The Kinetics of Coordinate Bond Formation

A novel method has been developed for determining the rates of very fast gas‐phase bimolecular reactions, which is based on interpretation of the temperature gradients in a flow system similar to that used for the study of the reactions of sodium vapor and alkyl halides. The kinetics of the reactions between boron tri‐fluoride and tri‐, di‐, and monomethylamine to form the corresponding coordinately bonded compounds have been studied. These reactions appear to have negligibly small activation energies, and their rates show a pressure dependence consistent with a mechanism: $$\begin{array}{c}{\mathrm{y+z\rightleftharpoons yz}}^{*}\\ {\mathrm{yz}}^{*}{\mathrm{+m\to yz+m}}^{*}\end{array}$$ in which the long‐lived intermediate yz^* must be stabilized by loss of energy in a collision. The random scatter of individual rate constants is about 20 percent.