Article
Green & Sustainable Science & Technology
Jeong Gil Seo, Reibelle Q. Raguindin, Bezawit Zerihun Desalegn, Mahlet N. Gebresillase
Summary: In this study, nickel-cobalt phosphides were synthesized and used as catalysts for the solvent-free hydrogenation of levulinic acid to gamma-valerolactone. The results showed that the phosphides exhibited excellent catalytic performance with high conversion rate. The outstanding performance of the catalysts can be attributed to their bifunctional substrate-and hydrogen-activating ability, acidity, and the synergistic effect between nickel and cobalt.
Article
Chemistry, Physical
A. Nijamudheen, Ryoichi Kanega, Naoya Onishi, Yuichiro Himeda, Etsuko Fujita, Mehmed Z. Ertem
Summary: Transition metal-catalyzed reversible hydrogenation of CO2 to formate in aqueous solutions is an environmentally friendly strategy for H2 storage and transportation. The mechanism of CO2 hydrogenation by Cp*Ir complexes has been investigated, with H-2 heterolysis identified as the rate determining step. Thermodynamic and kinetic hydricities of various complexes have been computed, providing insights for next-generation catalyst design.
Article
Chemistry, Physical
Eva Kratzer, Simon Schoetz, Sven Maisel, Dominik Blaumeiser, Sharmin Khan Antara, Leon Ewald, Daniel Dotzel, Marco Haumann, Andreas Goerling, Wolfgang Korth, Andreas Jess, Tanja Retzer
Summary: In this study, we used supported ionic liquid phase (SILP) catalysts to hydrogenate 1-alkenes in a continuous fixed-bed reactor. The SILP catalysts were prepared by dissolving the catalyst, tris(triphenylphosphine)rhodium(i) chloride [RhCl(PPh3)(3)], in the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C(4)C(1)Im][NTf2]. We observed an increase in activity due to restructuring of the catalyst via formation of supported metal nanoparticles (NPs). By varying the experimental conditions and catalyst design, we were able to stabilize the molecular Rh complex under hydrogenation conditions.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Bo Han, Miaomiao Zhang, Hongmei Jiao, Haojie Ma, Jijiang Wang, Yuqi Zhang
Summary: Research has shown that using inexpensive cobalt catalysts is an effective alternative to expensive noble metals in catalysis, particularly in the hydrogenation of polycyclic aromatic hydrocarbons (PAHs) and olefins. When diketimine is used as a ligand and magnesium as a co-agent, high catalytic activity and site-selectivity can be achieved in the hydrogenation reactions of PAHs. This provides a cost-effective and selective strategy for preparing partially reduced PAHs, which are difficult to obtain using common methods.
Article
Multidisciplinary Sciences
Piotr Cyganowski, Anna Dzimitrowicz, Mateusz M. M. Marzec, Sebastian Arabasz, Krystian Sokolowski, Anna Lesniewicz, Sylwia Nowak, Pawel Pohl, Andrzej Bernasik, Dorota Jermakowicz-Bartkowiak
Summary: This study investigates the catalytic reduction of nitroaromatic compounds using new Re-based heterogeneous catalysts. The results show that the use of small Re structures as catalysts significantly enhances the reaction rates under mild conditions.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Natalia Levin, Lisa Goclik, Henrik Walschus, Neha Antil, Alexis Bordet, Walter Leitner
Summary: Valuable substituted phenols can be synthesized through the selective decarboxylation of hydroxybenzoic acid derivatives using multifunctional catalysts. The catalyst, Fe(25)Ru75@SILP+IL-NEt2, provides high stability and activity by bringing metal and amine sites into close contact. Operating under a hydrogen atmosphere is crucial for achieving high selectivity and yields. This approach enables the production of valuable phenols from a wide range of substrates, including lignocellulosic biomass.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Marlene Fuhrer, Tomas van Haasterecht, Johannes Hendrik Bitter
Summary: This study demonstrates the potential of carbon supported Mo and W carbides to replace Pt in the hydrogenation of cinnamaldehyde. Although the carbide catalysts are less active than Pt, both the carbides and Pt exhibit selectivity towards C=C hydrogenation, with the carbides also producing beta-methylstyrene.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Haoyang Jiang, Feng Zhu, Renjie Zhou, Linyu Wang, Yongcheng Xiao, Miao Zhong
Summary: Co-modified Fe5C2 on TiC catalyst promotes photothermal catalytic CO hydrogenation with high C2+ selectivity and CO conversion rate by modulating the chemical state of Fe through light-induced hot electron injection from TiC to Fe5C2.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Chemistry, Physical
Pengxian Wang, Yue Ma, Yiran Shi, Fangying Duan, Meng Wang
Summary: Alkynol semi-hydrogenation plays a vital role in high-end chemical synthesis, but the selectivity and efficiency of the products are still challenging. This review discusses the challenges and advancements in catalysts under different reaction conditions and summarizes strategies to enhance the yield and rate of the products.
