Host-guest chemistry of a bis-calix[4]pyrrole derivative containing a trans/cis-switchable azobenzene unit with several aliphatic bis-carboxylates.

The azobenzene unit used as a photochemically and thermally switchable linker in the assembly of a bis-calix[4]pyrrole receptor provides a means to modulate the binding of bis-carboxylates of significant biological importance in cancer research. Conversely, the complexation of different bis-anionic guests has significant kinetic effects on both the photochemical and thermal trans/cis isomerization of the azobenzene unit.