Density functional theory (DFT) calculations were performed for twelve 5-substituted N-b-acetyl-1-methoxytryptamines (5-X: NO2, SO2CH3, CN, CF3, Cl, H, CH3, OH, OCH3, NHCOCH3, NH2, N(CH3)(2)) in methanol. The respective HOMO -> LUMO and HOMO-1 -> LUMO singly excited configurations are mainly responsible for the lowest and the second singlet excited states (S-1 and S-2)Observed UV absorption spectra of 5-H, 5-NHAc, and 5-CH3 derivatives are well predicted by simple time-dependent DFT calculations. Distinct substituent effects are found with respect to the energies of MOs responsible for S-1 <- S-0 and S-2 <- S-0 transitions. Both HOMO-1 and HOMO are destabilized by electron-donating groups, and stabilized by electron-withdrawing groups. LUMO+1 of 5-NO2 derivative should be classified into normal LUMO, which are found for eleven other derivatives as well as indole. Normal LUMO is not significantly affected in energy by electron-donating groups, but stabilized by electron-withdrawing groups.

Almost the same ultraviolet absorption spectra with a broad peak at 292-294 nm and a shoulder peak at 275 nm were observed for methanol solutions of 1-hydroxyindoles with various C-C-N b side chains at 3-position such as 1 -hydroxy-N b -methoxycarbonyltryptamine (1), N b -acetyl-11-hydroxytryptophan methyl ester (2), N, N-dimethyl-l-hydroxyindole-3-acetamide (3), and l-hydroxy-N b -pivaloyltryptamine (4). Dual fluorescence excitation and emission spectra resulting from 1 L a - 1 A and 1 L b - 1 A fluorescence emissions were observed for these 1-hydroxyindoles (1 - 4). Excitation spectra were found to be dependent on observing wavelength of broad fluorescence emission spectra (λ max = 346-350 nm for 1, 2, and 3; λ max = 366 nm for 4). Dual fluorescence behaviors can be explained by the fact that 1 L a state locates slight below 1 L b state, and it is supported by time-dependent density functional theory calculations of 1 - 4 in methanol. It is noteworthy that dual fluorescence behaviors are delicately modified by C-C-N b side chain at 3-position of indole ring.

Deoxygenation of 6-cyanophenanthridine 5-oxide (6CPNO) in the lowest triplet state was confirmed by triplet sensitization of proflavine with visible S 1 ←S 0 absorption band ( λ max =460 nm) in ethanol. Absorption bands of 6-cyanophenanthridine (6CP) grew up at the expense of those of the N -oxide in a selective steady-light (>420 nm) irradiation of proflavine in the presence of the N -oxide. In the 460 nm laser pulse excitation of proflavine, furthermore, weak transient absorption due to sensitized triplet of the N -oxide was detected around 410 nm.

Significantly Stokes-shifted fluorescence induced by the UV photoexcitation of 2,2'-bipyridin-3-ol in 3-methylpentane exhibits a dramatic temperature dependence such that dual fluorescence spectra (lambda(max) = 560 and 585 nm) at room temperature are replaced by a single fluorescence spectrum (lambda(max) = 560 nm) below 200 K. The respective emitting species responsible for the short- and long-wavelength bands may be ascribed to the excited-state primary phototautomer (S-1') and its rotamer (S-1 "), which is generated by, the rotational isomerization of S-1' with an activation barrier.

The quenching rates of the 1A2 fluorescence-state p-X-benzyls (X = F, Cl, OCH3, and OCH2ph) by molecular oxygen were determined to be (1.8-2.3) x 10(10) M-1 s-1, which are about 1 order of magnitude higher than the ground-state oxygenation rates. Physical quenching at the diffusion-limited rate and oxygenation reaction at a lower rate were demonstrated for the reactivities of the excited state (1A2) and the ground state (1B2) toward molecular oxygen, respectively. A poor quenching rate of 6.7 x 10(9) M-1 s-1 for p-cyanobenzyl in the 2B2 fluorescent state implies that the excited-state oxygenation competes with the physical quenching. The oxygenation rate of benzyl radical in the ground state (1B2) was reduced by the introduction of stabilizing substituents (Cl, phenyl, Br, NO2, and CN) at thc para position. A good correlation was found between the oxygenation rate and thc free radical substituent parameter (sigma.) based upon the NBS bromination of 4-substituted 3-cyanotoluene.