Article
Chemistry, Multidisciplinary
Chenghao Li, Shu-Xin Zhang, Yu Feng, Yan-Mei He, Qing-Hua Fan
Summary: The chiral ruthenium-catalyzed enantioselective hydrogenation of tetrapyridine-type N-heteroarenes was developed for the first time. The adjacent tetraheteroaromatic substrates showed high reactivity, enantioselectivity, and diastereoselectivity, with yields up to 93%, enantiomeric excess (>99% ee), and diastereomeric ratio of 92:8, respectively, in the presence of phosphine-free chiral cationic ruthenium diamine complexes. The potential application of chiral tetradentate pyridine-amine products as chiral ligands was demonstrated in the Cu-catalyzed asymmetric Friedel-Crafts alkylation reaction between indoles and nitroalkenes.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Ryma Haddad, Yingrui Zhao, Antoine Miche, Ferdaous Ben Romdhane, Nivedita Sudheer, Ovidiu Ersen, Francois Devred, Francois Ribot, Capucine Sassoye, Clement Sanchez, Damien P. Debecker, Corinne Chaneac, Cedric Boissiere
Summary: This article introduces an environmentally friendly synthesis method for catalysts, using the principle of frugal innovation to successfully prepare ruthenium-based catalysts through solvent-free sol-gel chemistry. This method eliminates the need for organic pore-generating agents, washing, and filtration, and produces no liquid waste, while achieving comparable synthesis results to traditional methods with lower environmental impact.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Fatemeh Koohestani, Samahe Sadjadi
Summary: A new strategy is proposed to enhance the catalytic activity of cross-linked chitosan beads by functionalizing them with vinyl and polymerizing them with 1-vinyl-3-butylimidazolium bromide to create a polyionic liquid on the beads. The resulting composite serves as a metal-free catalyst for various organic transformations with high efficiency and recyclability. Comparative studies show that the activity of this composite is superior to that of cross-linked bead and polyionic liquid.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Review
Chemistry, Multidisciplinary
Siqi Liu, Zhixiang Cheng, Dandan Jia, Hongyi Gao, Tian Li, Juan Chen, Jitti Kasemchainan, Guoqing An, Ge Wang, Xingtian Shu
Summary: Metal-organic frameworks (MOFs) derived nanomaterials have shown great potential as catalysts for oxidation and hydrogenation due to their uniform active sites, hierarchical porosity, composition diversity, easy functionalization, and high stability. This review summarizes recent research on MOF-derived catalysts, including their synthesis parameters, chemical composition, morphology, structure, and catalytic performance. The emphasis is on the influence of pore structure, size of active nanoparticles, and heteroatom doping on reactant conversion and product selectivity under green and mild reaction conditions.
