Spectroscopic studies on C2 hydrocarbon fragments. Part 2. Vibrational group frequencies and carbon-13 nuclear magnetic resonance chemical shifts of cluster-bound C2Hn(n= 1–4) fragments

Abstract

Vibrational and ¹³C n.m.r. spectra have been recorded on [Os₃(CO)₁₁(η²-C₂H₄)], [M₃(CO)₉(µ-H)₃(µ₃-CMe)](M = Ru or Os), [Os₃(CO)₁₀(µ₃-η²-HCCH)], [Os₃(CO)₉(µ-H)(µ₃-η²-CCH)], [Ru₂(CO)₃(η⁵C₅H₅)₂(µ-CHMe)], [Ru₂(CO)₃(η⁵-C₅H₅)₂(µ-CMe)]BF₄, and [Os₃(CO)₉(µ-H)(µ-SPrⁿ)L](L = CO, C₂H₄, or C₂H₂). In conjunction with published data, ¹³C n.m.r. shift ranges of C₁, and C₂ cluster-bound hydrocarbon fragments have been identified. Vibrational group frequencies of the C₂H_n(n= 1–4) moieties have also been proposed. On this basis, acetylene is suggested to rearrange to a µ₃-η²-vinylidene on Ni(111) and Fe(110) surfaces.