Article
Chemistry, Multidisciplinary
Niklas F. Both, Anke Spannenberg, Haijun Jiao, Kathrin Junge, Matthias Beller
Summary: The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation of esters was investigated. Various aromatic and aliphatic esters were successfully hydrogenated at mild temperatures and low catalyst loadings using complexes 3 with KHBEt3 as additive, highlighting the efficiency of the novel catalytic system. Additionally, the versatility of the developed catalytic system was demonstrated by the hydrogenation of other substrate classes like ketones, nitriles, N-heteroarenes, and alkenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Renat Kadyrov
Summary: An efficient and simple catalytic system has been developed for the hydrogenation of carboxylic esters using commercially available Ru-salts and imidazolium salts. This combination enables the reduction of esters to alcohols at moderate temperature and pressure, offering a practical method for alcohol synthesis.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Ondrej Mozdiak, Jiri Tydlitat, Zdenka Ruzickova, Libor Dostal, Roman Jambor
Summary: In this study, Ru complexes with N-bound 2-pyridonato ligand were prepared and their catalytic activity in base-free transfer-hydrogenation of ketones was investigated.
Article
Chemistry, Physical
Martin Soto, Vicente Gotor-Fernandez, Humberto Rodriguez-Solla, Walter Baratta
Summary: The transfer hydrogenation of flavanones and ortho-hydroxychalcones catalyzed by ruthenium pincer complexes allows the synthesis of ortho-hydroxy 1,3-diarypropanols with high yield and selectivity. The amount of co-catalyst is crucial for the reduction reaction, while using pincer catalysts with specific ligands can achieve high enantiomeric excess and moderate conversion rates in the reduction of flavanones.
Article
Chemistry, Multidisciplinary
Sebastian Martinez-Vivas, Macarena Poyatos, Eduardo Peris
Summary: H-1 NMR studies showed that a cationic complex with a pyridine-di-imidazolylidene pincer ligand exhibited high binding affinity with coronene in CH2Cl2. This binding was established through π-stacking interactions between coronene and the planar Rh-I complex. The interaction influenced the electron-donating strength of the pincer CNC ligand and increased the reaction rate of nucleophilic attack of methyl iodide on the rhodium (I) pincer complex, as well as enhancing its catalytic activity in the cycloisomerization of 4-pentynoic acid. These findings highlight the significance of supramolecular interactions in modifying the reactivity and catalytic activity of square-planar metal complexes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jana Hatzfeld, Steffen Skowaisa, Elisabeth Jackel, Julia Kaufmann, Edgar Haak
Summary: Various triaminocyclopentadienyl ruthenium complexes were synthesized from Ru-3(CO)(12) and tested for their ability to catalyze cascade conversions of propargyl alcohols. The substrate scope of catalytic cycloadditions was extended to terpenoid-derived propargyl alcohols containing an internal alkyne moiety, resulting in a wide range of cyclic terpenoid and phloroglucinol adducts obtained by complementary application of both types of catalysts.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Harikrishnan Jayaprakash
Summary: A series of Mn(i) catalysts with P'(O)N(H)P pincer ligands have been explored for the asymmetric transfer hydrogenation of aryl-alkyl ketones, leading to good to high enantioselectivities compared to other Mn-based catalysts for such reactions. The chiral backbone and phosphine moieties of P'(O)N(H)P make it an alternative ligand framework to the well-known PNP-type pincers.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Tanuja Tewari, Rohit Kumar, Amol C. Chandanshive, Samir H. Chikkali
Summary: Metal-catalyzed hydroformylation and hydrogenation heavily rely on ligands, with phosphorus ligands playing a pivotal role. This account presents three distinct classes of phosphorus ligands, their synthesis, performance in reactions, and the latest developments in iron-catalyzed hydroformylation of alkenes. The use of phosphines enabled iron-catalyzed hydroformylation under mild conditions, demonstrating the central role of phosphorus ligands in industrially relevant transformations.
Article
Chemistry, Physical
Lena Staiger, Tim Kratky, Sebastian Guenther, Ondrej Tomanek, Radek Zboril, Richard W. Fischer, Roland A. Fischer, Mirza Cokoja
Summary: Phosphanes have been found to increase both the reaction rate and selectivity towards olefins, with the ligand's steric and electronic effects playing a crucial role in catalyst performance.
