Modulating Decarboxylative Oxidation Photocatalysis by Ligand Engineering of Atomically Precise Copper Nanoclusters

Area of Science:

• * Nanomaterials Science
• * Photocatalysis
• * Organic Synthesis

Background:

• * Copper nanoclusters (Cu NCs) possess unique electronic and optical properties suitable for photocatalysis.
• * The potential of Cu NCs as green catalysts for demanding reactions like decarboxylative oxygenation under mild conditions is largely unexplored.
• * Ligand engineering is crucial for tuning the properties and catalytic activity of Cu NCs.

Purpose of the Study:

• * To investigate the efficacy of novel Cu NCs functionalized with naphthalene thiolate ligands for photochemical decarboxylative oxidation.
• * To compare the catalytic performance of Cu13(Nap)3(PPh3)7H10 (Cu13Nap) with isostructural and previously reported Cu NCs.
• * To elucidate the reaction mechanism and the role of ligand modification in enhancing catalytic activity.

Main Methods:

• * Synthesis and characterization of Cu13Nap and Cu13DCBT nanoclusters.
• * Photochemical decarboxylative oxidation reactions under visible light irradiation.
• * Spectroscopic analysis to study electronic structure and charge transfer.
• * Density Functional Theory (DFT) calculations to probe reaction mechanisms.

Main Results:

• * Cu13Nap achieved a high yield of 90% in decarboxylative oxidation, significantly outperforming Cu13DCBT (28%) and other reported Cu NCs (6-18%).
• * Naphthalene thiolate ligands enhanced visible light absorption and charge transfer within the Cu13 NCs.
• * DFT and experimental data indicated an energy transfer mechanism, which is uncommon for this reaction type.

Conclusions:

• * Strategically modifying ligands on atomically precise Cu NCs can create composite active sites for enhanced catalytic efficacy.
• * Cu13Nap represents a promising green catalyst for efficient and selective decarboxylative oxidation under mild photochemical conditions.
• * This work opens new avenues for designing advanced Cu NC catalysts by manipulating surface ligands.