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International audience; Catalytic transformation of oxygenated compounds is challenging in f-element chemistry due to the high oxophilicity of the f-block metals. We report here the first Meerwein–Ponndorf–Verley (MPV) reduction of carbonyl substrates with uranium-based catalysts, in particular from a series of uranyl(VI) compounds where [UO2(OTf)2] (1) displays the greatest efficiency (OTf = trifluoromethanesulfonate). [UO2(OTf)2] reduces a series of aromatic and aliphatic aldehydes and ketones into their corresponding alcohols with moderate to excellent yields, using iPrOH as a solvent and a reductant. The reaction proceeds under mild conditions (80 °C) with an optimized catalytic charge of 2.3 mol % and KOiPr as a cocatalyst. The reduction of aldehydes (1–10 h) is faster than that of ketones (>15 h). NMR investigations clearly evidence the formation of hemiacetal intermediates with aldehydes, while they are not formed with ketones.

With the rapid expansion of biodiesel industry, its main by-product, crude glycerol, is anticipated to reach a global production of 6 million tons in 2025. It is actually a worrying phenomenon as glycerol could potentially emerge as an excessive product with little value. Glycerol, an alcohol and oxygenated chemical from biodiesel production, has essentially enormous potential to be converted into higher value-added chemicals. Using glycerol as a starting material for value-added chemical production will create a new demand on the glycerol market such as lactic acid, propylene glycol, alkyl lactatehydrogen, olefins and others. This paper briefly reviews the recent development on value-added chemicals derived from glycerol through catalytic conversion of refined and crude glycerol that have been proven to be promising in research stage with commercialization potential, or have been put in a corporate marketable production. Despite of the huge potential of products that can be transformed from glycerol, there are still numerous challenges to be addressed and discussed that include catalyst design and robustness; focus on crude or refined glycerol; reactor technology, reaction mechanism and thermodynamic analysis; and overall process commercial viability. The discussion will hopefully provide new insights on justified direction to focus on for glycerol transformation technology. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

5-Hydroxymethylfurfural (HMF) is a biobased platform chemical that can be valorized into a spectrum of valuable products. In this report, supported Ir, Ir–Co, Ir–Ni, and Ir–Ru catalysts were investigated for this purpose. Only hydrogenation of HMF to 2,5-bis-(hydroxymethyl)furan (BHMF) occurred over all catalysts. The effect of the second metal (Co, Ni, and Ru) on Ir/SiO2 was reflected by the kinetic constants being in the order Ir–Ni/SiO2 > Ir–Co/SiO2 > Ir–Ru/SiO2. The oxophilic nature of the secondary metal improved the catalytic performance of the bimetallic catalysts compared to the monometallic iridium catalyst (Ir/SiO2). Addition of HCOOH and H2SO4 as cocatalysts is a strategy to reach one-pot conversion of HMF to 2,5-di-methylfuran (DMF). Over-hydrogenolysis products such as 2,5-dimethyltetrahydrofuran were formed when only H2SO4 was added, giving higher activity compared to addition of HCOOH. Simultaneous presence of acids gave the highest HMF conversion, promoting esterification to 5-formyloxymethyl furfural and allowing the one-pot transformation of HMF to DMF. Thermodynamic analysis of HMF transformations revealed that both hydrogenation and dehydration steps are feasible.

Mesoporous carbonaceous materials were functionalized with iron or copper by a mechanochemical approach. The structural and textural properties of these catalysts were characterized by N2 physisorp...

Zeolite deactivation during the methanol transformation into hydrocarbons is a complex chemical process that includes reversible and irreversible degradation of active sites. The irreversible deactivation of the catalyst is associated with the degradation of active sites during long-term functioning of the zeolite under high-temperature exposure conditions of to water vapor as one of the main reaction products. The carbon deposits formation on the catalyst surface is the main cause of reversible deactivation. The formation of carbon can occur both in the cavities of the zeolites channels, which usually leads to a change in the selectivity of the process for light hydrocarbons, and at the junctions of the channels, which leads to pores blockage and a decrease in the activity of the catalyst. In addition, carbon deposition can occur directly on the active site of the zeolite, which also reduces the activity of the catalyst. The study of the synthesized catalytic systems deactivation rate to process time correlation was carried out in a tubular reactor installation of continuous operation, consisting of a reactor for producing dimethyl ether and a reactor for transformation of dimethyl ether into hydrocarbons. Determination of the kinetic regularities of the deactivation process of zeolite H-ZSM-5 makes it possible to adequately describe the actual course of the catalytic transformation of methanol into hydrocarbons. As a result of solving the differential equations of catalyst deactivation by numerical methods, the values of the preexponential factors and activation energies were obtained. Base on the values of the preexponential factors and activation energies, the methanol into hydrocarbons conditions range optimal for the catalytic transformation was determined, providing the minimum rate of catalyst deactivation, Ptotal = 1 Bar, W (methanol) = 2.3 kg (methanol) / (kg (cat) × h), t = 330–360 °C, which correlates with the results of the literature data on the transformation of methanol into zeolite of the H-ZSM-5 type.

