding energy , metal , computational chemistry , atomic physics , electron , molecule , basis set , physics , linear combination of atomic orbitals , organic chemistry , quantum mechanics
High‐level density functional theory (DFT) calculations on XH 3 Cu + (XB, Al, Ga) complexes show that the attachment of the metal cation to the base takes place through agostic‐type interactions. These interactions that can be viewed as dative bonds from the σ XH bonding orbitals of the base toward low‐lying empty 4 s orbitals of the metal cation, and back‐donations from the lone pairs of the metal into the σ * XHantibonding orbitals of the neutral, are particularly favored when the XH bonds have a high X +δ H −δ polarity. Accordingly, the AlH 3 and GaH 3 Cu + binding energies are very similar, but much larger than that of BH 3 . Depopulation of the σ XH bonding orbital and the concomitant population of the σ * XHantibonding orbital involved in the agostic interaction result in a significant weakening of the corresponding XH linkages, whose bond length increases and whose stretching frequency appears red‐shifted. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006