The effect of dimethyl sulfoxide on the kinetics of azo dye-cyclomaltohexaose (α-cyclodextrin) inclusion complex formation

✍ Scribed by Aydin Örstan; John F. Wojcik

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 372 KB
• Volume: 176
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(88)84067-9

✦ Synopsis

Thermodynamic studies indicate that the inclusion complexes of cycloamyloses (cyclodextrins) are less stable either in pure organic solventsl, or in waterorganic solvent mixtureP4, than they are in pure water. Furthermore, according to the results of Harrison and Eftink*, and &tan and Ross4, the macroscopic solvent surface tension appears to be a critical solvent property in determining the thermodynamic stabilities of cycloamylose complexes.

To investigate the solvent effects on the kinetics of the formation of cycloamylose complexes, we have measured the rate constants for complex formation between cyclomaltohexaose ((Y-CD) and an azo dye (1) in mixtures of water with dimethyl sulfoxide (Me,SO) at 25" by use of the temperature-jump method. Our previous results5 indicated that the formation of a complex between dye 1 and a-CD in aqueous solution can be represented by Eq. ( 1), where k, and k_, are the forward