Synthese, Molekül-und Elektronenstruktur eines Radikal-Kationkomplexes [Cr(CO)4(Carben)2]+ / Synthesis, Molecular and Electronic Structure of a Radical Cationic Complex [Cr(CO)4(Carbene)2]+

Abstract

Abstract A new one-step synthesis for bis-carbene complexes cis-M(CO)4L2 (M = Cr, Mo, W) containing cyclic carbene ligands L has been developed. These compounds can be oxidized by ferrocenium salts to paramagnetic cation complexes [M(CO)4L2]+ which, for M = Cr, are isolable in the form of their PF6 salts. The chromium compounds with L= 1,3-dimethyl-4-imidazolin-2-ylidene permit for the first time a structural and spectroscopic comparison of a diamagnetic carbene complex with the corresponding paramagnetic cation; the experimental facts are interpreted by molecular orbital calculations.