Cation-dependent photochromic properties of novel ditopic receptors

Novel crown-containing 2-styrylbenzothiazoles were prepared to obtain optical ditopic receptors that can bind alkaline-earth metal cations by a crown ether fragment and could serve as host for the heavy metal cations and proton owing to the presence of the heterocyclic part. Photochemical transformations of the ditopic receptors depend on the type of metal cations present in solution. They include trans–cis-isomerization, [2+2]-cycloaddition, and electrocyclic reaction.