VINYLIDENE TRANSITION-METAL COMPLEXES .31. STANNYLALKYNES AS STARTING MATERIALS FOR THE SYNTHESIS OF VINYLIDENE RHODIUM COMPLEXES AND OF HETERODIMETALLIC COMPOUNDS CONTAINING A RH-HG OR RH-SN BOND

Reaction of [RhCl(PiPr3)2]n (1) with stannylalkynes RC=CSnPh3 [R = H, Me, Ph, CH2OH, CH2OMe, CMe2OH, CH(Me)OH, CH(Ph)OH, SiMe3, SnPh3] gives the vinylidenerhodium(I) complexes trans-[RhCl(=C=C(SnPh3)R)(PiPr3)2] (2a-j) in good to excellent yields. These compounds react with protic acids to give trans-[RhCl(=C=CHR)(PiPr3)2] and, for R = CH(Ph)OH, to give the allenylidene complex trans-[RhCl(=C=C=CHPh)-(PiPr3)2] (5). On treatment of 2b-j with PhHgCl, the heterodimetallic compounds [Rh(C=CR)(HgPh)Cl(PiPr3)2] (6a-i) are formed. The bis(alkynyl)rhodium(III) complexes [RhH(C=CSiMe3) (C=CSnPh3)(py)(PiPr3)2] (9) and [Rh(C=CSiMe3)(C=CCH2OMe)(SnPh3)(PiPr3)2] (10) are prepared from trans-[Rh(C=CSiMe3)(L)(PiPr3)2] (7, 8, L=py, C2H4) and HC=CSnPH3 or Ph3SnC=CCH2OMe, respectively. The crystal and molecular structures of trans-[RhCl(=C=C(SnPh3)CH2OMe)(PiPr3)2] (2e) and [Rh(C=CCH2OMe)(HgPh)Cl(PiPr3)2] (6d) have been determined.