Reactions of co-ordinated boron compounds in the gas phase. Part II. Triethylamine as scavanger of borine

Abstract

The thermal decomposition of borine carbonyl has been carried out in the presence of triethylamine, a very suitable scavenger of borine (BH₃). The bimolecular reaction does not compete with the unimolecular rupture of the B–C bond. At 0°, the pressure-dependence of the unimolecular rupture has been studied, k_unimol being equal to ½k_∞ at 90 torr when propane is used as third body. From the value of k_∞, and assuming a value of 10^13·4 sec.^–1 for the pre-exponential factor A, the activation energy is E_a= 21·4 ± 1·2 kcal./mole. The dissociation energy of the B–B bond in diborane is then calculated to be D(B–B)= 33·5 ± 2·4 kcal./mole, if the recombination reaction of borine and carbon monoxide has E_a= 0.