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

Reactions of laser-ablated group 6 metal atoms with ethane have been carried out, and the products identified in argon matrix IR spectra on the basis of deuterium shifts, correlation with computation results, and previous related works. Mo and W generated the insertion, metal-larydopropane, and ethylidyne complexes [CH3CH2-MH, (CH2)(2)-MH2, and CH3C MoH3], whereas Cr gave only the insertion product. The higher oxidation-state complex from ethane becomes relatively more stable in the heavier metal system, parallel to those from methane. The unobserved ethylidene CH3CH=MH2 is energetically higher than (CH2)(2)-MH2, and the energy barrier from CH3CH2-MH to the ethylidene is also substantially higher than that for the observed cyclic product. NBO calculations indicate that the C-M bonds of the group 6 metal ethylidenes and ethylidynes are true double and triple bonds.