Cheng-Juan Wu

Cross-coupling hydrogen evolution reaction in homogeneous solution without noble metals.

A highly efficient noble-metal-free homogeneous system for a cross-coupling hydrogen evolution (CCHE) reaction is developed. With cheap, earth-abundant eosin Y and molecular catalyst Co(dmgH)2Cl2, good to excellent yields for coupling reactions with a variety of isoquinolines and indole substrates and H2 have been achieved without any sacrificial oxidants. Mechanistic insights provide rich information on the effective, clean, and economic CCHE reaction.

Cobalt-Catalyzed Cross-Dehydrogenative Coupling Reaction in Water by Visible Light

By using catalytic amount of CoCl2 with dmgH (dimethylglyoxime) as ligand to form a photosensitizer in situ, a highly selective, efficient, and environmentally benign visible light mediated cross-dehydrogenative coupling (CDC) reaction has been developed in aqueous medium. The desired cross-coupling C-C bonds that involve Csp3 with Csp, Csp2, and Csp3, respectively, were achieved exclusively in high yields without formation of any other byproduct.

A unique 1,2-acyl migration for the construction of quaternary carbon by visible light irradiation of platinum(II) polypyridyl complex and molecular oxygen.

A unique 1,2-acyl migration for the construction of quaternary carbon in a one-pot reaction under visible light is described. By irradiating a platinum(II) polypyridyl complex with visible light, enamine 1 is able to react with alcohol 2 to yield compound 3 featuring a quaternary carbon via 1,2-acyl migration and concurrent esterification. Studies on the mechanism reveal that the platinum(II) complex is able to generate singlet oxygen ((1)O2) that is responsible for this unprecedented intramolecular 1,2-acyl migration transformation.

Visible Light Promoted Synthesis of Indoles by Single Photosensitizer under Aerobic Conditions

The construction of substituted indole skeletons is always an important concern of synthetic chemists because of its prevalent structure found in natural products and biological molecules. Here, we succeeded in preparing indoles and their derivatives from a wide variety of simple enamines via radical cyclization only with catalytic amounts of an iridium(III) photosensitizer (PS) in DMSO solution under air atmosphere. The mechanistic investigation suggests that the reaction involves a radical course to accomplish the conversion of enamines to indoles under visible light irradiation.

A beryllium-selective microcantilever sensor modified with benzo-9-crown-3 functionalized polymer brushes

Benzo-9-crown-3 functionalized polymer brushes were prepared via surface-initiated atom transfer radical polymerization on the gold surface of microcantilevers for the selective detection of Be2+. Other metal ions, such as Li+, Na+, K+, Mg2+ and Ca2+, have minimal effect on the deflection response of the microcantilevers. The microcantilever sensor exhibits high sensitivity for beryllium ions with a limit of detection (LOD) as low as 10−10 M. The mechanism of bending is discussed as well.

Photocatalytic hydrogen-evolution dimerization of styrenes to synthesize 1,2-dihydro-1-arylnaphthalene derivatives using Acr+-Mes and cobaloxime catalysts

Abstract We report a hydrogen-evolution dimerization of styrenes via the synergistic merger of Acr+-Mes photocatalyst and cobaloxime proton reduction catalysts. By utilizing this dual catalyst system, 1,2-dihydro-1-arylnaphthalene derivatives can be directly constructed from commercially available styrenes. Our reaction proceeds smoothly under mild conditions without the need for oxidants or hydrogen atom transfer reagents, and the sole byproduct is hydrogen gas. Mechanistic investigation suggests that the reaction is initiated by photoinduced electron transfer under visible-light irradiation.