METAL-HALOGEN BONDING STUDIES WITH GROUP IV A TRIALKYLMETAL HALIDES

Article abstract of DOI:10.1016/S0022-328X(00)81789-1

Halogen redistribution reactions have been found to take place between benzyl bromide or benzyl iodide and the Group IV A silicon, germanium, tin, and lead containing trialkylmetal chlorides.However, for the reactions of the Si, Ge and Sn compounds, a quaternary ammonium halide catalyst was necessary to enable the equilibria to be established at reasonably rapid rates.The equilibrium constants at 50 deg C have been measured for each of these halogen redistributions.They have been found to increase gradually on going down in Group IV A from silicon to lead, being conside rably less than unity in the case of silicon and somewhat greater than unity in the case of lead for both the R3MCl + BzBr and R3MCl + BzI reactions.The ΔG⁰ values for these equilibria have been calculated, and it is suggested that their differences may be explained in terms of the relative importance of p_?-d_? contributions to the halogen-metal bonding in the various Group IV A trialkylmetal halide systems.