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

Seven coordination polymers {[M(L)2(H2O)2]·(NO3)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.