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Selective condensation/bicycloaromatization of two different arylalkynes is firstly developed under ligand-free copper(i)-catalysis, which allows the direct synthesis of C–N axial biaryl compounds in high yields with excellent selectivity and functional group tolerance. Due to the critical effects of Cu(i) catalyst and HFIP, many easily occurring undesired reactions are suppressed, and the coupled five–six aromatic rings are constructed via the selective formation of two C(sp2)–N(sp2) bonds and four C(sp2)–C(sp2) bonds. The achievement of moderate enantioselectivity verifies its potential for the simplest asymmetric synthesis of atropoisomeric biaryls. Western blotting demonstrated that the newly developed compounds are promising targets in biology and pharmaceuticals. This unique reaction can construct structurally diverse C–N axial biaryl compounds that have never been reported by other methods, and might be extended to various applications in materials, chemistry, biology, and pharmaceuticals., Selective condensation/bicycloaromatization of two different arylalkynes is firstly developed under ligand-free copper(i)-catalysis, which allows the direct synthesis of C–N axial biaryl compounds in high yields with excellent selectivity and functional group tolerance.

A novel method to synthesize N-aryl-1-amino indoles was established by the photoinduced N-N coupling reaction. This protocol is by treatment of o-nitrobenzyl alcohols and indolines in the presence of TEAI and acetic acid with a 24 W ultraviolet (UV) light-emitting diode (LED) (385-405 nm) irradiation. The products bearing an aldehyde group can be further transformed to fluorescent probes based on Rhodamine 6G derivative 11, which shows a high specificity and sensitivity for Fe3+.

Herein, we develop a mild method for N-acylation of primary and secondary amines with α-diketones induced by ultraviolet (UV) light. Forty-six examples with various functional groups are explored at room temperature with irradiation by three 26 W UV lamps (350-380 nm). The yield reaches 97%. The gram scale experiment product yield is 76%. Moreover, this system can be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.

A simple and efficient methodology for the synthesis of large sterically hindered triarylamines in a single step was developed. A direct N,N-diarylation of 8-aminoquinoline with sterically hindered...

The enhancement of electron-and-hole separation efficiency and facile generation of reactive oxygen species are significant factors for performance improvement of photocatalysts in selective toluen...

We have developed a protocol for efficient synthesis of indolin-2-ones from benzofuranones and aryl amines using iodine as a mediator. A diverse range of benzofuranones and aryl amines undergo cros...

Simultaneous photocatalytic reactions of H2 evolution and real wastewater degradation have drawn much attention to practical energy and environmental applications. While these applications of photocatalyst often suffer from the high charge-carrier recombination and poor efficiency in reactants activation, resulting in unsatisfactory photocatalytic activity or need expensive platinum co-catalyst. Here, the unsaturated iron ion based coordination polymer (FeTMT) with weak Fe-N sites has been fabricated by a facile wet-chemical method. It exhibits outstanding photocatalytic performance for the simultaneous production of H2 (1272 μmol g-1 h-1) and degradation of real wastewater from brewing liquor (degradation efficiency is 60%) without using any cocatalyst, which is larger than that reported system. The density functional theory (DFT) calculations revealed that the unsaturated Fe-N bridge could transfer the electrons from C3N3S3 rings to Fe3+, boosting the separation and transportation efficiency of charge carriers. On the other hand, the N functional group close to the metal centers in FeTMT could regarded as a proton relay to enhance the surface of hydrophily. Further in-situ test demonstrated that unsaturated Fe sites could adsorb H+ to form H-Fe-H bond, while Fe-N sites serve as the catalytic active centers in FeTMT. This finding opens an avenue to construct a novel coordination polymer and deep understanding for the practical industrial photocatalysis application

A new tripodal C-anionic ligand, 2-{bis(benzothiazolyl)(methoxy)methyl}phenyl (L), was stably generated by the reaction of the ligand precursor (L'), the corresponding bromide (2-BrC6H4)(MeO)C(C7H4NS)2 (C7H4NS = 2-benzothiazolyl), with nBuLi at -104 °C in the presence of TMEDA (N,N,N',N'-tetramethylethylenediamine). The ligand lithium salt reacted with BiCl3 to give a 2 : 1 complex L2BiCl. A 1 : 1 complex LBiCl2 was obtained in good yield by the redistribution reaction between L2BiCl and BiCl3. X-ray diffraction analysis revealed that the ligand L coordinated in an expected κ3-C,N,N' coordination mode in LBiCl2, while it coordinated in κ3-C,N,O and κ2-C,O coordination modes in L2BiCl. The ligand precursor reacted with BiX3 (X = Cl, Br) to give 1 : 1 complexes L'BiX3 and was found to act as a neutral tripodal C(π),N,N-ligand.