ChemInformVolume 20, Issue 17 Physical Organic Chemistry ChemInform Abstract: Lifetime and Electronic Spectra of p-Methoxybenzyl Radical in the Lowest Excited Doublet State in Solution K. TOKUMURA, K. TOKUMURA Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorT. OZAKI, T. OZAKI Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorM. UDAGAWA, M. UDAGAWA Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorM. ITOH, M. ITOH Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this author K. TOKUMURA, K. TOKUMURA Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorT. OZAKI, T. OZAKI Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorM. UDAGAWA, M. UDAGAWA Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorM. ITOH, M. ITOH Fac. Pharm. Sci., Grad. Sch., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this author First published: April 25, 1989 https://doi.org/10.1002/chin.198917049Read the full textAboutPDF 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. Volume20, Issue17April 25, 1989 RelatedInformation

ChemInformVolume 18, Issue 28 Preparative Organic Chemistry ChemInform Abstract: Photochemistry of Transient Tautomer of 7-Azaindole H-Bonded Dimer (I) Studied by Two-Step Laser Excitation Fluorescence Measurements. K. TOKUMURA, K. TOKUMURA Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorY. WATANABE, Y. WATANABE Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorM. UDAGAWA, M. UDAGAWA Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorM. ITOH, M. ITOH Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this author K. TOKUMURA, K. TOKUMURA Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorY. WATANABE, Y. WATANABE Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorM. UDAGAWA, M. UDAGAWA Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this authorM. ITOH, M. ITOH Dep. Biochem., Univ. Tel Aviv, 69978 Tel Aviv, Isr.Search for more papers by this author First published: July 14, 1987 https://doi.org/10.1002/chin.198728116AboutPDF 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue28July 14, 1987 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDoublet-doublet fluorescence and coupling reactions of 9-anthrylmethyl radical in fluid hexane solution studied by two-step laser excitation fluorescence spectroscopyKunihiro Tokumura, Naruhiro Mizukami, Masahiro Udagawa, and Michiya ItohCite this: J. Phys. Chem. 1986, 90, 17, 3873–3876Publication Date (Print):August 1, 1986Publication History Published online1 May 2002Published inissue 1 August 1986https://pubs.acs.org/doi/10.1021/j100408a005https://doi.org/10.1021/j100408a005research-articleACS PublicationsRequest reuse permissionsArticle Views145Altmetric-Citations17LEARN 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 InRedditEmail Other access options Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo-step laser excitation fluorescence study of the reactions of the 1-naphthylmethyl radical produced in the 248-nm krypton fluoride laser photolysis of 1-(chloromethyl)naphthalene in hexane at room temperatureKunihiro Tokumura, Masahiro Udagawa, and Michiya ItohCite this: J. Phys. Chem. 1985, 89, 24, 5147–5149Publication Date (Print):November 1, 1985Publication History Published online1 May 2002Published inissue 1 November 1985https://doi.org/10.1021/j100270a003RIGHTS & PERMISSIONSArticle Views76Altmetric-Citations23LEARN 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

Aus der Titelverbindung entsteht bei UV-Bestrahlung in Ethanolglas bei 77 Kdas Oxaziridin (II), das bei Warmezufuhr mit dem flussigen Losungsmittel zum Ether (I) reagiert.

The photolysis of 6-cyanophenanthridine 5-oxide (1) in various solvents was reported. In addition to the expected 6-cyanodibenz [d, f] [1, 3] oxazepine (2), two new types of rearrangement products : 5-alkoxyphenanthridin-6 (5H)-one (3), as a byproduct in the photolyses using an aprotic solvent, were obtained in the present experiments. In order to account for the formation of these products (3 and 9), reasonable assumptions that the oxygen walk process from the oxaziridine species (11) leading to the oxazepine (2) is relatively inhibited to occur and thus 11 has a longer life time as compared to the related oxaziridines derived from α-cyanated bicyclic amine N-oxides were proposed. A mechanistic rationalization and characteristic features in the photochemical rearrangement reactions of 1 are discussed in detail, together with the structure determinations of the photoproducts.

Intersystem crossing probabilities φST of acridine in methanol, ethanol, and 2-propanol were determined by two newly developed methods, relative (r) and absolute (a). The results are as follows. Methanol; 0.27 (r), 0.31 (a). Ethanol; 0.29 (r), 0.33 (a). 2-Propanol; 0.43 (r), 0.45 (a). The above φST values added to the quantum yield values already obtained of photoreduction occurring at T(n-π*), viz., 2φRT (radical mechanism via T(n-π*), disproportionation of semiquinone being taken into account by a factor of 2) + φMT (molecular mechanism via T(n-π*)), become about the same for the three alcohols. Thus the present data are consistent with our previous data on photoreduction if the intersystem crossing is assumed to occur mainly via S*(π-π*)→T(n-π*)→T(π-π*) with the same total φST for the three alcohols but with T(n-π*) participating in the reaction in different extent according to the alcohol.