Synthesis, spectroscopic study and crystal structure of bis (4,6-dimethyl-2-thiopyrimidinium) tetrachlorozincatum(II) monohydrate and its solid state transformations

Abstract

The solid complex [H 2L] 2[ZnCl 4]·H 2O (HL=4,6-dimethyl-2-thiopyrimidine) has been obtained and characterized by IR, 1H and 13C NMR spectroscopies and thermal techniques. The molecular structure of this complex has been established by single crystal X-ray diffraction. Crystals of the compound are orthorhombic, of space group P2 12 12 1 with cell constants a=7.153(2), b=14.624(3), c=20.499(4) A ̊ , Z=6 and D c=1.572 g cm −3. The structure was solved and refined to R=0.049( R w=0.029). The asymmetric complex unit consists of two 4,6-dimethyl-2-thiopyrimidinium cations, a [ZnCl 4] 2− anion and a water molecule. The Zn(II) centres are tetracoordinated by chloride ions giving a tetrahedral arrangement. This asymmetric unit is stacked along the b axis giving rise to a packing of pyrimidine rings and [ZnCl 4] 2− anions which are linked by hydrogen bonds involving chlorine atoms, NH groups and water molecules. The thermal treatment of [H 2L] 2[ZnCl 4]·H 2O leads to two different solid complexes [Zn(HL) 2Cl 2] and [ZnL 2] which have been previously obtained and characterized by us.