Bi- and poly-metallic cyanide-bridged complexes of the redox-active cyanomanganese nitrosyl unit [Mn(CN)(PR3)(NO)-(η-C5H4Me)]

Cationic nitrile complexes and neutral halide and cyanide complexes, with the general formula [(MnLL2)-L-1(NO)-(eta-C5H4Me)](z), undergo one-electron oxidation at a Pt electrode in CH2Cl2. Linear plots of oxidation potential, Edegrees', vs. nu(NO) or the Lever parameters, E-L, for L-1 and L-2, allow Edegrees' to be estimated for unknown analogues. In the presence of TlPF6, [MnIL'(NO)(eta-C5H4Me)] reacts with [Mn(CN)L(NO)(eta-C5H4Me)] to give [(eta(5)-C5H4Me)(ON)LMn(mu-CN)MnL'(NO)(eta(5)-C5H4Me)][PF6] which undergoes two reversible one-electron oxidations;. E, the difference between the potentials for the two processes, differs significantly for stable cyanide-bridged linkage isomers. Novel pentametallic complexes such as [Mn{(mu-NC)Mn(CNBut)(NO)(eta(5)-C5H4Me)}(4)(OEt2)][PF6](2) and [Mn{(mu-NC)Mn(CNXyl)(NO)(eta(5)-C5H4Me)}(4)(NO3-O,O')][PF6], containing a trigonal bipyramidal and a distorted octahedral Mn(II) centre, respectively, result either from slow decomposition of the binuclear cyanide-bridged species or from the reaction of anhydrous MnI2 with four equivalents of [Mn(CN)L(NO)(eta(5)-C5H4Me)] in the presence of TlPF6.