Spectral and photophysical properties of the lowest excited triplet state of 4-thiouridine and its 5-halogeno derivatives

Taras-Goślińska, Katarzyna; Wenska, G.; Skalski, Bohdan; Maciejewski, Andrzej; Burdziński, Gotard; Karolczak, Jerzy

doi:10.1016/j.jphotochem.2004.06.003

Cited by 21 publications

(31 citation statements)

References 22 publications

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“…S 2 (ππ*) and the S 0 ! S 1 (nπ*) electronic transitions, respectively [10,18,19,34,200,201]. These assignments are supported by quantum chemical calculations [11,17,18,196,[202][203][204].…”

Section: Steady-state and Time-resolved Photochemistry Of The 4-thiousupporting

confidence: 60%

“…Taras-Goślińska et al [200] reported an intrinsic triplet decay lifetime for 1,3-dimethyl-4-thiouracil of τ [201]. This value is about four times longer than the intrinsic lifetime reported above for 1,3-dimethyl-4-thiouracil in the same solvent (Table 13).…”

Section: Triplet State Dynamicsmentioning

confidence: 76%

“…It was concluded that the methyl substituents at both the N3 and C5 positions of the 4-thiouracil ring influence, to different extents, the energy and electronic Calculated to infinite dilution configuration of the T 1 (ππ*) state [203]. In related work [201], an increase in the nonradiative rate constant (Table 11) was observed with increasing atomic number of the halogen atom in the 2 0 ,3 0 ,5 0 -tri-O-acetyl-4-thio-5-halogenouridine series (i.e., with C5-X═F, Cl, Br, or I). This trend with increasing atomic number of the halogen was also embodied by a corresponding decrease in phosphorescence quantum yield and shortening of triplet state lifetime (Table 13).…”

Section: Triplet State Dynamicsmentioning

confidence: 98%

“…S 0 and T 1 (ππ*) ! S 0 radiative transitions in the 4-thione, 2-keto uracil derivatives and exhibit fluorescence and phosphorescence quantum yields in the ranges of (0.4-1.5) Â 10 À4 and (0.2-123) Â 10 À4 , respectively, depending on the solvent and the concentration of the solute used [10,13,34,200,201,203]. In addition, some of the photophysical properties have been measured at infinite dilution in order to determine intrinsic triplet decay lifetimes and phosphorescence quantum yields (Tables 10, 12, 13, and 14) [200,203].…”

Section: Steady-state and Time-resolved Photochemistry Of The 4-thioumentioning

confidence: 99%

“…This value is about four times longer than the intrinsic lifetime reported above for 1,3-dimethyl-4-thiouracil in the same solvent (Table 13). The striking difference in the intrinsic triplet lifetimes between these two compounds was proposed to be a result of reversible intramolecular hydrogen abstraction in the T 1 (ππ*) state of 1,3-dimethyl-4-thiouracil from the ortho methyl group to the sulfur atom of the thiocarbonyl group [201]. However, recent work [203] using the deuterated compound (1-methyl-3-trideuteriomethyl-4-thiouracil) in PFDMCH has shown that the reversible intramolecular H-abstraction pathway is insignificant.…”

Section: Triplet State Dynamicsmentioning

confidence: 99%

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Photochemistry of Nucleic Acid Bases and Their Thio- and Aza-Analogues in Solution

Pollum

Martínez‐Fernández

Crespo‐Hernández

2014

Topics in Current Chemistry

111

200

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The steady-state and time-resolved photochemistry of the natural nucleic acid bases and their sulfur- and nitrogen-substituted analogues in solution is reviewed. Emphasis is given to the experimental studies performed over the last 3-5 years that showcase topical areas of scientific inquiry and those that require further scrutiny. Significant progress has been made toward mapping the radiative and nonradiative decay pathways of nucleic acid bases. There is a consensus that ultrafast internal conversion to the ground state is the primary relaxation pathway in the nucleic acid bases, whereas the mechanism of this relaxation and the level of participation of the (1)πσ*, (1) nπ*, and (3)ππ* states are still matters of debate. Although impressive research has been performed in recent years, the microscopic mechanism(s) by which the nucleic acid bases dissipate excess vibrational energy to their environment, and the role of the N-glycosidic group in this and in other nonradiative decay pathways, are still poorly understood. The simple replacement of a single atom in a nucleobase with a sulfur or nitrogen atom severely restricts access to the conical intersections responsible for the intrinsic internal conversion pathways to the ground state in the nucleic acid bases. It also enhances access to ultrafast and efficient inter-system crossing pathways that populate the triplet manifold in yields close to unity. Determining the coupled nuclear and electronic pathways responsible for the significantly different photochemistry in these nucleic acid base analogues serves as a convenient platform to examine the current state of knowledge regarding the photodynamic properties of the DNA and RNA bases from both experimental and computational perspectives. Further investigations should also aid in forecasting the prospective use of sulfur- and nitrogen-substituted base analogues in photochemotherapeutic applications.

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Section: Steady-state and Time-resolved Photochemistry Of The 4-thiousupporting

confidence: 60%

Section: Triplet State Dynamicsmentioning

confidence: 76%

Section: Triplet State Dynamicsmentioning

confidence: 98%

Section: Steady-state and Time-resolved Photochemistry Of The 4-thioumentioning

confidence: 99%

Section: Triplet State Dynamicsmentioning

confidence: 99%

See 3 more Smart Citations

Photochemistry of Nucleic Acid Bases and Their Thio- and Aza-Analogues in Solution

Pollum

Martínez‐Fernández

Crespo‐Hernández

2014

Topics in Current Chemistry

111

200

View full text Add to dashboard Cite

show abstract

Highly Efficient Fluorescent Interstrand Photo‐crosslinking of DNA Duplexes Labeled with 5‐Fluoro‐4‐thio‐2′‐O‐methyluridine

et al. 2014

Self Cite

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The formation of a fluorescent photoadduct between 5-fluoro-4-thiouridine ((FS) U), in the sequence context 5'-A(FS) UA-3' and incorporated into a synthetic oligonucleotide either at its 3'- or 5'-end, and one of the thymines of the TAT motif in a complementary target DNA strand led to photo-crosslinking of the two strands for several oligonucleotide constructs. Enzymatic digestion, MS, UV, and fluorescence spectral analyses of the interstrand crosslinked oligonucleotides revealed the identity of the thymidine that participates in the photo-crosslinking reaction as well as the diastereomeric structures of the crosslinks. The proposed pathways of interstrand photo-crosslinking are supported by experiments with isotopically labeled oligonucleotide constructs and visualized by means of molecular dynamics simulations.

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5-Fluoro-4-thiouridine phosphoramidite: New synthon for introducing photoaffinity label into oligodeoxynucleotides

Milecki

Nowak

Skalski

et al. 2011

Bioorganic & Medicinal Chemistry

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Spectral and photophysical properties of the lowest excited triplet state of 4-thiouridine and its 5-halogeno derivatives

Cited by 21 publications

References 22 publications

Photochemistry of Nucleic Acid Bases and Their Thio- and Aza-Analogues in Solution

Photochemistry of Nucleic Acid Bases and Their Thio- and Aza-Analogues in Solution

Highly Efficient Fluorescent Interstrand Photo‐crosslinking of DNA Duplexes Labeled with 5‐Fluoro‐4‐thio‐2′‐O‐methyluridine

5-Fluoro-4-thiouridine phosphoramidite: New synthon for introducing photoaffinity label into oligodeoxynucleotides

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