Structural analysis and magnetic properties of the 1D and 3D compounds [Mn(dca)2nbipym] (M = Mn, Cu; dca = dicyanamide; bipym = bipyrimidine; n = 1,2).

Compounds [Mn(dca)2bipym] (1), [Cu2(dca)4bipym] (2), and [Mn2(dca)4bipym] (3) have been synthesized and structural (2, 3) and magnetically characterized. Compound 1 is isomorphous with [Mn(dca)2bipy]. Compound 2 crystallizes in the monoclinic P2(1)/c space group, Z = 4, with a = 7.5609(9), b = 11.477(42), and c = 11.792(2) A and beta = 106.565(6) degrees. Compound 3 crystallizes in the monoclinic system, space group P2(1)/n, with a = 7.396(3) A, b = 11.498(7) A, and c = 12.349(9) A and beta = 106.61(5) degrees. While compound 1 is one-dimensional, with the manganese(II) ions bridged by double mu1,5-dicyanamide ligands, the structural arrangement in compounds 2 and 3 is three-dimensional based on ladder-like moieties. These units, whose steps are bipym groups, extend through mu1,5-dca bridges and are connected to another four on the plane perpendicular to the extension of the ladders to form the 3D arrangement. Magnetic susceptibility measurements show antiferromagnetic couplings in all cases, increasing for 1, 3, and 2, respectively.