Intramolecular electron transfer in cyanide bridged adducts comprising RuII/RuIII tetracarboxylate and [MnI(CO)(CN)(tBuNC)4] units

Reaction of mixed valence ruthenium tetracarboxylates [Ru2II,III(R1COO)2(R2COO)2Cl] (R1 = Me, R2 = 2,4,6-iPr-Ph or R1 = R2 = tBu) with two equivalents of the octahedral manganese complex [MnI(CO)(CN)(tBuNC)4] leads to the formation of cyanide bridged heteronuclear coordination compounds of the general formula {[Ru2II,III(R1COO)2(R2COO)2][MnI(CO)(CN)(tBuNC)4]2}Cl. In solution an intramolecular electron transfer from manganese towards the multiply bonded Ru2 core occurs that is verified by EPR and IR spectroscopy, magnetic measurements and DFT calculations. Nevertheless, disproportionation of an initially formed {MnI–Ru2II,III–MnI}+ adduct into {MnII–Ru2II,III–MnI}2+ and {MnI–Ru2II,II–MnI} species cannot be completely ruled out.