Observation and Characterization of CH₃CH₂–MH, (CH₂)₂–MH₂, and CH₃–CMH₃ Prepared\nin Reactions of Ethane with Laser-Ablated Group 6 Metal Atoms

Abstract

Reactions of laser-ablated group\n6 metal atoms with ethane have\nbeen carried out, and the products identified in argon matrix IR spectra\non the basis of deuterium shifts, correlation with computation results,\nand previous related works. Mo and W generated the insertion, metallacyclopropane,\nand ethylidyne complexes [CH₃CH₂–MH,\n(CH₂)₂–MH₂, and CH₃CMoH₃], whereas Cr gave only the insertion product.\nThe higher oxidation-state complex from ethane becomes relatively\nmore stable in the heavier metal system, parallel to those from methane.\nThe unobserved ethylidene CH₃CHMH₂ is\nenergetically higher than (CH₂)₂–MH₂, and the energy barrier from CH₃CH₂–MH to the ethylidene is also substantially higher than that\nfor the observed cyclic product. NBO calculations indicate that the\nC–M bonds of the group 6 metal ethylidenes and ethylidynes\nare true double and triple bonds.