1Pyridine and phosphine functionalised N-heterocyclic carbene complexes of rhodium and iridium

The pyridine functionalised N-heterocyclic carbene complexes [M(kappa(2)-NCDIPP)(COD)](+)A(-), NCDIPP = 3-(2, 6-(Pr2C6H3)-C-i)-1-[2-(3-picolyl)]-imidazol-2-ylideni, A(-) = [(Ar4B)-B-F](-), [{3,5-(CF3)(2)C6H2}(4)B](-), M = Rh, 1b, Ir, 4, have been prepared in two steps by reaction of the [M(COD)Cl](2) with the isolated NCDIPP to [Rh(kappa(1)-NCDIPP)(COD)Cl], 2, and [Ir(kappa(2)-NCDIPP)(COD)Cl], 3, followed by anion exchange with Na(+)A(-). The phosphine functionalised N-heterocyclic carbene complex [Rh(PCH2Cmes)(2)]Br, 6, PCH2Cmes = 1-(diphenylphosphino-methyl)-3-(2,4,6-Me3C6H2)-imidazol-2-ylidene, was prepared by the reaction of the [Rh(COD)Cl](2) with the corresponding N-heterocyclic carbene generated in situ. Monomeric [Rh(PCH2CH2CDIPP)(acac)], 7 was prepared by an analogous reactions from [Rh(COE)(2)(acac)]. In contrast, phosphine functionalised N-heterocyclic carbene complexes of iridium (I) were not easily accessible. However, the reaction of [Ir(COD)(mu-Cl)2(mu-H)]2 with PCH2CH2Cmes gave complex [Ir(COD)(PCH2CH2Cmes.)Br], 8, in which the carbene is coordinated to the metal in an 'abnormal' mode. (c) 2005 Elsevier B.V. All rights reserved.