Article
Chemistry, Organic
Ni Xiong, Yuanqi Dong, Bin Xu, Yang Li, Rong Zeng
Summary: This study describes a mild protocol for amide formation using nitroarenes as nitrogen sources and an inexpensive iron complex as a catalyst. The method utilizes pH-neutral conditions and avoids the use of strong oxidants or reductants, allowing for tolerance of a wide range of aldehydes and nitroarenes with various functional groups.
Article
Chemistry, Inorganic & Nuclear
Isabel Abanades Lazaro, Ross S. Forgan, Francisco. G. Cirujano
Summary: The influence of composition and textural characteristics of ultra-small isoreticular UiO-type metal-organic frameworks (MOFs) on catalytic performance is evaluated in this study. The activity of Zr-MOF nanoparticles is tested using two different amide bond formation reactions as proof-of-concept. The results provide insights into the catalytic mechanism and optimal properties for enhancing performance.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Xinyue Tan, Huadong Wang
Summary: The concept of frustrated Lewis pair (FLP) chemistry has become a rich and fruitful research area, contributing significantly to the revival of main group chemistry. The design of catalytic systems based on the FLP concept has been successfully applied to organic synthesis and polymer chemistry.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Rui Li, Yongmeng Wu, Changhong Wang, Meng He, Cuibo Liu, Bin Zhang
Summary: This study reports a room-temperature one-pot two-step transformation of aryl acetonitriles to alpha,beta-deuterio aryl ethylamines (alpha,beta-DAEAs) using D2O as a deuterium source. The process includes fast alpha-C - H/C - D exchange and tandem electroreductive deuteration over an in situ formed low-coordinated Fe nanoparticle cathode. The method demonstrates wide substrate scope, parallel synthesis of multiple alpha,beta-DAEAs, and potential for the preparation of alpha,beta-deuterated Melatonin and Komavine.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Gina Noh, Erwin Lam, Daniel T. Bregante, Jordan Meyet, Petr Sot, David W. Flaherty, Christophe Coperet
Summary: The presence of Lewis acid sites on Cu nanoparticles supported on tailored supports enhances CH3OH formation rate in CO2 hydrogenation, likely originating from the stabilization of formate and methoxy surface intermediates. The strength of Lewis acid M sites, characterized by pyridine adsorption enthalpies and C-13 chemical shifts of -OCH3 coordinated to M, serves as a molecular descriptor for Lewis acid strength and reactivity in CO2 hydrogenation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Biochemistry & Molecular Biology
Qiang Wan, Sen Lin, Hua Guo
Summary: This article reviews recent theoretical advances in understanding FLP-based heterogeneous catalysis in various applications, such as metal oxides, functionalized surfaces, and two-dimensional materials. It emphasizes the importance of a better understanding of the catalytic mechanism for the experimental design of novel heterogeneous FLP catalysts.
Article
Chemistry, Organic
Truong Thanh Tung, John Nielsen
Summary: The study presents a green, rapid, and simple method for direct coupling of carboxylate salts and ammonium salts at room temperature without the addition of tertiary amine bases, utilizing a water-soluble coupling reagent EDC·HCl. The reaction tolerates both carboxylate and amine salts, providing a clean product without column chromatography, and can be used as an alternative method in laboratory and industrial scales.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yuki Saito, Shu Kobayashi
Summary: The application of heterogeneous catalysts in continuous-flow enantioselective hydroacylation reactions was studied. Catalysts were prepared by mixing supports and rhodium complexes, and showed excellent activity and enantioselectivity. Under optimized conditions, the catalysts exhibited high turnover numbers and could be applied to various substrates. Furthermore, sequential-flow reactions with other heterogeneous catalysts were demonstrated for the synthesis of biologically active molecules and functional materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Peter A. Macdonald, Sumanta Banerjee, Alan R. Kennedy, Alexander van Teijlingen, Stuart D. Robertson, Tell Tuttle, Robert E. Mulvey
Summary: The catalytic reduction of aldimines and ketimines to amines using 1,4-dicyclohexadiene as the transfer hydrogenation agent has been studied. s-block pre-catalysts, specifically 1-metallo-2-tert-butyl-1,2-dihydropyridines (M(tBuDHP)), where M=Li-Cs, have been employed for this purpose. The efficiency of the catalysts shows a clear trend with the heavier alkali metal tBuDHPs demonstrating superior performance. Among the various catalysts, Cs(tBuDHP) is found to be the optimal pre-catalyst, yielding quantitative amine products within minutes at room temperature using only 5 mol % catalyst. Density Functional Theory (DFT) calculations support the experimental findings and suggest that Cs has a lower rate determining step compared to Li in its pathway.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Qingyao Li, Peng Dai, Haidi Tang, Muliang Zhang, Jie Wu
Summary: The significance of amide functional groups in organic synthesis and pharmaceutical studies is widely recognized. However, current synthesis methods often involve the use of stoichiometric activating reagents and metallic reductants, leading to the production of toxic chemical waste. In this study, a photo-mediated hydrogen atom transfer catalysis is developed for direct reductive amidation reaction, which avoids the use of metallic reductants and toxic chemical waste. The method provides an efficient and practical strategy for the synthesis of amides.
