Azo-Functionalized, Photo-Responsive Metal-Organic Supercontainers for Regulated Molecular Recognition — 39a — James Danielson, Kriti Chitrakar, Robyn Cook, and Rick Wang*
Department of Chemistry, University of South Dakota
414 E. Clark Street, Vermillion, SD 57069

Metal-organic supercontainers (MOSCs) are a family of synthetic receptors featuring nano-scaled endo and exo cavities capable of trapping, transforming, and transporting molecular or ionic guests. MOSCs are typically constructed from the assembly of container precursors, divalent metal ions, and carboxylate linkers. The tunable structure and molecular recognition capability of MOSCs make them promising for a range of applications including molecular storage, separation, chemical sensing, catalysis, and drug delivery. For these applications, photo-responsive MOSCs are of particular interest, since light may serve as an external stimulus and offer precise temporal and spatial control over these processes. However, prototypal MOSCs are typically rigid and non-responsive to light. To overcome this limitation, we synthesized a new MOSC by utilizing a carboxylate linker functionalized with an azobenzene group, which is known to undergo reversible trans-cis photoisomerization. The azo-MOSC exhibits reversible photoisomerization, as suggested by UV-Vis studies, demonstrating its responsiveness to light post-synthesis. Nuclear Magnetic Resonance (NMR) studies further reveal that this MOSC maintains its anion-binding capabilities, indicating that photoisomerization may indeed be incorporated into its functional properties. These findings suggest that photo-responsive MOSCs hold significant potential for advanced applications, particularly where smart materials are desired.

University of South Dakota
Dr. Rick Wang