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One-step synthesis of 2-propylheptanol (2-PH) from n-pentanal via a reaction integration of n-pentanal self-condensation and successive hydrogenation is of great significance for it can simplify process flow and reduce energy consumption. The key to promotion of 2-PH selectivity is to enhance the competitiveness of n-pentanal self-condensation with respect to its direct hydrogenation. For this purpose, a core-shell structured Ni/SiO2@TiO2 catalyst was designed and prepared. With the precise architecture of this core-shell structured catalyst, n-pentanal can be firstly in contact with TiO2 to 2-propyl-2-heptenal (2-PHEA) while the direct hydrogenation to n-pentanol can be effectively inhibited, and then 2-PHEA diffuses into the core of Ni/SiO2 and is hydrogenated to 2-PH. The spatial threshold of the core-shell catalyst significantly enhanced its catalytic performance; a 2-PH selectivity of 77.9% was reached with a 100% n-pentanal conversion. The 2-PH selectivity is much higher than that obtained by employing Ni/TiO2 catalyst. Furthermore, the reaction kinetics of one-step synthesis of 2-PH from n-pentanal catalyzed by Ni/SiO2@TiO2 was studied and its kinetic model was established which is useful for reactor design and scale-up.

Conversion of methane into liquid alcohol such as ethanol at low temperature in a straight, selective and low energy consumption process remains a topic of intense scientific research but a great challenge. In this work, CuFe2O4/CNT composite is successfully synthesized via a facile co-reduction method and used as catalysts to selectively oxidize methane. At a low temperature of 150 °C, methane is directly converted to ethanol in a single process on the as-prepared CuFe2O4/CNT composite with high selectivity. A mechanism is also proposed for the significant methane selective oxidation performance of the CuFe2O4/CNT composite catalysts.

Acyclic carbene–ruthenium catalysts were developed for the ethenolysis. Remarkable catalytic efficiency (turnover numbers of 100 000) and excellent α-olefin selectivity (up to 98%) were exhibited.

The semi-hydrogenation of alkynols to enols is a crucial process in the production of pharmaceuticals, agrochemicals, fragrances, and flavors that involves a complex set of parallel and consecutive isomerization and hydrogenation reactions and proceeds via several key intermediates. In view of the industrial importance of large-scale enol production through alkynol hydrogenation, various noble and non-noble metal (e.g., Ni and Pd)-based catalysts promoting this transformation have been developed. This paper reviews the design of highly selective catalysts for the semi-hydrogenation of alkynols, focusing on the role of additives, second metals, catalyst supports, and reaction conditions and combining catalytic reaction kinetics with theoretical calculations to establish the reaction mechanism and the decisive factors for boosting selectivity. Finally, a strategy for designing highly efficient and selective catalysts based on the characteristics of aqueous-phase alkynol hydrogenation is proposed.

Selective synthesis of higher oxygenates from syngas is an important but challenging research target, and the present methods for converting syngas into oxygenates suffer from low selectivity and h...

Pd-catalyzed carbonylation, as an efficient synthetic approach for the installation of carbonyl groups in organic compounds, has been one of the most important research fields in the past decade. Although elegant reactions that allow highly selective carbonylations have been developed, straightforward routes with improved reaction activity and broader substrate scope remain long-term challenges for new practical applications. Here, we show a new type of synergistic Cu/Pd-catalyzed carbonylation reaction using alcohols and dioxgen as the carbonyl sources. A broad range of aryl iodides and alcohols are compatible with this protocol. The reaction is concise and practical due to the ready availability of the starting materials and the scalability of the reaction. In addition, the reaction affords lactones and lactams in an intermolecular fashion. Moreover, DFT calculations have been performed to study the detailed mechanisms.

A new palladium-based heterogeneous material was synthesized by means of immobilization of Pd(OAc)2/1,10-phenanthroline on commercially available SiO2 and subsequent pyrolysis at 600 °C for 2 h in ...

Developing an earth-abundant catalyst that is sulfur-tolerant, active, and highly selective is of great interest for valorizing natural gas streams containing sour gas. A tin-modified alumina catal...

