Stimulus-Responsive Organometallic Assemblies Based on Azobenzene-Functionalized Poly-NHC Ligands.

The reversible photoisomerization of azobenzene (AZB) and its derivatives has been applied across various fields. Developing discrete AZB-functionalized organometallic cages is essential for manufacturing functional materials. In this work, we designed and fabricated a series of three-dimensional, hexaazobenzene-terminated poly-NHC-based (NHC=N-heterocyclic carbene) complexes [M(A)](BF) and [M(B)](BF) (M = Ag, Au). In the newly prepared M-C assemblies, these peripheral AZB units linked to the central backbones can undergo efficient and recyclable isomerization upon external stimulation, effectively creating a switchable organometallic assembly system. Compared to the NHC precursor, the metalized framework demonstrates higher isomerization efficiency, thereby establishing a foundation for the subsequent application of AZB-functionalized M-C assemblies.