Photocatalytic Aryl Sulfide Oxidation Using 4-Nitrophenylacetylene-Modified Cu₂O Crystals

Abstract

4-Nitrophenylacetylene-functionalized Cu 2 O rhombic dodecahedra and cubes have been used to photocatalyze aryl sulfide oxidation generating aryl sulfoxides. With an oxygen supply and light from a blue light-emitting diode (LED), the reaction can be completed in 12 h with a water and methanol mixed solution. Generally high product yields and excellent product selectivity of sulfoxides over sulfones were achieved. In particular, a thioanisole to methyl phenyl sulfoxide yield of 98% was obtained. A mechanistic study has revealed that photogenerated electrons, holes, and superoxide radicals are involved in the oxidation reaction. The benefit of simple photocatalyst preparation and molecular functionalization to boost catalytic performance shows that surface-controlled ionic solids can be very effective photocatalysts for some organic transformations.

Photocatalytic activity enhancement with 4-cyanophenylacetylene-modified Cu2O cubes and rhombic dodecahedra and use in arylboronic acid hydroxylation

“…[24][25][26][27][28] 4-NAfunctionalized Cu 2 O crystals are also very effective for photocatalytic aryl sulde oxidation. 29 In this work, Cu 2 O cubes, octahedra, and rhombic dodecahedra functionalized with 4-CNA molecules were prepared for methyl orange photodegradation examination. DFT results provide very useful insights to understand their dissimilar photocatalytic behaviors.…”

Photocatalytic Oxidative Amine Coupling with 4-Nitrophenylacetylene-Modified Cu2O Polyhedra

“…Thus, superoxide anion radicals are involved in the amine coupling reaction. Furthermore, previous electron paramagnetic resonance (EPR) spectrum of photoirradiated 4-NA-modified Cu 2 O rhombic dodecahedra, dispersed in methanol, indicates the generation of superoxide radicals …”

“…For example, Cu 2 O crystals can photocatalyze hydroxylation of arylboronic acids with clear facet dependence . Cu 2 O rhombic dodecahedra decorated with 4-NA molecules are good for aryl sulfide oxidation . Amine coupling to give imines can also be accomplished photochemically. , Imines are found in some biologically active molecules and can be used to make dye molecules .…”

Aqueous Phase Photocatalytic Hydroxylation of Arylboronic Acids Using Polyhedral Cu2O Crystals

“…Other than dye photodegradation to demonstrate semiconductor facet effects, we envision that the radicals generated can be utilized in organic synthesis. 16 A desirable reaction is to oxidize arylboronic acids to subsequently give phenols using the photogenerated superoxide radical anions. 17,18 Phenol derivatives commonly exist in natural products and drug molecules having biological activities, and some are intermediates in organic synthesis.…”

“…Other than dye photodegradation to demonstrate semiconductor facet effects, we envision that the radicals generated can be utilized in organic synthesis . A desirable reaction is to oxidize arylboronic acids to subsequently give phenols using the photogenerated superoxide radical anions. , Phenol derivatives commonly exist in natural products and drug molecules having biological activities, and some are intermediates in organic synthesis. − While Pd-catalyzed hydroxylation of aryl chlorides with boric acid and Cu 2 O nanoparticle-catalyzed hydroxylation of arylboronic acids by pure heating at 60 °C are known, they are not photocatalytic processes. , Initially, Ru/Ir complexes and methylene blue photocatalysts were used. , Phthalocyanine zinc photosensitizers can also work .…”