Copper(II) and cadmium(II) isothiocyanate coordination polymers with 4,4′-bi-1,2,4-triazole

The coordination polymers catena-poly[[[(4,4'- bi- 1,2,4- triazole- kappa N-1)bis(thiocyanato-kappa N) copper(II)]-mu-4,4'-bi-1,2,4- triazole- kappa N-2(1):N-1'] dihydrate], {[Cu(NCS)(2)(C4H4N6)(2)]center dot 2H(2)O}(n), (I), and poly[tetrakis(mu-4,4'-bi-1,2,4- triazole-kappa N-2(1):N-1') bis(mu-thiocyanato 2 N: S) tetrakis(thiocyanato- kappa N) tricadmium(II)], [Cd-3(NCS)(6)(C4H4N6)(4)](n), (II), exhibit chain and two-dimensional layer structures, respectively. The differentiation of the Lewis acidic nature of Cu-II and Cd-II has an influence on the coordination modes of the triazole and thiocyanate ligands, leading to topologically different polymeric motifs. In (I), copper ions are linked by bitriazole N: N'- bridges into zigzag chains and the tetragonal-pyramidal CuN5 environment is composed of two thiocyanate N atoms and three triazole N atoms [basal Cu-N = 1.9530 (18)-2.0390 (14) angstrom and apical Cu - N = 2.2637 (15) angstrom]. The structure of (II) contains two types of crystallographically unique CdII atoms. One type lies on an inversion center in a distorted CdN6 octahedral environment, with bitriazole ligands in the equatorial plane and terminal isothiocyanate N atoms in the axial positions. The other type lies on a general position and forms centrosymmetric binuclear [Cd-2(mu-NCS-kappa N-2:S)(2)(NCS)(2)] units (tetragonal-pyramidal CdN4S coordination). N: N'- Bridging bitriazole ligands link the Cd centers into a at (4,4)- network.