Bis(imidazole) coordination polymers controlled by oxalate as an auxiliary ligand

In hydrothermal reactions, seven coordination polymers were synthesized. Single-crystal X-ray diffraction analysis revealed that compounds 1-3 possess 2-D networks, whereas compounds 4-6 involve two kinds of oxalate chains. The structure of 7 adopts a 3-D framework structure due to various bridging modes of the oxalate ligand. Magnetic studies have revealed that compounds 1, 2, 4, 5, and 7 exhibit strong antiferromagnetic coupling. Seven coordination polymers {[M(L)(2)(H2O)(2)]center dot(NO)(2)}(n) (M = Co (1), Ni (2), Cd (3)) and [M(L) (ox)](n) (M = Co (4), Ni (5), Zn (6), and Mn (7)) have been synthesized (L = 2,6-bis(imidazol-1-yl) pyridine, ox = oxalate) under hydrothermal conditions. Single-crystal X-ray diffraction analysis has revealed that 1-3 are isomorphous and possess 2-D networks, whereas 4-6 are isomorphous, but involve two kinds of oxalate chains. The structure of 7 is different from those of 4-6 due to various bridging modes of the oxalate ligand. Magnetic studies have revealed that 1, 2, 4, 5, and 7 exhibit strong antiferromagnetic coupling. Among these, 1 exhibits an interesting spin-canting phenomenon.