Photochemical Reaction Of Benzophenone Research Articles

Photochemistry of aromatic ketones in sodium dodecyl sulphate micelles in the presence of unsaturated fatty acids

Laser-flash photolysis has been employed to characterize the behaviour of the free radicals created in the photochemical reaction of benzophenone (BZP), as well as of its lipoidal derivative, benzophenone-4-heptyl-4?-pentanoic acid (BHPA), with chosen unsaturated fatty acids in sodium dodecyl sulphate micelles. The calculated rate constants were used to study the "cage effect" i.e., the recombination of the created radical-pairs (BZP, BHPA ketyl radical - lipid radical) inside the highly limited space of the SDS micelles. The "cage effect" appears to be the dominant event inside SDS micelles, dependent on the structure of both the reactants-precursors. The fractions of the initially created radical-pairs which escape the "cage effect" and exit into the surrounding aqueous phase do not exceed 16 %. This fact is of enormous importance for the self-control of the pathogenic process of lipid peroxidation.

Determination of the kinetic parameters of radical pairs with heavy atom substitutions in micellar solution by optical detected × and Ku band ESR

A study is reported of the dynamics of radical pairs formed by the photochemical reaction of benzophenone and its heavy atom substitutions, dichlorobenzophenone and bromobenzophe-none, in a sodium dodecylsulphate micellar solution. Changes were observed in the time profiles of the transient absorptions and in the yields of the escaping radicals induced by the irradiation of an × (9.15 GHz) or Ku band (17.44 GHz) microwave short pulse. From these experiments, the hydrogen abstraction reaction rates, the recombination rates of the singlet radical pairs, the relaxation rates, the escape rates, the decay rates of the radical pairs without the external magnetic field, and the intersystem recombination rates due to the spin-orbit coupling were determined.

Photochemical reaction of excited benzophenone in the gas phase

Photochemical reactions of benzophenone with hydrogen-donating compounds have been studied in the gas phase. It has been found that the photoreduction of excited benzophenone proceeds to form benzophenone ketyl radical without contributions from surrounding solvents. The quenching rate constant measurements of benzophenone triplet have suggested that, in addition to its role in the condensed phase, the charge-transfer interaction also plays an important role in the photoreduction processof benzophenone-amine systems in the gas phase

Photochemistry of benzophenone in aliphatic amines studied by laser photolysis in the temperature range 300-77 K

Laser photolysis studies of benzophenone in both sec-butylamine and triethylamines were carried out in the temperature range 300-77 K. For the sec-butylamine solution of benzophenone, the transients observed after laser pulsing are found to be the ketyl and anion radicals of benzophenone. The ratio of the yield for the formation of ketyl radical to that of the anion radical is markedly dependent on temperature: the ketyl radical is the major product at high temperatures while the anion radical becomes predominant at low temperatures. On the other hand, the triethylamine solution of benzophenone gives solely the ketyl radical as a photoproduct in the temperature range studied. The photochemical reaction of benzophenone in both sec-butylamine and triethylamine is markedly suppressed on going from high to low temperatures. These results are discussed in detail on the basis of the photochemical reaction mechanism involving the formation of the triplet charge-transfer complex (i.e., triplet exciplex) between triplet benzophenone and an amine molecule. The solvent effects on the photoreaction are also discussed.

An anomalous phase effect in the individual hyperfine lines of the CIDEP spectra observed in the photochemical reactions of benzophenone in micelles

An anomalous phase effect in the individual hyperfine lines of the CIDEP spectra observed in the photochemical reactions of benzophenone in micelles

ChemInform Abstract: AN UNUSUAL CIDEP OBSERVATION IN THE PHOTOCHEMICAL REACTIONS OF BENZOPHENONE AND ASCORBYL PALMITATE: THE ELUSIVE NEUTRAL ASCORBATE RADICAL

Chemischer InformationsdienstVolume 16, Issue 27 Physical Organic Chemistry ChemInform Abstract: AN UNUSUAL CIDEP OBSERVATION IN THE PHOTOCHEMICAL REACTIONS OF BENZOPHENONE AND ASCORBYL PALMITATE: THE ELUSIVE NEUTRAL ASCORBATE RADICAL M. T. CRAW, M. T. CRAWSearch for more papers by this authorM. C. DEPEW, M. C. DEPEWSearch for more papers by this authorJ. K. S. WAN, J. K. S. WANSearch for more papers by this author M. T. CRAW, M. T. CRAWSearch for more papers by this authorM. C. DEPEW, M. C. DEPEWSearch for more papers by this authorJ. K. S. WAN, J. K. S. WANSearch for more papers by this author First published: July 9, 1985 https://doi.org/10.1002/chin.198527052AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue27July 9, 1985 RelatedInformation

An unusual CIDEP observation in the photochemical reactions of benzophenone and ascorbyl palmitate: the elusive neutral ascorbate radical