Review
Chemistry, Multidisciplinary
Stefan Ilic, Jonathan L. Gesiorski, Ravindra B. Weerasooriya, Ksenija D. Glusac
Summary: The catalytic reduction of carbon dioxide is important for carbon recycling technologies. The main challenge is product selectivity. Efforts have been made to develop catalysts that can suppress unwanted reactions and direct the reaction towards the desired products. This article summarizes recent findings on the thermodynamic and kinetic parameters that control the transfer of hydrides from metal-free sources to CO2. The article also discusses approaches to the regeneration of the hydrides through electrochemical and photochemical methods.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Physical
Yong Yan, Roong Jien Wong, Zhirui Ma, Felix Donat, Shibo Xi, Syed Saqline, Qianwenhao Fan, Yonghua Du, Armando Borgna, Qian He, Christoph R. Muller, Wei Chen, Alexei A. Lapkin, Wen Liu
Summary: The catalytic hydrogenation of CO2 to methanol can be improved by doping tungsten into CeO2, resulting in a Cu/CeW0.25Ox catalyst with enhanced activity and selectivity. Experimental investigation reveals that this promotion effect is attributed to the reduction of Ce4+ to Ce3+ by W-doping, the suppression of oxygen vacancy formation on CeO2, and the activation of the formate pathway for CO2 hydrogenation. This catalyst design strategy differs from conventional CeO2-supported catalysts.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Zahid Hussain, Yong-an Luo, Yile Wu, Douglas W. W. Stephan
Summary: The reactions of boranes with azodicarboxylates or azodicarbonylamide provide easy access to NBO heterocyclic compounds. The formation mechanism is proposed to involve transient hydroboration or hydroalumination of the N=N double bond.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jingjie Tan, Chaopeng Hu, Xin Yang, Shaoying Ju, Levy L. Cao, Yile Wu, Liu Leo Liu, Douglas W. Stephan
Summary: The aluminum analogue of Piers' borane, [HAl(C6F5)(2)](3)1, was prepared on a gram-scale. DFT calculations showed that 1 has a higher fluoride ion affinity (FIA) than Piers' borane, and the Al-H moiety proved to be a strong hydride donor, reacting with alcohol and terminal alkyne to give dehydrogenative products 3 and 4. Hydroalumination product 5 was obtained via the reaction of 1 with aldehyde. Additionally, 1 catalyzes the hydrosilylation of alkynes and alkenes.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Ting Chen, Yanbo Mei, Liu Leo Liu, Yufen Zhao, Yile Wu, Douglas W. Stephan
Summary: The combination of alkoxyphosphoranes and borane generates zwitterions that act as FLP and can alkylate nucleophiles to form C-C, C-N, C-H, and C-Cl coupling products. A DFT study reveals that the reaction proceeds through an FLP activation pathway, forming an alkoxyphosphonium intermediate that facilitates the alkylation of nucleophiles, similar to the Mitsunobu reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Editorial Material
Chemistry, Multidisciplinary
Zahid Hussain, Yong-an Luo, Yile Wu, Zheng-wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Interest in main group chemistry related to the Haber-Bosch process is less studied compared to transition metal species. In this study, steric demands in (tBuO(2)CN)(2) hinder the initial interaction of B(C6F5)(3) with nitrogen, leading to the loss of methylpropene and CO2 and the formation of diazene (N2H2) borane adduct 1 and the analogous hydrazine (N2H4) adduct 2. These species react with basic phosphines to form anions of 3 and 5, which contain N2H and N2H3 fragments and serve as metal-free models of plausible intermediates in N-2 reduction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Hyehwang Kim, Zheng-wang Qu, Stefan Grimme, Nahil Al-Zuhaika, Douglas W. Stephan
Summary: The phosphino-phosphonium cations can react with alkynes through frustrated Lewis pair-type addition reactions, leading to phosphino-phosphination reactions. This reactivity can also be utilized to prepare dissymmetric cis-olefin-linked bidentate phosphines.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Inorganic & Nuclear
Ting Chen, Shaoying Ju, Mengnan Tong, Yufen Zhao, Yile Wu, Douglas W. Stephan
Summary: Metal phosphates are significant in the field of synthesis chemistry. In this study, we synthesized and characterized phosphate-catecholate chelated Nd(III), Zr(IV), and Al(III) chlorides (2-5). These complexes were obtained via ethyl chloride elimination reaction of oxophosphoranes with corresponding metal chlorides. The resulting monometallic and bimetallic phosphate-catecholate chelated metal complexes, stabilized by P-O and catecholate-O donors, have potential applications in catalysis.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Dipendu Mandal, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: Cyclopropenium cations with electron deficient substituents exhibit Lewis acidity despite the presence of π-electrons. The chloride and electron affinities are analyzed computationally and experimentally, respectively. These cations form traditional Lewis acid-base adducts with PPh3, while sterically hindered phosphines lead to frustrated Lewis pairs that participate in FLP additions. Depending on the basicity of the phosphine, addition to alkynes or alkyne deprotonation can occur. In both cases, new C-C bonds are formed, thus expanding the application of FLP chemistry to these delocalized π-cations.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Douglas W. W. Stephan
