GAS-PHASE THERMOCHEMISTRY OF VH AND CRH

The homolytic bond dissociation energies of the transition-metal neutral hydrides, D(o)(M-H) (M=V, Cr), are experimentally determined by using guided ion beam tandem mass spectrometry to measure the kinetic energy dependence of the endothermic hydride abstraction reactions of M+ with mono-, di-, and trimethylamine. From the thresholds of these reactions, we derive the 0 K values of D(o)(V-H)=2.13+/-0.07 eV and D(o)(Cr-H)=1.93+/-0.07 eV. This thermochemistry is compared with theoretical values and previous experimental results.