Tetranuclear Mixed‐Valence Manganese Complexes with Reduced TCNE or TCNQ as η4 Bridging Ligands

Metal→ligand electron transfer during the coordination of [Mn]-fragments to the common π-acceptors tetracyanoethylene (TCNE) and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) leads to 1 and 2, respectively, the first tetranuclear complexes of this kind. The stable compounds are to be considered as mixed valence complexes, and accordingly have unusual spectroscopic properties (RHor CH3).