Rational tailoring of the atomic structure of photocatalysts with multiple functions to enhance the carrier transfer efficiency and surface activation of carbon nitride (C3N4) is promising and a challenge. Here, we make the first report of a facile strategy to construct amphiphilic carbon and C–O–C chain linked terminal melem units in functional carbon nitride (COCN) via copolymerizing formaldehyde with melem. By integrating the amphiphilic carrier bridge of carbon and C–O–C chains into the framework, the photogenerated carrier mobility and activated species (superoxide radicals, singlet oxygen) as well as surface interaction are significantly improved. Consequently, the optimal tailoring of C3N4 attains superior photocatalytic activity for hydrogen production (34.9 μmol h−1) and selective oxidation of sulfide to sulfoxide using air (nearly 100% conversion and selectivity after 3 h of illumination), which is about 7 times higher than that of pristine C3N4. This study provides deep insight into and strategies for the atomic tailoring of carrier transfer and surface reaction over organic-based photocatalysts.

The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However, their stability under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe-metal-organic framework (NiFe-MOFs) was conformally coated on oxygen-vacancy-rich BiVO4 (Ov-BiVO4 ) as the protective layer and cocatalyst, forming a core-shell structure with caffeic acid as bridging agent. The as-synthesized Ov-BiVO4 @NiFe-MOFs exhibits enhanced stability and a remarkable photocurrent density of 5.3±0.15 mA cm-2 at 1.23 V (vs. RHE). The reduced coordination number of Ni(Fe)-O and elevated valence state of Ni(Fe) in NiFe-MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov-BiVO4 to NiFe-MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of a thin NiFe-MOFs layer, leading to a photoanode of enhanced photocurrent and stability.

We disclose a novel method for the synthesis of fluorescent N,N'-chelate organoboron compounds in high efficiency by treatment of aminoquinolates with NaBAr4/R'COOH in the presence of an iodine cat...

Selective photooxidation of toluene to benzaldehyde using O2 as an oxidant has the advantages of mild reaction conditions and excellent atomic economy, but it often suffers from low conversion effi...

Bromine mediation has been regarded as one of the most efficient ways to activate and convert methane to useful organics. This article reports the effects of active components (Rh, Ru, Pd and Pt) and supports (SiO2, MgO and Al2O3) on the catalysis of methane oxybromination. Among the prepared catalysts, Rh/SiO2 is the best in performance (CH4 conversion of ca. 20% and CH3Br selectivity exceeding 70%). The results reveal that support type has a notable influence on the catalytic performance of Rh, especially on product distribution. The high selectivity to CH3Br over Rh/SiO2 is attributed to its low propensity for CH3Br oxidation. It was found that Rh small in particle size shows high catalytic activity and CH3Br selectivity. Although silicalite-1 zeolite suffers from a certain degree of structural damage due to the presence of high temperature steam, the use of silicalite-1 as support results in a performance comparable to that of Rh/SiO2.

In this work, a functionalized metal-organic layer (MTTB MOL) was first synthesized and characterized, where MTTB means that it was synthesized from TTB (4,4’,4”-s-triazine-2,4,6-triyl-tribenzoate)...

Octahedral CdS–ZnS composites were synthesized using a simple method of cation exchange and hydrothermal treatment, using Cd3(C3N3S3)2 (denoted as Cd3(TMT)2) as a precursor and Zn2+ for ion exchang...

Benzaldehyde is an important fine chemical widely used in spices, dyes, medicine, pesticides, auxiliaries and synthetic materials. Heterogenous photocatalytic synthesis of benzaldehyde from toluene has been drawing increasing attention due to the relatively mild reaction conditions, high selectivity and easy recycling of the catalyst. Centered on the development of efficient photocatalysts, this article reviews the research progress of the photocatalytic selective oxidation of toluene in the past ten years. Different types of photocatalysts (including TiO2-based, Bi-based, CdS-based, g-C3N4-based, etc.) are discussed, along with the design philosophies and reaction mechanisms. Finally, being a long-time participant in this field, we provide our prospects on the design and preparation of the photocatalysts, the reaction mechanism, as well as the development of high efficiency photocatalytic reactors.

