Influence of photo-isomerisation on host-guest interactions in poly(azocalix[4]arene)s

Poly(azocalix[4]arene)s with varying length of lower rim substituents (n-butyl and n-dodecyl) have been evaluated in terms of photo-isomerisation behaviour and its influence on the complex formation with a low molar mass pyridinium-based guest. Irradiation induces slight changes in the cone conformation of the calix[4]arene units. This in turn affects the degree of host-guest interaction, which is decreased when the polymers are in the cis-rich state. The complexation can thus be controlled by adjusting the photostationary state of the poly(azocalix[4]arene)s.