Metal dicyanamide layered coordination polymers with cyanopyridine co-ligands: Synthesis, crystal structures and magnetism

A series of metal dicyanamide (dca) coordination polymers combined with cyanopyridine (cypy) terminal co-ligands, namely, [Co2(dca)4(4-cypy)4]n (1), [Cd(dca)2(4-cypy)2]n (2), [Fe(dca)2(3-cypy)2]n (3) and [Co(dca)2(3-cypy)2]n (4), have been synthesized at the ambient conditions. X-ray single crystal diffraction reveals that complexes 1–4 have similar metal-dca coordination layers in which the octahedral metal centers are connected by μ1,5-dca linkers. Notably, three types of 3-D packing lattices are observed for these layered arrays. The thermal stabilities of such new crystalline materials have been studied by thermogravimetric analysis of mass loss. The magnetic properties of the CoII and FeII complexes have been investigated and discussed in detail. A discrete mononuclear molecule [Cd(dca)2(pyom)2] (5) is also described, in which the chelated ligand O-methyl picolinimidate (pyom) arises from the addition of methanol solvent across the Ctriple bond; length of mdashN bond of 2-cypy.