Direct catalytic transformation of C–H bonds to new functionalities has provided a powerful strategy to synthesize complex molecular scaffolds in a straightforward way. Unstinting efforts of the sy...

Catalytic transformation of renewable fatty acids into value-added fatty alcohols without the use of gaseous hydrogen is a versatile technique for the utilization of waste cooking oil, where Cu-bas...

Lignin is one of the most important biomacromolecules in the plant biomass and the largest renewable source of aromatic building blocks in nature. Selectively producing value-added chemicals from the catalytic transformation of renewable lignin is of strategic significance and meet sustainability targets owing to the excessive consumption of non-renewable petroleum resource, but remains a long-term challenge owing to the complexity of lignin structure. This Minireview provides a summary and perspective of the extensive research that provides insight into selectively catalytic transformations of lignin and its derived monomers via directed scissor of chemical linkages (C-O and C-C bonds) with product-oriented targets. Furthermore, some challenges and opportunities of lignin catalytic transformation are provided based on existing problems in this field for readers to discuss future research directions.

The universally depleting reserves of traditional hydrocarbons require the development of a technology for producing synthetic hydrocarbons from renewable sources or human waste. Currently, among the possible methods for producing synthetic hydrocarbons, it is necessary to note the Fischer–Tropsch method and the method of methanol / dimethyl ether catalytic transformation. Moreover, the production of synthetic hydrocarbons from synthesis gas — the Fischer–Tropsch method, is suitable for the production of linear hydrocarbons. The hydrocarbons synthesis using methanol / dimethyl ether is suitable for the production of olefins, branched paraffins, aromatic and polyaromatic hydrocarbons. Depending on the synthesis conditions, it is possible to preferentially obtain a certain type of hydrocarbon, which significantly increases the value of this process. In this article modification of zeolite type H-ZSM-5 with zinc is studied in order to increase the yield of liquid hydrocarbons. Zeolite in acid form was treated with zinс acetate solutions of different concentrations, followed by calcination of the samples. The efficiency of the catalysts was studied in a flow tube reactor set-up, and the surface acidity of the samples was also determined. An increase in the zinc content in zeolite contributed to a decrease in the acidity of the samples and modification of their active centers. However, at high zinc content, a separate oxide phase forms, which contributes to a slight increase in acidity. Modification of zeolite with zinc leads to a decrease in the rate of transformation of dimethyl ether and the rate of liquid hydrocarbons formation. However, a general decrease in acidity and modification of zeolite with zinc contributes to a significant decrease in the amount of heavy aromatic compounds formed, with an increase in the amount of gaseous and liquid hydrocarbons being formed.

With fossil energy resources increasingly drying up and gradually causing serious environmental impacts, pursuing a tandem and green synthetic route for a complex and high-value-added compound by using low-cost raw materials has attracted considerable attention. In this regard, the selective and efficient conversion of light olefins with CO2 into high-value-added organic cyclic carbonates (OCCs) is of great significance owing to their high atom economy and absence of the isolation of intermediates. To fulfill this expectation, a multifunctional catalytic system with controllable spatial arrangement of varied catalytic sites and stable texture, in particular, within a single catalyst, is generally needed. Here, by using a stepwise electrostatic interaction strategy, imidazolium-based ILs and Au nanoparticles (NPs) were stepwise immobilized into a sulfonic group grafted MOF to construct a multifunctional single catalyst with a highly ordered arrangement of catalytic sites. The Au NPs and imidazolium cation are separately responsible for the selective epoxidation and cycloaddition reaction. The mesoporous cage within the MOF enriches the substrate molecules and provides a confined catalytic room for the tandem catalysis. More importantly, the highly ordered arrangement of the varied active sites and strong electrostatic attraction interaction result in the intimate contact and effective mass transfer between the catalytic sites, which allow for the highly efficient (>74% yield) and stable (repeatedly usage for at least 8 times) catalytic transformation. The stepwise electrostatic interaction strategy herein provides an absolutely new approach in fabricating the controllable multifunctional catalysts, especially for tandem catalysis.

