Inorganica Chimica Acta 320 (2001) 178 – 183 www.elsevier.com/locate/ica Note Synthesis, crystal and molecular structure, spectroscopic and electrochemical studies of trichloro-oxo(4,6-dimethylpyrimidine- 2(1H )-thione)(triphenylphosphine oxide)rhenium(V) complex Gianantonio Battistuzzi *, Maria Cannio, Monica Saladini, Raffaele Battistuzzi Department of Chemistry, Uniersity of Modena and Reggio Emilia, ia Campi n 183, 41100 Modena, Italy Received 13 December 2000; accepted 23 April 2001 Abstract Reaction of 4,6-dimethylpyrimidine-2(1H)-thione (Me 2 pymSH) with mer -[ReOCl 3 (Me 2 S)(OPPh 3 )] synthon in 1:1 molar ratio in refluxing acetone, results in the replacement of the Me 2 S ligand to form the mer -[ReOCl 3 (Me 2 pymSH)(OPPh 3 )] species. X-ray diffraction shows that the structure of the title compound consists of monomeric units with a distorted octahedral coordination around the rhenium(V) centre which includes the axial ReO and ReOPPh 3 bonds, and in which three Cl - ions and a S-monodentate neutral Me 2 pymSH ligand act as equatorial ligands. The compound was also characterised using electrochemical measurements and UV – Vis – NIR and IR spectroscopy. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Crystal structures; Electrochemistry; Rhenium complexes; Thiopyrimidine complexes 1. Introduction A large variety of compounds can be obtained from the reaction of 2-thiopyrimidine derivatives with rheni- um(V) synthons. 2-Thiopyrimidines are biologically in- teresting molecules containing both nitrogen and sulfur as donor atoms. These tautomeric heterocyclic molecules can behave as neutral or charged mono- or bidentate ligands yielding metal complexes with a large variety of stochiometries, geometries and coordination modes. In this paper, we report the reaction of 4,6- dimethyl pyrimidine-2(1H )-thione (Me 2 pymSH) with rhenium(V) mer -[ReOCl 3 (Me 2 S)(OPPh 3 )] synthon. This study was carried out to establish the chemical be- haviour of the Me 2 pymSH ligand towards the Re(V) precursor and to determine the donor site(s). The new complex [ReOCl 3 (Me 2 pymSH)(OPPh 3 )] has been char- acterised by means of elemental analysis, electrochemi- cal measurements, UV – Vis and IR spectroscopy and by single-crystal X-ray structural analysis. 2. Experimental 2.1. Materials mer -[ReOCl 3 (Me 2 S)(OPPh 3 )] precursor and 4,6- dimethylpyrimidine-2(1H )-thione were prepared follow- ing the methods outlined in Refs. [1,2]. Acetone (RPA, C. Erba) and acetonitrile (Fluka, over molecular sieves) were used as received. 2.2. Synthesis Solid mer -[ReOCl 3 (Me 2 S)(OPPh 3 )] complex (0.4 mmol) and Me 2 pymSH ligand (0.4 mmol) were sus- pended in 10 cm 3 of acetone. The resulting mixture was stirred magnetically and heated to reflux for 2.5 h. After filtration, the bright-green solution was reduced in volume to about 5 cm 3 and stored overnight in a * Corresponding author. Tel.: +39-059-205-5117; fax: +39-059- 373-543. E-mail address: battistuzzi.gianantonio@unimo.it (G. Battistuzzi). 0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0020-1693(01)00478-9