Photocatalytic reduction of CO2 with water to valuable chemicals has been getting attention as an artificial photosynthetic system using CO2 as a resource. A barium tetratitanate, BaTi4O9, loaded with Ag nanoparticles (Ag/BaTi4O9) successfully promoted the photocatalytic CO2 reduction to yield CO with very high selectivity (> 99%) in an aqueous solution.

We have developed a versatile, mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions. The protocol is highly selective, operationally simple, and compatible with a wide array of sensitive functional groups. It can be used for late-stage functionalization of bioactive molecules, which makes it convenient for drug discovery.

CO2 hydrogenation has attracted great attention, yet the quest for highly-efficient catalysts is driven by the current disadvantages of poor activity, low selectivity, and ambiguous structure-performance relationship. We demonstrate here that C3N4-supported Cu single atom catalysts with tailored coordination structures, namely, Cu–N4 and Cu–N3, can serve as highly selective and active catalysts for CO2 hydrogenation at low temperature. The modulation of the coordination structure of Cu single atom is readily realized by simply altering the treatment parameters. Further investigations reveal that Cu–N4 favors CO2 hydrogenation to form CH3OH via the formate pathway, while Cu–N3 tends to catalyze CO2 hydrogenation to produce CO via the reverse water-gas-shift (RWGS) pathway. Significantly, the CH3OH productivity and selectivity reach 4.2 mmol g–1 h–1 and 95.5%, respectively, for Cu–N4 single atom catalyst. We anticipate this work will promote the fundamental researches on the structure-performance relationship of catalysts., CO2 hydrogenation has attracted intense scientific attention yet suffers from the disadvantage of poor activity and low selectivity. Here, the authors report that Cu single atom catalysts with tailored coordination environments on C3N4 serve as highly selective catalysts for CO2 hydrogenation.

A novel nickel-catalyzed highly selective reductive cross-coupling of alkyl bromides and chlorosilanes to construct the C-Si bond has been developed. Under benign reaction conditions, a series of structurally interesting organosilanes can be accessed without Ni-catalyzed isomerization. The utility of this chemistry is illustrated by further transformations of the product. Moreover, the radical mechanism of the reaction is illustrated by control experiments.

The reactivity of CH-acidic and structurally related enol-containing heterocycles towards N-oxyl radicals is disclosed. Traditionally, these substrates have been considered as reactants for ionic transformations. Highly selective and efficient N-oxyl radical mediated C–O coupling of substituted barbituric or Meldrum’s acids with N-hydroxy compounds (N-hydroxyimides, hydroxamic acids, oximes, and N-hydroxybenzotriazole) was achieved using inexpensive manganese-containing salts as oxidants. Metal-free C–O coupling was demonstrated using diacetyliminoxyl as both the oxidant (hydrogen-atom acceptor) and the coupling partner.

A mixture of HBPin with KOtBu was found to activate cobalt salt to form a heterotopic cobalt species that is highly active for catalytic intermolecular trimerization of alkynes. This protocol affords 1,2,4-regioisomers in good yields with high regioselectivities under mild conditions. These salient features, together with the operational simplicity and high efficiency, as well as obviating the use of any costly and/or air sensitive ligands, renders the protocol promising for practical applications.

We describe the synthesis and biological evaluation of a new natural product‐inspired compound class obtained by combining the conceptually complementary pseudo‐natural product (pseudo‐NP) design strategy and a formal adaptation of the complexity‐to‐diversity ring distortion approach. Fragment‐sized α‐methylene‐sesquiterpene lactones, whose scaffolds can formally be viewed as related to each other or are obtained by ring distortion, were combined with alkaloid‐derived pyrrolidine fragments by means of highly selective stereocomplementary 1,3‐dipolar cycloaddition reactions. The resulting pseudo‐sesquiterpenoid alkaloids were found to be both chemically and biologically diverse, and their biological performance distinctly depends on both the structure of the sesquiterpene lactone‐derived scaffolds and the stereochemistry of the pyrrolidine fragment. Biological investigation of the compound collection led to the discovery of a novel chemotype inhibiting Hedgehog‐dependent osteoblast differentiation, The combination of the conceptually complementary formal ring distortion‐ and pseudo‐natural product strategies yields novel natural product‐inspired bioactive pseudo‐sesquiterpenoid alkaloids.

