Nogueira, Mariana O T; da Silva, Pedro Henrique L; do Nascimento, Ana Carolina C; Soares, Nathan B; Diz, Joyce S F; Laplante, Steven 
ORCID: https://orcid.org/0000-0003-2835-5789; Lamego, Luiz Sérgio R; Franca, Tanos Celmar Costa et Miranda, Fabio S
(2026).
Intercalative binding, light-switch behavior, and theoretical analysis of Ru(bpy)(2)dppz-BTDZ](2+): A thiadiazole-extended ruthenium(II) complex
Journal of Inorganic Biochemistry
, vol. 274
, nº 113083.
pp. 1-15.
DOI: 10.1016/j.jinorgbio.2025.113083.
Résumé
The new ruthenium(II) polypyridyl complex [Ru(bpy)₂dppz-BTDZ](2+), featuring a thiadiazole-substituted dppz ligand, was synthesized and characterized to investigate its DNA-binding and photophysical properties. Its interaction with calf thymus DNA (Ct-DNA) was studied through UV-visible and emission spectroscopy, competitive binding assays with ethidium bromide (EB), anionic quenching with K(4)[Fe(CN)(6)], viscosity and molecular modeling. The results indicate that the complex intercalates into DNA, with a binding constant (K(b)) of 6.57 ± 0.9 × 10(6) M(-1) and has a 7 % enhancement in the light-switch effect compared to [Ru(bpy)₂dppz](2+). DFT calculations characterized the excited states, which were compared to those of [Ru(bpy)₂dppz](2+). The presence of the thiadiazole group promotes mixing of MLCT states. Franck-Condon analysis of emission spectra in MeCN, water, and DNA allowed for the estimation of the excited-state free energy. In water, the emissive bright state lies approximately 1300 cm(-1) higher than in DNA and approximately 1100 cm(-1) higher than in MeCN. This energy trend is consistent with the light-switch behavior observed in this class of complexes. Moreover, the bright-state energies correlated very well with all the observed lifetimes. Docking and molecular dynamics simulations revealed stable intercalative binding in the DNA minor groove, with the Δ-isomer showing enhanced stability.
| Type de document: | Article |
|---|---|
| Informations complémentaires: | This work is financially supported by FAPERJ (Grants: E-26/202.719/2018, SEI-260003/001190/2020 and E-02/202.961/2017), Brazilian Funding agencies: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq – Grant no: 305432/2022-2) The authors acknowledge the facilities provided by LAME-UFF and LAMATE-UFF. Tanos C. C. França is grateful for the support of the project - Long-term Development Plan UHK |
| Mots-clés libres: | Ruthenium polypyridyl complex; Dppz; Benzothiazole; Metallo-intercalator; Docking; Gap law |
| Centre: | Centre INRS-Institut Armand Frappier |
| Date de dépôt: | 12 févr. 2026 16:11 |
| Dernière modification: | 12 févr. 2026 16:11 |
| URI: | https://espace.inrs.ca/id/eprint/16686 |
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