Summary: Transition metal species readily capture and react with CO, while main group CO adducts and their subsequent reactivity have been less studied. This review focuses on the application of Frustrated Lewis Pairs (FLPs) to develop main group chemistry of CO, illustrating the ability to capture CO and subsequent reduction reactions. These developments suggest that FLPs provide an alternative strategy to enhance the reactivity of CO, promising future advances in homogeneous CO chemistry.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Zahid Hussain, Yong-An Luo, Yile Wu, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The reactions of (tBuO(2)CN)(2) with FLPs were investigated. B(C6F5)(3) interacts with the carbonyl oxygen atoms and causes the loss of CH2=CMe2. However, in the presence of basic donors, the protons are intercepted and form salts [Hbase](2) [((C6F5)(3)BO2CN)(2)]. In the presence of (o-Tol)(3)P, a proton transfers to the diazo-N atom and forms (o-Tol)(3)PN(CO(2)tBu)NHB(C6F5)(3). Further addition of B(C6F5)(3) prompts the loss of olefin CH2=CMe2 and CO2, resulting in the formation of (o-Tol)(3)PNHNHB(C6F5)(3). DFT calculations provide insights into the reaction mechanisms and confirm the nature of 5 as a FLP reduction product of a diazene fragment.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Hyehwang Kim, Douglas W. Stephan
Summary: A combination of a phosphinidene precursor, B(C6F5)(3), and 4-ethynyltoluene produced the FLP addition product, Et2N(C14H10)PC(Tol)=CH(B(C6F5)(3))2. Compound 2 reacted with halides, pseudo halides, or Me3SiSPh, providing an easy method for synthesizing salts of anionic phosphines, while the reaction with PEt3 resulted in the zwitterionic species, Et3PCH=C(SiMe3)P(NEt2)C(Tol)=CHB(C6F5)(3)8. This latter species reacted with an alkyne, yielding a phosphine donor with both olefin linked cationic and anionic substituents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Vaibhav Bedi, Dipendu Mandal, Zahid Hussain, Shi-Ming Chen, Yile Wu, Zheng-Wang Qu, Stefan Grimme, Douglas W. Stephan
Summary: The reaction of (tBuO(2)CN)(2) with 9-BBN leads to the formation of a bicyclic heterocyclic compound, while its reactions with BF3 or [Et3Si][B(C6F5)(4)] result in the isolation of different compounds. Computational studies reveal that the steric and electronic properties of the Lewis acid are important in the formation of one of the compounds.
DALTON TRANSACTIONS
(2024)
Article
Chemistry, Organic
Jiangkun Xiong, Maying Yan, Lvnan Jin, Weihong Song, Lei Xiao, Dong Xu, Chunyang Zhai, Douglas W. Stephan, Jing Guo
Summary: In this study, a new reaction method was reported for the synthesis of various organogermacycle compounds via a B(C6F5)(3) mediated domino hydrogermylation reaction of enones with dihydrogermanes. These germacyclic compounds were obtained in good to excellent yields under mild reaction conditions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Amir Yeganeh-Salman, Iris Elser, Karlee L. Bamford, Daniel Ebanks, Douglas W. Stephan
Summary: In this study, a catalytic conversion of B-X to B-H bond was achieved using a small amount of [Ph3C](+) as an initiator with Et3SiH. This method was successfully applied to six haloboranes. Additionally, C-F bond activation of benzyl fluorides was observed in the presence of arenes, leading to the formation of Friedel-Crafts products using B-H-9-BBN in the presence of Et3SiH. The protocol provides a simple, cost-effective, and mild route to 1,1-diarylmethanes from benzyl fluorides with high yields (up to 99%).
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Ryan J. Andrews, John R. De Backere, Douglas W. Stephan
Summary: In this study, stable thionylium dications were synthesized with high acidity comparable to BF3 and PF5. These compounds can activate C-F bonds of fluoroalkanes and effectively deoxygenate O2- through reactions with Ph3PO and CuO.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Linkun Miao, Amir Yeganeh-Salman, Jason Yeung, Douglas W. Stephan
Summary: Efforts were made to deprotonate halophosphonium cations and generate various derivatives. It was found that one derivative is particularly effective in synthesizing methylene phosphonium cations. Additionally, differences in reactions with different types of olefins were observed, enhancing the synthetic methods for related compounds.
DALTON TRANSACTIONS
(2022)