Article
Chemistry, Multidisciplinary
Hiroyuki Miyamura, Shu Kobayashi
Summary: This paper describes the development of cooperative and synergistic catalyst systems of heterogeneous Rh-Pt bimetallic nanoparticle catalysts, Rh-Pt/DMPSi-Al2O3, and Sc(OTf)(3) in the liquid phase for the hydrogenation of arenes under very mild conditions. The cooperative activation achieved significant rate acceleration and successful hydrogenation of challenging substrates with strong electron-donating groups and sterically hindered substituents was demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Francisco de Azambuja, Jille Lenie, Tatjana N. Parac-Vogt
Summary: Inorganic clusters, specifically polyoxometalates (POMs), can serve as effective ligands for Hf(IV) Lewis acid metals in homogeneous metal catalysis. The interplay between the dielectric constant of the medium and the ligand structure is crucial for optimizing catalytic activity and promoting efficient amide bond formation. Changes in the dielectric constant can significantly impact the performance of the catalyst, highlighting the importance of understanding the relationship between medium properties and catalyst reactivity.
Article
Chemistry, Multidisciplinary
Tsuyoshi Yamada, Kwihwan Park, Chikara Furugen, Jing Jiang, Eisho Shimizu, Naoya Ito, Hironao Sajiki
Summary: The research has developed flow reaction methods to selectively synthesize tertiary, secondary, and primary amines from nitriles using heterogeneous platinum-group metal catalysts under catalytic hydrogenation conditions. By controlling the metal catalyst and flow parameters, a wide variety of aliphatic and aromatic nitriles can be highly selectively transformed into the corresponding amines. The continuous-flow methodologies can be applied for at least 72 hours to produce three different types of amines in high yields without decreasing catalytic activities.
Article
Chemistry, Inorganic & Nuclear
Kyle D. Spielvogel, Nathan C. Stumme, Taylor Fetrow, Li Wang, Javier A. Luna, Jason M. Keith, Scott K. Shaw, Scott R. Daly
Summary: Metal-ligand cooperativity (MLC) is a powerful approach to achieve new chemical transformations with metal complexes by leveraging reactive ligands. However, quantifying the effect of ligand modifications on MLC binding strength remains a challenge. In this study, cyclic voltammetry (CV) was used to quantify the differences in MLC binding strength in a series of square-pyramidal Ru complexes.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Timon Schoenauer, Sabrina L. J. Thomae, Leah Kaiser, Mirijam Zobel, Rhett Kempe
Summary: The development of C-N bond formation reactions is crucial in biology and chemistry, with recent progress in 3d metal catalysis showing unique selectivity patterns. By using a novel cobalt catalyst, a catalytic C-N bond formation reaction was successfully reported, utilizing abundant and low-cost starting materials for reductive alkylation.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Yuki Nakaya, Eigo Hayashida, Ruikun Shi, Ken-ichi Shimizu, Shinya Furukawa
Summary: The role of subsurface carbon and the synergistic effects of Au and KOAc in the acetoxylation of ethylene have been investigated. The presence of subsurface carbon in Pd-Au/SiO2 catalyst was found to enhance the catalytic performance in VAM synthesis. Experimental and theoretical analysis also suggests that the coupling reaction between acetate and ethylene is effectively promoted by the synergistic contributions of Au and interstitial carbon, inhibiting ethylene dehydrogenation and CO2 formation. These insights provide new possibilities for the design of catalysts with improved catalytic performance.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Energy & Fuels
Shinta Miyazaki, Zirui Li, Lingcong Li, Takashi Toyao, Yuta Nakasaka, Yasushi Nakajima, Ken-ichi Shimizu, Zen Maeno
Summary: In this study, Ni-modified tungstate zirconia (Ni/WO3/ZrO2) was developed as an effective material for chemical looping dry reforming of methane (CL-DRM) under isothermal conditions. The performance of Ni/WO3/ZrO2 was strongly influenced by the loading amount of WO3, with the optimal amount being 10.0 wt%. Increasing the loading amount to 30.0 wt% resulted in the formation of crystalline WO3 species and diminished the CL-DRM performance. Comprehensive characterization studies revealed that surface dispersed tungstate species were reduced by CH4 and reoxidized by CO2, leading to efficient CL-DRM.
