Slow triplet energy transfer to lower excited states in ruthenium(II) acylpyridine complexes

1987 ◽  
Vol 109 (7) ◽  
pp. 2188-2190 ◽  
Author(s):  
Peter J. Wagner ◽  
Nicholas Leventis
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Triplet Energy ◽  
Triplet Energy Transfer

Studies on the Mechanism of the Photosensitized Dimerization of Pyrimidines

1972 ◽  
Vol 27 (5) ◽  
pp. 550-553 ◽  
Author(s):  
A. Kornhauser ◽  
M. A. Pathak
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Carbonyl Compounds ◽  
Physical Mechanism ◽  
Uv Light ◽  
Triplet Energy ◽  
Pyrimidine Dimers ◽  
Triplet Energy Transfer ◽  
Electron Donating Groups ◽  
Π State

Thymine-2-14C was irradiated with UV light (>300 nm) in water solutions in the presence of different sensitizers. Pyrimidines upon irradiation with wavelengths of 300—320 nm in the presence of some ketones as sensitizers, yield cyclobutyl pyrimidine dimers. The reaction occurs through a triplet-triplet energy transfer from the sensitizer to the substrate. The energy transfer, however, does not occur through a simple physical mechanism. The ability of a donor (e. g. ketone molecule) in its excited state to form a complex with the acceptor (pyrimidine molecule) appears to be a prerequisite in this type of photodimerization reaction. A correlation of the photochemical behavior of different ketones in this reaction with the nature of their excited states has been proposed. Carbonyl compounds possessing n, π* lowest triples are active in inducing pyrimidine dimerizations. By introducing some different electron donating groups to the ketone molecules that lower its π, π* state below its n, π* level, the sensitizing ability of the molecule appears to decrease or disappears completely. Ethylacetoacetate was found to be a more effective sensitizer than acetone or acetophenone. Likewise, dihydroxyacetone was found to be a potent photosensitizer in dimerization of thymine. Urocanic acid (UCA), a major UV absorbing compound in mammalian skin, did not show any sensitizing ability to induce cyclobutyl pyrimidine dimers on irradiation in the presence of thymine, with wavelengths greater than 300 nm.

Rate Constant of Bimolecular Triplet Energy Transfer from Chrysene in the Higher Triplet Excited States

2004 ◽  
Vol 108 (35) ◽  
pp. 7147-7150 ◽  
Author(s):  
Xichen Cai ◽  
Masanori Sakamoto ◽  
Michihiro Hara ◽  
Sachiko Tojo ◽  
Kiyohiko Kawai ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Rate Constant ◽  
Triplet Energy ◽  
Triplet Excited States ◽  
Triplet Energy Transfer

ChemInform Abstract: Slow Triplet Energy Transfer to Lower Excited States in Ruthenium(II) Acylpyridine Complexes

ChemInform ◽  
1987 ◽  
Vol 18 (33) ◽  
Author(s):  
P. J. WAGNER ◽  
N. LEVENTIS
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Triplet Energy ◽  
Triplet Energy Transfer

Preparation of Bodipy–ferrocene dyads and modulation of the singlet/triplet excited state of bodipy via electron transfer and triplet energy transfer

2016 ◽  
Vol 4 (14) ◽  
pp. 2843-2853 ◽  
Author(s):  
Xueyan Wu ◽  
Wenting Wu ◽  
Xiaoneng Cui ◽  
Jianzhang Zhao ◽  
Mingbo Wu
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Excited States ◽  
Singlet Excited State ◽  
Triplet Excited State ◽  
Triplet Energy ◽  
Triplet Excited States ◽  
Triplet Energy Transfer

Bodipy–ferrocene dyads were prepared for reversible electrochemical switching of the singlet excited state (fluorescence), as well as the triplet excited states of Bodipy.

Some triplet energy-transfer reactions initiated by photoexcitation of triplet excited state of dibenz[a,h]anthracene to the higher triplet excited states

2003 ◽  
Vol 44 (32) ◽  
pp. 6117-6120 ◽  
Author(s):  
Xichen Cai ◽  
Michihiro Hara ◽  
Kiyohiko Kawai ◽  
Sachiko Tojo ◽  
Mamoru Fujitsuka ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Excited States ◽  
Transfer Reactions ◽  
Triplet Excited State ◽  
Triplet Energy ◽  
Triplet Excited States ◽  
Triplet Energy Transfer

Thymine Dimerization Induced by Oxidative DNA Lesions and Epigenetic Intermediates via Triplet-Triplet Energy Transfer

2020 ◽  
Author(s):  
Mauricio Lineros-Rosa ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Miguel Angél Miranda ◽  
Virginie Lhiaubet-Vallet
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Transient Absorption ◽  
Theoretical Calculations ◽  
Dna Lesions ◽  
Transient Absorption Spectroscopy ◽  
Triplet Energy ◽  
Pyrimidine Dimers ◽  
Triplet Energy Transfer ◽  
Dna Nucleobases

Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidative lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of the highly toxic and mutagenic cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA photodamage and of potential use in the development of biomarkers and non-conventional photodynamic therapy agents.

Photochemical Deracemization of Primary Allene Amides by Triplet Energy Transfer: A Combined Synthetic and Theoretical Study

2021 ◽  
Author(s):  
Manuel Plaza ◽  
Johannes Großkopf ◽  
Stefan Breitenlechner ◽  
Christoph Bannwarth ◽  
Thorsten Bach
Keyword(s):  
Energy Transfer ◽  
Theoretical Study ◽  
Triplet Energy ◽  
Triplet Energy Transfer

Photoinduced Intramolecular Electron Transfer and Triplet Energy Transfer in a Steroid-Linked Norbornadiene–Carbazole Dyad

2003 ◽  
Vol 9 (12) ◽  
pp. 2763-2769 ◽  
Author(s):  
Li-Ping Zhang ◽  
Bin Chen ◽  
Li-Zhu Wu ◽  
Chen-Ho Tung ◽  
Hong Cao ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Intramolecular Electron Transfer ◽  
Triplet Energy ◽  
Triplet Energy Transfer

Triplet energy transfer in conjugated polymers. II. A polaron theory description addressing the influence of disorder

2008 ◽  
Vol 78 (4) ◽  
Author(s):  
Ivan I. Fishchuk ◽  
Andrey Kadashchuk ◽  
Lekshmi Sudha Devi ◽  
Paul Heremans ◽  
Heinz Bässler ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Conjugated Polymers ◽  
Triplet Energy ◽  
Polaron Theory ◽  
Triplet Energy Transfer
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