CRYSTAL-STRUCTURES OF SILVER(I) NICOTINATE AND SILVER(I) ISONICOTINATE TETRAHYDRATE

Silver(I) nicotinate C5H4NCO2Ag (A) is orthorhombic, P2(1)2(1)2(1) (no. 19) with a = 3.646(l) angstrom, b = 7.734(1) angstrom, c = 20.433(3) angstrom, V = 576.2(3) angstrom3, M(r) = 229.97, Z = 4, D(c) = 2.65 g . cm-3, while silver(I) isonicotinate (C5H4NCO2H) (C5H4NCO2)Ag, 4 H2O (B) is triclinic, P1BAR, with a = 5.856(1) angstrom, b = 8.478(1) angstrom, c = 8.862(1) angstrom, alpha = 108.56(1)degrees, beta = 103.40(2)degrees, gamma = 102.52(2)degrees, V = 385.0(2) angstrom3, M(r) = 425.24, Z = 1, D(c) = 1.84 g . cm-3. The R final indices are 0.056 for A and 0.067 for B. The structure A shows zigzag chains of silver atoms with d(Ag-Ag) = 3.034 (1) angstrom. Each Ag atom is fivefold linked to two oxygen atoms of two different nicotinate ligands (Ag-O = 2.258(7) and 2.272(7) angstrom), to one nitrogen atom of a third ligand (Ag-N = 2.359(7) angstrom) and to two other Ag atoms, having a dissymmetric trigonal bipyramid. The crystal is a three-dimensional network polymer. The complex B shows monomeric units. Each Ag atom, located on a symmetry centre, is linearly bound to two ligands through two pyridinic N atoms (Ag-N = 2.166(3) angstrom). The acidic H atom, located on a centre of symmetry, belongs to two carboxylate O atoms.