TY - JOUR
T1 - Effects of colloidal SiO2 and cyclodextrins on the aggregation of dyes in aqueous solutions
AU - Dan, Phyllis
AU - Willner, Itamar
AU - Dixit, Nagaraj S.
AU - Mackay, Raymond A.
PY - 1984
Y1 - 1984
N2 - Aggregation of two positively charged dyes, Methylene Blue, MB+ (1), and pinacyanol chloride, PC+, (2) is induced in aqueous SiO 2 colloids. In colloidal SiO2, MB+ aggregates into the dimeric form, and PC+ is aggregated into H-assemblies. The aggregation processes are a result of high local dye concentrations in the vicinity of the colloid owing to binding of the positively charged dyes to the negatively charged colloidal interface. De-aggregation of thionin, (3), is accomplished in water by the addition of cyclohexaamylose, α-CD, and cyclohepta-amylose, β-CD. Monomeric thionin binds to α-CD and β-CD (Kass. = 6.67 x 1O2 M-1 and 1.78 x 103 M-1, respectively). Conversion of thionin dimer into the monomeric form, upon addition of α-CD or β-CD, is attributed to association of the monomeric form to the hydrophobic cavity of CD. This conversion is accompanied by changes in the absorption and fluorescence spectra of the dye.
AB - Aggregation of two positively charged dyes, Methylene Blue, MB+ (1), and pinacyanol chloride, PC+, (2) is induced in aqueous SiO 2 colloids. In colloidal SiO2, MB+ aggregates into the dimeric form, and PC+ is aggregated into H-assemblies. The aggregation processes are a result of high local dye concentrations in the vicinity of the colloid owing to binding of the positively charged dyes to the negatively charged colloidal interface. De-aggregation of thionin, (3), is accomplished in water by the addition of cyclohexaamylose, α-CD, and cyclohepta-amylose, β-CD. Monomeric thionin binds to α-CD and β-CD (Kass. = 6.67 x 1O2 M-1 and 1.78 x 103 M-1, respectively). Conversion of thionin dimer into the monomeric form, upon addition of α-CD or β-CD, is attributed to association of the monomeric form to the hydrophobic cavity of CD. This conversion is accompanied by changes in the absorption and fluorescence spectra of the dye.
UR - http://www.scopus.com/inward/record.url?scp=37049091725&partnerID=8YFLogxK
U2 - 10.1039/P29840000455
DO - 10.1039/P29840000455
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AN - SCOPUS:37049091725
SN - 1472-779X
SP - 455
EP - 459
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 3
ER -