Double Self‐Inclusion by Rotating Glucopyranose Units in Per‐O‐methylated β‐Cyclodextrin Moieties Attached to a Porphyrin in Aqueous Solution

Double self‐inclusion of the porphyrin part by two per‐O‐methylated β‐cyclodextrin moieties, which were attached to the 4‐positions of the phenyl groups of 10,20‐bis(3,5‐dicarboxylatophenyl)‐5,15‐diphenylporphyrin, occurred through 360° rotation of two glucopyranose units in the per‐O‐methylated cyclodextrin moieties. The self‐inclusion proceeded quantitatively in aqueous solution. As the porphyrin ring was completely covered by two cyclodextrin moieties, no fluorescence quenching of the porphyrin by 9,10‐anthraquinone‐2‐sulfonate took place. The intramolecular self‐inclusion is achieved by destroying a hydrogen‐bond belt at the secondary OH group side of the native cyclodextrin by O‐methylation and extremely strong hydrophobic effects resulting from complexation of the porphyrin with per‐O‐methylated β‐cyclodextrin. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)