Strategy for the Construction of Diverse Poly‐NHC‐Derived Assemblies and Their Photoinduced Transformations

Abstract A series of supramolecular assemblies of types [Ag 8 ( L ) 4 ](PF 6 ) 8 and [Ag 4 ( L ) 2 ](PF 6 ) 4 , obtained from the tetraphenylethylene (TPE) bridged tetrakis(1,2,4‐triazolium) salts H 4 ‐L(PF 6 ) 4 and Ag I ions, is described. The assembly type obtained dependends on the N‐wingtip substituents of H 4 ‐L(PF 6 ) 4 . Changes in the lengths of the N4‐wingtip substituents enables controlled formation of assemblies with either [Ag 4 ( L ) 2 ](PF 6 ) 4 or [Ag 8 ( L ) 4 ](PF 6 ) 8 stoichiometry. The molecular structures of selected [Ag 8 ( L ) 4 ](PF 6 ) 8 and [Ag 4 ( L ) 2 ](PF 6 ) 4 assemblies were determined by X‐ray diffraction analyses. While H 4 ‐ L (PF 6 ) 4 does not exhibit fluorescence in solution, their tetra‐NHC (NHC=N‐heterocyclic carbene) assemblies do upon NHC–metal coordination. Upon irradiation, all assemblies undergo a light‐induced, supramolecule‐to‐supramolecule structural transformation by an oxidative photocyclization involving phenyl groups of the TPE core, resulting in a significant change of the luminescence properties.