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 [M3(A)2](BF4)3 and [M3(B)2](BF4)3 (M = Ag, Au). In the newly prepared MI-CNHC 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 MI-CNHC assemblies.