Study on the aggregation and electrochemical properties of Rose Bengal in aqueous solution of cyclodextrins.
The interactions of Rose Bengal (RB) with alpha-cyclodextrin (alpha-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD), heptakis(2,3,6-tri-O-methyll)-beta-cyclodextrin (TM-beta-CD) were studied in aqueous solutions of 0.1 M KClO(4) and 0.1 M LiClO(4) by vis absorption, fluorescence spectroscopy as well as electrochemical measurements at 298 K. The spectrophometric results indicate that RB is included in all beta- and gamma-CDs forming complexes with a stoichiometry 1:1 whose stability is slightly higher in KClO(4) than in LiClO(4) solutions. The complex stability constants determined for salt-containing CD solutions are lower than those for water solutions. The complexation of RB with beta- and gamma-CD and the differences between the complexes obtained in the presence of the two salts were confirmed by an electrochemical study.
Fini
Paola
P
IPCF-CNR, sezione di Bari, c/o Dipartimento di Chimica, Università degli Studi di Bari, Via Orabona 4, 70126 Bari, Italy. p.fini@ba.ipcf.cnr.it
Loseto
Raffaele
R
Catucci
Lucia
L
Cosma
Pinalysa
P
Agostiano
Angela
A
D003505:Cyclodextrins / Q000737:chemistry*; D004563:Electrochemistry; D015394:Molecular Structure; D012395:Rose Bengal / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis
D003505:Cyclodextrins; D012996:Solutions; D012395:Rose Bengal