Article
Chemistry, Physical
Meilin Tao, Satoshi Ishikawa, Takuji Ikeda, Shunsaku Yasumura, Kosuke Shimoda, Ryota Osuga, Yuan Jing, Takashi Toyao, Ken-ichi Shimizu, Hiromi Matsuhashi, Wataru Ueda
Summary: In this study, the crystal structure and acid properties of Zr3SO9 were investigated. It was found that Zr3SO9 exhibited excellent catalytic activity for acid reactions, surpassing typical acid catalysts. The introduction of H2O transformed the acid sites of Zr3SO9, resulting in a shift from Lewis to Bronsted acid sites.
Article
Chemistry, Physical
Ningqiang Zhang, Shinta Miyazaki, Yucheng Qian, Yuan Jing, Takashi Toyao, Ken-ichi Shimizu
Summary: Kinetic analyses of Ce4+ <-> Ce3+ redox and CO2/H-2 formation for the unsteady-state water-gas shift (WGS) reaction are carried out on Cu/CeO2 catalysts under periodic CO <-> H2O feeds at 350 degrees C. The results provide quantitative evidence of the redox-based mechanism of the reaction and suggest that Ce3+- reoxidation by H2O has a lower barrier than Ce4+-O reduction. The number of interfacial sites between CeO2 and Cu species affects the turnover frequencies for the redox reaction and CO2/H-2 formation. An associative redox mechanism based on the redox reaction between Cu2+-OH and Ce4+-OH/Ce4+ and Cu+--Ce3+ is proposed as the main catalytic cycle of the reaction.
Article
Chemistry, Physical
Yusuke Inomata, Hiroe Kubota, Yoshinori Honmatsu, Hiroaki Takamitsu, Sosuke Sakotami, Kazuhiro Yoshida, Takashi Toyao, Ken-ichi Shimizu, Toru Murayama
Summary: NH3-SCR is a key technique for reducing harmful NOx emissions. The study shows that Na-intercalated vanadium oxide can accelerate the reaction and improve the efficiency of NH3-SCR.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Engineering, Environmental
Ningqiang Zhang, Jiahuan Tong, Shinta Miyazaki, Shirun Zhao, Hiroe Kubota, Yuan Jing, Shinya Mine, Takashi Toyao, Ken-ichi Shimizu
Summary: This study investigates the active sites and reaction mechanism for the selective catalytic reduction of NO by NH3 over phosphate-loaded ceria catalysts. The results reveal the presence of H3PO4 and H2P2O6 species on the catalysts, which interact with Ce4+(OH-) species and undergo reduction/oxidation half-cycles to produce N2, H2O, and Ce3+ species.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Shunsaku Yasumura, Kenichiro Saita, Takumi Miyakage, Ken Nagai, Kenichi Kon, Takashi Toyao, Zen Maeno, Tetsuya Taketsugu, Ken-ichi Shimizu
Summary: Automated reaction route mapping is used to design catalysts for low-temperature CH4 combustion with ozone. A suitable proton-type zeolite catalyst with Bronsted acid sites was predicted and shown to have superior performance in CH4 combustion.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Nat Phongprueksathat, Kah Wei Ting, Shinya Mine, Yuan Jing, Ryo Toyoshima, Hiroshi Kondoh, Ken-ichi Shimizu, Takashi Toyao, Atsushi Urakawa
Summary: Low temperature and high pressure are advantageous conditions for achieving high conversion and selectivity in CO2 hydrogenation. Re/TiO2 has been identified as a promising catalyst with higher activity than the industrial Cu/ZnO/Al2O3 catalyst at high pressure and low temperature. The study provides insights into the nature of active sites and active species, demonstrating the active role of cationic Re species in CO2 activation and formate intermediate formation.
