Synthesis and crystal structure of mononuclear complex of Pd(II) with cyclic thiourea

Abstract

Thiourea derivatives have been actively used in technology of rare and scattered elements, for example, as the specific ligands for isolation of the platinum group metals from the solutions of radioactive wastes [1]. The compounds are interesting in view of investigation of the processes leading to in vivo inactivation of cytostatic drugs in the course of therapy of oncological diseases [2].Herein we report on synthesis and X-ray diffraction analysis of new mononuclear complex of palladium(II) with (4-thioxo-2,3,5,6-tetrahydro-1,3,5-triazin-1-yl) acetic acid (HL). The compound was prepared via Scheme 1.The prepared complex crystallized in monoclinic crystal system with the space group P2 1 /n; the parameters of unit cell were as follows: a = 7.9745 (4) , outer-sphere nitrate anion, and four solvating water molecules. Palladium atom was situated in the distorted square planar surrounding PdNNSS formed by a molecule of 2,2'-bipyridyl with two molecules of (4-thioxo-2,3,5,6-tetrahydro-1,3,5-triazin-1-yl)acetic acid coordinated at the palladium atom through the sulfur atoms (Fig. 1). One of the ligands L contained a deprotonated carboxyl group.Hydrogen bonding was revealed in the complex structure, involving both the inner-sphere molecules of the ligand and the outer-sphere molecules of water and nitrate anions (Fig. 2).Complex [Pd(HL)(L)(bipy)]NO 3 ·4H 2 O. 10 mL of a solution of AgNO 3 (0.204 g, 1.2 mmol) was added to aqueous suspension of Pd(bipy)Cl 2 (0.2 g, 0.6 mmol) acidified to pH 2-3. The formed suspension was homogenized and incubated during 1 h at 60°C. After