Utilization of CO2 for the synthesis of fine chemicals and pharmaceuticals has attracted tremendous attention. In fact, reductive transformation of CO2 is also an interesting approach in this direction. Obviously, using hydrogen as a reducing agent is the most promising pathway for this reductive transformation. However, alternative to hydrogen, hydrosilanes have been also in the forefront due to their ready availability, nontoxic nature and easy handling procedure. Based on all this information, this work summarizes the recent applications of hydrosilylation of CO2 using different catalysts such as metal catalysts, organocatalysts, and heterogeneous catalysts.

Global warming due to the accumulation of atmospheric CO2 has received great attention in recent years. Hence, it is urgent to reduce CO2 emissions into the atmosphere and develop sustainable technologies for a circular carbon economy. In this regard, CO2 capture coupled with the conversion into chemicals and fuels provides a promising solution to reduce CO2 emissions as well as to store and utilize renewable energy. Among the many possible CO2 conversion pathways, CO2 hydrogenation to higher alcohols is considered an important strategy for the synthesis of carbon-based fuels and feedstock and holds great promise for the chemical industry. Thus, this review provides an overview of advances in CO2 hydrogenation to higher alcohols that have been achieved recently in terms of catalyst design, catalytic performance, and insight into the reaction mechanism under different experimental conditions. First, the limitations provided by reaction thermodynamics and the indispensability of catalysts for CO2 hydrogenation to higher alcohols are discussed. Then, four main categories of catalysts will be introduced and discussed (i.e. Rh-, Cu-, Mo-, and Co-based catalysts). Moreover, important factors significantly influencing the efficiency of the catalytic transformation such as alkali/alkaline earth metal promoters, transition metal promoters, catalyst supports, catalyst precursors, and reaction conditions, as well as the reaction mechanism are explained. Finally, the review discusses emerging methodologies yet to be explored and future directions to achieve a high efficiency for the hydrogenation of CO2 to higher alcohols.

Transition metal sulfides are an extraordinarily vital class of semiconductors with a wide range of applications in the photocatalytic field. A great number of recent advances in photocatalytic transformations of lignocellulosic biomass, the largest renewable carbon resource, into high-quality fuels and value-added chemicals has been achieved over metal sulfide semiconductors. Herein, the progress and breakthroughs in metal-sulfide-based photocatalytic systems for lignocellulose valorization with an emphasis on selective depolymerization of lignin and oxidative coupling of some important bioplatforms are highligted. The key issues that control reaction pathways and mechanisms are carefully examined. The functions of metal sulfides in the elementary reactions, including CO-bond cleavage, selective oxidations, CC coupling, and CH activation, are discussed to offer insights to guide the rational design of active and selective photocatalysts for sustainable chemistry. The prospects of sulfide photocatalysts in biomass valorization are also analyzed and briefly discussed. ispartof: Advanced Materials vol:33 issue:50 ispartof: location:Germany status: published

Metal–organic frameworks (MOFs) are emerging porous materials with highly tunable structures developed in the 1990s, while organometallic chemistry is of fundamental importance for catalytic transformation in the academic and industrial world for many decades. Through the years, organometallic chemistry has been incorporated into functional MOF construction for diverse applications. Here, we will focus on how organometallic chemistry is applied in MOF design and modifications from linker-centric and metal-cluster-centric perspectives, respectively. Through structural design, MOFs can function as a tailorable platform for traditional organometallic transformations, including reaction of alkenes, cross-coupling reactions, and C–H activations. Besides, an overview will be made on other application categories of organometallic MOFs, such as gas adsorption, magnetism, quantum computing, and therapeutics.

Acceleration of the catalytic transformation of molecules via heterogeneous materials occurs through design of active binding sites to optimally balance the requirements of all steps in a catalytic...

Cobalt catalysts bearing 2-imino-1,10-phenanthroline ligands are quite efficient bench-stable catalysts for the oligomerization of ethylenes. Herein, their further application was developed in the catalytic transformation of N,N-diallylanilines to pyrrolidines through a cycloisomerization process. In this protocol, chlorobenzene is a vital additive to promote reaction efficiency.