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn unusual CIDEP observation in the photochemical reactions of benzophenone and ascorbyl palmitate: the elusive neutral ascorbate radicalMarjory T. Craw, M. Catherine Depew, and Jeffrey K. S. WanCite this: J. Am. Chem. Soc. 1985, 107, 4, 1084–1085Publication Date (Print):February 1, 1985Publication History Published online1 May 2002Published inissue 1 February 1985https://doi.org/10.1021/ja00290a069RIGHTS & PERMISSIONSArticle Views101Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (268 KB) Get e-Alerts Get e-Alerts

Spin-polarized radical pairs transiently produced by the photochemical reaction of benzophenone with aromatic amines

Spin-polarized triplet radical pairs produced by the photochemical reaction of triplet benzophenone with aromatic amines were detected in glassy matrices at 77 K using a time-resolved ESR method. By analysis of the spectra, it is concluded that the population of the Z spin sublevel of the radical pair whose principal axis is nearly parallel to the direction of the carbonyl group of benzophenone is predominant and its spin polarization is transferred from the initial polarization of the triplet state of benzophenone.

Polymer Effect on the Photochemical Reaction of Benzophenone with Tetrahydrofuran and with Diphenylamine in Benzene

The rate constant of hydrogen abstraction by the n, π* triplet state of poly(4-vinylbenzophenone) (PVBP) from tetrahydrofuran was compared with that of benzophenone (BP) in benzene solution at 25°C, the former being about twice as large as the latter. The electronic behavior of the triplet BP group in the polymer was investigated by T—T absorption and phosphorescence, being the same as that of BP. A well-resolved ESR spectrum of the diphenylamino radical was detected upon UV irradiation of a benzene solution of PVBP and diphenylamine (DPA) and its concentration was compared with that of the poly(vinylbenzophenone-co-methyl methacrylate)—DPA or BP—DPA system. The concentration decreased in the order: PVBP>copolymer>BP. The polymer effect on the rate constant and the radical formation was explained in terms of the increase in the reaction efficiency on account of energy migration along the side chain of the polymer.

Photochemical reactions of aromatic ketones with nucleic acids and their components. I. Purine and pyrimidine bases and nucleosides.

Abstract— The photochemical reactions of benzophenone and acetophenone with purine and pyrimidine derivatives in aqueous solutions have been investigated by flash photolysis and steady‐state experiments.Upon excitation of these two ketones in aqueous solutions, two transient species are observed: molecules in their triplet state and ketyl radicals. The triplet state lifetimes are 65 μsec for benzophenone and 125 μsec for acetophenone. The ketyl radicals disappear by a second order reaction, controlled by diffusion. In the presence of pyrimidine derivatives, the triplet state is quenched and the ketyl radical concentration is decreased without any change in its kinetics of disappearance. Ketone molecules in their triplet state react with purine derivatives leading to an increase in the yield of ketyl radicals due to H‐atom abstraction from the purines.Steady‐state experiments show that benzophenone and acetophenone irradiated in aqueous solution at wavelengths longer than 290 nm undergo photochemical reactions. The rate of these photochemical reactions is increased in the presence of pyrimidine derivatives and even more in the presence of purine derivatives. Following energy transfer from the triplet state of benzophenone to diketopyrimidines, cyclobutane dimers are formed. The energy transfer rate decreases in the order orotic acid > thymine > uracil. Benzophenone molecules in their triplet state can also react chemically with pyrimidine derivatives to give addition photoproducts.All these results are discussed with respect to photosensitized reactions in nucleic acids involving ketones as sensitizers.

The photochemical reaction of benzophenone with diphenylamine

The photochemical reaction of benzophenone with diphenylamine affords 4-(N-phenylamino)phenyldiphenylmethanol (I) in a good yield, and an ion-pair intermediate is suggested.

Photochemical reaction of benzophenone with enamines

Work-up of products of the title reaction gives γ-hydroxy ketones produced formally by addition of benzophenone at the β-position of ketones on which the enamines are based. Benzpinacol is the major product isolated in all cases. While morpholine enamines give oxetanes resulting from cycloaddition of benzophenone at the enamine double bond, the reaction of piperidine enamines does not afford similar adducts. Accounts for the reaction mechanism are given by assuming benzophenone triplet as a reactive species.

Photochemical reactions with phenols. I. The photochemical reaction of benzophenone with 2,6-di-ert-butylphenol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical reactions with phenols. I. The photochemical reaction of benzophenone with 2,6-di-ert-butylphenolHans Dieter BeckerCite this: J. Org. Chem. 1967, 32, 7, 2115–2124Publication Date (Print):July 1, 1967Publication History Published online1 May 2002Published inissue 1 July 1967https://doi.org/10.1021/jo01282a012RIGHTS & PERMISSIONSArticle Views200Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Photochemical Reactions of Benzophenone in Alcohols1

Photochemical Reactions of Benzophenone in Alcohols¹