Syntheses, structures and magnetic properties of two one-dimensional coordination polymers of cobalt(II) and nickel(II) dicyanamide containing a tridentate N-donor Schiff base

Two neutral one-dimensional coordination polymers of the type [M(L)(μ_1,5-dca)(dca)]_n [M = Co (1), Ni (2); L = (N,N-diethyl,N′-(pyridin-2-yl)benzylidene)ethane-1,2-diamine; dca = dicyanamide] are isolated through single-pot reactions of a 1:1:2 M ratio of M(OAc)₂·4H₂O, L and Na(dca) in MeOH solution at room temperature and characterized on the basis of microanalyses, spectroscopic, thermal and other physicochemical results. X-ray structural study reveals that each metal(II) center in both compounds adopts a distorted octahedral geometry with an MN₆ chromophore coordinated by three N atoms of the tridentate Schiff base (L) and three nitrile N atoms of one terminal and two single μ_1,5 bridged dca units in a meridional alignment; each μ_1,5 bridged dca unit connects other neighboring metal centers in a non-ending fashion affording a 1D chain. Variable-temperature magnetic susceptibility measurements of 1 and 2 show weak antiferromagnetic interactions among the metal centers through μ_1,5 dca bridges.