Specific features of reversible E—Z-photoisomerization of crown-containing 4-styrylpyridine complexes with various cations

The reversible photochemical E — Z -isomerization of crown-containing 4-styrylpyridine was studied. The reaction was carried out in the presence of alkaline-earth metals capable of forming complexes with the crown-ether fragment and heavy metal perchlorates (Hg 2+ , Cd 2+ ) that are able to coordinate the nitrogen atom of the heterocyclic residue. The influence of complex formation on the E — Z -photoisomerization was determined by electronic spectroscopy and 1 H NMR spectroscopy. The studies performed confirm that the E — Z -photoisomerization can be controlled using supramolecular complex formation.