Chloro-, Methyl- und Hydrido-Iridiumkomplexe mit Ph 2CN 2 und anderen Diazoalkan-Liganden

Abstract

Diazoalkane iridium complexes of the general composition trans-[IrCl(N 2CRRt ) ́ (PPh 3) 2] ( 6, 7), trans-[IrCl(N 2 CRR′)-(P iPr 3) 2] ( 9, 10, 14), trans-[IrCH 3(N 2CRR′)(P iPr 3) 2] ( 16, 17) and [IH 2Cl(N 2CRR′)(P iPr 3) 2] ( 19– 21) were prepared from trans-[IrCl(N 2)-(PPh 3) 2], trans-[IrCl(C 8H 14) (P iPr 3) 2], trans-[IrCH 3(C 2H 4)(P iPr 3) 2] ( 15) and [IrH 2Cl(P iPr 3) 2] by ligand displacement or addition reactions. The previously unknown methyl iridium derivative 15 was obtained almost quantitatively from trans-[IrCl(C 2H 4) (P iPr 3) 2] ( 13) and CH 3Li in toluene / ether. The reaction of 15 with PhCHN 2 gave trans-[IrCH 3(N 2)(P iPr 3) 2] ( 18). Neither on thermal nor on photochemical treatment did the diazoalkane complexes react to give the corresponding carbene iridium compounds; instead, in most cases the dinitrogen complexes trans-[IrX(N 2)(PR 3) 2] (X = Cl, CH 3) were obtained. The reaction of ethene, propene or styrene with diphenyldiazomethane led, in presence of [IrCl(C 2H 4) 2] 2 or [IrCl(C 8H 14) 2] 2 as catalyst, to the formation of 1,1-diphenylpropene, 1,1-diphenylbutene and 1,1,3-triphenylpropene, respectively, by C-C coupling. The olefin iridium derivatives, however, are less active catalytically than their rhodium counterparts.