Reductive Transformation of CO to Organic Compounds.

Carbon dioxide is a major greenhouse gas and a safe, abundant, easily accessible, and renewable C1 resource that can be chemically converted into high value-added chemicals, fuels and materials. The preparation of urea, organic carbonates, salicylic acid, etc. from CO through non-reduction conversion has been used in industrial production, while CO reduction transformation has become a research hotspot in recent years due to its involvement in energy storage and product diversification.

C═N Bond Ozonolysis and β-Scission: A Breakthrough Approach to the Synthesis of ω-Functionalized Compounds from Carbonyl Derivatives.

This work discloses a two-step, one-pot approach to ω-functionalized esters via cleavage of the alicyclic fragment of cycloalkanone semicarbazones. This approach is based on a combination of the synthesis of various alkoxyhydroperoxides via cycloalkanone semicarbazone ozonolysis and interaction of these peroxides with transition metal salts, leading to cleavage of the aliphatic cycle and subsequent ω-functionalized ester formation. A broad series of ω-halogen or pseudohalogen esters have been successfully synthesized in yields ranging from 23 to 73% per starting semicarbazone.

Electrochemical hydrocarboxylation of enol derivatives with CO: access to β-acetoxycarboxylic acids.

Electrochemical hydrocarboxylation of enol acetates with CO is developed. The disclosed process provides β-acetoxycarboxylic acids in 25-66% yields, in contrast to the electrolysis of ketones, silyl enol ethers and vinyl tosylates with CO, which leads mainly to alcohols.

Hydroformylation of Olefins with CO/H and Hydrosilane by Copper/Cobalt Tandem Catalysis.

A Cu/Co tandem catalysis protocol was developed to conduct the hydroformylation of olefins using CO/H and PMHS (polymethylhydrosiloxane) as a readily available and environmentally friendly hydride source. This methodology was performed via a two-step approach consisting of the copper-catalyzed reduction of CO by hydrosilane and subsequent cobalt-promoted hydroformylation with H and the in situ formed CO. The optimized triphos oxide ligand, which presumably facilitates the migratory insertion of CO gives moderate to excellent yields for both terminal and internal alkenes.

CO Valorization in Deep Eutectic Solvents.

The deep eutectic solvent (DES) has emerged in recent years as a valuable medium for converting CO into valuable chemicals because of its easy availability, stability, and safety, and its capability to dissolve carbon dioxide. CO valorization in DES has evolved rapidly over the past 20 years. As well as being used as solvents for acid/base-promoted CO conversion for the production of cyclic carbonates and carbamates, DESs can be used as reaction media for electrochemical CO reduction for formic acid and CO.

Electrochemical -Selective Semireductive Dicarboxylation of Aryl Alkynes with CO.

Herein, we report an electrochemical protocol for the dicarboxylation of aryl alkynes using CO. With a graphite rod as the cathode and Al as the sacrificial anode, a series of valuable butenedioic acids are obtained in moderate to excellent yields with an / ratio up to 50:1. This method features high -selectivity, high step and atom economy, easy scalability, and a nice substrate scope, which renders it appealing for promising applications in organic synthesis and materials chemistry.

Interrupted Dance of Five Heteroatoms: Reinventing Ozonolysis to Make Geminal Alkoxyhydroperoxides from C═N Bonds.

Four heteroatoms dance in the cascade of four pericyclic reactions initiated by ozonolysis of C═N bonds. Switching from imines to semicarbazones introduces the fifth heteroatom that slows this dance, delays reaching the thermodynamically favorable escape path, and allows efficient interception of carbonyl oxides (Criegee intermediates, CIs) by an external nucleophile. The new three-component reaction of alcohols, ozone, and oximes/semicarbazones greatly facilitates synthetic access to monoperoxyacetals (alkoxyhydroperoxides).

Synthesis of Dimethyl Carbonate via Transesterification of Ethylene Carbonate and Methanol over Mesoporous KF-loaded Mg-Fe Oxides.

A series of KF/Mg-Fe oxides were fabricated via the solid-state reaction between KF and Mg-Fe oxides. Especially, when 20 wt % KF was supported on the Mg-Fe bi-metal oxides and calcined at 400-600 °C, the solid material with more basic sites than the support itself was obtained. When applied as catalyst to dimethyl carbonate (DMC) synthesis through transesterification of ethylene carbonate (EC) and methanol, this material can afforded up to 88 % yield and 97 % selectivity toward DMC in 2 h under reflux conditions with the molar ratio of methanol to ethylene carbonate set at 8.

