Synthesis and crystal structure of thiosemicarbazide complexes of nickel(II) and copper(II)

Abstract

Thiosemicarbazide complexes of nickel(II) [Ni(TSC) 2 ](HSal) 2 (I) and copper (II) [Cu(TSC) 2 ](HSal) 2 (Ia) (TSC is thiosemicarbazide and HSal is a salycilate anion), as well as complexes [Ni(TSC) 2 ](SO 4 ) ⋅ 2H 2 O (II) and [Ni(TSC) 3 ]Cl 2 ⋅ H 2 O (III), are synthesized and characterized by IR spec troscopy and X ray diffraction. Monoclinic crystals I and Ia are isostructural; space group P2 1 /n, Z = 2. Crys tals II are monoclinic, space group P2 1 /m, Z = 2. Crystals III are orthorhombic, space group Pbca, Z = 8. In I and Ia, two planar salycilate anions sandwich a planar centrosymmetric [Ni(TSC) 2 ] 2+ cation to form a supermolecule. The cation and anions are additionally bound by hydrogen bonds. Other hydrogen bonds connect supermolecules into planar layers. In structure II, centrosymmetric [Ni(TSC) 2 ] 2+ cations are con nected by π stacking interactions into supramolecular ensembles of a specific type. The ensembles, water molecules, and (SO 4 ) 2-anions are bound in the crystal via hydrogen bonds. In the [Ni(TSC) 3 ] 2+ cation of structure III, ligands coordinate the Ni atom by the bidentate chelate pattern with the formation of five membered metallocycles. These metallocycles have an envelope conformation unlike those in I and II, which are planar. In III (unlike in analogous complexes), a meridional isomer of the coordination octahedron of the Ni atom is formed. Together with Cl1 -and Cl2 -anions, cations form supermolecules, which are packed into planar layers with a square cellular structure. The layers are linked by hydrogen bonds formed by crystalliza tion water molecules that are located between the layers.

Synthesis and crystal structure of a copper(II) 5-sulfosalicylate complex with thiosemicarbazide

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508Our results of studying Ni(II) and Cu(II) bis(thio semicarbazide) complexes with different anions [1,2] and available literature data on the structures of anal ogous compounds [3][4][5][6][7][8][9] have revealed a considerable variety of the structures of these compounds in spite of a rather stereotypic structure of the complex cation.The [М(TSC) 2 ] 2+ cation (M = Ni(II), Cu(II)) in these compounds has a square of near square shape owing to the bidentate chelating (N,S) coordination of the TSC ligand. Sometimes, the metal coordination sphere is completed to tetragonal pyramidal or tetra gonal bipyramidal by axial atoms at elongated dis tances.

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