AB-INITIO STUDY OF THE INSERTION PRODUCT OF THE BORON METHANE REACTION - CH3BH

Ab initio self-consistent-field (SCF), second-order Moller-Plesset (MP 2) and coupled cluster theory including single and double excitations (CCSD) calculations have been used to examine the structure and to hel p in the assignment of the vibrational absorption of the primary inser tion product in the boron-methane reaction. Unlike CH3AlH, CH3BH has n o symmetry; C-s structures are first-order saddle points, the imaginar y frequency being the torsional mode around the B-C bond. The insertio n reaction is exothermic by about 50 kcal/mol. The energetics of sever al CH3BH dissociation or rearrangement channels have been examined. Di ssociation into CH2BH + H or rearrangement to CH2BH2 is energetically favorable. This agree with recent matrix isolation study: CH2BH and CH 2BH2 were the major products after reaction of boron with methane. The title species can be identified experimentally by its strongest calcu lated IR band at 2680 cm(-1) (CCSD/DZP) corresponding to the B-H stret ching mode.