Desenvolvimento e parametrização de potenciais intermoleculares para compostos quadráticos-planos de platina(II) em solução aquosa

Abstract

In this work a general procedure was developed to obtain the Lennard-Jones parameters (ε e σ) for platinum atom on the cisplatin molecule. These parameters can be applied in computational simulation studies of cisplatin in aqueous solution. A computationalcode was developed using a variation of the Newton-Raphson method, for the fitting of the intermolecular potential using reference data from high level quantum mechanical calculations. The transferability of the parameters was checked for some cisplatin analogues. Monte Carlo simulations were carried out in order to verify the applicability of these parameters to study the interactions between cisplatin and water. The electronic spectrum calculation, of cisplatin was also calculated in gas phase and aqueos solution and the results compared with experimental data. The preliminary results show a qualitative agreement with the UV-visible experimental spectrum. During the parameterization step some strong interactions involving Pt...H were found, due the limitation of the calculations, were carried out in gas phase and with rigid geometries. In spite of this, a study involving some charge models was performed in order to investigate this interaction. The results from this analysis showed a charge transference between the metallic center and the hydrogen atom whose nature depends on the charge model used.