Self-Assembly and Host–Guest Interactions of Pd₃L₂ Metallo-cryptophanes with Photoisomerizable Ligands

New photoswitchable pyridyl-azo-phenyl-decorated tripodal host ligands (Laz) that belong to the cyclotriveratrylene family have been synthesized, and their photoswitching behavior crystal structures determined. The latter includes a remarkable 7-fold Borromean-weave entanglement of π–π stacked layers. Trigonal bipyramidal {[Pd(en)]3(Laz)2}6+ metallo-cryptophanes (en = ethylenediamine) were formed from these previously known ligand. These coordination cages dissociate at low concentrations are less robust Laz than reported Ir(III)-linked with similar ligands, reflecting greater lability Pd–N bonds. all act as hosts, binding octyl sulfate anions, or N-[2-(dimethylamino)ethyl]-1,8-naphthalimide in dimethyl sulfoxide solution.