Centro de Investigação em Química, Departamento de Química da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

Acylcalcogenourea ligands are known to be useful ligands for the potential determination of transition metal (TM) traces by means of normal phase chromatography[1] and have been shown to selectively extract TM in the form of stable neutral metal chelates[2]. However, structural and energetic information about these metal complexes is scarce and conclusions are not straightforward[3]. To fulfil lack of knowledge about geometry and energetics of metal-ligand bonding, density functional (DF) calculations were carried out on complexes schematically shown in Figure 1.

Figure 1: Structural model for [dialkylacylthioureatoM(II)] complex; M=Ni, Cu, Zn; R= -C6H5, -CnH2n+1; R'= -CnH2n+1.

In this communication, we will present geometric and energetic results computed using different basis sets and DF approaches that will be compared with available experimental data[3].

Thanks are due to the Funda��o para a Ci�ncia e Tecnologia (FCT) for financial support to Centro de Investiga��o em Qu�mica. JRBG thanks FCT for the award of a scholarship ref. BPD/22098/99

[1]- M. Schuster, Fresenius Z. Anal. Chem. 1992, 342, 791.

[2]- K. K�nig, M. Schuster, G. Schneeweiss, B. Steinbrech, Fresenius Z. Anal. Chem. 1985, 325, 621.

[3]- E. Guillon, I. D�champs-Olivier, J. -P. Barbier, Polyhedron 1998, 17, 3255; V. R. Richter, L. Breyer, J. Kaiser, Z. anorg. all. Chem. 1980, 461, 67; M. A. V. R. Silva, M. D. M. C. R. Silva, L. C. M. Silva, F. Dietze, E. Hoyer, Thermoch. Acta 2001, 378, 45.