1D to 3D heterobimetallic complexes tuned by cyanide precursors: synthesis, crystal structures, and magnetic properties

Inorg Chem. 2014 Apr 7;53(7):3494-502. doi: 10.1021/ic4029386. Epub 2014 Mar 21.

Abstract

Five new heterobimetallic complexes, namely, {[Ni(L)][Fe(bpb)(CN)2]}ClO4 (L = 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene, bpb(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate) (1), {[Ni(L)]3[M(CN)6]2}·7H2O (M = Fe (2), Cr (3)), {[Ni(L)]2[Mo(CN)8]}·CH3CN·13H2O (4), and {[Ni(L)]2[W(CN)8]}·16H2O (5), were assembled from the polyaza macrocycle nickel(II) compound and five cyanidometalate precursors containing different numbers of cyanide groups. Single-crystal X-ray diffraction analysis reveals their different structure ranging from a cyanide-bridged cationic polymeric single chain for 1, a two-dimensional network for 2 and 3, and a three-dimensional network for 4 and 5. In addition, a systematic investigation over the magnetic properties of 1-3 indicates the ferromagnetic magnetic coupling between neighboring Fe(III)/Cr(III) and Ni(II) ions through the bridging cyanide group. For complex 1, the magnetic susceptibility has been simulated by the Seiden model using the Hamiltonian H = -J∑i=0(N)SiSi+1, leading to the magnetic coupling constant of J = 3.67 cm(-1). The two-dimensional magnetic complexes exhibit three-dimensional magnetic ordering behavior with a magnetic phase transition temperature of TC = 4.0 K for 2 and TN = 6.0 K for 3, respectively.