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)<sub>2</sub>]}­ClO<sub>4</sub> (L = 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]­heptadeca-1(17),13,15-triene, bpb<sup>2–</sup> = 1,2-bis­(pyridine-2-carboxamido)­benzenate) (<b>1</b>), {[Ni­(L)]<sub>3</sub>[M­(CN)<sub>6</sub>]<sub>2</sub>}·7H<sub>2</sub>O (M = Fe (<b>2</b>), Cr (<b>3</b>)), {[Ni­(L)]<sub>2</sub>[Mo­(CN)<sub>8</sub>]}·CH<sub>3</sub>CN·13H<sub>2</sub>O (<b>4</b>), and {[Ni­(L)]<sub>2</sub>[W­(CN)<sub>8</sub>]}·16H<sub>2</sub>O (<b>5</b>), 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 <b>1</b>, a two-dimensional network for <b>2</b> and <b>3</b>, and a three-dimensional network for <b>4</b> and <b>5</b>. In addition, a systematic investigation over the magnetic properties of <b>1</b>–<b>3</b> indicates the ferromagnetic magnetic coupling between neighboring Fe­(III)/Cr­(III) and Ni­(II) ions through the bridging cyanide group. For complex <b>1</b>, the magnetic susceptibility has been simulated by the Seiden model using the Hamiltonian <i>H</i> = <i>–J</i>∑<sub><i>i=</i>0</sub><sup><i>N</i></sup><i>S</i><sub><i>i</i></sub><i>S</i><sub><i>i+</i>1</sub>, leading to the magnetic coupling constant of <i>J</i> = 3.67 cm<sup>–1</sup>. The two-dimensional magnetic complexes exhibit three-dimensional magnetic ordering behavior with a magnetic phase transition temperature of <i>T</i><sub>C</sub> = 4.0 K for <b>2</b> and <i>T</i><sub>N</sub> = 6.0 K for <b>3</b>, respectively.