Low dimensional cyano-bridged heterobimetallic M-FeIII (M = NiII, CuII) complexes constructed from Mer-[FeIII(qcq)(CN)3]- building blocks: syntheses, structures and magnetic properties

Four cyano-bridged heterobimetallic trinuclear complexes, {[Ni(en)(2)][Fe(qcq)(CN)(3)](2)}center dot 2H(2)O (1) [en = 1,2-ethylenediamine; qcq(-) = 8-(2-quinoline-2-carboxamido)quinoline anion], {[Ni(teta)][Fe(qcq)(CN)(3)](2)}center dot 2DMF center dot 2H(2)O (2) (teta = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, DMF = N,N-dimethylformamide), {[CuL1][Fe(qcq)(CN)(3)](2)}center dot 0.61H(2)O (3) (L-1 = 3,10-dibutyl-1,3,5,8,10,12-hexaazacyclotetradecane) and {[CuL2][Fe(qcq)(CN)(3)](2)}center dot 4.75H(2)O (4) (L-2 = 3,10-dipropyl-1,3,5,8,10,12-hexaazacyclotetradecane) have been synthesized and characterized both structurally and magnetically. The structural analyses reveal that 1-4 are all trinuclear centrosymmetric clusters, and the intercluster pi-pi interactions and hydrogen bonds extend 1-4 into high dimensional supermolecular networks. Magnetic investigation indicates that 1 and 2 exhibit intracluster ferromagnetic couplings accompanied by significant magnetic anisotropy. In contrast, 3 and 4 show unusual intracluster antiferromagnetic couplings, which could even be decoupled by a strong applied field.