Article
Structural isomerism of Ru(II)-carbonyl complexes: synthesis, characterization and their antitrypanosomal activities
Registro en:
BARBOSA, Marília Imaculada Frazão et al. Structural isomerism of Ru(II)-carbonyl complexes: synthesis, characterization and their antitrypanosomal activities. New Journal of Chemistry, v. 41, p. 4468-4477, 2017.
1144-0546
10.1039/C7NJ00125H
Autor
Barbosa, Marília Imaculada Frazão
Correa, Rodrigo de Sousa
Bastos, Tanira Matutino
Pozzi, L. V.
Moreira, Diogo Rodrigo de Magalhães
Ellena, Javier Alcides
Doriguetto, Antonio Carlos
Silveira, Rafael Gomes da
Oliveira, C. R.
Kuznetsov, Aleksey Evgenyevich
Malta, Valeria Rodrigues dos Santos
Soares, Milena Botelho Pereira
Batista, Alzir Azevedo
Resumen
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Processo 2014/10516-7) and Fundação de Amparo a` Pesquisa do Estado da Bahia (FAPESB, grant PET0042/2013 and PRONEX PNX0002/2014). New complexes with the general formula [RuCl(CO)(dppb)(diimine)]PF6, [dppb = 1,4-bis(diphenylphosphino) butane; diimine = 2,20-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.