A series of rhodium(I) complexes, including carbene, vinylidene and allenylidene derivatives, with the bifunctional arsine Pri 2AsCH2CH2OMe as ligand

Abstract

A series of rhodium(I) complexes containing the new bifunctional arsine ligand Pri2AsCH2CH2OMe 1 has been prepared. Most of the compounds were obtained from the ethene derivative trans-{RhCl(C2H4)(Pri2AsCH2CH2OMe)2}5 which was obtained from [{RhCl(C2H4)2}2] and 1 in about 80% yield. The ethene can be displaced by CO, CNBut, CH2CHC(O)Me, CH2CHCO2Me, HCCPh. HCCCO2Me, PhCCSiMe3, MeCCMe, PhCCMe, MeCCCCMe or Me3SiCCCCSiMe3(L) to give the four-co-ordinated rhodium(I) complexes trans-[RhCI(L)(Pri2AsCH2CH2OMe)2] almost quantitatively. The reaction of 5 with H2 affords the dihydride (RhH2Cl(Pri2AsCH2CH2OMe)2 which appears to be fluxional in solution. Photolysis of 5 leads to the elimination of CH2CHOMe and the formation of trans-[RhCl(C2H4)(HAsPri2)2] which is also accessible from 3 and HAsPr12. The vinylidene complexes trans-[RhCl(CCHR)(Pri2AsCH2CH2OMe)2] are obtained either on photochemically induced rearrangement of the isomerie alk-1-yne derivatives (R = Ph or CO2Me) or directly from 5 and HCCR (R = Me or But). The reaction of 5 with a large excess of HCCMe or MeCCBut gives the rhodium(I) allenes trans-[RhCl(CH2CCHR)(Pri2AsCH2CH2OMe)2](R = H or But). The allenylidene compounds trans-[RhCl(CCCRR′)(Pri2AsCH2CH2OMe)2](R = Ph, R′= Ph or C6H4Me-O) are obtained from the functionalized vinylidene derivatives trans-[RhCl(CCHCRR′OH)(Pri2AsCH2CH2OMe)2] upon treatment with Al2O3. From trans-[RhCl(CCCRR′)(Pri2AsCH2CH2OMe)2] and NaC5H5 the half-sandwiches [C5H5Rh(CCCRR′)(Pri2AsCH2CH2OMe)] have been prepared. Compound 5 reacts with N2CPh2 and N2C(C6H4Me-p)2 to yield the carbene complexes trans-[RhCl(CR2)(Pri2AsCH2CH2OMe)2] whereas from 5 and N2CRC(O)Ph (R = H or Ph) the diazoalkane rhodium compounds trans-[RhCl(N2CRC(O)Ph)(Pri2AsCH2CH2OMe)2] are obtained.