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

Area of Science:

• Supramolecular Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Azobenzene (AZB) derivatives are known for reversible photoisomerization.
• Functional organometallic cages are crucial for developing advanced materials.
• Integrating AZB units into organometallic frameworks offers potential for switchable systems.

Purpose of the Study:

• To design and synthesize novel three-dimensional, hexaazobenzene-terminated poly-N-heterocyclic carbene (poly-NHC)-based organometallic complexes.
• To investigate the photoisomerization behavior of these AZB-functionalized metal-organic assemblies.
• To establish a foundation for switchable organometallic assembly systems.

Main Methods:

• Synthesis of hexaazobenzene-terminated poly-NHC ligands.
• Fabrication of three-dimensional organometallic complexes using silver (Ag) and gold (Au) metals.
• Characterization of the synthesized complexes.
• Evaluation of photoisomerization efficiency upon external stimulation.

Main Results:

• Successful design and fabrication of [M3(A)2](BF4)3 and [M3(B)2](BF4)3 complexes (M = Ag, Au).
• Demonstration of efficient and recyclable photoisomerization of peripheral AZB units within the metalized framework.
• Observation of higher isomerization efficiency in the metalized framework compared to the NHC precursor.

Conclusions:

• Developed a series of switchable organometallic assembly systems based on AZB-functionalized poly-NHC complexes.
• The metalized framework enhances the photoisomerization efficiency of AZB units.
• These findings provide a basis for future applications of AZB-functionalized metal-organic assemblies.