Submicron-sized SAPO-34 zeolites were synthesized via nanosheet seed-assisted method using cheap diethylamine as the template. Only 2 wt % seeds are needed to obtain the submicron-sized SAPO-34 (ca. 700 nm). Further increase of seed dosage has little effect on reducing the crystal size but leads to an increase of acidity. Among the as-prepared samples, S-0.3-2% (SiO2/Al2O3 = 0.3, 2 wt % seed) shows the best catalytic performance (CH3Br conversion of up to 95%, ethylene and propylene selectivity of 94%, and a lifetime of over 125 min) ever reported in the studies of CH3Br conversion to light olefins. The results undoubtedly demonstrate that lifetime and olefin selectivity are highly dependent on the particle size and acidity of SAPO-34 zeolites. The decrease of particle size and acidity is beneficial to alleviating carbon deposition, resulting in enhanced catalyst lifetime. In addition, the decrease of particle size and lowering of acidity could diminish the second hydrogen transformation reactions of olef...

The activation of C–H bonds is an efficient approach for the production of value-added organics. The partial oxidation of hydrocarbons to oxygen-containing products at mild conditions is a profound...

Shape-selective zeolites (HZ-x/y) were synthesized by a one-pot method using TPAOH (y) and/or MeEt3N+ I− (x) as templates. The use of MeEt3N+ I− affects the crystal growth and the distribution of acid sites on the external surface of the zeolites. The catalysts show excellent catalytic activity towards toluene alkylation with CH3Br. With toluene conversion of 36.3% and p-xylene selectivity of 66.2%, HZ-40/0 is the most effective among the prepared catalysts, showing a p-xylene yield of 21.2%. The improved para-selectivity is mainly due to the decrease of acid sites on the external surface of the catalysts.

Metal-organic framework (MOF) is one of the most promising porous materials in photocatalysis. In this study, copper was deposited on as well as encapsulated in a semiconductor-like MOF (UiO-66) to fabricate the Cu/Cu@UiO-66 catalyst via an advanced double-solvent approach followed by one-step reduction. Even with ultralow amount of copper, Cu/Cu@UiO-66 shows significantly enhanced photocatalytic activity as well as stability for partial oxidation of aromatic alcohols under visible light irradiation. The result is attributed to the integration of plasmonic effect (Cu nanoparticles on UiO-66) and Schottky junction (Cu quantum dots encapsulated in UiO-66) which can be considered as a promising noble-metal-free way for the enhancement of visible-light-driven photocatalytic activity of MOFs.

We report the synthesis of mesoporous alumina (MA)-supported sodium tripolyphosphate (STPP)/chitosan (Ch) composite (denoted as MA@STPP/Ch) by a layer-by-layer self-assembly method. The multilayered MA@STPP/Ch is nontoxic and shows excellent CO2 adsorption capacity (maximum: 278.96 mg g−1 at 50 °C) and reusability, better than that of MA (97.24 mg g−1 at 50 °C). The enhanced CO2 adsorption could be ascribed to the synergism between porous structure and functional groups of Ch.

A convenient photocatalyst-free method for the synthesis of redox-active 1,2-dihydro-3H-indazol-3-one derivatives from (2-nitroaryl)methanol and amines was developed. The reaction proceeded efficiently at room temperature by irradiation of UV light under CO2 atmosphere (1.0 atm, flow) without any photocatalysts or additives. This mild, operationally simple method shows wide functional tolerance. The carbamate formed in situ from CO2 and amine is proposed to be the key of this reaction. Some of these compounds synthesized by the present method were found to exhibit high anticancer activities, which can lower the viability of cancerous cell lines such as HeLa, MCF-7 and U87.

Oxygen-containing organics have high potentials in the synthesis of functionalized organics, and their direct generation from alcohols and alkanes by photocatalytic processes under mild conditions has aroused tremendous interest. In the past decades, much progress has been made especially in the area of heterogeneous photocatalysis under visible light irradiation. In this article, we focus on the selective oxidation of alcohols and hydrocarbons into useful oxygen-containing organics, highlighting the recent advances. Despite the achievements, scale-up production of target oxygen-containing organics is not realized due to low catalytic efficiency. The efficacy of a photocatalyst is greatly dependent on its nature, and a slight change of physicochemical properties could result in significant deviation of photocatalytic activity. For better catalyst design, the related mechanistic aspects have to be understood thoroughly. Furthermore, factors such as reactor design and reaction conditions (e.g. light region and intensity, solvent, oxidant) are critical for optimization of performance. To realize practical application in organic synthesis, it is essential to clarify the underlying mechanism. Once the parameters for optimal performance have been determined, the design of an efficient photocatalytic reactor could be properly considered.

