Syntheses, structures and magnetic properties of the dicyanamide (dca) polynuclear compounds [Mn(ac)(terpy)(μ1,5-dca)]n, [Mn(pdz)2(μ1,5-dca)2]n and [{Mn(dca)(terpy)(MeOH)}2(μ-terephthalate)]

Dicyanamide, (dca, N(CN)(2)(-)) is found to form, as bridging ligand, two compounds of formula [Mn(ac)(terpy)( mu(1,5)-dca)](n) (1) and [Mn(pdz)(2)(mu(1,5)-dca)(2)](n) (2) (ac = acetate; terpy = 2,2':6',2"-terpyridine; pdz = pyridazine). The X-ray diffraction analysis reveals one-dimensional systems, with single dca bridges the compound 1 and double dca bridges the compound 2. The manganese atom in 1 is heptacoordinated, with a MnN5O2 pentagonal bipyramid environment, whereas in 2 the manganese atom is hexacoordinated. The susceptibility measurements of 1 and 2 indicate slight antiferromagnetic coupling. In an attempt to obtain a double chain with terephthalate and dicyanamide bridges, the dinuclear terephthalate bridged compound [{Mn(dca)(terpy)(MeOH)}(2)( mu-terephthalate)] (3) was obtained. The manganese atom in 3 is heptacoordinated, with a MnN4O3 pentagonal bipyramid environment. The susceptibility measurements of 3 indicate also slight antiferromagnetic coupling. (C) 2002 Elsevier Science B.V. All rights reserved.