The surface electron density significantly affects the photocatalytic efficiency, especially the photocatalytic CO2 reduction reaction, which involves multi-electron participation in the conversion process. Herein, we propose a conceptually different mechanism for surface electron density modulation based on the model of Au anchored CdS. We firstly manipulate the direction of electron transfer by regulating the vacancy types of CdS. When electrons accumulate on vacancies instead of single Au atoms, the adsorption types of CO2 change from physical adsorption to chemical adsorption. More importantly, the surface electron density is manipulated by controlling the size of Au nanostructures. When Au nanoclusters downsize to single Au atoms, the strong hybridization of Au 5d and S 2p orbits accelerates the photo-electrons transfer onto the surface, resulting in more electrons available for CO2 reduction. As a result, the product generation rate of AuSA/Cd1−xS manifests a remarkable at least 113-fold enhancement compared with pristine Cd1−xS.

The main shortcomings of NCM811 could be solved at the same time via a facile Zr surface modification approach.

Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide.

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Ar hodium(II)/chiral phosphoric acid system has been developed for the asymmetric catalytic insertion of a-diazo esters into the O-H bond of carboxylic acids to generate an array of synthetically useful a-hydroxy ester derivatives in good ee (up to 95% ee). Furthermore,t he substrate scope could be successfully extended to ar ange of phenols and alcohols with high yield (up to 92%) and excellent enantioselectivity (up to 97%) under mild reaction conditions.A dditionally,adensity functional theory (DFT) studyw as performed to elucidate the reactionmechanism.Keywords: asymmetric catalysis;c hiral phosphoric acids; a-diazo esters;r eactionm echanism;r hodium Thec onstruction of carbon-heteroatom bonds in a controlled and selective manner is an importantt ask in synthetic organic chemistry. [1] In particular,o ne of the most direct and effectivem ethodsf or the enantioselectivef ormation of C-X bonds is the transition metal-catalyzed insertion of carbenes into heteroatom-hydrogen bonds.R emarkablep rogress [2] has been madei nt his area. Fore xample,h igh enantioselectivities have been achieved in the process of carbene insertion into N-H, [3] S-H, [4] B-H [5] andS i-H bonds [6] etc. Over the past few decades,m any reports have specifically concentrated on catalytic asymmetric O-H insertion reactions.T he corresponding product, ac hiral a-hydroxye ster is ak ey substructure of many naturally occurringc ompounds anda ctive pharmaceutical ingredients [7] (Figure 1). It wasd emonstrated that through the combination of metal catalysts and chiral ligands (Cinchona alkaloids, [8] bisoxazoline, [9] bisazaferrocene [10] andi midazoindolephosphine [11] etc.), highly enantioselective insertions of a-diazo compounds into the O-H bonds of alcohols,p henols, and water have been realized.Althought hese examples show at remendous advance toward the synthesiso fo pticallya ctive a-hydroxycarbonyl-containing compounds,additional studies on various metal complexes to achieve highly enantioselective carbenoid insertions into O-H bond Figure1.Selected important a-hydroxy ester-containing compounds.

An organocatalytic asymmetric reaction of benzofuran-2(3H)-ones with naphthoquinones is disclosed. The current method provides a direct way to facilitate arylation of benzofuran-2(3H)-ones in high yields with excellent enantioselectivities. A cooperative visible light photocatalysis with asymmetric hydrogen-bond catalysis has also been developed, thus allowing the more widely available 1-naphthols instead of naphthoquinones to be applied to facilitate the arylation with satisfactory results (up to 95% ee).

This work describes the first enantioselective 1,6-additions of azlactones to para-quinone methides. In the presence of a chiral phosphoric acid, 1,6-adducts were obtained in high yields (up to 96%) with excellent diastereoselectivities and enantioselectivities (all >20:1 diastereoselectivity ratio (dr), up to 99% enantiomeric excess (ee)). Importantly, the method offers a facile synthetic approach, not only to enantiopure α,α-disubstituted α-amino acid esters, but also to unnatural enantioenriched β,β-diaryl-α-amino acid esters bearing adjacent tertiary and quaternary stereogenic centers.