Article
Chemistry, Inorganic & Nuclear
Sangeeta Kumari, Charu Sharma, Avinash K. Srivastava, Naveen Satrawala, Kamal N. Sharma, Raj K. Joshi
Summary: A Ru(II) complex was synthesized for C-H bond activation alkenylation of arenes using thioether directing groups, achieving high yields under milder conditions compared to previous methods utilizing precious noble metal catalysts. Broad substrate scope was demonstrated with good tolerance towards benzyl thioethers and vinyl, making it the first report of its kind utilizing a Ru-based catalyst for thioether alkenylation.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Shrouq Mujahed, Evamarie Hey-Hawkins, Dmitri Gelman
Summary: Traditionally, low-valent metals dominate the field of catalytic hydrogenation, but high-valent metals can also achieve catalytic hydrogenation through heterolytic bond activation, with better efficiency than low-valent metals. The Ru-IV catalyst with a bifunctional PCP pincer ligand can efficiently catalyze the hydrogenation of aldehydes and carboxylic compounds under molecular hydrogen, even at room temperature.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Anand B. Shabade, Dipesh M. Sharma, Priyam Bajpai, Rajesh G. Gonnade, Kumar Vanka, Benudhar Punji
Summary: Chemoselective hydrogenation of C=C, C=O and C=N bonds in alpha,beta-unsaturated ketones, aldehydes and imines can be achieved at room temperature using a well-defined Mn(I) catalyst and hydrogen gas. The method shows tolerance towards various sensitive functional groups and can be applied to unsaturated ketones containing indole, pyrrole, furan, thiophene, and pyridine moieties. In the reaction, the C=C bond is selectively hydrogenated, while the C=O and C=N bonds in aldehydes and imines are preferentially reduced.
Article
Chemistry, Inorganic & Nuclear
Alexander J. Bukvic, Martin Albrecht
Summary: Gold-based homogeneous catalysis is mainly achieved through AuI systems. The limited availability of AuIII catalysts for redox reactions is due to the unfavorable potentials for redox cycles between AuI and AuIII. This study presents gold(III) complexes with pincer-based PYA ligands to address these issues. The complexes act as electron reservoirs through two resonance structures, allowed by the flexible coordination sites of the ligands. The presence of a neutral L-type resonance form, as observed in solution data, prevents reversible AuIII reduction and impedes the removal of a chloride ligand. Additionally, a novel macrocyclic-PYA ligand with secondary metal-ligand interactions is introduced.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Veronica Papa, Johannes Fessler, Francesco Zaccaria, Julien Hervochon, Phong Dam, Christoph Kubis, Anke Spannenberg, Zhihong Wei, Haijun Jiao, Cristiano Zuccaccia, Alceo Macchioni, Kathrin Junge, Matthias Beller
Summary: In this study, several imidazolylphosphine pincer ligands and corresponding Mn complexes were synthesized, characterized, and studied in depth using experimental and theoretical investigations. The complexes showed good to excellent performance in various hydrogenation reactions, particularly in the reduction of N-heterocycles. Spectroscopic studies provided evidence for a classical metal-ligand cooperative mechanism and identified amido and hydrido species.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Froze Jameel, Matthias Stein
Summary: In the global effort to combat climate change, the design and development of new procedures for complex chemical multi-step reactions play a crucial role in the transformation of the chemical industry. Solvent effects on thermodynamics and kinetics are important considerations, with various roles including promoting intermediate formation but also compromising overall pathways. Solvent coordination is critical for the activity of reducing catalysts, impacting regioselectivity and reaction rates in complex multi-step reactions.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Inorganic & Nuclear
Joshua S. Sapsford, Sarah J. Gates, Laurence R. Doyle, Russell A. Taylor, Silvia Diez-Gonzalez, Andrew E. Ashley
INORGANICA CHIMICA ACTA
(2019)
Article
Chemistry, Physical
Meera A. Shah, Samuel Raynes, David C. Apperley, Russell A. Taylor
Article
Chemistry, Physical
Elise Peeters, Ibrahim Khalil, Pierre Eloy, Sergio Calderon-Ardila, Jan Dijkmans, Paola Ferrini, Damien P. Debecker, Russell A. Taylor, Alexios P. Douvalis, Michiel Dusselier, Bert F. Sels
Summary: This study focuses on enhancing catalytic activity in Sn beta catalysts with Sn loadings up to 10 wt % through tandem reduction-reoxidation, and explores the impact on Lewis acid density, Sn dispersion, Sn speciation, and catalytic performance. Characterization of different samples reveals that higher catalytic activity may result from redispersion of SnO2 clusters at lower Sn content (<5 wt %) and respeciation of SnO2 clusters at higher Sn content (>= 5 wt %).
