Abstract

The crown conformer of a calix[4]resorcinarene (CRA) possessing eight carboxymethylated units at the lower rim and four cinnamoyl residues at the upper rim was prepared to fabricate photofunctional monomolecular layers. The CRA derivative was adsorbed on a fused silica plate from a THF solution to form a monomolecular layer through hydrogen bonds. The monolayer exhibited photocycloaddition, together with photoisomerization, upon UV irradiation. Whereas the desorption of the macrocyclic compound from the plate occurred partially in polar solvents including ethanol, UV irradiation exhibited a suppressive effect on the desorption, suggesting that the number of hydrogen bonds between the molecules and a silica surface per molecule are much enhanced by intermolecular photodimerization of the cinnamoyl residues leading to an increment of the molecular weight of the adsorbate. The monolayer of the CRA on a silica plate exhibited the ability to transform the alignment of a nematic liquid crystal upon UV irradiation from homeotropic (perpendicular) to planar (parallel) orientation. The photoalignment of the liquid crystal was stabilized toward heat treatment possibly owing to the photodimerization of cinnamoyl units.