Structural Modulation of Porphyrin-Based Supramolecular Prisms for Efficient and Selective Photocatalysis.

Area of Science:

• Supramolecular Chemistry
• Photocatalysis
• Materials Science

Background:

• Porphyrins are effective photocatalysts due to visible light absorption.
• Extended π-conjugated systems in porphyrins can cause aggregation, reducing photocatalytic efficiency.

Purpose of the Study:

• To construct supramolecular prisms with porphyrin motifs to overcome aggregation issues.
• To investigate the effect of porphyrin spacing on photocatalytic activity.

Main Methods:

• Assembly of terpyridine-based ligands and Zn²⁺ to form supramolecular prisms (S1 and S2).
• Characterization using NMR, ESI-MS, TWIM-MS, and single-crystal X-ray diffraction.
• Testing photocatalytic oxidation of sulfide to sulfoxide.

Main Results:

• Supramolecular prisms S1 and S2 were successfully synthesized and characterized.
• Supramolecular prism S2, with increased porphyrin distance, achieved complete sulfide to sulfoxide conversion in 25 min without byproducts.
• Enhanced photocatalytic efficiency in S2 was attributed to suppressed π-π stacking and improved exciton separation and charge-carrier mobility.

Conclusions:

• Rational molecular design of supramolecular prisms can effectively tune photocatalytic performance.
• Reducing close packing of functional motifs, like porphyrins, enhances efficiency in chemical transformations.
• Supramolecular structural design is crucial for optimizing photocatalytic processes.