Excited-state proton transfer of weak photoacids adsorbed on biomaterials: 8-hydroxy-1,3,6-pyrenetrisulfonate on chitin and cellulose.
J Phys Chem A
; 119(10): 1973-82, 2015 Mar 12.
Article
em En
| MEDLINE
| ID: mdl-25692323
ABSTRACT
Time-resolved and steady-state florescence measurements were used to study the photoprotolytic process of an adsorbed photoacid on cellulose and chitin. For that purpose we used the 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) photoacid which transfers a proton to water with a time constant of 100 ps, but is incapable of doing so in methanol or ethanol. We found that both biopolymers accept a proton from the electronically excited acidic ROH form of HPTS. The excited-state proton-transfer (ESPT) rate of HPTS adsorbed on chitin is greater than that on cellulose by a factor of 5. The ESPT on chitin also occurs in the presence of methanol or ethanol, but at a slower rate. The transferred protons can recombine efficiently with the conjugate excited base, the RO(-) form of HPTS.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Prótons
/
Pirenos
/
Ácidos Sulfônicos
/
Celulose
/
Quitina
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article