Article
Chemistry, Physical
Yuan Jing, Chenxi He, Ningqiang Zhang, Yu Murano, Ryo Toyoshima, Hiroshi Kondoh, Yuuta Kageyama, Hironori Inomata, Takashi Toyao, Ken-ichi Shimizu
Summary: In this study, the addition of Ag was found to enhance the catalytic efficiency of RhOx/Al2O3 catalyst, especially at low temperatures. The promotional effect was mainly achieved by enhancing the thermal reduction of Rh oxide.
Article
Chemistry, Physical
Shunsaku Yasumura, Ken Nagai, Yucheng Qian, Takashi Toyao, Zen Maeno, Ken-ichi Shimizu
Summary: Rh-loaded mordenite zeolite was used as a catalyst for NO reduction using CO + H2O as a H2 source. Operando IR measurements revealed that Rh dicarbonyl species ([Rh(CO)(2)](+)) captured CO in the zeolite, which reacted with H2O to produce H(2)via the water gas shift (WGS) reaction. TPSR measurements showed that the formed H-2 was directly used for NO reduction into NH3. The study also investigated the mechanism of the WGS reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Huang Mengwen, Shinsaku Yasumura, Takashi Toyao, Ken-ichi Shimizu, Zen Maeno
Summary: Metal-exchanged zeolites show potential for catalyzing small molecules like light alkanes by forming unique active metal species. Ga-exchanged zeolites have been studied extensively as heterogeneous catalysts for dehydrogenation of light alkanes. However, research on In-exchanged zeolites and their active species has been limited. This study summarizes investigations on In- and Ga-exchanged zeolites for light-alkane transformations, including the formation of In-oxo clusters and In-hydrides, as well as the catalytic properties of Ga-oxo clusters and Ga-hydrides.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Shunsaku Yasumura, Taisetsu Kato, Takashi Toyao, Zen Maeno, Ken-ichi Shimizu
Summary: By using the SC-AFIR algorithm, the catalytic reaction of NO and OH/OOH species over the Ag-4(2+) cluster in a zeolite was investigated. It was found that the formation of OH and OOH species has lower activation barriers, and the addition of hydrogen promotes their formation, thus enhancing the activity of the SCR reaction. The study highlights the power of automated reaction route mapping in elucidating complicated reaction pathways on multi-nuclear clusters.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Mengwen Huang, Yosuke Tomimuro, Shinta Miyazaki, Shinya Mine, Takashi Toyao, Yoyo Hinuma, Yasuharu Kanda, Masaaki Kitano, Ken-ichi Shimizu, Zen Maeno
Summary: This study investigates propane metathesis reactions over metal hydrides, with TiH2 showing the highest butane yield. Fully-hydrogenated TiH2 is more active than dehydrogenated TiH and Ti metal. Surface low-valent Ti species on TiH2 are involved in the propane metathesis reaction. This study is the first to observe carbon-carbon bond cleavage and catalytic formation over bulk metal hydrides.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Mengwen Huang, Tetsuya Kinjo, Shunsaku Yasumura, Takashi Toyao, Daiju Matsumura, Hiroyuki Saitoh, Ken-ichi Shimizu, Norikazu Namiki, Zen Maeno
Summary: This study investigates the catalytic performance of Ga-exchanged zeolites at actual operating temperatures using in situ analysis. The results show that Ga-exchanged zeolites exhibit higher absorption peak intensity under hydrogen and ethane atmospheres, indicating the importance of hydride species in their catalytic activity.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Mengwen Huang, Yosuke Tomimuro, Shinta Miyazaki, Shinya Mine, Takashi Toyao, Yoyo Hinuma, Yasuharu Kanda, Masaaki Kitano, Ken-ichi Shimizu, Zen Maeno
Summary: This study investigated propane metathesis reactions over group 2-5 metal hydrides, with TiH2 showing the highest butane formation. Fully-hydrogenated TiH2 was found to be more active than dehydrogenated TiH and Ti metal. Surface low-valent Ti species on TiH2 were involved in the propane metathesis reaction. This study represents the first example of carbon-carbon bond cleavage and catalytic formation over bulk metal hydrides.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