Mononuclear Iron Pyridinethiolate Complex Promoted CO Photoreduction via Rapid Intramolecular Electron Transfer.

Designing earth-abundant metal complexes as efficient molecular photocatalysts for visible light-driven CO reduction is a key challenge in artificial photosynthesis. Here, we demonstrated the first example of a mononuclear iron pyridine-thiolate complex that functions both as a photosensitizer and catalyst for CO reduction. This single-component bifunctional molecular photocatalyst efficiently reduced CO to formate and CO with a total turnover number (TON) of 46 and turnover frequency (TOF) of 11.

Molecular Engineering of Copper Phthalocyanine for CO Electroreduction to Methane.

Efficient electrochemical CO reduction reaction (ECORR) to multi-electron reductive products remains a great challenge. Herein, molecular engineering of copper phthalocyanines (CuPc) was explored by modifying electron-withdrawing groups (EWGs) (cyano, sulfonate anion) and electron-donating groups (EDGs) (methoxy, amino) to CuPc, then supporting onto carbon paper or carbon cloth by means of droplet coating, loading with carbon nanotubes and coating in polypyrrole (PPy). The results showed that the PPy-coated CuPc effectively catalysed ECORR to CH.

Surpassing the Performance of Phenolate-derived Ionic Liquids in CO Chemisorption by Harnessing the Robust Nature of Pyrazolonates.

Superbase-derived ionic liquids (SILs) are promising sorbents to tackle the carbon challenge featured by tunable interaction strength with CO via structural engineering, particularly the oxygenate-derived counterparts (e. g., phenolate).

Incorporating Catalytic Units into Nanomaterials: Rational Design of Multipurpose Catalysts for CO Valorization.

ConspectusCO conversion to valuable chemicals is effective at reducing CO emissions. We previously proposed valorization strategies and developed efficient catalysts to address thermodynamic stability and kinetic inertness issues related to CO conversion. Earlier, we developed molecular capture reagents and catalysts to integrate CO capture and conversion, i.

Revolutionizing Porous Liquids: Stabilization and Structural Engineering Achieved by a Surface Deposition Strategy.

Facile approaches capable of constructing stable and structurally diverse porous liquids (PLs) that can deliver high-performance applications are a long-standing, captivating, and challenging research area that requires significant attention. Herein, a facile surface deposition strategy is demonstrated to afford diverse type III-PLs possessing ultra-stable dispersion, external structure modification, and enhanced performance in gas storage and transformation by leveraging the expeditious and uniform precipitation of selected metal salts. The Ag(I) species-modified zeolite nanosheets are deployed as the porous host to construct type III-PLs with ionic liquids (ILs) containing bromide anion , leading to stable dispersion driven by the formation of AgBr nanoparticles.

Advancements and Challenges in Reductive Conversion of Carbon Dioxide via Thermo-/Photocatalysis.

Carbon dioxide (CO) is the major greenhouse gas and also an abundant and renewable carbon resource. Therefore, its chemical conversion and utilization are of great attraction for sustainable development. Especially, reductive conversion of CO with energy input has become a current hotspot due to its ability to access fuels and various important chemicals.

Cobalt Phthalocyanine Cross-Linked Polypyrrole for Efficient Electroreduction of Low Concentration CO To CO.

Immobilizing cobalt phthalocyanine (CoPc) onto the electrode surface is a significant approach to performing efficient electrochemical CO reduction reaction (ECO RR). Herein, sulfylphenoxy decorated CoPc cross-linked polypyrrole is prepared by in situ polymerization on the surface of carbon cloth. The synthesized N-rich catalyst exhibits above 95 % Faradaic efficiency toward CO (FE ) at -0.

Cost-Effective 2D Ultrathin Metal-Organic Layers with Bis-Metallic Catalytic Sites for Visible Light-Driven Photocatalytic CO Reduction.

Invited for the cover of this issue is the group of Liang-Nian He at Nankai University. The image depicts that 2D ultrathin metal organic layers (MOLs) with bis-metallic catalytic sites make an efficient photocatalyst resulting in efficient and selective visible-light-driven CO reduction. Read the full text of the article at 10.

