Charge Separation to Facilitate The Conversion of Copper‐Phenylacetylide from Aggregation‐Induced Emission to Efficient Photocatalysis

Abstract

Aggregation‐induced emission (AIE) materials are considered promising photocatalyst candidates due to their robust light‐harvesting and efficient photoexcitation, if their photoexcited carriers can be separated effectively. Herein, by skillfully selecting multi‐alkynyl ligands instead of phenylacetylene to construct multi‐channel charge separation, copper‐phenylacetylide (CP‐1) with AIE properties is successfully transformed into efficient photocatalysts CP‐2P (copper‐1,4‐diethynylbenzene) and CP‐2M (copper‐1,3‐diethylnylbenzene). In these structures, the multi‐alkynyl ligands connects the copper‐ladder into multi‐dimensional metal‐organic frameworks with greatly reduced bandgap, enhances charge transfer and separation, and facilitated oxygen adsorption and activation. As a representative, CP‐2P has the best photocatalytic activity and stability for photocatalytic aerobic oxidation, such as thioanisole oxidation (conv. > 99%, methyl phenyl sulfoxide sel. ≧ 94%), benzyl alcohol oxidation (conv. > 99%, benzaldehyde sel. > 99%) and benzylamine oxidation (conv. > 99%, N‐benzylidene benzylamine sel. > 99%), which can be used for large‐scale sunlight‐driven organic photosynthesis. This work confirms the feasibility of controlled conversion of the conventional copper‐alkynyl from AIE material to efficient photocatalyst using charge separation strategy, which provides an important guidance for the rational design of new high‐efficiency photocatalyst.

Copper Phenylacetylide and TiO2 Modification for an Efficient Visible-Light-Driven Oxidative Coupling of Amines

“…These may be the reasons for the obvious decrease in the photocatalytic activity for the fourth cycle. Thus, we further fabricate the catalyst utilizing 1,4-diethynylbenzene with multialkynyl instead of phenylacetylene (CuC 2 PhC 2 Cu) to inhibit its decomposition during reaction . As shown in Figure S12, the decomposition of the catalyst or phenylacetylene coupling product was not observed, suggesting the CuC 2 PhC 2 Cu possesses good stability.…”

“…Thus, we further fabricate the catalyst utilizing 1,4-diethynylbenzene with multialkynyl instead of phenylacetylene (CuC 2 PhC 2 Cu) to inhibit its decomposition during reaction. 39 As shown in Figure S12, the decomposition of the catalyst or phenylacetylene coupling product was not observed, suggesting the CuC 2 PhC 2 Cu possesses good stability. Imine yields of 77.7 and 89.8% were achieved for CuC 2 PhC 2 Cu and 3.6% TiO 2 / CuC 2 PhC 2 Cu (Figure 8c,d), respectively.…”

Constructing Isoreticular Metal–Organic Frameworks by Silver–Carbon Bonds

“…Alkynyl is a common C ligand for organometallic compounds, and its coordination with different metals in stable small molecules or metal clusters has been studied adequately. 33 In contrast, studies of alkynyl as linkages for MOFs or ligands for coordination polymers have focused solely on Cu(I), 32,34,35 and the crystallinity is relatively low. As ligands of MOFs, the compatibility of alkynyl with other metals is yet to be discovered.…”

“…Compared to previous MOFs or coordination polymers formed by Cu(I) and multialkynyl ligands, the crystallinity of AgC-MOFs was improved to a great extent. 32,34,35 The morphologies of AgC-MOFs were explored by scanning electron microscopy (SEM). The AgC-MOFs all exhibited homogeneous rodlike micromorphology with diameters from 100 to 500 nm (Figure S12a−c) and lengths of a few micrometers.…”