Ein neuartiger T-förmiger 14-Elektronen-Iridium(I)-Komplex stabilisiert durch eine agostische Ir–H-Wechselwirkung

The reaction of [{Ir(µ-Cl)(coe)2}2] (1, coe = cis-cyclooctene) with the bulky tertiary phosphane P(o-tolyl)3 in dichloromethane at room temperature was investigated. It afforded in good yield the tri-coordinate iridium(I) complex [IrCl{P(o-tolyl)3}2] (2) which was characterized in the solid state by a single-crystal X-ray diffraction study revealing a molecular structure of a rare tri-coordinate complex. The iridium(I) complex is stabilized by an agostic interaction of a hydrogen atom from the methyl group of the bulky phosphane ligand to fill the fourth unsaturated coordination site. The title compound crystallized from dichloromethane/diethyl ether as orange crystals in a mixture of two modifications (monoclinic P21/c, 2a, and orthorhombic Pbca, 2b). The co-existence of the two components as a nearly 1:1 mixture in the crystalline bulk material was supported by solid-state 31P{1H} NMR measurements.