http://www.cnr.it/ontology/cnr/individuo/prodotto/ID273074
Geometrical effects on the intramolecular quenching of pi,pi * aromatic ketones by phenols and indoles (Articolo in rivista)
- Type
- Label
- Geometrical effects on the intramolecular quenching of pi,pi * aromatic ketones by phenols and indoles (Articolo in rivista) (literal)
- Anno
- 2004-01-01T00:00:00+01:00 (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
- 10.1021/jo048973v (literal)
- Alternative label
Perez-Prieto, J. and Stiriba, S. E. and Bosea, F. and Lahoz, A. and Domingo, L. R. and Monti, S. and Miranda, M. A. (2004)
Geometrical effects on the intramolecular quenching of pi,pi * aromatic ketones by phenols and indoles
in Journal of organic chemistry
(literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Perez-Prieto, J. and Stiriba, S. E. and Bosea, F. and Lahoz, A. and Domingo, L. R. and Monti, S. and Miranda, M. A. (literal)
- Pagina inizio
- Pagina fine
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- 44 AMER CHEMICAL SOC 877EJ (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
- Rivista
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- Departamento de Quimica Organica/ICMOL, Universidad de Valencia, Av. Vicent Andres Estelles s/n,
46100 Burjassot, Valencia, Departamento de Quimica/Instituto de Tecnologia Quimica UPV-CSIC,
Universidad Politecnica de Valencia, Camino de Vera s/n, 46071 Valencia, and Istituto per la Sintesi
Organica e la Fotoreattivita´, CNR, Via Piero Gobetti 101, 40129 Bologna (literal)
- Titolo
- Geometrical effects on the intramolecular quenching of pi,pi * aromatic ketones by phenols and indoles (literal)
- Abstract
- Laser flash photolysis of a series of bichromophoric compounds 1-12 containing the 2-benzoylthiophene (BT) and phenol (PhOH) or indole (InH) moieties has been used to determine the possible geometrical effects in the intramolecular quenching of triplet excited ketones, resulting in formal hydrogen abstraction. The results are compared with those obtained in the intermolecular process. In both cases, substitution either at the thienyl or the phenyl moiety has a marked influence on the photoreactivity. Time-resolved experiments showed that the rate constants for bimolecular quenching by phenol and indole of 2-benzoylthiophene substituted at the thienyl 5-position were lower than those for BT substituted at the phenyl p-position, which agrees with the higher energy found for the excited triplet state of the latter compounds. However, the rate constant for hydrogen abstraction in the bichromophoric compounds by the triplet state of the derivatives with the spacer linked to the thienyl 5-position are higher than those of their regioisomers. These results indicate a possible geometry-dependence in the intramolecular quenching process. Theoretical DFT studies have been carried out in order to estimate the optimum conformation for hydrogen abstraction in two pairs of phenolic and indolic bichromophoric regioisomers. The energy profile for photoactivation/deactivation of the aromatic ketone and the structures of the triplet states and biradicals involved in the process have been determined. The observed regiodifferentiation in the experimental studies is consistent with a dependence of the rate constant on orbital overlap between the carbonyl oxygen and the X-H bonds. (literal)
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