The complexation chemistry of cycloamyloses: Equilibrium constants by novel spectrophotometric methods

✍ Scribed by Robert I. Gelb; Lowell M. Schwartz; Beatriz Cardelino; Daniel A. Laufer

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 634 KB
• Volume: 103
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(80)90624-7

✦ Synopsis

Formation constants for binary complexes of cyclohexaamylose (Cy) and p-nitrophenoll p-nitrophenolate (PNP/PNP-) are determined by means of a novel acid-base spectrophotometric analysis. Thermodynamic parameters A Ho and AS0 are derived from the temperature dependences of these constants in the range 20-40°C. The Cy/PNP/PNP-system is then employed as a spectrophotometric indicator to estimate Cy complex formation constants with acid-base inactive substrates potassium perchlorate and sodium benzoate at 25°C and pH 6.8. The advantages and limitations of these methods in comparison with spectrophotometric analyses relying on the Hildebrand-Benesi equation are discussed.