Cyano-bridged Mn(III)3M(III) (M(III) = Fe, Cr) complexes: synthesis, structure, and magnetic properties

Two cyano-bridged tetranuclear complexes composed of Mn(III) salen (salen = N,N'-ethylene bis(salicylideneiminate)) and hexacyanometalate(III) (M = Fe, Cr) in a stoichiometry of 3:1 have been selectively synthesized using {NH2(n-C12H25)2}3M(III)(CN)6] (M(III) = Fe, Cr) starting materials: {Mn(salen)(EtOH)}3{M(CN)6}] (M = Fe, 1; Cr, 2). Compounds 1 and 2 are isostructural with a T-shaped structure, in which M(CN)6]3- assumes a meridional-tridentate building block to bind three Mn(salen)(EtOH)]+ units. The strong frequency dependence and observation of hysteresis on the field dependence of the magnetization indicate that 1 is a single-molecule magnet.