The electronic spectra of the pyrimidine bases uracil and thymine in a supersonic molecular beam

Brady, Brian B.; Peteanu, Linda A.; Levy, Donald H.

doi:10.1016/0009-2614(88)80264-1

Cited by 148 publications

(139 citation statements)

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“…Nir et al reported REMPI and hole burning spectra and concluded that the keto and enol tautomers have band origins that differ by a remarkable half electron volt at 314 nm and 278 nm, respectively (42,43). The REMPI spectra of U and T exhibit a very broad structure with an onset in the frequency range of the origin of the enol cytosine first reported by Brady et al (4).. No spectroscopic detail could be extracted from these broad spectra and tautomeric information was limited for a long time to bulk measurements.…”

Section: Purinesmentioning

confidence: 96%

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Gas-Phase IR Spectroscopy of Nucleobases

Vries

2014

Topics in Current Chemistry

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Abstract.IR spectroscopy of nucleobases in the gas phase reflects simultaneous advances in both experimental and computational technique. Important properties, such as excited state dynamics, depend in subtle ways on structure variations, which can be followed by their infrared signatures. Isomer specific spectroscopy is a particularly powerful tool for studying the effects of nucleobase tautomeric form and base pair hydrogen bonding patterns.

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Section: Purinesmentioning

confidence: 96%

“…Gas-phase spectroscopy of neutral molecules, as opposed to ions, usually involves the use of supersonic molecular beams (1)(2)(3)(4). For smaller compounds this can be achieved by seeding in the inert drive gas.…”

Section: Techniquesmentioning

confidence: 99%

Gas-Phase IR Spectroscopy of Nucleobases

Vries

2014

Topics in Current Chemistry

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“…The paper also presents equivalent MPI measurements on thymine, for which no analogous ring-opening process has been predicted [9]. A distinctly higher pump energy (5.64 eV, 220 nm) was applied than in the previous MPI studies of thymine (4.34-4.77 eV, 285.7-260 nm) [6,12,13,14,15,16,17], increasing the likelihood of isomeric transitions during radiationless deactivation. Finally, MPI and electron impact ionization (EII) experiments were carried out on uracil-adenine clusters as a step towards better understanding the dissociative ionization pathways of uracil within RNA.…”

Section: Introductionmentioning

confidence: 97%

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Ryszka

Pandey

Rizk

et al. 2016

International Journal of Mass Spectrometry

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Recent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C 3 H 4 N 2 O + (uracil + less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine do not reveal an analogous CO loss channel, suggesting greater stability of the excited DNA base. MPI and electron impact ionization experiments have been carried out on uracil-adenine clusters in order to better understand the radiation response of uracil within RNA.Evidence for C 3 H 4 N 2 O + production from multi-photon-ionized uracil-adenine clusters is tentatively attributed to a significant population of π-stacked configurations in the neutral beam. Graphical AbstractHighlights UV multi-photon ionization measurements on deuterated uracil have identified a CO loss pathway that may indicate ring opening in the electronically excited neutral molecule. The first dissociative ionization experiments on uracil-adenine complexes have revealed that the CO loss channel is also accessible in these clusters.Keywords: Uracil; adenine-uracil clusters; fragmentation; multi-photon ionization; electron impact ionization; mass spectrometry Ryszka et al. Int. J. Mass. Spectrom. 396 (2016) 48 2 IntroductionThe dynamics and stabilities of nucleobases following excitation to their bright S 2 (ππ* of the ring-opening crossing seam [9] and the geometry of the predicted isomer indicates likely CO abstraction. Therefore MPI production of this fragment ion was proposed as a potential experimental marker for ring opening in neutral excited uracil, suggesting possibilities for diverse measurements exploring the process in depth (e.g. using coincidence and / or time-resolved methods). The first aim of the present work was to test if the new fragment ion is indeed due to CO loss by studying MPI of deuterated uracil (dominantly C 4 D 4 N 2 O 2 ). These results have the added value of identifying several previously debated fragments from the radical cation, while further evidence to assign specific peaks is provided by high-resolution MPI mass spectra. The paper also presents equivalent MPI measurements on thymine, for which no analogous ring-opening process has been predicted [9]. A distinctly higher pump energy (5.64 eV, 220 nm) was applied than in the previous MPI studies of thymine (4.34-4.77 eV, 285.7-260 nm) [6, 12, 13, 14, 15, 16, 17], increasing the likelihood of isomeric transitions during radiationless deactivation. Finally, MPI and electron impact ionization (EII) experiments were carried out on uracil-adenine clusters as a step towards better understanding the dissociative ionization pathways of uracil within RNA. Whereas several spectroscopic studies have been carried out on adenine-thymine complexes in supersonic beams [18,19,20], to our knowledge no previous experiments on isolated u...

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“…21 Microwave spectra of DNA bases were also obtained in the gas phase. 22 Electronic spectra of thymine and uracil in a supersonic jet were first reported by Fujii et al, 23 and more thoroughly investigated and clarified by Brady et al 24 Recently, Nir et al carried out resonant two-photon ionization ͑R2PI͒ spectroscopy on jet-cooled guanine, which revealed a wellresolved vibronic spectrum. 25 In this study, we report the R2PI and laser induced fluorescence ͑LIF͒ spectroscopy of the DNA base adenine in a supersonic jet.…”

Section: Introductionmentioning

confidence: 98%

Resonant two-photon ionization and laser induced fluorescence spectroscopy of jet-cooled adenine

Kim

Jeong

Kim

et al. 2000

The Journal of Chemical Physics

163

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Articles you may be interested inElectronic spectra of the jet-cooled DNA base adenine were obtained by the resonant two-photon ionization ͑R2PI͒ and the laser induced fluorescence ͑LIF͒ techniques. The 0-0 band to the lowest electronically excited state was found to be located at 35 503 cm Ϫ1 . Well-resolved vibronic structures were observed up to 1100 cm Ϫ1 above the 0-0 level, followed by a slow rise of broad structureless absorption. The lowest electronic state was proposed to be of n * character, which lies ϳ600 cm Ϫ1 below the onset of the * state. The broad absorption was attributed to the extensive vibronic mixing between the n * state and the high-lying * state.

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The electronic spectra of the pyrimidine bases uracil and thymine in a supersonic molecular beam

Cited by 148 publications

References 13 publications

Gas-Phase IR Spectroscopy of Nucleobases

Gas-Phase IR Spectroscopy of Nucleobases

Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Resonant two-photon ionization and laser induced fluorescence spectroscopy of jet-cooled adenine

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