Condensed phase properties of platinum group metal complexes from computational simulations

[摘要] ENGLISH ABSTRACT: A variety of computational techniques are used to calculate structural, thermodynamic and transportproperties of two specific Platinum Group Metal (PGM) complex systems. The first system consists ofa PGM complex ([PdCl4]2-; [PtCl4]2-; [PtCl6]2- or [RhCl6]3-) with sodium counter-ions in a watersolution at 30ºC and at a concentration of 0.106 mol/dm3. The second system under consideration isthat of a PGM complex ([PdCl4]2-; [PtCl4]2-; [PtCl6]2- or [RhCl6]3-) with sodium counter-ions in a watersolution in the presence of four poly (ethylene oxide) (PEO) chains at 30ºC and at a concentration of0.013 mol/dm3. A conformational study of the two types of dihedral angles in a PEO chain (-C-O-C-Cand-O-C-C-O-) is performed and the extreme flexibility of the polymer is confirmed. Dihedral angledistributions of the two dihedral angles are calculated and explained in terms of the potential energysurface obtained from the conformational study. The solvation geometries of the PGM complexes areconfirmed and the results are contrasted with those in the system where the polymer (PEO) is present.It is concluded that the effect of the polymer on the structure and degree of solvation is negligible. Thefree energy of solvation values of the PGM complexes are calculated to provide insight into theirstructural characteristics such as solvation shell volume and geometry. The structural andthermodynamic properties of the PGM complexes in solution are also used to explain the trendsobserved in the calculated diffusion coefficients. Comments are made on the accuracy of the calculateddiffusion coefficients as well as the legitimacy of the mechanistic speculations which results fromthem. Suggestions regarding possible future improvements to the computational methods are made.

[发布机构] Stellenbosch University