Theoretical Study For The Interaction Between The Pt(â…¡) Complexes With The Active Sites Of DNA And Amino Acid With The Divalent Metal Cations

The influence of a series of square planar Pt(II) adducts on the Watson-Crick base pair AT and GC was investigated by the DFT/B3LYP method and HF level of theory using the standard 6-31+G(d) basis set, and the effective core potential (ECP) was used for the metal cations. The result showed that the AT and GC base pair was mainly influenced by the electrostatic effect. The platinated purine and pyrimidine base pair was moderately strengthened. Whereas the interaction (base-pairing energy) between the purine and pyrimidine base was slightly influenced as compared to the isolated one. Further calculations on the Pd(II) and Ni(II) analogs showed the similar trends. The thermodynamics characteristic of the novel traws-platinum (with one of the normal ammine ligand replaced by the planar nitrogen ligand-thiazole) antitumor drug binding to guanine and adenine bases was considered using the density functional theory B3LYP method, the 6-31G(d) base set was employed for the light atoms, and for the metal cations, the effective core potential (ECP) was used. The interaction energy terms of the monofunctional adducts provided an efficient way for the studying of the complexes, and the preference of guanine base over adenine for the metal moiety was shown by analysis of the interaction energies. The favor of guanine base was additionally identified by the calculation of Pd(II) and Ni(II) analogs, and moreover, by the analysis of the bifunctional adducts. On the other hand, the mechanism properties of novel /raws-platinum with one of the normal ammine ligand replaced by the planar nitrogen ligand quinoline antitumor drug were explored using the B3LYP method in the present paper, the 6-3G(d) base set was used for the light atoms and the effective core potential (ECP) was employed for the platinum. The interaction energy and stabilization energy terms indicated a preference for the N-containing ligands. Environment effect has been systematically* investigated using the PCM model with a series of dielectric constant e (4.9, 9.0 and 78.4) at the same level of theory and compared with the gas phase results, similar trends were observed. The influence of a series of square planar Pt(II) and Pd(II) and Ni(II) metal adducts on the protonation ability of adenine has been investigated using ab initio calculation. The 6-31 G(d) basis set was used for the first-and second-row elements and the diffuse function was added to chlorine for an adequate description of its high polarizable ability, for the metal cations, the LANL2DZ basis set was imposed. The results suggested that the protonation ability was mainly influenced by the long-range electrostatic effect in gas phase, no strong influence of different metals had been detected for the system studied; the solvent effect calculations proposed that the polar solvent efficiently compensated for the long-range electrostatic effect. The NBO population analysis indicated that the protonation ability was mainly affected by the changes of electron density on the selected atoms. The interaction between glycine and a series of divalent metal cations was theoretically studied using Density Functional Theory (DFT) with the 6-31+G(d), 6-3 ll+G(d) base set. The results showed that the bidentated complexes were more stable compared with the monodentated one. The most stable one was found for complexes with the metal cations chelated between two oxygen of the carboxylate. The relative interaction abilities for the different cations were: Cu2+>Ni2+>Zn2+>Mn2+>Mg2+>Ca2+, the interaction between glycine anc the subgroup metal cations was more favored, which was in consisted with previ* us study. The changes of stabilization energy were in good accord with the interaction energy terms. The stabilization energy was mainly influenced by the interaction energy with deformation energy playing a second role.