IMIDAZOLATE BRIDGED POLYNUCLEAR RHODIUM(I) COMPLEXES. X-RAY STRUCTURE OF 4

Article abstract of DOI:10.1016/S0022-328X(00)89040-3

The synthesis and properties of polynuclear complexes of general formulae x, x and x (M=Rh, Ir; RIm=imidazolate, 2-methylimidazolate, 2-benzylbenzimidazolate; L=PPh3 or P(OPh)3) are reported.The crystal structure of the novel complex 4 (2-MeIm=2-methylimidazolate) has been determined by X-ray methods.The crystals are orthorhombic, space group P2₁2₁2₁, with Z=4 in a unit cell of dimensions a 19.427(12), b 13.419(8), c 12.346(9) Angstroem.The structure has been solved by combined Patterson and direct methods and refined by full-matrix least-squares to R=0.043 for 937 independent observed reflections.It consists of discrete tetrameric complexes in which each Rh atom is in a nearly cis square planar arrangement, bonded to two carbon atoms of carbonyl groups and to two nitrogen atoms of two 2-methylimidazolate ligands, each of which, acting as an exo-bidentate ligand, bridging two metal atoms, so that the four bridging 2-MeIm ligands and the four Rh atoms form a multiatomic ring.