Acta Crystallographica Section C

Crystal Structure Communications

Volume 64, Part 3 (March 2008)

metal-organic compounds

 

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

E. V. Govor, A. B. Lysenko, K. V. Domasevitch, E. B. Rusanov and A. N. Chernega

Abstract: The coordination polymers catena-poly[[[(4,4'-bi-1,2,4-triazole-N¹)bis(thiocyanato-N)copper(II)]--4,4'-bi-1,2,4-triazole-²N¹:N^1'] dihydrate], {[Cu(NCS)₂(C₄H₄N₆)₂]·2H₂O}_n, (I), and poly[tetrakis(-4,4'-bi-1,2,4-triazole-²N¹:N^1')bis(-thiocyanato-²N:S)tetrakis(thiocyanato-N)tricadmium(II)], [Cd₃(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) Å and apical Cu-N = 2.2637 (15) Å]. The structure of (II) contains two types of crystallographically unique Cd^II 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 [Cd₂(-NCS-²N:S)₂(NCS)₂] units (tetragonal-pyramidal CdN₄S coordination). N:N'-Bridging bitriazole ligands link the Cd centers into a flat (4,4)-network.

Formula: [Cu(NCS)₂(C₄H₄N₆)₂]·2H₂O and [Cd₃(NCS)₆(C₄H₄N₆)₄]

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