Against the Norm: Non Irving–Williams Transmetalation in Transition Metal Dimers

We report the synthesis and characterization of three dinuclear 3d3d′ complexes,CuCu([CuII2L(NO3)2] CuII2L(NO3)2]),MnMn([MnII2L(MeOH)2(NO3)2][MnII2L(MeOH)2(NO3)2]), andCuMn([CuIIMnIIL(NO3)2]), that utilize the ligand, H2L(6,6′-dimethoxy-2,2’-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol). The relative stabilities of these complexes were investigated using experimental and computational techniques, revealing a non-Irving-Williams transmetalation, whereby a MnIIion can displace a CuIIion from its binding pocket inCuCuto yield the more stableCuMncomplex. Magnetic characterization of the reported complexes revealed an unexpected ferromagnetic coupling between the two CuIIions ofCuCuwithJ= +63.0 cm–1.