An arrayed host:guest fluorescence sensor system can discriminate among and classify multiple different noncanonical DNA structures by exploiting selective molecular recognition. The sensor is highly selective and can discriminate between folds as similar as native G-quadruplexes and those with bulges or vacancies. The host and guest can form heteroternary complexes with DNA strands, with the host acting as mediator between the DNA and dye, modulating the emission. By applying machine learning algorithms to the sensing data, prediction of the folding state of unknown DNA strands is possible with high fidelity.

The copper-catalyzed highly selective protoboration of CF3 -containing conjugated diene with proton source and B2 Pin2 has been developed. This chemistry could suppress the well-known defluorination and provide borated reagents with an intact CF3 -group. Further studies indicated that the functional group tolerance of this chemistry is very well, and the products could be used as versatile precursors for different types of transformations. Importantly, using chiral diphosphine ligand, we have developed the first example for using such starting material to synthesis allylic boron-reagents which bearing a CF3 -containing chiral center. Notably, the reaction mechanism was intensively studied by DFT calculations, which could reveal the reason that defluorination was inhibited.

A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(III)-catalyzed [4 + 2] annulation of N-arylbenzamidines with 1,4,2-dioxazol-5-ones. This reaction features excellent regioselectivity, broad substrate scope and high step economy, which would provide the reference for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.

Indole oxidation represents a real challenge for selectivity because it typically leads to complex mixtures of products even when highly selective enzymes are used. Here, we describe the catalytic potential of an artificial enzyme, Mn-Mimochrome VI*a (Mn-MC6*a), in promoting indole oxidation. This mini-enzyme contains a manganese-deuteroporphyrin active site within a scaffold of two synthetic small peptides covalently linked to porphyrin. Mn-MC6*a promotes the selective oxidation of indole at its C3 position, leading to a 3-oxindole derivative (2-TFE-3-oxindole) with unprecedented product selectivity (86% at pH 8.5) compared to native or artificial heme-enzymes. We also suggest a possible reaction mechanism based on the effect of pH, cosolvent, and indole substitution on the reaction outcome. These studies demonstrate that Mn-MC6*a is an excellent artificial peroxygenase for the production of 3-oxindole-containing compounds as key building blocks for the synthesis of fine chemicals.

Indole dearomatization has been achieved via radical hydroarylation. Under mild photoredox conditions, a range of indole derivatives undergo hydroarylation to form 2-arylindoline products. Mechanistically, radical termination occurs primarily via stepwise reduction/protonation, with a small contribution from concerted hydrogen atom transfer. This mechanistic understanding prompted the extension of this reactivity to benzenoid dearomatization. This work formed the foundation of our program, which utilizes reductive radical-polar crossover to drive highly selective dearomatization pathways.

Graphitic carbons are suitable supports of metal nanoparticles with catalytic activity. In the present study, the preparation of N-doped graphitic carbon supporting clusters of Fe-Co alloys starting from biomass waste is reported. These sub-nanometric Co-Fe clusters supported on N-doped graphitic carbon at a metal loading below 0.2 wt % exhibit high activity for the selective hydrogenation of CO2 to CO. Operating at 500 °C and 10 bar with an H2/CO2 molar ratio of 7 and a space velocity of 600 h-1, a conversion of 56% with a selectivity of over 98% to CO, and remarkable stability over 30 h operation was obtained. Interestingly, analogous catalysts based on N-doped graphitic carbon with much higher Co-Fe loadings and an average particle size range of 1-5 nm exhibit only half of this activity, with similar CO selectivity. This contrasting behavior reveals the dramatic effect of the particle size on the catalytic activity. In comparison, SiO2 as support under similar conditions affords CH4 as the main product., Financial support by the Spanish Ministry of Science, Innovation, and University (Severo Ochoa and RTI2018.98237-B-CO1) and Generalitat Valenciana (Prometeo 2017/083) is gratefully acknowledged. L.P. thanks the Generalitat Valenciana for a Santiago Grisolía scholarship. BASF is thanked for financial support.

New film-forming copolymers PIM-1 with 2,3,6,7-tetrahydroxy-9,10-(p-fluorophenyl)anthracene units in the main chain have been synthesized and investigated. The investigated gas separation characteristics of these copolymers show that despite a decrease in permeability, the copolymer containing 20% tetrahydroxyanthracene is a highly selective material that goes beyond the upper bounds in Robeson’s plots as compared to the initial PIM-1.

