Tuning the structures of manganese(III) (Schiff base) complexes: Syntheses, crystal structures and magnetic properties

摘要

Four new coordination complexes, [Mn-III(3-EtO-salpn)(H2O)(CH3OH)]ClO4 (1), [Mn-III(3-EtO-salpn)(H2O)(2)]center dot H2O center dot ClO4 (2), {[Mn-III(3-EtO-salpn)(H2O)][Fe-III(qcq)(CN)(3)]}center dot 3H(2)O center dot CH3OH center dot CH3CN (3) and {[Mn-III(3-EtO-salpn)(H2O)][Fe-III(qcq)(CN)(3)]}center dot 3H(2)O center dot CH3CN (4) (salpn = N,N'-1,2-propylenebis(salicylideneiminato)dianion; qcq = 8-(2-quinoline-2-carboxamido)quinoline anion) were synthesized and characterized both structurally and magnetically. The results reveal that complexes 1 and 2 are mononuclear Mn-III structures crystallizing in different space groups, while 3 and 4 are dinuclear Mn-III-NC-Fe-III entities with different local arrangement of the subunits. Interestingly, the structures of these complexes are highly dependent on the reaction conditions though the reaction precursors are the same. Magnetic investigation indicates that intra- and/or intermolecular antiferromagnetic interactions are presented in complexes 1-4. Notably, these weak antiferromagnetic interactions could be overcome by high direct-current magnetic field, showing the field induced metamagnetic behaviors. (C) 2014 Elsevier B.V. All rights reserved.