Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Complexation dynamics of xanthone and thioxanthone to beta-cyclodextrin derivatives
Autore:
Okano, LT; Barros, TC; Chou, DTH; Bennet, AJ; Bohne, C;
Indirizzi:
Univ Victoria, Dept Chem, Victoria, BC V8W 3V6, Canada Univ Victoria Victoria BC Canada V8W 3V6 em, Victoria, BC V8W 3V6, Canada Simon Fraser Univ, Dept Chem, Burnaby, BC V5A 1S6, Canada Simon Fraser Univ Burnaby BC Canada V5A 1S6 , Burnaby, BC V5A 1S6, Canada
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 11, volume: 105, anno: 2001,
pagine: 2122 - 2128
SICI:
1520-6106(20010322)105:11<2122:CDOXAT>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTERSYSTEM CROSSING KINETICS; ULTRASONIC RELAXATION METHOD; TRIPLET-TRIPLET ABSORPTION; EQUILIBRIUM-CONSTANTS; AQUEOUS-SOLUTION; SOLVENT DEPENDENCE; AROMATIC KETONES; PHOTOCHEMISTRY; FLUORESCENCE; NAPHTHYLETHANOLS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Bohne, C Univ Victoria, Dept Chem, POB 3065, Victoria, BC V8W 3V6, Canada Univ Victoria POB 3065 Victoria BC Canada V8W 3V6 V8W 3V6, Canada
Citazione:
L.T. Okano et al., "Complexation dynamics of xanthone and thioxanthone to beta-cyclodextrin derivatives", J PHYS CH B, 105(11), 2001, pp. 2122-2128

Abstract

The complexation dynamics of xanthone to substituted beta -cyclodextrins (CDs) and of thioxanthone to beta -CD was studied by directly following the relocation of the excited triplet-state ketones from the CD cavity to the aqueous phase. Equilibrium constants for the ground-state complexation of both ketones with CDs were determined from fluorescence studies. The complexation efficiency and dynamics of thioxanthone with beta -CD were the same aspreviously observed for the xanthone/beta -CD system. Substitution of someof the hydrogens on the alcohol groups by methyl moieties at both entrances to the beta -CD cavity increased the equilibrium constant for ground-state xanthone, but decreased that for the excited triplet state, leading to a larger difference for the binding behavior of these two electronic States of the guest. Addition of one pendant arm containing a carboxyl moiety to the rim where xanthone is bound does not change the binding efficiency of theground state or the binding dynamics of triplet xanthone. In contrast, when this arm contains an ethyl ester moiety, the binding efficiencies of boththe ground and excited triplet states are increased. The higher binding constant for triplet xanthone is due to an increase of the association rate constant and a decrease for the dissociation rate constant.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/03/20 alle ore 10:32:25