The thermochemistry of o- and p-tolyldichloroboranes and the boron-to-carbon bond strength

Abstract

The standard enthalpies of formation of o- and p-tolyldichloroboranes have been determined from a thermochemical study of their oxidative hydrolyses in an isoperibol reaction calorimeter. Combination of these results with enthalpies of vaporization give the standard enthalpies of formation of these compounds in the gas phase (–253·8 ± 2·7 and –294·1 ± 3·8 kJ mol^–1 respectively) from which the boron–carbon bond energy is derived. Structural implications of these results are discussed.