Bimetallic Materials Derived from Manganese(III) Schiff Base Complexes and Pentacyanidonitrosylferrate(II) Precursor: Structures and Magnetic Properties

Three complexes, [Mn(salphen)(H2O)]2[Fe(CN)5(NO)]·2CH3OH (1) (salphen = N,N′-phenylenebis(salicylideneiminato) dianion), [Mn(naphtmen)(CH3OH)]2[Fe(CN)5(NO)] (2) (naphtmen = N,N′-(1,1,2,2-tetramethylethylene)bis(naphthylideneiminato) dianion), and {[Mn(salen)]2[Fe(CN)5(NO)]·H2O}n (3) (salen = N,N′-ethylene-bis(salicylideneiminato) dianion), were synthesized and structurally characterized by X-ray single-crystal diffraction. The structural analyses show that complexes 1 and 2 consist of the discrete linear trinuclear [Mn(SB)]2[Fe(CN)5(NO)] units (SB = salphen for 1, naphtmen for 2); in complex 3, the nitroprusside anion coordinates to the axial sites of the four [Mn(salen)]+ entities through its four cyano nitrogen atoms, providing a two-dimensional network. The magnetic analysis indicates that the nitroprusside bridging ligand propagates a very weak antiferromagnetic exchange and single-ion anisotropy (D) plays an important role in the overall magnetic properties. Different from complexes 2 and 3, complex 1 shows a typical spin-flop transition with a critical field of 20 kOe.