The interactions of Rose Bengal (RB) with α-cyclodextrin (α-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxypropyl-γ-cyclodextrin (HP-γ-CD), heptakis(2,3,6-tri-O-methyll)-β-cyclodextrin (TM-β-CD) were studied in aqueous solutions of 0.1 M KClO4 and 0.1 M LiClO4 by vis absorption, fluorescence spectroscopy as well as electrochemical measurements at 298 K. The spectrophometric results indicate that RB is included in all β- and γ-CDs forming complexes with a stoichiometry 1:1 whose stability is slightly higher in KClO4 than in LiClO4 solutions. The complex stability constants determined for salt-containing CD solutions are lower than those for water solutions. The complexation of RB with β- and γ-CD and the differences between the complexes obtained in the presence of the two salts were confirmed by an electrochemical study.
Study on the aggregation and electrochemical properties of Rose Bengal in aqueous solution of cyclodextrins
CATUCCI, Lucia;COSMA, Pinalysa;AGOSTIANO, Angela
2007-01-01
Abstract
The interactions of Rose Bengal (RB) with α-cyclodextrin (α-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), hydroxypropyl-γ-cyclodextrin (HP-γ-CD), heptakis(2,3,6-tri-O-methyll)-β-cyclodextrin (TM-β-CD) were studied in aqueous solutions of 0.1 M KClO4 and 0.1 M LiClO4 by vis absorption, fluorescence spectroscopy as well as electrochemical measurements at 298 K. The spectrophometric results indicate that RB is included in all β- and γ-CDs forming complexes with a stoichiometry 1:1 whose stability is slightly higher in KClO4 than in LiClO4 solutions. The complex stability constants determined for salt-containing CD solutions are lower than those for water solutions. The complexation of RB with β- and γ-CD and the differences between the complexes obtained in the presence of the two salts were confirmed by an electrochemical study.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
