Anion-modulated photoswitching of a tetraurea-bridged azobenzene

Abstract

Here, we report a new ortho-phenylene-spaced oligourea receptor, L¹, functionalized at its termini with photoresponsive azobenzene units. This peripheral design minimizes steric constraints, increasing conformational freedom and enabling dynamic responsiveness. Complexation of L¹ with diverse anions (HPO₄²⁻, PO₄³⁻, SO₄²⁻, Cl⁻, Br⁻) affords stable assemblies (EE-1 to EE-7), and demonstrates robust reversible photoresponse. The distinct photo-dynamic responses elicited by different anions offer new insights for the design of advanced supramolecular photo-reversible materials.