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Photocatalytic splitting of hydrogen sulfide (H2S) for hydrogen evolution is a promising method to solve the energy and environmental issues. In this work, S,N-codoped carbon dots (S,N-CDs)/graphitic carbon nitride (g-C3N4) nanosheet is synthesized by hydrothermal method as an efficient photocatalyst for the decomposition of H2S. In addition to the characterization of the morphology and structure, chemical state, optical and electrochemical performances of S,N-CDs/g-C3N4, hydrogen evolution tests show that the activity of g-C3N4 is improved by introducing S,N-CDs, and the enhancement depends strongly on the wavelength of incident light. The photocatalytic hydrogen production rate of S,N-CDs/g-C3N4 composite reaches 832 μmol g−1h−1, which is 38 times to that of g-C3N4 under irradiation at 460 nm. Density functional theory calculations and electron paramagnetic resonance as well as photoluminescence technologies have altogether authenticated that the unique wavelength-dependent photosensitization of S,N-CDs on g-C3N4; meanwhile, a good match between the energy level of S,N-CDs and g-C3N4 is pivotal for the effective photocatalytic activity. Our work has unveiled the detailed mechanism of the photocatalytic activity enhancement in S,N-CDs/g-C3N4 composite and showed its potential in photocatalytic splitting of H2S for hydrogen evolution.

Rare-earth catalysis has become a hot topic in the field of catalytic organic reaction. Chain ethers mostly have lower reactivity and lower boiling points which limited their reaction scope. Herein, we found a rare-earth Y(OTf)3 can catalyze the coupling reaction of ethers especially chain ethers and thioethers with azaarenes. This protocol features simple operations, a broad substrate scope (31 examples), moderate to good yields (up to 85%), and atom economy.

Here we report the facile preparation of a urea-containing UiO-68 isoreticular zirconium metal–organic framework (MOF) with mixed dicarboxylate struts by utilizing a microwave-assisted heating method. It can work as an efficient hydrogen-bond-donating heterogeneous catalyst for Henry reactions of benzaldehydes and nitroalkanes. This mixed strut MOF exhibits improved catalytic activity compared to the pure urea-functionalized linker based analogue.

A simple, mild and efficient approach to access fluorinated dibenz[b,e]azepines via visible-light photoredox catalysis is presented. Inexpensive and commercially available fluoroalkyl anhydrides in concert with pyridine N-oxide are employed as the source of the fluoroalkyl radicals. A one-pot process involving the trifluoroacetylation of unprotected secondary benzyl amines followed by radical cyclization could also afford the desired fluorinated dibenz[b,e]azepines.

A novel direct alkylation of thiophenes via bis-coupling with vinyl acetates has been developed. To the best of our knowledge, this represents the first report of the iron-catalysed coupling of two thiophenes with vinyl groups. Utilizing earth-abundant, inexpensive, and non-toxic iron catalysts, this methodology converts simple thiophenes to symmetrical dithienylethane derivatives under mild conditions in one step.

A facile and efficient one-pot reaction for aerobic oxidative synthesis of 2-substituted quinazolines has been developed by visible light catalysis. A variety of substituted aldehydes and 2-aminobenzylamines are amenable to producing the corresponding quinazolines in good to excellent yield under metal-free condition. Electron spin resonance (ESR) measurement provides clear evidence on the formation of superoxide radical anion (O2*) rather than singlet oxygen (1O2), which is responsible for this effective chemical transformation.

A water-soluble polypyridine copper complex Cu(dpp)(ClO 4 ) 2 ( 1 , dpp = 2,9-di(pyridin-2-yl)-1,10-Phenanthroline) enables to electrocatalyze H 2 generation from neutral phosphate buffer solution at a relatively low overpotential of 520 mV vs. SHE. Sustained proton reduction catalysis occurs at glassy carbon electrode at −1.4 V vs. SHE for 2 h to give H 2 with TONs of 734 mol H 2 (mol catalyst) −1 cm −2 and 95% Faradaic yield. CVs, UV–Vis spectra, SEM, EDX and Tyndall analysis reveals that 1 has the desired stability and functions as a molecular electrocatalyst under the conditions. Due to the relatively low overpotential and high stability, light-driven hydrogen production based on 1 were also carried out with a TONs of 6 mol H 2 (mol catalyst) −1 in an aqueous solution.

A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynylsilane intermediate was first in situ generated, which was then trapped by CO2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure.

A novel mononuclear cobalt complex 1 was synthesized by treatment of CoCl2·6H2O with a COOMe functionalized TPA ligand (TPA=tris(2-pyridylmethyl)amine). In a basic borate buffer, 1 acts as an efficient catalyst for water oxidation, which is confirmed by an extinct catalytic oxidant wave in electrochemistry. Visible light-driven water oxidation has been achieved by 1 with a TON of 127.7 and a TOF of 3.8 s−1 respectively in a homogeneous system. In comparison to the reference RC with naked TPA, the higher efficiency of 1 evidences COOMe on ligand can improve the catalytic efficiency, leading to an effective pathway towards construction of a robust and stable artificial photosynthesis system.

