Determination of the Inclusion Constants for the Inclusion Complexes between meso-Tetrakis (4-sulfonatophenyl) Porphyrin and Cyclodextrins by Three Methods

摘要

In this paper, the interactions of meso-Tetrakis (4-sulfonatophenyl) porphyrin (TPPS_4) and six cyclodextrins have been studied, respectively, by fluorescence spectroscopy, polarography and thin-layer chromatography. The inclusion constants of different methods are determined and the comparison of inclusion capacity of various cyclodextrins indicates that for the ionic cyclodextrins the charge interaction plays an important role in the inclusion procedure. The thermodynamic parameters of interaction imply that the inclusion process shows the enthalpy-entropy compensation effect. Cyclodextrin, being regarded as an artificial analogue of proteinoid of heme, provides a protective sheath for porphyrin. However, the TPPS_4, encapsulated within this saccharid-coated barrier, its solubility is enhanced prominently, which exhibits that this interaction may modify the biological properties of TPPS_4 that owned the similar properties as hematoporhyrin.