Bismuth oxyhalides (BiOX), as a typical photocatalytic material, have attracted much attention due to their unique layered structure, non-toxicity and excellent stability. However, the photocatalytic performance of BiOX is limited by their weak light absorption ability and rapid recombination of photo-generated carriers. In the present work, first-principles calculations have been performed to comprehensively explore the structural, electronic and optical properties of black phosphorus (BP)/BiOX (X = Cl, Br, I) heterostructures, revealing the inherent reasons for their enhanced photocatalytic performance. By combining band structures and work function analysis, the migration paths of photo-generated electrons and holes are obtained, proving a direct Z-scheme photocatalytic mechanism in BP/BiOX heterostructures. Moreover, the BP/BiOX heterostructures have decent band edge positions, which are suitable for photocatalytic overall water splitting. Compared with single BiOX, the light absorption performance of BP/BiOX heterostructures is significantly improved, in which BP/BiOI exhibits the highest optical absorption coefficient among the BP/BiOX heterostructures. Meanwhile, the better carrier migration performance of the BP/BiOX heterostructures is attributed to the reduction in effective mass. The present work offers theoretical insight into the application of BP/BiOX heterostructures as prominent photocatalysts for water splitting.

Esters and their derivatives are distributed widely in natural products, pharmaceuticals, fine chemicals and other fields. Esters are important building blocks in pharmaceuticals such as clopidogrel, methylphenidate, fenofibrate, travoprost, prasugrel, oseltamivir, eszopiclone and fluticasone. Therefore, esterification reaction becomes more and more popular in the photochemical field. In this review, we highlight three types of reactions to synthesize esters using photochemical strategies. The reaction mechanisms involve mainly single electron transfer, energy transfer or other radical procedures.

N,N′-chelate organoboron compounds have been successfully applied in bioimaging, organic light-emitting diodes (OLEDs), functional polymer, photocatalyst, electroluminescent (EL) devices, and other science and technology areas. However, the concise and efficient synthetic methods become more and more significant for material science, biomedical research, or other practical science. Here, we summarized the organoboron-N,N′-chelate derivatives and showed the different routes of their syntheses. Traditional methods to synthesize N,N′-chelate organoboron compounds were mainly using bidentate ligand containing nitrogen reacting with trivalent boron reagents. In this review, we described a series of bidentate ligands, such as bipyridine, 2-(pyridin-2-yl)-1H-indole, 2-(5-methyl-1H-pyrrol-2-yl)quinoline, N-(quinolin-8-yl)acetamide, 1,10-phenanthroline, and diketopyrrolopyrrole (DPP).

Metal-organic framework (MOF) is an ideal precursor/template for porous carbon, and its active components are uniformly doped, which can be used in energy storage and catalytic conversion fields. Metal-organic framework PCN-224 with carboxylporphyrin as the ligand was synthesized, and then Zn2+ and Co2+ ions were coordinated in the center of the porphyrin ring by post-modification. Here, PCN-224-ZnCo with different ratios of bimetallic Zn2+ /Co2+ ions were used as the precursor, and the metal-nitrogen-carbon(M-N-C) material of PCN-224-ZnCo-950 was obtained by pyrolyzing the precursor at 950 °C in Ar. Because Zn is easy to volatilize at 950 °C, the formed M-N-C materials can reflect different Co contents and different basic site concentrations. The formed material still maintains the original basic framework. With the increase of Zn2+ /Co2+ ratio in precursor, the concentration of N-containing alkaline sites in pyrolysis products gradually increase. Compared with the precursor, PCN-224-ZnCo1 -950 with Zn2+ /Co2+ =1 : 1 has greatly improved basicity and suitable acidic/ alkaline site concentration. It can be efficiently used to carbon dioxide absorption and catalyze the cycloaddition of CO2 with epoxide. More importantly, the current method of adjusting the acidic/basic sites in M-N-C materials through volatilization of volatile metals can provide an effective strategy for adjusting the catalysis of MOF derivatives with porphyrin structure.

