Novel M(II)-Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 • (H2O)2 (M = Cu, Ni, Co) and HgCl2

A new class of M(II)-Hg(II) (M = Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)(2)HgCl, (4), [Co(2-pyrazinecarboxylate)(2)(HgCl2)(2)].0.61H(2)O (5) and [Ni(2-pyrazinecarboxylate)(2)(HgCl2)(2)].0.77H(2)O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)(2). (H2O)(2) (M = Cu(II), Co(II), Ni(II)), with HgCl2. Compounds 4-6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a = 17.916(5) Angstrom, b = 7.223(2) Angstrom, c = 13.335(4) Angstrom, beta = 128.726(3)degrees, V = 1346.2(6) Angstrom (3), Z = 4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)-Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P (1) over bar, with a = 6.3879(7) Angstrom, b = 6.6626(8) Angstrom, c = 13.2286(15) Angstrom, alpha = 96.339(2)degrees beta = 91.590(2)degrees, gamma = 113.462(2)degrees, V = 511.71(10) Angstrom (3), Z = 1. Compound 6 also crystallized in the triclinic space group P (1) over bar, with alpha = 6.3543(8) Angstrom, b = 6.6194(8) Angstrom, c = 13.2801(16) Angstrom, alpha = 96.449(2)degrees, beta = 92.263(2)degrees, gamma = 113.541(2)degrees, V = 506.67(11) Angstrom (3), Z = 1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II). . .M(II). . . Hg(II) units are connected by Hg,CI, linkages to produce a novel M(II)-Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M-M'-M'-M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)(2). (H2O)(2) (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl2 depending on the metal cation contained within them. (C) 2000 Editions scientifiques et medicales Elsevier SAS. All rights reserved.