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)(SO4) ⋅ 2H2O (II) and (Ni(TSC)3)Cl2 ⋅ H2O (III), are synthesized and characterized by IR spec� troscopy and Xray diffraction. Monoclinic crystals I and Ia are isostructural; space group P21/n, Z = 2. Crys� tals II are monoclinic, space group P21/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 ensemb les of a specific type. The ensembles, water molecules, and (SO4) 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 squarecellular structure. The laye rs are linked by hydrogen bonds formed by crystalliza� tion water molecules that are located between the layers.