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Samuel G. Meacham, Russell A. Taylor
Summary: A commercial zeolite is an effective heterogeneous catalyst for the Friedel-Crafts alkylation of mandelic acid with aromatic substrates. The reaction proceeds in one step, eliminating the need for inert atmosphere techniques or superacids. The selectivity to mixed diarylacetic acids depends on the zeolite framework, with the FAU framework showing very high selectivity.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Samuel J. Raynes, Russell A. Taylor
Summary: In this study, a catalyst system consisting of ZnO supported on alkali cation-exchanged mordenite was developed for the direct dehydrogenation of ethanol to acetaldehyde. The optimized catalyst showed excellent selectivity and stability beyond 120 hours of operation, with high acetaldehyde productivity and selectivity. The use of a zeolite support greatly improved the efficiency of Zn atoms and led to low ethylene selectivity and extended lifetimes in the reaction, which has not been reported previously.
SUSTAINABLE ENERGY & FUELS
(2021)
Review
Chemistry, Inorganic & Nuclear
Samuel Raynes, Meera A. Shah, Russell A. Taylor
DALTON TRANSACTIONS
(2019)
Article
Chemistry, Physical
Ming-Yi Chen, Ngoc Thanh Thuy Tran, Ahmed Abubakar Alao, Wen-Dung Hsu
Summary: This study demonstrates the significance of surface Pt atom arrangement for the efficiency of ORR in PEMFCs and reveals the correlation between Pt-Pt average distance and O2 dissociation barrier. Furthermore, the study discovers a robust correlation between the level of the catalyst's d-band center and O2 adsorption energy. High-entropy alloy substrates provide potential for controlling Pt arrangement and O2 dissociation barrier.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Eduardo C. Atayde Jr, Babasaheb M. Matsagar, Yu-Cheng Wang, Kevin C. -W. Wu
Summary: This study presents the first application of an acidic MOF, Sulfated MOF-808, in catalyzing the HAA reactions of furan oligomers for the production of biofuel precursors. The catalyst showed high yield, selectivity, and recyclability, making it versatile for different starting materials.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Maria do Carmo Rangel, Francieli Martins Mayer, Soraia Jesus de Oliveira, Sergio Gustavo Marchetti, Fabricio Luiz Faita, Doris Ruiz, Giovanni Saboia, Mariana Kieling Dagostini, Jonder Morais, Maria do Carmo Martins Alves
Summary: This study developed a new catalyst by investigating the effect of magnesium on the catalytic properties of hematite in ethylbenzene dehydrogenation. The catalyst showed important differences in activity, selectivity, and stability, making it a promising candidate for commercial applications.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Yanjun Li, Qian Wang, Hui Tian, Mingyuan Zhu, Yuanyuan Liu
Summary: A novel strategy using microwave-assisted precipitation was proposed to prepare defective CsH3PMo11VO40 catalyst for the oxidation of methacrolein to methacrylic acid. Microwave treatment accelerates crystallization, increases vanadyl species content, and forms defective Keggin structures, thereby enhancing the oxidation capacity of the catalyst.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Rajeshwari Athavale, Sailee Gardi, Fatima Choudhary, Dayanand Patil, Nandkishor Chandan, Paresh More
Summary: In this study, a novel acidic ionic liquid catalyst was prepared and used for the synthesis of bis-indolyl methane derivatives. The catalyst exhibited short reaction times, easy purification, and reusability.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Masatomo Hattori, Takato Hattori, Masakuni Ozawa
Summary: Cu-added gamma-Al2O3 catalysts were prepared with varying Cu loadings and the effects of copper oxidation states on catalytic activity were investigated. The results showed that the addition of copper increased the catalyst activity, but excessive copper loading decreased catalytic activity. XRD and TEM analysis indicated the formation of a solid solution of copper oxide species on the surface of gamma-Al2O3. XAS and TPR data demonstrated variations in copper oxidation states among the catalysts.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Liwei Fang, Shiyang Niu, Shengsen Wang, Yiqing Lu, Yuanhui Cheng