A highly selective palladium-catalyzed carbonylative arylation of weakly acidic benzylic C(sp3)–H bonds of azaarylmethylamines with aryl bromides under 1 atm of CO gas has been achieved. This work represents the first examples of use of such weakly acidic pronucleophiles in this class of transformations. In the presence of a NIXANTPHOS-based palladium catalyst, this one-pot cascade process allows a range of azaarylmethylamines containing pyridyl, quinolinyl and pyrimidyl moieties and acyclic and cyclic amines to undergo efficient reactions with aryl bromides and CO to provide α-amino aryl-azaarylmethyl ketones in moderate to high yields with a broad substrate scope and good tolerance of functional groups. This reaction proceeds via in situ reversible deprotonation of the benzylic C–H bonds to give the active carbanions, thereby avoiding prefunctionalized organometallic reagents and generation of additional waste. Importantly, the operational simplicity, scalability and diversity of the products highlight the potential applicability of this protocol., Introduced is a method for the deprotonative carbonylation of azaarylmethyl amines with aryl bromides. The reaction employs a Pd(NIXANTPHOS)-based catalyst and takes place under 1 atm CO.

We have studied the catalytic activity of LiZr2(PO4)3-based NASICON-type phosphates for conversion of C2 and C3 aliphatic alcohols with the aim of selectively preparing C2–C4 olefins. Selectivity has been controlled via partial heterovalent substitutions of In3+ or Nb5+ for Zr4+ or Mo for phosphorus. We have investigated the structure and morphology of the synthesized catalysts. The nature of the dopants has been shown to play a key role in determining the selectivity of the catalysts studied. Partial In3+ substitution for Zr4+ improves the dehydrogenating properties of the materials, whereas partial substitutions of Nb5+ for Zr4+ and Mo6+ for P5+ improve their dehydrating properties. We have demonstrated the possibility of highly selective preparation of ethylene and butylenes from ethanol and of propylene from propanol-1 and propanol-2.

Since anions are vital for many chemical, biological and environmental processes, their recognition and separation continue to attract attention from chemists, materials scientists and engineers. Employing exo-binding of artificial macrocycles to recognize selectively anions remains a challenge in supramolecular chemistry. Herein, we report the instantaneous co-crystallization and concomitant co-precipitation between hexachloroplatinate dianions and cucurbit[6]uril, a phenomenon which relies on the selective recognition of these dianions through the noncovalent bonding interactions on the outer surface of cucurbit[6]uril. The selective hexachloroplatinate dianion recognition is driven by the weak [Pt-Cl···H-C] hydrogen bonding and [Pt-Cl···C=O] ion-dipole interactions. The synthetic protocol is highly selective. It is not observed in combinations between cucurbit[6]uril and other Pt- and Pd- or Rh-based chloride anions. We have also demonstrated that cucurbit[6]uril is able to separate selectively hexachloroplatinate dianions from mixtures of hexachloroplatinate, tetrachloropalladate, and hexachlororhodate anions. This highly selective and fast co-crystallization process, in principle, could be exploited to recover platinum from the spent vehicular three-way catalytic converters and other platinum-bearing metal waste.

We report an unprecedented C-H bond functionalization of cyclopropenes enabled by dinuclear gold catalysis. Highly selective C-H allylation, alkynylation and halogenation of cyclopropenes with organic halides have been realized. The reaction does not require strong external oxidants and affords access to functionalized cyclopropenes in moderate to good yields. The reductive elimination process to controllably construct C-C or C-X bonds can be tuned by using different dinuclear gold catalysts.

Under mild conditions (room temperature, 80 psi of H(2)) Cp*Rh(2-(2-pyridyl)phenyl)H catalyzes the selective hydrogenation of the C═C bond in α,β-unsaturated carbonyl compounds, including natural product precursors with bulky substituents in the β position and substrates possessing an array of additional functional groups. It also catalyzes the hydrogenation of many isolated double bonds. Mechanistic studies reveal that no radical intermediates are involved, and the catalyst appears to be homogeneous, thereby affording important complementarity to existing protocols for similar hydrogenation processes.

