2002 Volume 75 Issue 11 Pages 2371-2377
In pH 10.1 buffers, the interactions of tetrakis(4-carboxyphenyl)porphyrin (TCPP) with γ-cyclodextrin (γ-CD), heptakis(2,3,6-tri-O-methyl)-β-CD (TM-β-CD), and 1,1′-diheptyl-4,4′-bipyridinium dibromide (HB) have been examined by studying absorption, fluorescence, and induced circular dichroism spectra of TCPP. TCPP has been found to form inclusion complexes with γ-CD and TM-β-CD. The stoichiometries of the γ-CD–TCPP and TM-β-CD–TCPP inclusion complexes are 1 : 1 and 2 : 1, respectively. Because the equilibrium constant for the formation of the 2 : 1 TM-β-CD–TCPP inclusion complex is exceedingly large (4.34 × 1018 mol−2 dm6), the TM-β-CD–TCPP inclusion complex is quantitatively formed in TCPP solutions containing two equivalents of TM-β-CD. TCPP also forms an organic cation–organic anion complex with HB. In the presence of γ-CD, the TCPP–HB complex forms a 1 : 1 : 1 γ-CD–TCPP–HB inclusion complex, although TM-β-CD causes the dissociation of the TCPP–HB complex into its components. The equilibrium constant for the formation of the γ-CD–TCPP–HB inclusion complex from the TCPP–HB complex and γ-CD has been evaluated to be 905 mol−1 dm3.
This article cannot obtain the latest cited-by information.