Allene and cyclic allene pentamer complexes of rhodium(I)

Abstract

Reaction of allene with [RhCl(C₂H₄)₂]₂ gave an air-stable yellow complex, RhCl(C₃H₄)₅, in which a cyclic allene pentamer, 1,2,5,6,8-pentamethylenecyclodecane co-ordinates to the metal as a novel quadridentate olefinic ligand. I.r., ¹H n.m.r., and mass spectra of the complex as well as reactions with hydrogen or with (Ph₂PCH₂)₂ were examined to infer the structure. Allene monomer complexes, RhX(PPh₃)₂C₃H₄(X = Cl, Br, I) are prepared by the reaction of allene with RhX(PPh₃)₃.