Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil
Abstract
:1. Introduction
2. Results
2.1. Geometric Structures and Time-Dependent Density Functional Theory (TDDFT) Calculations [2-TU-H]− and [2-TU·H]+
2.2. Deprotonated 2-Thiouracil
2.2.1. Gas-Phase Absorption Spectrum of Deprotonated 2-Thiouracil
2.2.2. Photofragmentation of Deprotonated 2-Thiouracil
2.3. Protonated 2-Thiouracil [2-TU·H]+
2.3.1. Gas-Phase and Solution-Phase Absorption Spectra of [2-TU·H]+
2.3.2. Photofragmentation of Protonated 2-Thiouracil
2.3.3. Comparison of Photofragmentation and HCD Fragmentation of [2-TU·H]+
3. Further Discussion
3.1. Deprotonated 2-Thiouracil
3.2. Protonated 2-Thiouracil [2-TU·H]+
4. Materials and Methods
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Sample Availability: Not available. |
Ion | Tautomer | Relative Energy (kJ mol−1) a,b | % Boltzmann Population b,c | VDE |
---|---|---|---|---|
[2-TU-H]− | D1 | 0.0 (0.0) | 99.9 (99.8) | 3.82 |
D2 | 45.9 (15.3) | 0 (<0.1) | 3.66 | |
D3a | 101 (58.9) | 0 (<0.1) | 2.91 | |
D3b | 74.6 (49.5) | 0 (<0.1) | 3.00 | |
D4a | 58.2 (51.7) | 0 (<0.1) | 3.93 | |
D4b | 56.5 (51.5) | 0 (<0.1) | 2.54 | |
[2-TU·H]+ | P1a | 0.0 (0.0) | 93.9 (35.9) | |
P1b | 6.81 (1.32) | 6.01 (21.1) | ||
P1c | 17.6 (8.10) | 0.077 (1.37) | ||
P1d | 26.8 (9.55) | 0.003 (0.76) | ||
P2 | 20.2 (-0.32) | 0.026 (40.9) |
Photofragment m/z | Proposed Ion Structures | Associated Neutral | Present in HCD a | Photofragment Intensity at 3.6 eV b |
---|---|---|---|---|
58 | SCN− | C3H3NO | √ | √ (w) |
93 | | H2S | X | √ (vw) |
Photofragment m/z | Proposed Structure | Neutral or Radical Loss | HCD a | Photofragment Intensity at 4.6 eV b,c | Photofragment Intensity at 5.2 eV b,c |
---|---|---|---|---|---|
128 | | H· | √ | √ (w) | √ (m) |
112 | C4H2NO+ | NH3 | √ | √ (w) | √ (w) |
96 | | HS· | X | √ (vs) | √ (vs) |
79 | C4HNO+ | HS· + NH3 | X | X | √ (vw) |
70 | | HNCS | √ | √ (m) | √ (m) |
68 | C3H4N2+ | HS· + CO | X | X | √ (vw) |
60 | CNSH2+ | NH3 + C3O | √ | √ (vw) | √ (vw) |
53 | | NH3 + HNCS | √ | √ (vw) | √ (vw) |
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Uleanya, K.O.; Cercola, R.; Nikolova, M.; Matthews, E.; Wong, N.G.K.; Dessent, C.E.H. Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil. Molecules 2020, 25, 3157. https://doi.org/10.3390/molecules25143157
Uleanya KO, Cercola R, Nikolova M, Matthews E, Wong NGK, Dessent CEH. Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil. Molecules. 2020; 25(14):3157. https://doi.org/10.3390/molecules25143157
Chicago/Turabian StyleUleanya, Kelechi O., Rosaria Cercola, Maria Nikolova, Edward Matthews, Natalie G. K. Wong, and Caroline E. H. Dessent. 2020. "Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil" Molecules 25, no. 14: 3157. https://doi.org/10.3390/molecules25143157