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In catalysis science, the electronic structure of the active site determines the structure–activity relationship of the catalyst to a large extent. Therefore, modulating the electronic structure has become a main route for the rational design of metal‐based catalyst materials. In this work, we prepared a LaCoSiHx material that has more electronegativity and a lower workfunction than traditional supported Co‐based catalysts. Using CO2 methanation as a model catalytic reaction, the facile dissociation of CO2 and CO (a key reaction intermediate) on the surface of the LaCoSiHx catalyst is observed by various experimental methods (e.g., in situ Raman and FTIR) at room temperature. Moreover, theoretical calculation results further show that LaCoSiHx has a much stronger capacity for carbon–oxygen bond activation than the Co surface. The intrinsic mechanism is attributed to the marked electron transfer from catalysts into the antibonding orbital of CO2 and CO. [ABSTRACT FROM AUTHOR]

The dicarbonylation of 1,3‐butadiene to adipic acid derivatives offers the potential for a more cost‐efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium‐catalysed process in the presence of 1,2‐bis‐di‐tert‐butylphosphin‐oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3‐butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom‐economy under scalable conditions. Under optimal conditions a variety of di‐ and triesters from 1,2‐ and 1,3‐dienes can be obtained in good to excellent yields. [ABSTRACT FROM AUTHOR]

The first general and regioselective Pd‐catalyzed cyclocarbonylation to give α‐methylene‐β‐lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N‐arylated imidazole (L11) in the presence of Pd(MeCN)2Cl2 as pre‐catalyst. A variety of easily available alkynols provide under additive‐free conditions the corresponding α‐methylene‐β‐lactones in moderate to good yields with excellent regio‐ and diastereoselectivity. The applicability of this novel methodology is showcased by the direct carbonylation of biologically active molecules including natural products. [ABSTRACT FROM AUTHOR]

Density functional theory computations have been carried out to investigate the base free acceptor‐less dehydrogenative coupling of benzyl alcohol to benzyl benzoate catalyzed by defined Mn and Re PNP pincer amido M(CO)2(PNP) and amino HM(CO)2(PNHP) complexes [M = Mn, Re; PNP = N{CH2CH2P(isopropyl)2}2]. Benchmark calculations show that B3PW91 have the best and closest agreement with the experiments than DLPNO‐CCSD(T). Within all proposed elementary steps, the non‐innocent outer‐sphere mechanism incorporating the amido complex and the N–H bond is more kinetically favored than the innocent outer‐sphere mechanism without the amido complex as well as the inner‐sphere mechanism via the de‐coordination of one phosphine ligand to create a vacant site for β‐hydride elimination. The dehydrogenation of hemiacetal to ester represents the rate‐determining step. Both Mn and Re‐based catalysts have close free energy barriers and similar catalytic activity. However, the computed apparent barrier is overestimated on the basis of the experimentally determined TOF for the Mn‐based complexes. DFT calculations help elucidate the mechanism of the base free acceptorless dehydrogenative coupling of benzyl alcohol to benzyl benzoate catalyzed by Mn and Re PNP pincer amido and amino complexes. It was determined that the non‐innocent outer‐sphere mechanism is more favorable than the innocent outer‐sphere and inner‐sphere mechanisms, and the dehydrogenation of hemiacetal to ester represents the rate‐determining step. [ABSTRACT FROM AUTHOR]

For the first time, structurally defined manganese pincer complexes catalyze the dehydrogenation of aqueous methanol to hydrogen and carbon dioxide, which is a transformation of interest with regard to the implementation of a hydrogen and methanol economy. Excellent long-term stability was demonstrated for the Mn-PNP iPr catalyst, as a turnover of more than 20 000 was reached. In addition to methanol, other important hydrogen carriers were also successfully dehydrogenated. [ABSTRACT FROM AUTHOR]

The direct asymmetric reductive amination (DARA) of ketones with anilines is described by combining a chiral Brønsted acid (TRIP) and the non-chiral Knölker iron complex as the catalyst system. In situ-formed imines are reduced with molecular hydrogen to give chiral amines in high yields (90%) and enantioselectivities of up to 99% ee. [ABSTRACT FROM AUTHOR]

A convenient and efficient catalyst system for the hydrogenation of aliphatic nitriles towards the corresponding primary amines in high to excellent yields is presented. In addition, aromatic nitriles are reduced smoothly, too. The use of low catalyst loadings and molecular hydrogen make this protocol an attractive methodology. [ABSTRACT FROM AUTHOR]

In this review, we have mainly shown the recent computational studies on formic acid adsorption and selective dissociation to produce hydrogen (NCOOH → CO2 + H2) on several metal (Pt, Pd, Ni, Cu, Rh and Au) and metal oxide (TiO2, MgO, ZnO and NiO) surfaces, and both thermal decomposition and electro-catalytic oxidation have been discussed. The decomposition mechanisms of formic acid have been studied by using different computational models and methods, not only interesting and exciting but also different and controversial results have been reported. It is noted that the model systems used in these studies are too simple and idealized, and they cannot represent the real catalysts or the catalytic systems, and more sophisticated computational methodologies and real model systems under the consideration of the working conditions are therefore needed. [ABSTRACT FROM AUTHOR]