COVID-19 has broken out rapidly in nearly all countries worldwide, and has blossomed into a pandemic. Since the beginning of the spread of COVID-19, many scientists have been cooperating to study a vast array of old drugs and new clinical trial drugs to discover potent drugs with anti-COVID-19 activity, including antiviral drugs, antimalarial drugs, immunosuppressants, Chinese medicines, Mpro inhibitors, JAK inhibitors, etc. The most commonly used drugs are antiviral compounds, antimalarial drugs and JAK inhibitors. In this review, we summarize mainly the antimalarial drugs chloroquine and hydroxychloroquine, the antiviral drugs Favipiravir and Remdesivir, and JAK inhibitor Ruxolitinib, discussing their biological activities, clinical trials and synthesis progress.

8-Aminoquinoline is a common nitrogen-containing heterocyclic framework in many natural products, functional materials and useful drugs. It has been developed as a powerful bidentate directing group or ligand auxiliary in the field of C-H bond activation/functionalization in recent years. In this context, the synthesis of substituted 8-aminoquinoline is of great importance. In this review we focus on the functionalization of positions C2-C7 on the 8-aminoquinoline ring, which involves the formation of C-C and C-Z (Z = heteroatom) bonds by transition metal catalysts, photocatalysts or metal-free conditions. Mechanistically, a single electron transfer (SET) pathway is suggested in most cases.

Bi2MoO6 nanosheets different in thickness (~ 6 nm, ~ 15 nm and ~ 120 nm) were facilely prepared by hydrothermal and solvothermal methods. They were tested as photocatalysts for selective oxidation of toluene to benzaldehyde in the presence of O2 and under visible light irradiation. It was found that the photocatalytic activity is closely related to the thickness of Bi2MoO6 nanosheets. Apparently, thinner nanosheets could induce higher photocatalytic activity. Among them, the ultrathin Bi2MoO6 nanosheets (about 6 nm in thickness) which were prepared by a simple solvothermal method using MoO3 rods as precursor and ethylene glycol as solvent showed the highest activity (toluene conversion 12.7% and benzaldehyde production rate 778 μmol/g/h). The excellent activity is ascribed to the ultrathin sheet-like structure that facilitates efficient separation and transfer of charge carriers. Holes was found to be the main active species. Based on the controlled experiment and active species trapping results, a possible reaction mechanism was proposed.

An efficient metal-free method for the synthesis of organophosphorus compounds via oxidative cross dehydrogenative coupling of benzylic C(sp3)-H bonds in methylarenes with P(O)-OH compounds catalysed by cetyltrimethyl ammonium bromide (CTAB) is reported. Various methylarenes and P(O)-OH compounds are tolerated in the reaction with moderate to good yields. Compared to previous studies, the present study extends the substrate scope and adopts a new reaction system of an ammonium salt catalyst (CTAB) and an oxidant (DTBP). The results of control and mechanistic experiments are generally in agreement with the overall proposed pathway. This method circumvents the use of toxic P-halogen reagents and P(O)-H compounds for the synthesis of organophosphorus compounds.

Herein, we developed a protocol for the efficient synthesis of 3-aryl benzofuran-2(3H)-ones under solvent-free conditions from phenols and mandelic acids using Ni(OTf)2 as a catalyst. A diverse range of mandelic acids and phenols undergo C–H/O–H bond dual functionalization to generate products in moderate to good or excellent yields. The nickel catalyst can be easily recycled in a test of three runs at the scale of 10 mmol without significant decline in the product yield. It was demonstrated that the yield of the desired product could be increased, for example, in the synthesis of the antioxidant Irganox HP-136 to a scale of 166 g.

A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts. The results of a systematic structure-activity relationship study demonstrated that the strength of N→Sb donor-acceptor interaction could be synergistically modulated by tuning the properties of the nitrogen substituents and halogen atoms adjacent to the central antimony atom, and consequently resulted in distinct catalytic performances towards organic reactions such as Mannich, cross-condensation, cyclization-aromatization and epoxide aminolysis reaction. The fluorinated organoantimony(iii) derivatives were found to be more active than those of the chlorinated, brominated and iodinated analogues, owing to the use of an Sb-F moiety as a hydrogen bond acceptor. By comparison, the compound 6-cyclohexyl-12-fluoro-5,6,7,12-tetrahydrodibenzo[c,f][1,5] azastibocine (1d) is found to exhibit the highest catalytic activity, together with facile reusability in scale enlarged synthesis.

A selective functionalization of C–C═C bonds toward N–C═O bonds is realized by an n-Bu4NI-catalyzed reaction of 3-methylindoles with primary amines using TBHP as the unique oxidant. The systematic ...

Novel TiO2/Bi2MoO6 heterostructures with TiO2 particles loaded on a Bi2MoO6 sheet were fabricated by a simple solvothermal process. A series of characterization techniques such as SEM, TEM, XRD, XP...

