Fabrication of 0D/1D S-scheme CoO-CuBi2O4 heterojunction for efficient photocatalytic degradation of tetracycline by activating peroxydisulfate and product risk assessment.

The step-scheme (S-scheme) heterojunction has excellent redox capability, effectively degrading organic pollutants in wastewater. Combining S-scheme heterojunction with activated persulfate advanced oxidation process reasonably can further enhance the degradation of Emerging Contaminants. Herein, a novel zero-dimensional/one-dimensional (0D/1D) CoO-CuBi2O4 (CoO-CBO) photocatalyst with S-scheme heterojunction was designed by hydrothermal and solvothermal methods. The band structure and electron and hole transfer pathway of CoO-CBO were analyzed using the ex-situ and in-situ X-ray photoelectron spectroscopy (XPS), Ultraviolet and Visible Spectrophotometer (UV-Vis) and optical radiation Kelvin probe force microscope (KPFM), and the formation of S-scheme heterojunction was demonstrated. The photocatalytic activity of ·S-scheme CoO-CBO heterojunction was carried out by degrading tetracycline (TC) with activating potassium monopersulfate triple salt under visible light. Compared with pure CuBi2O4 and pure CoO, 30%CoO/CuBi2O4 catalyst exhibited the highest TC degradation performance after activating persulfate, degrading 89.5% of TC within 90 min. On the one hand, the S-scheme heterojunction formed between CoO and CBO had a high redox potential. On the other hand, the activation of persulfate by Co and Cu could accelerate redox cycles and facilitate the generation of active radicals such as SO4-, O2- and OH, promoting the separation of the photogenerated e- and h+ in the composite, enhancing the peroxydisulfate (PDS) activation performance and improving the degradation effect of TC. Then, a gradual decrease in the toxicity of the intermediates in the TC degradation process was detected by ECOCER. In all, this study provided an S-scheme CoO/CuBi2O4 heterojunction that can activate PDS to degrade TC efficiently, which provided a new idea for the study of novel pollutant degradation and environmental toxicology.

Rh-Catalyzed Asymmetric Hydrogenation of α,ß- and ß,ß-Disubstituted Unsaturated Boronate Esters.

A highly enantioselective hydrogenation of α,ß-unsaturated boronate esters catalyzed by Rh-(S)-DTBM-Segphos complex has been developed. Both (Z)-α,ß- and ß,ß-disubstituted substrates can be successfully hydrogenated to afford chiral boronates with excellent enantioselectivities, up to 98 % ee. Furthermore, the obtained chiral boronate esters, as important versatile synthetic intermediates are successfully transformed to the corresponding chiral alcohols, amines and other important derivatives with maintained enantioselectivities.

Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation.

A highly efficient and enantioselective Rh-( R, R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-( R, R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,ß-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[ b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to ( S)-(+)- ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.

Enantioselective Direct Synthesis of Free Cyclic Amines via Intramolecular Reductive Amination.

Chiral cyclic amines can be prepared via intramolecular reductive amination of N-Boc-protected amino ketones in a one-pot process. With the complex of iridium and f-spiroPhos as the catalyst, a range of N-Boc-protected amino ketones are smoothly transformed into chiral cyclic free amines in high yields and excellent enantioselectivities (up to 97% ee). Moreover, this method can also be successfully applied to the synthesis of a κ-opioid receptor selective antagonist, (S)-1.

Enantioselective Hydrogenation of ß,ß-Disubstituted Unsaturated Carboxylic Acids under Base-Free Conditions.

An additive-free enantioselective hydrogenation of ß,ß-disubstituted unsaturated carboxylic acids catalyzed by the Rh-(R,R)-f-spiroPhos complex has been developed. Under mild conditions, a wide scope of ß,ß-disubstituted unsaturated carboxylic acids were hydrogenated to the corresponding chiral carboxylic acids with excellent enantioselectivities (up to 99.3% ee). This methodology was also successfully applied to the synthesis of the pharmaceutical molecule indatraline.

Highly Efficient Rh-Catalyzed Asymmetric Hydrogenation of α,ß-Unsaturated Nitriles.

A highly efficient enantioselective hydrogenation of α,ß-unsaturated nitriles catalyzed by Rh-(R,R)-f-spiroPhos complex has been developed. With Rh-(R,R)-f-spiroPhos catalyst and under mild conditions, a wide range of α,ß-unsaturated nitriles including the (E)- and (Z)-isomers of 3-alkyl-3-aryl, 3,3-diaryl, and 3,3-dialkyl α,ß-unsaturated nitriles were hydrogenated to the corresponding chiral nitriles with excellent enantioselectivities (up to 99.9% ee) and high turnover numbers (TON up to 10,000).

Highly efficient iridium-catalyzed asymmetric hydrogenation of ß-acylamino nitroolefins.

The first highly efficient Ir-catalyzed enantioselective hydrogenation of ß-acylamino nitroolefins is reported. This reaction provides straightforward access to chiral ß-amino nitroalkanes in high yields and excellent enantioselectivities (up to >99.9% ee) catalyzed by an Ir-(R,R)-f-spiroPhos complex.