Comparative study on the inclusion interaction between meso-tetrakis(4-N-ethylpyridiniurmyl) porphyrin and β-cyclodextrin derivatives

The interaction of beta-cyclodextrin (beta-CD) and the modified cyclodextrins, hydroxy propyl-beta-cyclodextrin (HP-beta-CD), sulfobutylether-beta-cyclodextrin (SBE-beta-CD) and synthesized meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) in aqueous solution has been studied by spectroscopic methods systematically. A significant change in fluorescence and absorption properties has been observed in the presence of beta-CD, HP-beta-CD and SBE-beta-CD. The stoichiometry and formation constants have been determined by the steady-state fluorescence technique. The results showed that the beta-CD derivatives were prior to the native beta-CD and the hydrogen bonding and static electric forces played important roles in the formation of the inclusion complexes. The conformation was further confirmed by NMR spectroscopy.