1D to 3D Heterobimetallic Complexes Tuned by Cyanide Precursors: Synthesis, Crystal Structures, and Magnetic Properties

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,
bpb2– = 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=0NSiSi+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.