936. Prototropic equilibria of electronically excited molecules. Part I. 3-Hydroxyquinoline

Haylock, J. C.; Mason, S. F.; Smith, Bennett E.

doi:10.1039/jr9630004897

Cited by 18 publications

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“…The neutral molecules (II and VII), not unexpectedly (see , appear to be non-fluorescent. The neutral form of 3-hydroxyquinoline, which is a comparable form, is also nonfluorescent in water (Haylock, Mason & Smith, 1963).…”

Section: Resultsmentioning

confidence: 99%

Fluorescence studies on some hydroxypyridines including compounds of the vitamin B6 group

Bridges¹,

Davies²,

Rd³

1966

Biochemical Journal

123

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1. The variations with pH (from 36n-sulphuric acid to 10n-sodium hydroxide) of the excitation and fluorescence wavelengths and fluorescence intensity of 2-, 3- and 4-hydroxypyridine and their O- and N-methyl derivatives were investigated. 2. 4-Hydroxy- and 4-methoxy-pyridine were non-fluorescent at all pH values. 3. The cations and dipolar ions of the 3-hydroxypyridine derivatives and the anion of 3-hydroxypyridine were fluorescent, but the neutral forms were not. 4. All the forms of the 2-hydroxypyridine derivatives were fluorescent. 5. Pyridoxol, pyridoxal and its 5-phosphate, pyridoxamine and pyridoxic acid and its lactone were studied similarly. All these compounds, except pyridoxal 5-phosphate, were more fluorescent than 3-hydroxypyridine. 6. The most fluorescent forms of these compounds are the anions, except for pyridoxol, where the dipolar ion was the most fluorescent form. The least fluorescent forms are the neutral molecules. The dipolar ions were appreciably fluorescent in all cases. 7. The most fluorescent form examined was the dianion of pyridoxic acid lactone. 8. The cations were all fluorescent except the cations of 2- and 3-methoxypyridine. All the cations showed excited-state ionization. The excited pK(a) values of these cations were determined and the results are discussed with reference to Weller's (1952) equation relating ground- and excited-state dissociation constants. 9. The pK(a) values for all ionizations undergone by the compounds examined were determined from fluorescence data. 10. Stokes shifts for the various ionic and neutral species of the compounds examined were calculated and are discussed.

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Section: Resultsmentioning

confidence: 99%

Fluorescence studies on some hydroxypyridines including compounds of the vitamin B6 group

Bridges¹,

Davies²,

Rd³

1966

Biochemical Journal

123

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“…indole derivatives, show pH-dependent variations in the intensity and spectral properties of the fluorescence because of acid-base dissociation, i.e. effects of the first type ( HAYLOCK et al 1963;BRIDGES and WILLIAMS 1968;CHEN 1968). The pH-dependent variations of the formaldehyde-induced tryptamine fluorescence can also be explained by transitions between ionic species of the fluorophore, as exemplified for 3,4-dihydronorharman in Fig.…”

Section: The Influence Of Phmentioning

confidence: 93%

Histochemical Demonstration of Tryptamine. Properties of the Formaldehyde‐induced Fluorophores of Tryptamine and Related Indole Compounds in Models

Björklund

Falck

Håkanson

1968

Acta Physiologica Scandinavica

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Summary A sensitive histochemical fluorescence procedure for the demonstration of tryptamine by a formaldehyde condensation reaction has been devised. This gives a 13–18 fold increase in the fluorescence yield of tryptamine compared with the conventional Falck‐Hillarp method. The conditions of the conventional formaldehyde condensation reaction were modified in the following two ways: 1. A gaseous oxidant (ozone) was introduced into the reaction vessel. Up to a certain concentration of ozone, the yield of the formaldehyde‐induced tryptamine fluorescence was markedly increased, probably because of an increased oxidative dehydrogenation of the initial condensation product. None of the other compounds tested showed such an increase in the fluorescence yield upon the combined formaldehyde‐ozone procedure. In fact, the fluorescence yields of catecholamines and 5‐HT were reduced to about 20 % compared with the yields in the conventional formaldehyde treatment. This decrease in the fluorescence intensity was presumably caused by an oxidative break‐down of the amines or of their fluorophores. 2. The amine models were acidified by means of HC1‐vapour or glacial acetic acid after the conventional formaldehyde treatment, causing a marked increase in the fluorescence yield of tryptamine. The microspectrofluorimetric characteristics of the fluorophores of different indole compounds (tryptamine, N‐methyl tryptamine, 5‐HT, and tryptophan) where studied at various pH both after conventional formaldehyde treatment and after combined formaldehyde‐ozone treatment. The behaviour of the tryptamine fluorophore under various conditions was characteristic and differed from that of the other indoles and catechols tested, which makes possible the microspectrofluorimetric identification of tissue tryptamine. The combined formaldehyde‐ozone reaction and the acidification after the formaldehyde reaction have been successfully applied to tissues incubated with tryptamine, and they provide sensitive and almost selective methods for the detection of tryptamine at the cellular level.

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“…al., 1950; Baciocchi & Illuminati, 1957], poucos trabalhos tem sido relatados sobre a transmissão de efeito de substituíntes para reações em outros sítios de reação da quinolina. Estudo realizado por Illuminati eco-autores [Illuminati & Marino, 1958; [Haylock et al, 1963;Mason et al, 1968].…”

Section: Efeito De Solventeunclassified

Propriedades fotofísicas e Fotoquímicas de derivados de naftol e quinolina um estudo de fotoácido e fotobase como possíveis fios moleculares

Chang¹

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Primeiramente gostaria de agradecer ao meu orientador, Prof. Dr. Politi, pela orientação e discussões, por ter me ensinado muito do pouco que sei sobre química e pela paciência e ajuda experimental e teórica no transcorrer de meu trabalho e pela ajuda em todos os momentos que foi preciso. A todos os professores do grupo do Bl0 e do B12. Em especial ao Prof. Hernan por assistir minha apresentação, à Iolanda pela simpatia e disponibilidade com que sempre me ajudou, ao Willi pelas discussões sobre fotoquímica, ao Lique pela ajuda no início do meu doutorado, ao Ivan e à Daisy pelas discussões em espectroscopia RMN, ao Farah pelo interesse acerca de modelagem molecular durante minha qualificação e ao Maurício pela colaboração. Ao Dr. Luís, ao Guilherme e ao Erick pelas ajudas em cálculos, à Dra. Teresa Cristina pela correção do meu português e pela gentileza, ao Dr. Sérgio pela discussão acerca dos mecanismos fotoquímicos envolvidos na tese, aos Dr. Valdecir e Dr. Carlos meus amigos, pela amizade e consultas no lab, à Dra. Magali pela ajuda e amizades, ao Dr. Marcos e ao. Emiliano pelas conversas animadoras, ao Dr. Greg e Tiago por ajudar em informática e pela amizade; ao David pela "organização" do seminário e aos amigos de trabalho,

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936. Prototropic equilibria of electronically excited molecules. Part I. 3-Hydroxyquinoline

Cited by 18 publications

References 0 publications

Fluorescence studies on some hydroxypyridines including compounds of the vitamin B6 group

Fluorescence studies on some hydroxypyridines including compounds of the vitamin B6 group

Histochemical Demonstration of Tryptamine. Properties of the Formaldehyde‐induced Fluorophores of Tryptamine and Related Indole Compounds in Models

Propriedades fotofísicas e Fotoquímicas de derivados de naftol e quinolina um estudo de fotoácido e fotobase como possíveis fios moleculares

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