Copper(II) Thiosemicarbazone Complexes and Their Proligands upon UVA Irradiation: An EPR and Spectrophotometric Steady-State Study
| Autor: | Vladimir B. Arion, Milan Mazúr, Oleg Palamarciuc, Vlasta Brezová, Angela Sîrbu, Michal Hricovíni |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Thiosemicarbazones
Ultraviolet Rays Radical Substituent Pharmaceutical Science chemistry.chemical_element 010402 general chemistry Photochemistry Ligands 01 natural sciences Article Analytical Chemistry law.invention lcsh:QD241-441 chemistry.chemical_compound lcsh:Organic chemistry law copper(II) complexes Drug Discovery Computer Simulation Physical and Theoretical Chemistry Hydrogen peroxide Electron paramagnetic resonance reactive oxygen species Aqueous solution Spin trapping 010405 organic chemistry Chemistry spin trapping Organic Chemistry Electron Spin Resonance Spectroscopy Copper sodium 5-sulfonate-salicylaldehyde thiosemicarbazones 0104 chemical sciences Solutions Q- and X-band EPR spectroscopy UVA exposure Salicylaldehyde Chemistry (miscellaneous) Molecular Medicine Spectrophotometry Ultraviolet Spin Labels Crystallization |
| Zdroj: | Molecules, Vol 23, Iss 4, p 721 (2018) Molecules : A Journal of Synthetic Chemistry and Natural Product Chemistry Molecules; Volume 23; Issue 4; Pages: 721 |
| Popis: | X- and Q-band electron paramagnetic resonance (EPR) spectroscopy was used to characterize polycrystalline Cu(II) complexes that contained sodium 5-sulfonate salicylaldehyde thiosemicarbazones possessing a hydrogen, methyl, ethyl, or phenyl substituent at the terminal nitrogen. The ability of thiosemicarbazone proligands to generate superoxide radical anions and hydroxyl radicals upon their exposure to UVA irradiation in aerated aqueous solutions was evidenced by the EPR spin trapping technique. The UVA irradiation of proligands in neutral or alkaline solutions and dimethylsulfoxide (DMSO) caused a significant decrease in the absorption bands of aldimine and phenolic chromophores. Mixing of proligand solutions with the equimolar amount of copper(II) ions resulted in the formation of 1:1 Cu(II)-to-ligand complex, with the EPR and UV-Vis spectra fully compatible with those obtained for the dissolved Cu(II) thiosemicarbazone complexes. The formation of the complexes fully inhibited the photoinduced generation of reactive oxygen species, and only subtle changes were found in the electronic absorption spectra of the complexes in aqueous and DMSO solutions upon UVA steady-state irradiation. The dark redox activity of copper(II) complexes and proligand/Cu(II) aqueous solutions towards hydrogen peroxide which resulted in the generation of hydroxyl radicals, was confirmed by spin trapping experiments. |
| Databáze: | OpenAIRE |
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