A series of metal-modified hierarchical M/H-ZSM-5 catalysts were prepared for catalytic conversion of cellulose in an aqueous medium. Characterization of the catalysts showed that the impregnation of metal into H-ZSM-5 did not change the basic framework and pore structure of H-ZSM-5, but it decreased the total acidity. Analysis of the products indicated that the catalysts significantly affected products distribution. When Co/H-ZSM-5 and Fe/H-ZSM-5 were used as the catalysts, the yields of lactic acid and cyclic ketones obviously increased. At last, a recommendable catalytic transformation pathway of cellulose over M/H-ZSM-5 was proposed on the basis of the obtained experimental results and the published literatures. In this paper, a series of metal-modified hierarchical M/H-ZSM-5 (M = Ce, Co, Ga, and Fe) catalysts were prepared and employed in catalytic conversion of cellulose in aqueous media to examined the products distribution of cellulose catalytic conversion. Based on our results and previous works, the plausible general reaction pathways of cellulose over M/H-ZSM-5 were proposed.

The first catalyst for the alkoxycarbonylation of gem-difluoroalkenes is described. This novel catalytic transformation proceeds in the presence of Pd(acac)2 /1,2-bis((di-tert-butylphosphan-yl)methyl)benzene (btbpx) (L4) and allows for an efficient and straightforward access to a range of difluoromethylated esters in high yields and regioselectivities. The synthetic utility of the protocol is showcased in the practical synthesis of a Cyclandelate analogue using this methodology as the key step.

Asymmetric hydroformylation (AHF) of alkenes is a prototypical, complicated catalytic transformation with a mechanism that comprises three concurrent, isomeric catalytic cycles. A persistent challe...

The construction of carbon–carbon bonds is a central tenet of modern synthetic chemistry. Metal-catalyzed C–H functionalization can serve as a particularly powerful tool for achieving carbon–carbon bond formation. This review summarizes the early adventures and recent advancements in catalytic transformation of unactivated C(sp3)–H bonds into C(sp3)–C(sp3) bonds. To date, three main strategies have emerged to enable this transformation, namely, metallocarbene-triggered C(sp3)–H alkylation, auxiliary-directed C(sp3)–H alkylation, and photo-induced C(sp3)–H alkylation. Compared with traditional cross-coupling reactions having both coupling partners activated with functional groups or base-promoted enolate chemistry, catalytic alkylation of unactivated C(sp3)–H bonds for C(sp3)–C(sp3) bond formation not only offers novel disconnections in retrosynthetic analysis, but also represents the future trend in green and atom-economic chemistry.

A metal free gem selective dimerization of terminal alkynes catalyzed by a pyridonate borane complex is described. Each individual step of the catalytic cycle was verified experimentally and a protocol for the catalytic reaction was developed. The mechanism of the reaction was further investigated by DFT and DLPNO-CCSD(T) computations. The catalytic transformation commences with C–H cleavage by a boroxypyridine that displays frustrated Lewis pair reactivity. The pyridone borane complex that forms upon C–H cleavage dissociates into a pyridone and an alkynylborane. An unprecedented 1,2-carboboration and a protodeborylation effected by the pyridone yield the 1,3-enyne and complete the catalytic cycle. The change in the coordination mode of the boroxypyridine upon C–H cleavage, described by the term boron-ligand cooperation, enables the dissociation of the formed pyridone borane complex and the 1,2-carboboration and is thus vital for the catalytic reaction.

The use of small molecules with defined cavities that catalyze unique chemical transformations to emulate enzyme sites have resulted in sustainable catalytic transformation with unprecedented selectivity that proceed under ambient conditions using benign solvents and clean energy. Of these reported host molecules, Werner-type capsules have been of particular interest to researchers because of their structural modifiability and rich chemical properties arising from their uniform cavities. In this review, we focus on the catalytic properties of several important catalytic transformations that have occurred within the confined pockets of these Werner-type capsules with special attention to the aspects that are derived from the ‘confined space effect’ of these Werner-type capsules.

