Controllable Direction of Porphyrin Derivatives in Two Cyclodextrin Cavities

Porphyrin-trimethyl-β-cyclodextrin (TMe-β-CDx) complexes have pseudorotaxane structures in which two mesophenyl and/or pyridyl moieties penetrate the upper rim of two TMe-β-CDx molecules. Porphyrin derivatives with one to three pyridyl moieties at meso-positions formed complexes with TMe-β-CDx in which penetration of the upper rim of the two TMe-β-CDxs by the pyridyl moieties was minimized. In contrast, in TMe-β-CDx complexes formed with porphyrin derivatives with two 2-methoxyphenyl moieties and two pyridyl moieties, the pyridyl moieties penetrated the upper rim of the two molecules because steric hindrance prevented penetration by the 2-methoxyphenyl moieties.This work was supported by a JSPS KAKENHI Grant-in-Aid for Scientific Research (B) (Grant No. JP16H04133), a Grant-in-Aid for Challenging Exploratory Research (Grant No. JP16K13982), and the Electric Technology Research Foundation of Chugoku