Structural isomerism of Ru(II)-carbonyl complexes: synthesis, characterization and their antitrypanosomal activities
| Autor: | Rodrigo S. Corrêa, Javier Ellena, Diogo Rodrigo Magalhães Moreira, Clayton Rodrigues de Oliveira, Antonio C. Doriguetto, Marília I.F. Barbosa, Rafael G. Silveira, Lucas V. Pozzi, Valéria R. S. Malta, Alzir A. Batista, Aleksey E. Kuznetsov, Tanira Matutino Bastos, Milena Botelho Pereira Soares |
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| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Chemistry Stereochemistry Ligand chemistry.chemical_element General Chemistry Carbon-13 NMR 010402 general chemistry 01 natural sciences Catalysis 0104 chemical sciences Ruthenium Octahedron Materials Chemistry Structural isomer CRISTALOGRAFIA Cyclic voltammetry HOMO/LUMO Diimine |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | New complexes with the general formula [RuCl(CO)(dppb)(diimine)]PF6, [dppb = 1,4-bis(diphenylphosphino)butane; diimine = 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen)], were prepared. Thus, the complexes ct-[RuCl(CO)(dppb)(bipy)]PF6 (1), ct-[RuCl(CO)(dppb)(phen)]PF6 (2), tc-[RuCl(CO)(dppb)(bipy)]PF6 (3), tc-[RuCl(CO)(dppb)(phen)]PF6 (4), cc-[RuCl(CO)(dppb)(bipy)]PF6 (5) and cc-[RuCl(CO)(dppb)(phen)]PF6 (6) were obtained and characterized. In this case, the first letter in the prefixes indicates the position of CO with respect to the chlorido ligand and the second one is related to the phosphorus atoms. The compositions of the complexes were confirmed by analytical techniques and an octahedral environment around the ruthenium was confirmed by single-crystal X-ray diffraction of the complexes ct-[RuCl(CO)(dppb)(bipy)]PF6 and cc-[RuCl(CO)(dppb)(phen)]PF6. The oxidation potentials of the complexes were determined by cyclic voltammetry and it was found that they vary according to the CO position in the complexes. In order to obtain information on the stability of the ct, tc and cc-[RuCl(CO)(dppb)(bipy)]PF6 (1), (3) and (5) isomers, computational studies were carried out, and they showed large differences between the HOMO/LUMO energies. As monitored by 13C NMR, the stability of the complexes with respect to CO displacement, for at least 72 h, in DMSO-d6 solution, is independent of the CO position in the complexes. Pharmacological evaluation of the complexes against the Trypanosoma cruzi parasite revealed the structure–activity relationships, showing that the presence and position of the CO ligand in the complexes are relevant for the antiparasitic activity of the compounds. The most active compound, the tc-[RuCl(CO)(dppb)(bipy)]PF6 isomer, presented potent antiparasitic activity, which was achieved by causing oxidative stress followed by parasite cell death through necrosis. Thus, the findings presented here demonstrate that the use of a carbonyl ligand provides stability and pharmacological properties to ruthenium/diphosphine/diimine complexes. |
| Databáze: | OpenAIRE |
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