Oxide-supported noble metal catalysts have been extensively studied for decades for the water gas shift (WGS) reaction, a catalytic transformation central to a host of large volume processes that variously utilize or produce hydrogen. There remains considerable uncertainty as to how the specific features of the active metal-support interfacial bonding—perhaps most importantly the temporal dynamic changes occurring therein—serve to enable high activity and selectivity. Here we report the dynamic characteristics of a Pt/CeO2 system at the atomic level for the WGS reaction and specifically reveal the synergistic effects of metal-support bonding at the perimeter region. We find that the perimeter Pt0 − O vacancy−Ce3+ sites are formed in the active structure, transformed at working temperatures and their appearance regulates the adsorbate behaviors. We find that the dynamic nature of this site is a key mechanistic step for the WGS reaction., Revealing the structure and dynamics of active sites is essential to understand catalytic mechanisms. Here the authors demonstrate the dynamic nature of perimeter Pt0−O vacancy−Ce3+ sites in Pt/CeO2 and the key effects of their dynamics on the mechanism of the water gas shift reaction.

Funding: This work was supported by Sasol Ltd. SC is grateful for a St Leonard’s postgraduate fellowship by the University of St Andrews. A bis-ethene chromium(I) species, which is the postulated key intermediate in the widely accepted metallacyclic mechanism for ethene oligomerization, is experimentally observed. This catalytic transformation is an important commercial route to linear α-olefins (primarily, 1-hexene and 1-octene), which act as comonomers for the production of polyethene. Here, electron paramagnetic resonance studies of a catalytic system based on [Cr(CO)4(PNP)][Al(OC(CF3)3)4] [PNP = Ph2PN(iPr)PPh2] activated with Et6Al2 provide the first unequivocal evidence for a chromium(I) bis-ethene complex. The concentration of this species is enhanced under ethene and isotope labeling studies that confirm its composition as containing [Cr(C2H4)2(CO)2(PNP)]+. These observations open a new route to mechanistic studies of selective ethene oligomerization. Publisher PDF

A copper/silver co-catalyzed cross-dehydrogenative coupling reaction is developed to achieve exclusively remote C5–H coupling of 8-aminoquinoline amides with the methylenic sp3 C–H bond of 1,3-dicarbonyl compounds. This protocol provides a highly regioselective synthetic route for the functionalization of 8-aminoquinoline amides at C5 under mild conditions. Preliminary experiments reveal that radicals may be involved in this catalytic transformation.

A simple and high‐efficiency method is proposed to synthesize hierarchical ZSM‐5 zeolites with micropore and multistage mesopores by adopting water‐soluble carbon dots (CDots) with various size distributions, such as 1‐stage size distribution of CDots‐1 of around 23 nm, 2‐stage size distribution of CDots‐2 of 6 and 9 nm, 3‐stage size distribution of CDots‐3 of 5, 8, and 18 nm. The abundant OH and COOH groups on the surface of CDots provide high solubility in water. The characterization techniques confirmed that the dual‐porous h‐ZSM‐5 (MIcro–mEsopores) and multi‐porous h‐ZSM‐5 (MIcro–mEso–mEsopores), h‐ZSM‐5 (MIcro–mEso–mEso–mEsopores, M‐IEEE) catalysts are obtained. Notably, the hierarchical ZSM‐5(M‐IEEE) catalyst with micropore of 0.55 nm, two small mesopores of 4.8 and 7.4 nm, and one large mesopore of 17.5 nm show excellent catalytic performance with the highest 1,3,5‐triisopropylbenzene (TIPB) cracking conversion (97.3%) and high stability. Similarly, the h‐ZSM‐5(M‐IEEE) shows the high ethanol to olefins conversion (100%). The improved catalytic activity can be attributed to the more efficient diffusion of reactants and products in the crystals with the help of multistage mesopores, improved anti‐coking stability, combined with the effect of suitable acidity, and the increased accessibility of the acid sites.

MoVOx-type catalysts are very active and very selective in the commercially important oxidation of acrolein to acrylic acid. To contribute to unravelling the thus far poorly understood mechanism, we carried out hybrid DFT calculations on embedded cluster models, focusing on the so-called pentameric unit as active site. In the absence of water, we calculated a large energy span, 169 kJ mol–1, for this transformation. After addressing the hydrolysis of the surface, we examined four scenarios of the acrolein conversion to explore the effect of water. The most favorable variant has a notably lower energy span, 146 kJ mol–1, in line with experimental observations that indicate a strong acceleration of the catalytic transformation in the presence of water.

Fe-catalyzed direct transformation of nitro compounds to aldehyde under batch/continuous flow module is reported. This catalytic transformation is highly selective for syntheses of various aldehyde...

The synthesis of aromatic ketones by chromium-catalyzed Kumada arylation of secondary amides with organomagnesium reagents is described. This reaction was enabled by using low-cost chromium(III) salt as a precatalyst, combined with trimethylsilyl chloride as an additive, and presents a rare example of catalytic transformation of secondary amides to ketones at room temperature. It was shown that catalytically active low-valent chromium species might be responsible for the amide–ketone exchange by mechanism involving the activation of benzimidate intermediate.