Make it green: The Pd‐catalyzed carbonylation of allylic alcohols with aliphatic alcohols represents a cost‐effective, salt‐free, and atom‐economic carbonylation process generating water as the sole by‐product. Mechanistic studies uncovered a new domino CO coupling/carbonylation reaction pathway. [ABSTRACT FROM AUTHOR]

Invited for this month's cover is the group of Matthias Beller at the Leibniz‐Institute for Catalysis in Rostock. The image illustrates the catalytic dehydrogenation of secondary alcohols to the corresponding ketones using iron‐based pincer complexes. The Communication itself is available at10.1002/cssc.201900308. [ABSTRACT FROM AUTHOR]

The article presents the molecular structure of the reactivity and stability of CpCoI complexes as catalysts for cycloaddition reactions using systematic ligand variations.

This is a general and efficient method for the preparation of furan-2-ones and alkynones under mild conditions in good to excellent yields. [ABSTRACT FROM AUTHOR]

Abstract: The reaction mechanism of thiophene hydrodesulfurization (HDS) on a Mo3S9 model catalyst has been investigated at the GGA level of density functional theory. On the basis of the computed energetic data, 2,5-dihydrothiophene has been identified as the most important intermediate of HDS processes, and it is responsible for the direct formation of butadiene as the principal product. Neither the stepwise formation of cis-2-butene nor that of butane is competitive. However, butene (or butane) can be obtained from the hydrogenation of the formed butadiene. [Copyright &y& Elsevier]

Abstract: The entire catalytic hydrodesulfurization (HDS) cycle of benzothiophene over Mo3S9 cluster has been investigated at the level of density functional theory. It is found that the hydrogenation and hydrogenolysis route with dihydrobenzothiophene (DHBT) as intermediate is more favored than the hydrogenolysis and hydrogenation route with styrene as intermediate. The stepwise hydrogenolysis of SB–C9 (C(aryl)–S) bond in DHBT leading to the formation of 2-phenylethanethiol is more favored than that of SB–C2 (C(alkyl)–S) bond with 2-ethylthiophenol as intermediate. The computed activation free energy and rate constant of benzothiophene hydrogenation to DHBT agree well with the available experimental data. The difference in HDS reactivity between benzothiophene and thiophene has been discussed. [Copyright &y& Elsevier]

This developed protocol for the efficient Ru-catalyzed reduction of nitriles allows the conversion of aliphatic, aromatic, and heteroaromatic into the corresponding amines. [ABSTRACT FROM AUTHOR]

The reaction succeeds using aromatic, heteroaromatic and aliphatic ketones with generally moderate to good reaction yields and high enantioselectivities. [ABSTRACT FROM AUTHOR]

A variety of esters is reduced for the first time selectively using an iridium pincer-type complex as catalyst. [ABSTRACT FROM AUTHOR]

A new, efficient, and salt free method to prepare synthetically important β,γ-unsaturated esters is reported. [ABSTRACT FROM AUTHOR]

Abstract: Density functional theory computations have been employed to investigate the decomposition of formic acid (HCO2H) into CO2 and hydrogen on the β-Mo2C(101) surface. The adsorption configurations and energies of the surface intermediates (HCO2H, CO2, CO, H2O, HCO2, CO2H, CHO, OH, O and H) have been systematically characterized. Among the different dissociation steps considered, our results showed the formate route (HCO2H → H + HCO2; HCO2 → H + CO2) is the minimum energy path for hydrogen formation and CO2 has very strong chemisorption. The adsorption and dissociation of formic acid on the Mo2C(101) surface have been compared with those of Pt group metals. [Copyright &y& Elsevier]

Abstract: Using the B3LYP density functional theory method we have computed the potential energy surface of the (η5-C5H5)Ir-catalyzed acetylene cyclotrimerization. The first step is the oxidative addition which forms the iridacyclopentadiene complex (2) from the bisacetylene complex (η5-C5H5)Ir(η2-HCCH)2 (1), and this is the rate-determining step. On the potential energy surface, acetylene addition to complex (2) forms the iridacyclopentadiene(acetylene) complex (3), and this step is barrier-free and highly exergonic; and complex (3) forms the benzene complex (4) via an intramolecular [4 + 2] cycloaddition. Alternatively, complex (2) and acetylene form the iridabicyclo[3.2.0]heptatriene complex (5) via an intermolecular [2 + 2] cycloaddition, and complex (5) can further isomerize into the aromatic iridacycloheptatriene complex (6a), which is a trap on the potential energy surface. This potential energy surface is qualitatively close to that for the CpRh-catalyzed reaction, but differs strongly from that for the CpCo-catalyzed reaction, which undergoes a spin crossing (or non-adiabatic) mechanism. The differences among these mechanisms as well as the relative stability of their intermediates have been compared and discussed accordingly. [Copyright &y& Elsevier]

