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Updated: Mar 10, 2026
Author Spotlight: Characterizing DNA G-Quadruplex by Bis-3-Chloropiperidine Based Chemical Mapping
Published on: May 12, 2023
Chloride complexes [RuII(N-N)(tpy)Cl]+ coordinated to diimine ligand: Kinetic insights into DNA affinity and
Evelyn Christine de Souza Arantes1, Naiara Cristina Bessas2, Rafaela Luciano de Oliveira Sanches3
1Instituto de Química, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Abstract:
The development of ruthenium(II) polypyridyl complexes as drug candidates requires understanding the influence of geometry and co-ligands on their chemical reactivity and biological activity. In this work, two chloride complexes of the type [RuIICl(bd)(tpy)]PF6 and [RuIICl(bdq)(tpy)]PF6, where tpy = 2,2':6',2″-terpyridine, bd = o-phenylenediamine and bdq = 3,4-diaminobenzoic acid, were synthesized and characterized. The corresponding aquo complexes, [RuII(OH2)(bd)(tpy)](PF6)2 and [RuII(OH2)(bdq)(tpy)](PF6)2 - were obtained in situ. To understand the kinetics for the spontaneous aquation reaction of the complex chlorides, spectroscopic variation studies in the UV-VIS. region and HPLC were carried out, revealing that [RuIICl(bd)(tpy)]PF6 has a higher rate constant than the complex with bdq ligand in the aquation reaction. The experimental results were complemented by theoretical calculations to determine the aquation kinetic constants as well as the activation parameters. The associative mechanism was proposed for the aquation reaction, with the steric effect of the COOH substituent group influencing the entry of the aquo ligand. In understanding their interaction with biomolecules, spectroscopic studies showed that both complexes interact with fs-DNA by intercalation, with apparent binding constants of (2.4 ± 0.1) × 106 and (1.3 ± 0.3) × 106 L mol-1 for [RuIICl(bd)(tpy)]PF6 and [RuIICl(bdq)(tpy)]PF6, respectively, and DNA cleavage only by [RuIICl(bd)(tpy)]PF6. Both chloride ruthenium(II) complexes not showed decreasing in the MDA-MB-231 viability cells. While, the [RuIICl(bd)(tpy)]PF6, demonstrated interested efficacy in inhibiting Zika and Chikungunya viruses.
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