Preparation, thermal analysis and spectral characterization of the 1 : 1 complexes of mercury(II) halides and Pseudohalides with 3,4,5,6-Tetrahydropyrimidine-2-thione. Crystal structures of bis(3,4,5,6-tetrahydropyrimidine-2-thione-S)mercury(II) tetrachloro and tetrabromomercurate(II)

Mercury(II) complexes of the type HgX2(H(4)pymtH) (X Cl- Br I-, SCN-, CN-; H(4)pymtH = 3,4,5, 6-tetrahydropyrimidine-2-thione) have been obtained and structurally characterized by X-ray diffraction, IR, H-1 and C-13 NMR spect roscopy. Single crystal X-ray structure analysis was performed for the chlo ro and bromo complexes, which were found to be isostructural. Their crystal structures consist of [Hg(H(4)pymtH)(2)](2+) complex cations and [HgX4](2- ) complex anions interconnected by Hg . . .X contacts into puckered sheets. The crystal structure of H(4)pymtH has been redetermined to greater accura cy. In solution NMR spectra of complexes, the greatest complexation effects were found on the C-13 chemical shift of the thioketo-carbon atom and on t he H-1 chemical shift of the NH protons.