SPECTROSCOPIC STUDIES OF METAL-PYRIMIDINE COMPLEXES. CRYSTAL STRUCTURES OF 4,6-DIMETHYL-2-THIOPYRIMIDINE COMPLEXES WITH Zn(II) AND Cd(II)

Abstract

The structures of Zn(DMTP)₂Cl₂ and Cd(DMTP)₂Cl₂ (DMTP = 4,6-dimethyl-2-thio-pyrimidine), have been obtained by X-ray diffraction methods. Both compounds crystallize in the monoclinic system. Zn(DMTP)₂Cl₂ crystals are of the P2₁ space group, with a = 7.133(2), b = 16.315(8), c = 7.403(2) and β = 92.48(2), V = 860.7 ų, Z = 2, F(000) = 420 and Dm = 1.60 g cm⁻³. Cd(DMTP)₂Cl₂ crystals are of the P2₁/c space group, with a = 13.197(3), b = 8.438(3), c = 15.862(5) and β = 97.30(2), V = 1752.0 ų, Z = 4, F(000) = 912 and Dm = 1.75 g cm⁻³. The structures were refined anisotropically to R = 0.028 and R_w = 0.027 on the basis of 2178 observed reflections (Zn(DMTP)₂Cl₂ complex) and to R = 0.038 R_w = 0.035 on the basis of 2687 observed reflections (Cd(DMTP)₂Cl₂ complex). The structures contain individual Zn(DMTP)₂Cl₂ and Cd(DMTP)₂Cl₂ distorted tetrahedral units in which DMTP molecules are S-bonded as monodentates to the corresponding metal ions; chloride ions are also coordinated. On the basis of the crystallographic data of the above complexes, different coordination patterns of DMTP with several metal ions were established in a set of DMTP complexes (Hg(DMTP)Cl₂,Pd(DMTP)₂Cl₂, Pt(DMPT)₂Cl₂ and Au(DMTP)Cl₃) by a study of their ir, ¹H and ¹³C NMR spectra.