2D conjugated MOFs have attracted significant interests in recent years owing to their special structural features and promising physical and chemical properties. These intriguing attributes, to a large extent, stem from the nature of incorporated ligands. The available ligands for the construction of 2D conjugated MOFs are still limited, especially those that have heteroatoms included and exposed to the pores. In this work, we designed and synthesized a highly symmetric hexaazatrinaphthylene (HATNA)-based ligand with two different coordination sites. Through selective coordination, a highly crystalline and porous 2D conjugated copper metal-organic framework was constructed. Due to the synergic effects of HATNA and copper catecholate node, this HATNA-based 2D conjugated MOF can mediate the electrocatalytic reduction of CO2 to methane with high selectivity of 78 % at high current density of 8.2 milliamperes per square centimetre (mA cm-2 ) for long durability over 12 hours.

Conversion from CO2 to C2H4 is important for the development of energy and the environment, but the high energy barrier of hydrogenation of the *CO intermediate and C-C coupling step tend to result in C1 compounds as the main product and thus restrict the generation of C2H4. Here, we report a metal-organic framework (denoted as PcCu-Cu-O), composed of 2,3,9,10,16,17,23,24-octahydroxyphthalo-cyaninato)copper(II) (PcCu-(OH)8) ligands and the square-planar CuO4 nodes, as the electrocatalyst for CO2 to C2H4. Compared with the discrete molecular copper-phthalocyanine (Faradaic efficiency (FE) of C2H4 = 25%), PcCu-Cu-O exhibits much higher performance for electrocatalytic reduction of CO2 to C2H4 with a FE of 50(1)% and a current density of 7.3 mA cm-2 at the potential of -1.2 V vs RHE in 0.1 M KHCO3 solution, representing the best performance reported to date. In-situ infrared spectroscopy and control experiments suggested that the enhanced electrochemical performance may be ascribed to the synergistic effect between the CuPc unit and the CuO4 unit, namely the CO on the CO-producing site (CuO4 site) can efficiently migrate and dimerize with the *CO intermediate adsorbed on the C2H4-producing site (CuPc), giving a lower C-C dimerization energy barrier.

The operating window (OW) is a primary performance criterion for the selective hydrogenation of acetylene in excess ethylene. Currently, most state-of-the-art catalyst systems have an OW of less th...

It is highly desirable to achieve solar-driven conversion of CO2 to valuable fuels with controlled selectivity. The existing catalysts are mainly explored for CO production but rarely for formate generation. Herein, highly selective photoreduction of CO2 to formate (99.7%) was achieved with a high yield of 3040 μmol g-1 in 10 h by hierarchical integration of photosensitizers and monometallic [bpy-Cu/ClX] (X = Cl or adenine) catalysts into a stable Eu-bpy metal-organic framework. However, replacing X with pyridine in [bpy-CuCl/X] significantly reduced formate production while increasing the CO yield to 960 μmol g-1. Systematic investigations revealed that the catalytic process is mediated by the H-bond synergy between Cu-bound X and CO2-derived species, and the selectivity of HCOO- can be controlled by simply replacing the coordination ligands. This work provides a molecularly precise structural model to provide mechanistic insights for selectivity control of CO2 photoreduction.

The hydroisomerization of n-hexadecane over Pt-Pd bimetallic catalysts is an effective way to produce clean fuel oil. This work reports a useful preparation method of bimetallic bifunctional catalysts by a co-impregnation or sequential impregnation process. Furthermore, monometallic catalysts with loading either Pt or Pd are also prepared for comparison. The effects of the metal species and impregnation order on the characteristics and catalytic performance of the catalysts are investigated. The catalytic test results indicate that the maximum iso-hexadecane yield over different catalysts increases as follows: Pt/silicoaluminophosphate SAPO-41 < Pd/SAPO-41 < Pt*-Pd/SAPO-41 (prepared by sequential impregnation) < Pt-Pd/SAPO-41 (prepared by co-impregnation). Owing to the synergic effects between Pt and Pd, the Pt-Pd/SAPO-41 catalyst prepared by the co-impregnation method demonstrates the effective promotion of (de)hydrogenation activity. Therefore, this catalyst exhibits the highest iso-hexadecane yield of 89.4% when the n-hexadecane conversion is 96.3%. Additionally, the Pt-Pd/SAPO-41 catalyst also presents the highest catalytic activity and best stability even after 150 h long-term tests.