This paper introduces a simple way to the homocoupling of tertiary halides induced by photocatalysis. This method features mild reaction conditions, excellent functional group tolerance, high yields, low photocatalyst loading and successful application to the highly sterically hindered systems. On the basis of the reaction results, a novel stable-radical-induced homocoupling reaction mechanism has been proposed.

The water-soluble polypyridine copper complex [Cu(F3TPA)(ClO4)2] [1; F3TPA=tris(2-fluoro-6-pyridylmethyl)amine] catalyzes water oxidation in a pH 8.5 borate buffer at a relatively low overpotential of 610 mV. Assisted by photosensitizer and an electron acceptor, 1 also exhibits activity as a homogeneous catalyst for photo-induced O2 evolution with a maximum turnover frequency (TOF) of (1.58 ± 0.03) × 10(-1) s(-1) and a maximum turnover number (TON) of 11.61 ± 0.23. In comparison, the reference [Cu(TPA)(ClO4)2] [TPA=tris(2-pyridylmethyl)amine] displayed almost no activity under either set of conditions, implying the crucial role of the ligand in determining the behavior of the catalyst. Experimental evidence indicate the molecular catalytic nature of 1, leading to a potentially practical strategy to apply the copper complex in a photoelectrochemical device for water oxidation.

By combining visible light catalysis and transfer hydrogenation, we are able to convert a series of alkynes to their corresponding alkenes in high chemical yields. Then the visible light catalytic transfer hydrogenation reaction can couple photoisomerization to produce E-alkenes or Z-alkenes exclusively depending on the aryl or alkyl substituted alkynes.

The visible light catalytic cross coupling reaction from two different C–H bonds provides an efficient protocol for C–H bond activation and C–C bond construction. The application of the oxidative photoredox strategy to couple C–H bonds next to an oxygen atom with other C–H bonds is more challenging because of the more positive oxidation potential of ethers than that of amines. Here, we take advantage of organic dye 9-mesityl-10-methylacridinium perchlorate (Acr+-Mes ClO4−) as the photosensitizer and BrCCl3 as the terminal oxidant to achieve the addition of β-keto esters to oxonium species, directly generated from isochromans, leading to the formation of alkylation products in the α-position of an oxygen atom under visible light irradiation.

A new long-lived Donor–Acceptor (D–A) fluorophore based on carbazolyl dicyanobenzene was developed as an ON–OFF–ON multifunctional fluorescent probe 1 for sequential detection of Cu2+ and biothiols (Cys, Hcy and GSH). The fluorescence of probe 1 can be significantly and selectively quenched by Cu2+. Meanwhile, the fluorescence lifetime decreased from 2.1 μs to 18.5 ns. The limit of detection was determined to be 33.6 nM. Upon addition of biothiols (Cys, Hcy and GSH), the generated ensemble 1-Cu2+ displayed a “turn-on” fluorescent response at 555 nm and an obvious recovery in fluorescence lifetime and UV–vis absorption within 1 min. The limit of detection for Cys, Hcy and GSH were calculated by fluorescence titration experiments to be 0.19, 0.21 and 0.29 μM, respectively. The ensemble 1-Cu2+ was further successfully applied in bioimaging.

Cu(II) salts can activate C–H bonds of aromatic amines or imines to construct C–C bonds in air without external photosensitizer., Copper compounds involved in photocatalysis have recently spurred considerable interest for their novel transformations. However, mechanistic investigations are still in infancy. We find a new type of reaction, that is, Cu(II) salt–catalyzed C–H functionalization of aromatic amines triggered by visible light irradiation. An array of mechanistic observations, including high-resolution mass spectrometry, ultraviolet-visible absorption spectrum, electron spin resonance, x-ray absorption near-edge structure, and density functional theory calculation, have identified the key intermediates generated in situ in the transformation. Integration of single-electron transfer, singlet oxygen (1O2), and new absorption species, intermediate I and intermediate II formed in situ from Cu(II) salts and substrate amines or imines, respectively, is responsible for the N–H and C–H bond activation of secondary amines to couple with nucleophiles in air, thereby leading to the formation of quinoline, indolo[3,2-c]quinoline, β-amino acid, and 1,4-dihydropyridine derivatives in moderate to good yields under visible light irradiation at room temperature.

A controlled new oxidant sulfate radical anion (SO4.–) was found and it can be easily prepared by mixing Na2S2O4 and TBHP with stirring. In this new metal-free oxidation system (Na2S2O4/TBHP), SO4.– can be used as a controllable oxidant to oxidize various aromatic alcohols to the corresponding aldehydes in good yields without any acid formation at room temperature. SO4.– was determined by a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) spin-trapping EPR method at room temperature on a Bruker E500 spectrometer and the results suggested that SO4.– was generated in this transformation.

A redox shuttle strategy is demonstrated to be a promising approach to accelerate hole removal for efficient O2 production with mesoporous graphitic carbon nitride, WO3 , BiVO4 , NiTi-LDH, and Ag3 PO4 water-oxidation catalysts under visible-light irradiation.