Summary: In this study, PtNi alloy on nitrogen-doped carbon and SnO2 dual-support was designed to modulate the metal-support interaction, resulting in improved catalytic activity and stability for oxygen reduction reaction. The SnO2/PtNi/NC catalyst exhibited a strongly coupled interface, enhanced electron transfer, and higher half-wave potential compared to PtNi/NC and commercial Pt/C.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Shohei Harada, Duanxing Li, Kenta Iyoki, Masaru Ogura
Summary: This study investigates the catalytic performance of a composite catalyst composed of ZnZrOX and H-zeolite for the hydrogenation of CO2. The deactivation of the composite catalyst is influenced by ion exchange of Zn2+ and/or coke, with their effects differing based on the zeolite structure. Separating the grains of the composite catalyst can prevent deactivation.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Laura Proano, Christopher W. Jones
Summary: In this study, NiGa alloy particles supported on CeO2, ZrO2, and ZrO2-CeO2 solid solutions were prepared and characterized. The nature of the support was found to have a significant influence on the catalyst's activity and selectivity, with the crystalline structure of ZrO2 having the greatest impact. Pure ZrO2 showed the highest methanol selectivity and CO2 conversion at high Zr:Ce ratios. In equimolar and Ce-rich conditions, basic sites and oxygen vacancies were found to be the key parameters affecting methanol production.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Liyan Zhang, Yinze Yang, Leilei Zhou, Fengyu Zhao, Haiyang Cheng
Summary: 1,6-Hexamethylenediamine was successfully synthesized via the reductive amination of 1,6-hexanediol using a Ru/PRL(x)-Al2O3 catalyst. The highly dispersed and anchored Ru species, formed by 1,10-phenanthroline (PRL), played a crucial role in the catalytic reaction. The formation of new acid-base pairs, electron deficient Ru species, and smaller nanoparticles contributed to the improved catalytic performances of the Ru/PRL-Al2O3 catalyst.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Anita Horvath, Miklos Nemeth, Andrea Beck, Gyorgy Safran, Valeria La Parola, Leonarda Francesca Liotta, Gregor Zerjav, Matevz Roskaric, Albin Pintar
Summary: This study investigates the catalytic and structural changes caused by the addition of 0.25 wt% indium in a 3% Ni/CeO2-Al2O3 catalyst prepared by impregnation method. The results show that the addition of indium can decrease the activity of the catalyst, but it improves its stability and reduces coking.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Ankush Kularkar, Vaibhav Vilas Khedekar, Sachin D. Chaudhari, Mudavath Ravi, Sadhana S. Rayalu, Penumaka Nagababu
Summary: Efficiently addressing the challenges of photocatalytic CO2 reduction to CH3OH is crucial. This study developed Zn-BTC MOF and its composites with CaIn2S4, achieving highly efficient and robust photocatalytic CO2 reduction to CH3OH under ambient conditions, using H2O2 as the hydrogen source. Among the composites, ZMCIS4 demonstrated excellent performance with a CH3OH evolution of 49100 μmol/g.cat and a quantum efficiency of approximately 78.41%. The enhanced performance was attributed to the production of nascent hydrogen atoms (H center dot) through the photo-splitting of H2O2 on the ZMCIS surface.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Dan Liu, Yudong Li, Chengyu Wang, Haiyue Yang, Rong Wang, Shujun Li, Xiaohui Yang
Summary: In this study, a self-supporting three-dimensional porous Co3O4 nanobelt array decorated on nickel foam (P-Co3O4 -NBA@NF) electrode with numerous active sites was successfully constructed for the oxidation of 5-Hydroxymethylfurfural (HMF) to 2,5-furan dicarboxylic acid (FDCA). The P-Co3O4 -NBA@NF electrode demonstrated high conversion efficiency, selectivity, and Faraday efficiency, as well as remarkable long-term stability. This research provides a promising electrocatalyst for biomass conversion.
APPLIED CATALYSIS A-GENERAL
(2024)
Article
Chemistry, Physical
Yimin Li, Enggah Kurniawan, Fumiya Sato, Takayoshi Hara, Yasuhiro Yamada, Satoshi Sato
Summary: In this study, several silica-alumina catalysts modified with Ag were examined for the dehydration of 1,3-butanediol to 1,3-butadiene. Among them, an amorphous silica-alumina catalyst (SAL-3) modified with Ag showed the highest improvement in catalytic activity and stability when operated in H2 flow. The generation of reversible acid sites was found to be the reason behind the enhanced activity and stability of this Ag/SAL-3 catalyst. The effects of various parameters on the catalytic activity of Ag/SAL-3, such as reaction temperature, contact time, Ag content, and carrier gas, were investigated.
APPLIED CATALYSIS A-GENERAL
(2024)