Zeitschrift für Naturforschung B · 1983 · 25 citations · 0 references
Natural SciencesChemistryInorganic ChemistryOrganic ChemistryOrganometallic ChemistryCarbene ComplexesCoordination ChemistryMetal-ligand BondingMolecular Orbital TheoryTransition Metal ChemistryTransition Metal ComplexesCarbene Complex SynthesisCarbene Coordination ChemistryElectronic Structure AnalysisElectronic Structure Of Carbene ComplexesMolecular Orbital AnalysisParamagnetic ComplexesParamagnetic SpeciesTransition Metal Carbene Complexes
Abstract A new one-step synthesis for bis-carbene complexes cis-M(CO) 4 L 2 (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) 4 L 2 ] + which, for M = Cr, are isolable in the form of their PF 6 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.