Mechanisms of the Reaction of Unsaturated Organic Halides with Small Gas-PhaseVanadium Clusters

摘要

Small gas-phase vanadium clusters synthesized in a molecular beam sy stem by alaser vaporization technique are reacted with 1-bromopropene, 3-bromopropene, 3-chloropropene, and propene in a fast-flow reactor, and the analysis of the products was made by laser ionization-time-of-flight mass spectrometry. The results observed can be explained in terms of three different mechanisms for the reaction of halopropene: halogen abstraction, halogen substitution followed by molecular hydrogen evaporation, and molecular addition followed by evaporation of molecular hydrogen evaporation can account for the reaction involving propene. The dependence of the relative importance of the three different mechanisms on the vanadium cluster size and the structure of the halopropene is discussed. Transition-metal clusters, Reprints, Cluster reactivity, Pulsed molecular beam studies. (jg)