A direct phosphorylation of the sp3C-CN bond catalyzed by a nickel catalyst is disclosed. A wide range of primary nitriles readily coupled with secondary phosphine oxides to produce the corresponding phosphorylated products in high yields. As a key step, this new method was applied to the synthesis of anticancer drug Combretastatin-A4, significantly shortening its synthetic path.

For the first time Bi2WO6/CdWO4 (BCW) hierarchical heterostructure of CdWO4 microrods decorated with uniform Bi2WO6 nanoplates was prepared. Using BCW as photocatalyst and O2 as oxidant, we achieved satisfactory catalytic activity (benzene conversion 7.3% and selectivity of phenol > 99%) in the hydroxylation of benzene to phenol at room temperature. It was found that the unique hierarchical heterostructure is beneficial for the absorption of visible light and the separation of photoinduced charge carriers. Moreover, we confirm the pivotal role of hydroxyl radicals and propose a plausible mechanism for the hydroxylation reaction.

A simple hydrothermal approach was adopted for the construction of novel porous Cd3(C3N3S3)2/CdS composites that were endowed with heterojunctions. In the synthesis, Cd3(C3N3S3)2 (denoted as Cd3(TMT)2) was adopted as precursor, and a spontaneous self-decomposition process is responsible for the formation of heterojunctions and porous structure. By controlling the hydrothermal temperature and hence the level of Cd3(TMT)2 decomposition, the photocatalytic activity of the Cd3(TMT)2/CdS composites can be regulated. The composite prepared at 155 °C exhibits outstanding photocatalytic performance towards toluene selective oxidation to benzaldehyde, giving a benzaldehyde formation rate of 787 μmol g−1 h-1 under visible light (λ ≥ 420 nm) without the need of any solvent. The excellent performance is ascribed to the unique Cd3(TMT)2/CdS porous structure: large in surface area and rich in heterojunctions. In photocatalysis, the large surface area of a catalyst enables enrichment of adsorbed reactants, and the presence of heterojunctions facilitates separation and transfer of photogenerated electrons and holes. It is envisaged that the method is suitable for the generation of organic/inorganic composites for photocatalytic purposes.

A novel, transition-metal-free phosphorylation of cinnamic acids with P(O)H compounds has been developed via radical-promoted decarboxylation under mild conditions. This method provides simple, efficient, and versatile access to valuable ( E)-alkenylphosphine oxides in satisfactory yields with a wide variety of substrates.

Inert C–H bonds activation at room temperature has been regarded as the control step in photocatalytic generation of valuable products from hydrocarbons. Herein, lead-free perovskite Cs3Bi1.8Sb0.2Br9 nanosheets with a proper amount of Sb in Cs3Bi2Br9 not only improves optical absorption due to anomalous band gap behavior, but also promotes the generation of holes (h+). The convergence of h+ on the surface of Cs3Bi1.8Sb0.2Br9 is crucial for the dissociation of toluene C(sp3)–H bond, which was proved by the density functional theory calculation and isotopic labelling results. The excellent activity in photocatalytic selective oxidation of toluene with a conversion rate of 5.83 mmol g−1h−1 under visible light is the highest ever achieved. This work sheds light on the modification of halide perovskites through the regulation of B-site cations for photocatalytic applications.

To optimize the synergistic effects among hydrogen bond donors, halogen anions and basic sites, we synthesized a series of graphene oxide (GO) materials multi-functionalized with silanol group, multi-cationic quaternary ammonium salt and tertiary amine in a one-pot approach. Hexamethylenetetramine which is cheap and rich with tertiary amine was used as precursor. As characterized by elemental analysis and X-ray photoelectron spectroscopy, the loading of quaternary ammonium salt and tertiary amine was up to 2.56 and 1.84 mmol/g, respectively. This is the first time that a multi-functionalized GO (MF-GO) enriched with multi-cationic quaternary ammonium salt was prepared and used for the cycloaddition of CO 2 towards epoxides under mild conditions (90 °C, 2 MPa and 4 h) with high efficiency (TOF = 46.1 h −1 ) without the need of a solvent and a co-catalyst. The advantage of the combined use of the “multi-cationic approach” and “multi-synergetic strategy” was illustrated by comparing the performance of MF-GO with those of the GO samples that are endowed with different functional groups. A plausible mechanism is proposed for the cycloaddition reaction over MF-GO. Moreover, the MF-GO catalyst can be easily separated and reused for at least five times without significant loss of activity.