Novel routes to alkynyl and vinylidene iridium complexes. The first example of:CCH 2 ligand transfer from a 4d to a 5d transition metal atom

Square-planar vinylidene iridium(I) complexes trans-[IrCl(CCHR)(PPri3)2](R = H, Me, Ph, SiMe3, CO2Me) are prepared from IrH2Cl(PPri3)2 and alk-1-ynes HC2R, via IrH(C2R)Cl(PPri3)2 as intermediates; the parent member of the series with R = H has also been obtained from C5H5Rh(CCH2) PPri3 and IrCl(PPri3)2, i.e. by transfer of a :CCH2 ligand from a 4d to a 5d transition metal atom.