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Coordination Polymers of Dicyanamide and Methylpyrazine:  Syntheses, Structures, and Magnetic Properties

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journal contribution
posted on 05.05.2004, 00:00 authored by Anna M. Kutasi, Alexander R. Harris, Stuart R. Batten, Boujemaa Moubaraki, Keith S. Murray
The crystal structures of M(dca)2(Mepyz)2·H2O, M = Co (1), Ni (2), dca = dicyanamide, N(CN)2-, and Mepyz = methylpyrazine; [Mn(dca)2(Mepyz)2][Mn(dca)2(Mepyz)]2·2MeCN (3); and Mn2(dca)3(NO3)(Mepyz)2 (4) are reported. Compounds 1 and 2 are isomorphous and consist of two-dimensional (2D) (4,4) sheets, with bridging μ1,5-dca ligands and trans-disposed monodentate Mepyz ligands. Compounds 3 and 4 were obtained as an intimate mixture from the same reaction mixture. Compound 3 contains both one-dimensional (1D) chains, in which Mn atoms are bridged by double μ1,5-dca bridges and the Mepyz ligands are trans and monodentate, and 2D (4,4) sheets, in which similar 1D chains are connected by bridging Mepyz ligands. The structure of 4 contains two interpenetrating 4,6-connected three-dimensional networks, with bridging μ1,5-dca anions, bridging Mepyz ligands, and chelating NO3- anions. Only very weak coupling and no long-range magnetic ordering intrinsic to these materials were observed for 1 or 2, although traces of the ferromagnets α-Co(dca)2 and α-Ni(dca)2 were observable in very small applied fields, with ordering temperatures at 9 and 21 K, respectively.

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