Amides are generally considered as a low-reactive chemical entity among the carbonyl group, and therefore fewer opportunities to be involved in catalytic transformations as substrates. The origin of the stable nature of amides is resonance stabilization in the planar structure, which has drawn considerable attention from organic and physical chemists, leading to the discovery of distorted amides that exhibit a substantially reactive nature. Recent focus in this field is on the catalytic transformation of designed amides with moderate distortion or reduced resonance stabilization. This digest reviews the brief history of the quest for highly distorted amides and introduces a collection of recent studies on catalytic transformations of designed amides.

The direct transformation of lignocellulosic biomass into valuable chemicals and fuels, which is recognized as a promising strategy for easing the present situation of energy depletion, has brought...

[Fe4N(CO)12]− is a first-row transition element electrocatalyst that selectively produces C–H bonds to give formate from CO2 in water at −1.2 V vs SCE. We present a thermochemical analysis which probes the possibility that [H-Fe4N(CO)12]2– ((H-1)2–) is an intermediate in this process: we show that (H-1)2– is accessible at −1.2 V vs SCE, but if it were formed, we predict that it would generate H2. [Fe4N(CO)12]3– and (H-1)2– were interrogated spectroscopically, and the product of CO loss, [Fe4N(CO)9(μ-CO)2]3–, was synthesized and characterized. Ultimately, we demonstrate that (H-1)2– is an unlikely participant in the catalytic transformation of CO2 to formate.

A catalytic transformation of allylic hydroperoxides into α,β-unsaturated carbonyl compounds using IBX as a dehydration catalyst is described. The combination of a singlet oxygen ene reaction and the IBX-catalyzed dehydration provides α,β-unsaturated carbonyl compounds from alkenes via oxygenative allylic transposition with H2O as the only byproduct.

A novel catalytic behavior of simple rare-earth metal amides RE[N(SiMe3)2]3 (RE = La(1), Nd(2), Sm(3), Yb(4), Y(5)) in the intermolecular addition of alcohols to carbodiimides was disclosed. A series of isoureas were obtained in good to excellent yields via the addition reaction in the presence of the optimal lanthanum amide La[N(SiMe3)2]3. Kinetic studies were also conducted and a possible mechanism of catalytic transformation was suggested.

A ligand-free bimetal-catalyzed aminosulfonylation of aryl iodides is successfully developed. The protocol provids a straightforward approach to access a broad range of structral intriguing sulfonamides in one-pot manner at low catalyst loading from the sulfur dioxide surrogate DABSO and O-benzoyl hydroxylamines under mild conditions. Even without additional ligands, the protocol reveals broad substrate scope for both partners and tolerates all kinds of functional groups. Furthermore, the plausible intermediate sulfinate is critical for this ligand-free catalytic transformation.

Amide, as a ubiquitous functional group, is essential in various aspects of chemistry and biology. Although the history of studying amide is rich and fruitful, the synthetic application of amide is very limited due to the inertness of amide C–N bond. Recently, significant advances have been achieved towards the nickel-mediated C–N activation of amides. This approach allows a facile generation of acyl-nickel intermediates, and a number of unique transformations have been designed and realized based on the amide C–N bond activation. Focused on the catalytic transformation, this review summarizes and categorizes the recent advances on the synthetic applications of Ni-mediated C–N bond activation of amides.

A Cu-catalyzed oxidative coupling reaction of arylboronic acids, amines and carbon dioxide is described for the first time in this paper. The reaction tolerates a wide range of functional groups, providing a convenient protocol for the synthesis of various O-aryl carbamates. The successful development of the transformation was enabled by the use of BF3·OEt2 as the promoter and molecular oxygen as the oxidant. Mechanistic studies suggested that the CuII carbamato complex is involved in the catalytic transformation.

MIL-100(Fe) was used for the first time in the catalytic transformation of hexose sugars into lactic acid (LA). The as-synthesized MIL-100(Fe) was systematically characterized, and its superior morphological and textural properties were demonstrated to contribute greatly to the pronounced catalytic performance in fructose-to-LA conversion (up to 32% yield), as compared with other catalysts like Cu-BTC and MIL-100(Cr). The effects of reaction conditions including temperature, reaction time, and substrate loading were explored. In addition, MIL-100(Fe) could be easily reused for 4 cycles with no evident decrease in catalytic activity.