Abstract: Hydrogen adsorption on the Fetet1- and Feoct2-terminated Fe3O4(111) surfaces has been computed at the level of density functional theory. At 2/5 monolayer (ML), the most favored hydrogen adsorption on the Fetet1-terminated surface is homolytic and dissociative on surface O atoms, while other adsorption modes become possible at higher coverages. On the Feoct2-terminated surface at 1/3 ML, hydrogen prefers to adsorb heterolytically and dissociatively on surface Fe and O atoms, while other adsorption modes become in close energy at 2/3 and 1 ML. The Fetet1-terminated surface is more favored than the Feoct2-terminated surface for hydrogen adsorption. The adsorption mechanism has been analyzed on the basis of the calculated local density of state. [Copyright &y& Elsevier]

Abstract: Density functional theory computations have been carried out on the adsorption of NO, NO2, pyridine and pyrrole on the α-Mo2C(0001) surface for understanding the hydrodenitrogenation processes. On the Mo-terminated surface, NO decomposes into surface N and O, and NO2 dissociates into surface O and NO without any barriers, while the most stable adsorption modes of pyridine and pyrrole have π-face coordination over the three-fold molybdenum hollow sites with strongly destroyed aromatic systems. On the C-terminated surface, adsorbed surface species have been found for NO and NO2, while destroyed ring systems are found for pyridine and pyrrole. It is found that adsorption on the Mo-terminated surface is much stronger than that on the C-terminated surface. [Copyright &y& Elsevier]

Abstract: A 24T model containing a complete two-layered 12-membered ring connected by an 8-membered side pocket was used to represent the channel of the MOR framework. On the basis of this model, the structures of the acid sites in the main channels of Li- and Na-MOR as well as their interaction with pyridine probe molecule were investigated using the ONIOM2 (QM/QM; B3LYP/6-31G(d,p):HF/3-21G) and ONIOM2 (QM/MM; B3LYP/6-31G(d,p):UFF) methods. There are two stable structures for the Li-MOR cluster; one has Li+ interacting with two oxygen atoms around Al, and the other has Li+ interacting with four oxygen atoms belonging to a five-membered ring. This four-fold Li+ coordination is consistent with Na+ in Na-MOR, and is the same as the Na+ coordination in the intersection model of Na-ZSM-5. The ONIOM2 (QM/MM) method overestimates the adsorption energies of pyridine (195.0/192.8 and 170.6kJ/mol for Li-MOR and Na-MOR, respectively), while the ONIOM2 (QM/QM) method gives reasonable results (171.6/154.7 and 131.3kJ/mol, respectively) compared to the available experimental values (153–195 and 120kJ/mol, respectively). The structural parameters of the adsorption complexes showed that coordination of the alkali ion to the nitrogen atom of pyridine dominates the overall interaction between the zeolite and pyridine, and the adsorption complexes were further stabilized by hydrogen bonding between the hydrogen atoms of pyridine and the lattice oxygen atoms of the zeolite framework. [Copyright &y& Elsevier]

Abstract: Density functional theory computations have been carried on the hydrogen adsorption mechanism on a Mo27S54 single layer cluster, which has a size (15–20Å) close to that of real catalysts. For one molecule of H2 adsorption, the most stable adsorption form (E ads =−27.2kcal/mol) is the homolytic dissociation on the S edge with the hydrogen atoms keeping away from the plane consisting of all Mo atoms, followed by the heterolytic dissociation (E ads =−26.1kcal/mol) on the intersection of S and Mo edges with the formation of Moc–H and Sc–H bonds. At high coverage with two and three H2, however, dissociated hydrogen adsorption on the Mo sites are much more favored thermodynamically than on the S sites. Moreover, the corner sites are more favored thermodynamically for hydrogen adsorption and formation of coordinatively unsaturated sites than the edge sites. In addition, the activation energy of H2 dissociation and hydrogen transfer processes have been computed to be 2.7–19.2kcal/mol, and these rather low barriers indicate the enhanced mobility of the adsorbed hydrogen on the surface. [Copyright &y& Elsevier]

The catalytic performance of Cu/ZrO2 calcined at different temperatures was investigated with XRD and XPS. It was found that the activity of Cu/ZrO2 depends on the interaction between copper and zirconia, rather than on their crystal sizes. The XRD and XPS results illustrated that the reinforced interaction between copper and zirconia can hinder the increase of the copper crystal size in the reaction process. In addition, B3LYP/LACVP density functional calculation revealed electron transfer from copper to zirconia and weakening effect of surface hydroxyl on zirconia near copper center. [Copyright &y& Elsevier]

A recently published protocol for hydrogenation of esters to alcohols is improved by using a sterically less hindered iron pincer complex, that shows superior catalytic activity. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to the article "A Convenient and Selective Palladium-Catalyzed Aerobic Oxidation of Alcohols" by S. Gowrisankar and others, published in the periodical "European Journal" in 2013.