Nickel-Catalyzed Stereoselective Alkenylation of Ketones Mediated by Hydrazine.

The direct conversion of naturally abundant carbonyl compounds provides a powerful platform for the efficient synthesis of valuable chemicals. In particular, the conversion of ketones to alkenes is a commonly encountered chemical transformation, often achieved via the multistep Shapiro reaction with tosylhydrazone and over stoichiometric organolithium or Grignard reagent. Herein, we report an earth abundant nickel-catalyzed alkenylation of naturally abundant methylene ketones to afford a wide range of alkene derivatives, mediated by hydrazine.

Molecular Engineering of Metal Complexes for Electrocatalytic Carbon Dioxide Reduction: From Adjustment of Intrinsic Activity to Molecular Immobilization.

The electrocatalytic CO reduction reaction (ECO RR) is one promising method for storing intermittent clean energy in chemical bonds and producing fuels. Among various kinds of catalysts for ECO RR, molecular metal complexes with well-defined structures are convenient for studies of their rational design, structure-reactivity relationships, and mechanisms. In this Review, we summarize the molecular engineering of several N-based metal complexes including Re/Mn bipyridine compounds and metal macrocycles, concluding with general modification strategies to devise novel molecular catalysts with high intrinsic activity.

Cost-Effective 2D Ultrathin Metal-Organic Layers with Bis-Metallic Catalytic Sites for Visible Light-Driven Photocatalytic CO Reduction.

As novel generated 2D materials, metal-organic layers (MOLs) have recently emerged as a potential platform for photocatalytic CO reduction reaction (PCO RR). Such 2D structures negate the blemish of low-density catalytic sites and low electron transmission efficiency on the surface of metal organic frameworks (MOFs), while retaining the advantage of low expenditure when using earth-abundant metal nodes and meritorious applicability in the PCO RR. Herein, it is reported that the 2D ultrathin layer material with bis-metallic catalytic sites (Ni-O metal node and the Ni-N metal site) from bidentate ligand 2,2'-bipyridine-5,5'-dicarboxylate (H bpydc) and nickel(II) remarkably boosts the visible light-driven PCO RR performance with a CO yield of 2400 mmol g for 18 h and a selectivity up to 99 %.

Palladium-catalyzed carboxylative cyclization of propargylic amines with aryl iodides, CO and CO under ambient pressure.

A palladium-catalyzed four-component carboxylative cyclization comprising propargylic amines, aryl iodides, CO and CO was developed. By selecting EtN and 1,5,7-triazabicyclo[4.4.

Visible light-driven carbamoyloxylation of the α-C(sp)-H bond of arylacetones radical-initiated hydrogen atom transfer.

Photocatalytic synthesis has emerged as an efficient route to transform CO into functionalized organic carbamates by photocatalysis. Herein, a catalyst-free carbamoyloxylation of arylacetones with CO and amines under visible light was developed for the synthesis of -β-oxoalkyl carbamates in yields up to 93%. This protocol proceeded smoothly with the assistance of inexpensive carbon tetrabromide at room temperature under atmospheric CO pressure, leading to simultaneous construction of C-O and C-N bonds.

Amphiphilic Polycarbonate Micellar Rhenium Catalysts for Efficient Photocatalytic CO Reduction in Aqueous Media.

A triblock amphiphilic polymer derived from the copolymerization of CO and epoxides containing a bipyridine rhenium complex in its backbone is shown to effectively catalyze the visible-light-driven reduction of CO to CO. This polymer provides uniformly spherical micelles in aqueous solution, where the metal catalyst is sequestered in the hydrophobic portion of the nanostructured micelle. CO to CO reduction occurs in an efficient visible-light-driven process in aqueous media with turnover numbers up to 110 (>99 % selectivity) in the absence of a photosensitizer, which is a 37-fold enhancement over the corresponding molecular rhenium catalyst in organic solvent.

Metal-Free Hydroxymethylation of Indole Derivatives with Formic Acid as an Alternative Way to Indirect Utilization of CO.

The selective N-alkylation of indole substrates remains an ongoing research challenge for the relative attenuated nucleophilicity toward nitrogen. Herein, we developed the hydroxymethylation of indole derivatives to afford N-alkylated indole products with formic acid. This metal-free process was promoted by the organic base 1,5,7-triazabicyclo[4.