An investigation of the properties and thermochemistry of complexes of pyridine with triphenyl-boron, -aluminium, -gallium, and -indium, and diphenylgallium chloride

Abstract

Pyridine reacts with crystalline Ph₃B, Ph₃Al, Ph₃Ga, Ph₃ln, and Ph₂GaCl to give white 1:1 complexes which are monomeric in benzene solution. The melting points and heats of formation of the solid adducts from liquid pyridine and crystalline acceptors are: Ph₃B,py 240°, 17·9 kcal. mole^–1; Ph₃Al,py 168°, 22·3 kcal. mole^–1; Ph₃Ga,py 167°, 19·5 kcal. mole^–1; Ph₃ln,py 130°, 13·9 kcal. mole^–1; Ph₂GaCl,py 18·0 kcal. mole^–1. The problems attending the estimation of gas-phase heats of formation and the calculation of reorganization energies are discussed and the results compared with those available on other Group III acceptors.