Photochemical reactions have an important place in photodynamic treatments. A good use of this therapeutic method requires a good mastery of the mechanisms of the reactions involved. Therefore, we have explored in thi...Photochemical reactions have an important place in photodynamic treatments. A good use of this therapeutic method requires a good mastery of the mechanisms of the reactions involved. Therefore, we have explored in this work the photosensitization mechanism of an organometallic complex of azopyridine <em>δ</em>-OsCl<sub>2</sub>(Azpy)<sub>2</sub> through a calculation with the method of Time Dependent Density Functional Theory TDDFT. First, we evaluated the effect of polar and non-polar solvents on the triplet and singlet excited states of this complex. Then secondly, we highlighted the photosensitization mechanism to understand how the complex acts over the diseased cells. These investigations have shown that the <em>δ</em>-OsCl<sub>2</sub>(Azpy)<sub>2</sub> complex is likely to develop photodynamic activity according to two mechanisms: on one hand, it can generate damage to DNA bases or target tissues indirectly through the production of singlet oxygen in water and in DMSO. On the second hand, through the production of the anionic superoxide radical <img src="Edit_a1e628d6-dcd2-41c6-bf3c-7e3cad491857.png" alt="" />in water can act directly or indirectly on these substrates. In addition, polar solvents are assumed to better carry out the photochemical reactions of this azopyridine complex of osmium.展开更多
We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach....We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach. The analysis is based on a direct comparison with the highly correlated CASSCF（MS-CASPT2） ab initio approach. 49 DFT functionals were considered and applied to the study. Among the tested functionals, mPW3PBE, B3PW91 and B3P86 give the best performance for ground-state geometry, absorption spectrum, excited-state geometry and emis- sion spectrum.展开更多
文摘Photochemical reactions have an important place in photodynamic treatments. A good use of this therapeutic method requires a good mastery of the mechanisms of the reactions involved. Therefore, we have explored in this work the photosensitization mechanism of an organometallic complex of azopyridine <em>δ</em>-OsCl<sub>2</sub>(Azpy)<sub>2</sub> through a calculation with the method of Time Dependent Density Functional Theory TDDFT. First, we evaluated the effect of polar and non-polar solvents on the triplet and singlet excited states of this complex. Then secondly, we highlighted the photosensitization mechanism to understand how the complex acts over the diseased cells. These investigations have shown that the <em>δ</em>-OsCl<sub>2</sub>(Azpy)<sub>2</sub> complex is likely to develop photodynamic activity according to two mechanisms: on one hand, it can generate damage to DNA bases or target tissues indirectly through the production of singlet oxygen in water and in DMSO. On the second hand, through the production of the anionic superoxide radical <img src="Edit_a1e628d6-dcd2-41c6-bf3c-7e3cad491857.png" alt="" />in water can act directly or indirectly on these substrates. In addition, polar solvents are assumed to better carry out the photochemical reactions of this azopyridine complex of osmium.
基金Supported by the National Natural Science Foundation of China（Nos.21173099, 20973078, 51164017）, the Applied Basic Research Plans Program of Yunnan Province, China（No.2011FZ040）, the Scientific Research Fund of Yunnan Provincial Educa- tion Department, China（No.2012Y545）, the Training Foundation for Talents of Kunming University of Science and Technolo- gy（No.KKSY201232040） and the Foundation of State Key Laboratory of Theoretical and Computational Chemistry, China.
文摘We analyzed the excited-state structures and emission spectra of firefly emitter, the anionic keto form of firefly oxyluciferin（keto-l）, determined by the time dependent-density functional theory（TD-DFT） approach. The analysis is based on a direct comparison with the highly correlated CASSCF（MS-CASPT2） ab initio approach. 49 DFT functionals were considered and applied to the study. Among the tested functionals, mPW3PBE, B3PW91 and B3P86 give the best performance for ground-state geometry, absorption spectrum, excited-state geometry and emis- sion spectrum.