The oxidation of sp 3 C H bonds in N- alkylhydrazides was achieved en route to the efficient synthesis of a broad series of 1,3,4-oxadiazoles. Mechanistic studies have revealed that N- acylhydrazone is a key intermediate in this catalytic transformation.

We report a manganese-catalyzed hydrosilylative reduction of various primary amides to amines (25 examples). On simple modification of the reaction conditions such as in the presence of a catalytic amount of secondary amide, the same catalyst can transform the primary amides into intermediate nitrile compounds (16 examples) in excellent yields. This is the first example where such a controlled catalytic transformation of primary amides to amines or nitriles with a single catalyst has been demonstrated.

A general and efficient copper-catalyzed benzylation reaction of triazolopyridine with N-tosylhydrazones was developed. This reaction forms a C(sp2)-C(sp3) bond through cross-coupling, and represents an exceedingly practical method to afford 3-benzylated triazolopyridines in moderate to good yields. A proposed mechanistic pathway underlying this reaction was outlined. This catalytic transformation should enable broad synthetic applications in functionalization chemistry, allowing the synthesis of new pharmaceutically relevant triazolopyridine derivatives.

The escalating rate of fossil fuel combustion contributes to excessive CO2 emission and the resulting global climate change has drawn considerable attention. Therefore, tremendous efforts have been devoted to mitigate the CO2 accumulation in the atmosphere. Carbon capture and storage (CCS) strategy has been regarded as one of the promising options for controlling CO2 build-up. However, desorption and compression of CO2 need extra energy input. To circumvent this energy issue, carbon capture and utilization (CCU) strategy has been proposed whereby CO2 can be captured and in situ activated simultaneously to participate in the subsequent conversion under mild conditions, offering valuable compounds. As an alternative to CCS, the CCU has attracted much concern. Although various absorbents have been developed for the CCU strategy, the direct, in situ chemical conversion of the captured CO2 into valuable chemicals remains in its infancies compared with the gaseous CO2 conversion. This review summarizes the recent progress on CO2 capture and in situ catalytic transformation. The contents are introduced according to the absorbent types, in which different reaction type is involved and the transformation mechanism of the captured CO2 and the role of the absorbent in the conversion are especially elucidated. We hope this review can shed light on the transformation of the captured CO2 and arouse broad concern on the CCU strategy.

Here, via a strategy of in situ capture of partially dehydrogenated cyclic amine motifs, we present an acceptorless dehydrogenative coupling of benzocyclic amines with indole derivatives that enables to access various quinoline-indole linked N-biheteroarenes in an efficient manner. The catalytic transformation is characteristic of operational simplicity, a readily available catalyst system, good substrate and functional compatibility, mild conditions, high atom efficiency, and no need for oxidant and halogenated coupling agents.

International audience; Operando DRIFTS is used to identify the nature and the role of the surface sites of hydroxyapatites (HAps) involved in the catalytic transformation of ethanol to n‐butanol. The surface processes occurring upon a first reaction step followed by a step under He flow greatly influence the reactivity of HAps in a subsequent second reaction step. Ethanol is found to be mostly activated by the basic OH− groups of HAps, as indicated by the concomitant recovery of ethanol conversion and OH− groups under He flow. The drastic changes in selectivity observed during the second reaction step reveal the key role of acidic sites cooperatively acting with basic sites for basic reaction steps. Once the POH groups are poisoned by extensive formation of polymeric carbon species and the Ca2+ sites are available, the production of acetaldehyde is drastically promoted at the expense of that of n‐butanol. It is concluded that i) acetaldehyde acts as an intermediate in the formation of n‐butanol, and ii) various active sites are involved in the key basic reaction steps such as Ca2+−OH− and POH−OH− acid‐base pairs in the dehydrogenation of ethanol to acetaldehyde and the aldol condensation for n‐butanol formation, respectively.