The application of a cobalt pincer complex, (PPClP)CoCl2, as a precatalyst for the hydroboration of terminal alkenes with pinacolborane (HBPin) is described. The reactions proceed rapidly under mil...

The enantioselective aminocatalytic α-chlorination of aldehydes is a challenging reaction because of its tendency to proceed through neutral intermediates in unselective pathways. Herein we report the rational shift to a highly selective reaction pathway involving charged intermediates using hexafluoroisopropanol as solvent. This change in mechanism has enabled us to match and improve upon the yields and enantioselectivities displayed by previous methods while using cheaper aminocatalysts and chlorinating agents, 80-95% less amount of catalyst, convenient temperatures, and shorter reaction times.

There is a growing awareness of the underlying power of catalytic reactions in water that is not limited to innate sustainability alone. Some Type III reactions are catalytically accelerated without dissolution of reactants and are occasionally highly selective, as shown by comparison with the corresponding reactions run in organic solvents or under solvent-free conditions. Such catalysts are highly diversified, including hydrophilic, lipophilic, and even solid catalysts. In this Outlook, we highlight the impressive characteristics of illustrative catalysis that is exerted despite the immiscibility of the substrates and reveal the intrinsic benefits of these enigmatic reactions for synthetic organic chemistry, albeit with many details remaining unclear. We hope that this brief introduction to the expanding field of synthetic organic “aquachemistry” will inspire organic chemists to use the platform to invent new transformations., The counterintuitive and underexplored catalysis that is exerted at the reactant(s)−water interface is discussed. Illustrative examples are presented to highlight the benefits of the approach to synthetic organic chemistry.

A dispersive liquid-phase microextraction method combined with UV–vis spectrophotometry was utilized to highly selective determination of creatinine in human serum and urine samples. To overcome the interferences in complex matrices, creatinine reacted with 1,4-naphthoquinone-2- potassium sulfonate reagent to produce a red coloured product that could be extracted into a small volume of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF6) ionic liquid solvent. To increase the sensitivity of the assay, gluconic acid capped silver nanoparticles (Ag NPs) were used. On addition of Ag NPs to the red coloured extracted product, the solution turned to blue accompanied with a red shift in wavelength around 620 nm that could be detected by the naked eye. The effective variables on the determination of creatinine such as concentration of the reagent, amount of formic and hydrochloric acids, type and volume of the extractant, and concentration of Ag NPs were investigated. Under the optimal conditions, the calibration plot was bimodal with linear ranges from 0.1 to 1.5 µg mL−1 and 1.5 to 105 µg mL−1 creatinine with a limit of detection 0.1 µg mL−1. The relative standard deviation for five measurements at 35 µg mL−1 concentration level was 3.8%. The newly developed assay was used for the determination of creatinine in human serum and urine specimens with satisfactory results.

The resulting supported catalytic materials were probed for a series of Pty/TixCe(1-x)O2 (y = 0.005, 0.05, 0.5, 1, 5; x = 0.98, 0.9, 0.7, 0.5, 0.3, 0.02) supports primed by the sol-gel method. By u...

Herein, a highly selective and sensitive “OFF–ON” fluorescent biosensor was designed for intracellular Cu2+ detection. Compared to the fluorescent Cu2+ biosensors reported so far, this work tackled...

Diverse C-P cross-couplings of arylthianthrenium salts with diarylphosphines producing various triarylphosphines via highly selective C-S bond cleavage are reported. In the absence of catalyst, the reaction of arylthianthrenium salts with diarylphosphines undergoes phosphinative ring opening exclusively via the cleavage of an endocyclic C-S bond of a thianthrene skeleton. The use of a palladacycle catalyst under otherwise the same conditions enables the phosphination via the cleavage of an exocyclic C-S bond with significantly higher speed.

ZnS is one of the promising earth-abundant catalysts for photoreduction reactions. The performance of ZnS in CO2 reduction is, however, limited because of its wide band gap, fast recombination of c...