Carbon–hydrogen cleavage reactions of some trimethyl- and triethyl-phosphine complexes of osmium

Abstract

A new type of metallation reaction is reported in which the complexes Os₃(CO)₁₁(PR₃) or Os₃(CO)₁₀(PR₃)₂(R = Me or Et) on heating in refluxing n-nonane give the derivatives H₂Os₃(R₂PCX)(CO)₉ or H₂Os₃(R₂PCX)(CO)₈(PR₃) where X = H or Me. The ligands R₂PCX bridge the three metal atoms and the nonacarbonyl complexes show rapid exchange between hydrides as well as between R-groups. Isomerism observed for H₂Os₃(Me₂PCH)(CO)₈(PMe₃) is probably due to the PMe₃ occupying different co-ordination positions.