[EN] Thought as raw materials clay minerals are often disregarded in the development of advanced materials. However, clays of natural and synthetic origin constitute excellent platforms for developing nanostructured functional materials for numerous applications. They can be easily assembled to diverse types of nanoparticles provided with magnetic, electronic, photoactive or bioactive properties, allowing to overcome drawbacks of other types of substrates in the design of functional nanoarchitectures. Within this scope, clays can be of special relevance in the production of photoactive materials as they offer an advantageous way for the stabilization and immobilization of diverse metal-oxide nanoparticles. The controlled assembly under mild conditions of titanium dioxide and zinc oxide nanoparticles with clay minerals to give diverse clay-semiconductor nanoarchitectures are summarized and critically discussed in this review article. The possibility to use clay minerals as starting components showing different morphologies, such as layered, fibrous, or tubular morphologies, to immobilize these types of nanoparticles mainly plays a role in i) the control of their size and size distribution on the solid surface, ii) the mitigation or suppression of the nanoparticle aggregation, and iii) the hierarchical design for selectivity enhancements in the catalytic transformation and for improved overall reaction efficiency. This article tries also to present new steps towards more sophisticated but efficient and highly selective functional nanoarchitectures incorporating photosensitizer elements for tuning the semiconductor-clay photoactivity., Authors thank the MINECO (Spain, project MAT2015-71117-R) for financial support.

A porous Zr-based MOF, [Zr6(BTEB)4(μ3-O)4(μ3-OH)4(H2O)4], which contains partially hydrated, 12-connected {Zr6} nodes and extended carboxylate ligands (BTEB3−), was synthesized and physicochemically characterised. The resulting (12,3)-connected, 3D framework adopts an uncommon llj topology with a large, solvent accessible void volume of ca. 79% of the unit cell volume. The porous structure facilitates the uptake of N2 and activated samples give rise to BET surface areas of >1000 m2 g−1. Furthermore, the porosity and accessibility of Lewis acidic Zr(IV) sites promote the catalytic transformation of gaseous CO2 to cyclic carbonates via cycloaddition reactions using epoxide reactants, whereby solvated MOFs exhibit higher catalytic performance than thermally treated samples.

The objective of this Special Issue is to provide new diverse contributions that can demonstrate recent applications in biomass transformation using heterogeneous catalysts. In recent decades, a wide variety of biomass-derived chemicals have emerged as key platform chemicals for the production of fine chemicals and liquid fuels using heterogeneous catalysts as the preferred option for most of the developed and proposed catalytic processes. A range of heterogeneous catalysts have been evaluated for effective biomass conversion, such as supported metal nanoparticles, mixed metal oxides and zeolites, where the control of particle size, porosity, acid-basic and redox properties is crucial for providing active, stable and selective heterogeneous catalysts. Moreover, the crucial role of the solvent, choice of reactor design and final chemical processes for controlling activity, selectivity and deactivation phenomena has been demonstrated

The catalytic hydration of nitriles into amides, in water under neutral conditions, has been studied using a series of arene–ruthenium(II) complexes containing commercially available chlorophosphines as auxiliary ligands, i.e. compounds [RuCl2(η6-p-cymene)(PR2Cl)] (R = aryl, heteroaryl or alkyl group). In the reaction medium, the coordinated chlorophosphines readily undergo hydrolysis to generate the corresponding phosphinous acids PR2OH, which are well-known “cooperative” ligands for this catalytic transformation. Among the complexes employed, best results were obtained with [RuCl2(η6-p-cymene){P(4-C6H4F)2Cl}]. Performing the catalytic reactions at 40 °C with 2 mol% of this complex, a large variety of organonitriles could be selectively converted into the corresponding primary amides in high yields and relatively short times. The application of [RuCl2(η6-p-cymene){P(4-C6H4F)2Cl}] in the preparation of synthetically useful β-ketoamides is also presented.

Biomass has emerged as a potential alternative to the dwindling fossil fuel reserves. Catalytic conversion of biomass has become the main route for the transformation of biomass into a variety of commodity chemicals or liquid fuels. Currently, many reviews have effectively documented the use of homogeneous and heterogeneous catalysts for the catalytic transformation of biomass into chemicals and fuels; however, comparatively less attention has been paid to the use of magnetic catalysts in biomass transformation. Magnetic nanoparticles are a well-designed way to bridge the gap between heterogeneous and homogeneous catalysts. The introduction of magnetic nanoparticles in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation. The present review will highlight the recent advances in the development of magnetic catalysts for the transformation of carbohydrates or carbohydrate-derived chemicals into valuable chemicals an...

Few-layer black phosphorus (BP) nanosheets that are clean and of high quality, are efficiently produced by exfoliating bulk BP crystals, which are prepared by a scalable gas-phase catalytic transformation method in water. They are stable enough in water for further processing and applications. As an example, these BP nanosheets are combined with graphene to give high-performance flexible lithium-ion batteries.