Abstract: Theoretical calculations on a series of intramolecular α-hydrogen transfer reactions for organometallic tantalum complexes were carried out using the B3LYP method. Optimal structures for reactants, transition states, and products were located. Calculated results indicate that sp2 hybridization is adopted by the central carbon atoms, from which the hydrogen atom shifts, for all 16 transition states. Both electron donating groups and electron withdrawing groups will delocalize the unpaired electron in the pz orbital of the central carbon atomin some way and will thus result in a lower reaction barrier. The reaction barrier of Ta(CH3)4CH(SiMe3)2 had the lowest value.

Key words: Organometallic tantalum complex, α-Hydrogen transfer, Reaction barrier