Interactions of formate ion with triplets of anthraquinone-2-sulfonate, 1,4-naphthoquinone, benzophenone-4-carboxylate and benzophenone-4-sulfonate

Loeff, I.; Goldstein, Sara; Treinin, A.; Linschitz, Henry

doi:10.1021/j100164a048

Cited by 62 publications

(76 citation statements)

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“…The lifetime of the radical anion spectra observed here are consistent with the literature data on the transient absorption spectra. 16 In the case of NQ, the radical anion bands are observed at 1603, 1537, 1441, 1327, and 1158 cm -1 , whereas MQ radical anion bands are present at 1605, 1539, 1468, 1442, 1339 and 1139 cm -1 . The assignments of the neutral and radical anion vibrational frequencies have been carried out with the use of both the results obtained from ab initio calculations and by qualitative comparison with literature data on other quinones as discussed below.…”

Section: Resultsmentioning

confidence: 94%

“…The observed Raman spectra are then analyzed with the help of ab initio calculations. Ab initio studies have also been extended to investigate the effect of isotopic substitution of 16 O to 18 O and to provide appropriate potential energy distributions (PEDs) in the normal modes involved. Finally, our results have been critically compared with the reported FTIR data on the NQ derivatives, and the vibrational assignments for all the experimentally observed bands are presented.…”

Section: Introductionmentioning

confidence: 99%

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Time-Resolved Resonance Raman Spectroscopic Studies on the Radical Anions of Menaquinone and Naphthoquinone

1996

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Quinones and their radical ion intermediates have been much studied by vibrational spectroscopy to understand their structure-function relationships in various biological processes. In this paper, we present a comprehensive analysis of vibrational spectra in the structure-sensitive region of both the naphthoquinone (NQ) and 2-methyl-1,4-naphthoquinone (MQ, menaquinone) radical anions using time-resolved resonance Raman and ab initio studies. Specific vibrational mode assignments have been made to all the vibrational frequencies recorded in the experiment. It is observed that the carbonyl and CdC stretching frequencies show considerable coupling in NQ and MQ radical anions. Further, the asymmetric substitution present in MQ with respect to NQ shows important signatures in the radical anion spectrum. It is concluded that assignments of vibrational frequencies of asymmetrically substituted quinones must take into consideration the influence of asymmetry on structure and reactivity.

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Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Time-Resolved Resonance Raman Spectroscopic Studies on the Radical Anions of Menaquinone and Naphthoquinone

1996

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“…The advantage of using AQ2S is that it produces neither 1 of AQ2S is that its triplet state ( 3 AQ2S) is more reactive than other 3 OM proxies. 39,40 Therefore, the use of AQ2S provides an upper limit for the role of the triplet states. The steady-state concentration of 3 AQ2S was determined indirectly by following the AQ2S degradation via HPLC, as described in the Supporting Information on the basis of a kinetic model reported elsewhere.…”

Section: •−mentioning

confidence: 99%

Conceptual Model and Experimental Framework to Determine the Contributions of Direct and Indirect Photoreactions to the Solar Disinfection of MS2, phiX174, and Adenovirus

Mattle

Vione

Kohn

2014

Environ. Sci. Technol.

122

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Sunlight inactivates waterborne viruses via direct (absorption of sunlight by the virus) and indirect processes (adsorption of sunlight by external chromophores, which subsequently generate reactive species). While the mechanisms underlying these processes are understood, their relative importance remains unclear. This study establishes an experimental framework to determine the kinetic parameters associated with a virus' susceptibility to solar disinfection and proposes a model to estimate disinfection rates and to apportion the contributions of different inactivation processes. Quantum yields of direct inactivation were determined for three viruses (MS2, phiX174, and adenovirus), and second-order rate constants associated with indirect inactivation by four reactive species ((1)O2, OH(•), CO3(•-), and triplet states) were established. PhiX174 exhibited the greatest quantum yield (1.4 × 10(-2)), indicating that it is more susceptible to direct inactivation than MS2 (2.9 × 10(-3)) or adenovirus (2.5 × 10(-4)). Second-order rate constants ranged from 1.7 × 10(7) to 7.0 × 10(9) M(-1) s(-1) and followed the sequence MS2 > adenovirus > phiX174. A predictive model based on these parameters accurately estimated solar disinfection of MS2 and phiX174 in a natural water sample and approximated that of adenovirus within a factor of 6. Inactivation mostly occurred by direct processes, though indirect inactivation by (1)O2 also contributed to the disinfection of MS2 and adenovirus.

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“…[15][16][17] The one-electron reduction potential of AQS in the triplet excited state ( 3 AQS*; E rdn = 2.30 V vs. a normal hydrogen electrode (NHE)) [18] has a much higher positive value relative to that of the m C base (E ox = 1.73 V vs. NHE). [19] It is therefore most likely that the triplet excited-state chromophore 3 (Figure 2 b).…”

Section: Resultsmentioning

confidence: 99%

Anthraquinone‐Sensitized Photooxidation of 5‐Methylcytosine in DNA Leading to Piperidine‐Induced Efficient Strand Cleavage

Yamada

Kitauchi

Tanabe

et al. 2011

Chemistry A European J

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One-electron photooxidations of 5-methyl-2'-deoxycytidine (d(m)C) and 5-trideuteriomethyl-2'-deoxycytidine ([D(3)]d(m)C) by sensitization with anthraquinone (AQ) derivatives were investigated. Photoirradiation of an aerated aqueous solution containing d(m)C and anthraquinone 2-sulfonate (AQS) afforded 5-formyl-2'-deoxycytidine (d(f)C) and 5-hydroxymethyl-2'-deoxycytidine (d(hm)C) in good yield through an initial one-electron oxidation process. The deuterium isotope effect on the AQS-sensitized photooxidation of d(m)C suggests that the rate-determining step in the photosensitized oxidation of d(m)C involves internal transfer of the C5-hydrogen atom of a d(m)C-tetroxide intermediate to produce d(f)C and d(hm)C. In the case of a 5-methylcytosine ((m)C)-containing duplex DNA with an AQ chromophore that is incorporated into the backbone of the DNA strand so as to be immobilized at a specific position, (m)C underwent efficient direct one-electron oxidation by the photoexcited AQ, which resulted in an exclusive DNA strand cleavage at the target (m)C site upon hot piperidine treatment. In accordance with the suppression of the strand cleavage at 5-trideuterio-methylcytosine observed in a similar AQ photosensitization, it is suggested that deprotonation at the C5-methyl group of an intermediate (m)C radical cation may occur as a key elementary reaction in the photooxidative strand cleavage at the (m)C site. Incorporation of an AQ sensitizer into the interior of a strand of the duplex enhanced the one-electron photooxidation of (m)C, presumably because of an increased intersystem crossing efficiency that may lead to efficient piperidine-induced strand cleavage at an (m)C site in a DNA duplex.

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Interactions of formate ion with triplets of anthraquinone-2-sulfonate, 1,4-naphthoquinone, benzophenone-4-carboxylate and benzophenone-4-sulfonate

Cited by 62 publications

References 0 publications

Time-Resolved Resonance Raman Spectroscopic Studies on the Radical Anions of Menaquinone and Naphthoquinone

Time-Resolved Resonance Raman Spectroscopic Studies on the Radical Anions of Menaquinone and Naphthoquinone

Conceptual Model and Experimental Framework to Determine the Contributions of Direct and Indirect Photoreactions to the Solar Disinfection of MS2, phiX174, and Adenovirus

Anthraquinone‐Sensitized Photooxidation of 5‐Methylcytosine in DNA Leading to Piperidine‐Induced Efficient Strand Cleavage

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