INTERMOLECULAR AND INTRAMOLECULAR OXIDATIVE COUPLING OF MANGANESE CARBENE ANIONS IN THE PRESENCE OF COPPER-SALTS - SYNTHESIS OF (MU-BIS(CARBENE))DIMANGANESE COMPLEXES

The carbene anions resulting from in situ deprotonation of the ''Fisch er-type'' carbene complexes Cp'(CO)(2)Mn=C(OEt)CH(2)R (R = H, Me) and Cp'(CO)(2)-Mn=CN(Ph)CH(Ph)CH2 undergo oxidative coupling in the presen ce; of copper salts to produce the corresponding neutral (mu-bis(carbe ne))dimanganese complexes {Cp'(CO)(2)Mn}(2){mu-=C(OEt)CH(R)CH(R)(OEt)C =} and (CO)(2)Mn}(2){mu-=CN(Ph)CH(Ph)CHCHCH(Ph)-N(Ph)C=}. Double depro tonation of {Cp'(CO)(2)Mn}(2){mu-=C(OEt)CH2CH2(OEt)C=} gives a dianion ic species that undergoes an intramolecular oxidative coupling in the presence of copper(II) to give the (mu-vinylbis(carbene))-dimanganese complex (E)-{Cp'(CO)(2)Mn}(2){mu-=C(OEt)-CH=CH(OEt)C=}. Controlled red uction, of the Latter gives a Mn-0/Mn-1 mixed-valence complex which ha s been characterized by EPR.