Article
Chemistry, Multidisciplinary
Yunshuo Yang, Giulia Alice Volpato, Elena Rossin, Nicola Peruffo, Francesco Tumbarello, Catia Nicoletti, Ruggero Bonetto, Lorenzo Paoloni, Paolo Umari, Elena Colusso, Luca Dell'Amico, Serena Berardi, Elisabetta Collini, Stefano Caramori, Stefano Agnoli, Andrea Sartorel
Summary: Dye-sensitized photoanodes are assembled using a nanosized rods form of quinacridone dye on different substrate slides. These photoanodes display extended absorption and ultrafast electron injection into the semiconductor. The reactivity of the dye is used for C-H bond activation, providing a mechanistically oriented route for the design of selective organic transformations.
Article
Chemistry, Multidisciplinary
Fang-Che Hsueh, Luciano Barluzzi, Megan Keener, Thayalan Rajeshkumar, Laurent Maron, Rosario Scopelliti, Marinella Mazzanti
Summary: This study investigates the complex compounds formed by thorium nitrides and azide/nitride thorium complexes. The results show that stable multimetallic azide/nitride thorium complexes can be generated by reducing thorium azide precursors. These complexes are stable in solution, but their synthesis requires careful control of reaction conditions, and different anions result in structural differences. Reactivity studies demonstrate the ability of thorium nitrides to cleave CO in ambient conditions, yielding CN-.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Review
Biochemistry & Molecular Biology
Katarzyna Kabala, Malgorzata Janicka
Summary: There are two ATP-dependent proton pumps in plant cells, the Plasma membrane H+-ATPase (PM H+-ATPase) and the vacuolar H+-ATPase (V-ATPase). While the PM H+-ATPase transfers protons from the cytoplasm to the apoplast, the V-ATPase pumps protons into the organelle lumen. These enzymes belong to different protein families and have distinct structures and mechanisms of action. However, they can be regulated by the same mechanisms and may coordinate in certain processes.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Inorganic & Nuclear
Lingying Meng, Yujiao Dong, Bo Zhu, Yujie Liang, Zhongmin Su, Wei Guan
Summary: This study reveals a unique radical mechanism activated by decatungstate as a photocatalyst, which can successfully construct C(sp(3))-C(sp(2)) bonds. This mechanism involves hydrogen atom transfer and proton-coupled electron transfer reactions.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Bicheng Hu, Yuhui Zhang, Jincheng Zhang, Jiazan Liu, Meng Lei, Chenxi Zhao, Qiujun Lu, Haiyan Wang, Fuyou Du, Shiying Zhang
Summary: A novel flower-shaped NV-g-C3N5@VS2 heterojunction was synthesized by hydrothermal in situ synthesis using NV-g-C3N5 as the matrix and thioacetamide as the precursor. The heterojunction exhibited a flower-like and layered structure, which broadened the visible light absorption range and facilitated the usage of visible light. The NV-g-C3N5@VS2 heterojunction showed excellent photoelectrocatalytic nitrogen reduction activity and achieved outstanding photocatalytic degradation activity, making it a promising candidate for solar light-driven photocatalytic and photoelectrocatalytic applications in fertilizers, energy utilization, and environmental remediation.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Yang Liu, Wusheng Guo
Summary: This study reports the development of metal-free chemical processes using recyclable heterogeneous catalysts at ambient conditions, which is highly desired in pharmaceutical production. By using insoluble carbon nitride as a photocatalyst, pharmaceutically relevant organophosphorus(V) compounds were efficiently synthesized through the coupling of readily available starting materials. The photocatalyst exhibited wide functional group tolerance and the reactions were performed under visible-light irradiation at room temperatures. The recyclable g-CN photocatalyst could be easily separated and reused for multiple cycles without decreasing the reaction efficiency, indicating its great potential for larger-scale synthesis in industrial manufacturing.
Article
Chemistry, Organic
Bin Sun, Yu Jiang, Pan-Yi Huang, Pei-Xuan Li, Chun Lv, Yan Xu, Jia-Yang Wang, Can Jin
Summary: In this study, a photoinduced desaturative β-C(sp(3))-H bond amidation of N-phenylpiperidine using phthalimide as an aminating source enabled by an electron donor-acceptor (EDA) complex was explored. This protocol offers an environmentally friendly, simple, and efficient method for accessing β-C(sp(2))-H amidation piperidine derivatives without the need for high temperatures, transition metals, and photosensitizers required for traditional C(sp(3))-H functionalization. Moreover, the obtained products can be further modified and transformed into enamines by treatment with hydrazine.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Thermodynamics
Samhita Pappu, Tata N. Rao, Surendra K. Martha, Sarada V. Bulusu
Summary: Aqueous supercapacitors with enhanced energy densities are in high demand due to their non-toxic and environmentally friendly nature. Metal oxide based pseudocapacitors can enhance the specific capacitance and energy density of the device by enlarging the potential window of the aqueous electrolyte and participating in faradaic reactions. In this study, MnO2 nanosheets were synthesized using an ecofriendly electrodeposition technique, and were found to be the best positive electrode for asymmetric supercapacitors (ASCs) due to their high charge storage capability. The effect of potassium iodide (KI) redox additive in the electrolyte on the energy density and device performance was also investigated. ASCs designed with YP-50 carbon and MnO2 as negative and positive electrodes, and optimized KI concentration, exhibited superior specific capacitance, capacity retention, and high energy density. The research provides a deeper understanding of MnO2's charge storage properties and the role of redox mediators in enhancing overall device performance in aqueous ASCs.
Article
Engineering, Environmental
A. Alrebh, M. Plunkett, L. Gaburici, M. Couillard, T. Lacelle, C. T. Kingston, K. S. Kim
Summary: This study presents a new method for the synthesis of boron nitride nanotubes (BNNTs) using ammonia borane (AB) as the raw material in hydrogen-assisted thermal plasma. The results show that AB can enhance the synthesis of BNNTs with reduced impurities and increased density of nucleating seeds.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Wen Zi-Hao, Li Shuang, Zhang Min-Yi
Summary: This study investigated the formation and hydroxylation mechanisms of Mn(PDP) complexes through density functional theory calculations. The results showed that Mn(III)(PDP) complexes can react with H2O2 and carboxylic acid to form a key oxidation intermediate that acts as a two-electron oxidant for C-H bond functionalization. This provides new insights for the development of non-heme manganese catalysts.
CHINESE JOURNAL OF STRUCTURAL CHEMISTRY
(2021)
Article
Chemistry, Physical
L. Anders Hammarback, Amy L. Bishop, Christina Jordan, Gayathri Athavan, Jonathan B. Eastwood, Thomas J. Burden, Joshua T. W. Bray, Francis Clarke, Alan Robinson, Jean-Philippe Krieger, Adrian Whitwood, Ian P. Clark, Michael Towrie, Jason M. Lynam, Ian J. S. Fairlamb
Summary: This study investigates the influence of the ortho-fluorine effect on the kinetic and thermodynamic control of C-H bond activation in manganese(I)-mediated reactions. The results show that a kinetically controlled irreversible sigma-complex-assisted metathesis mechanism is operative in these reactions. Additionally, the generation of the regioisomeric cyclomanganated intermediates plays a critical role in governing C-H bond site selectivity under catalytic conditions.
Article
Chemistry, Multidisciplinary
Anthony Wong, Arunavo Chakraborty, Deependra Bawari, Guang Wu, Roman Dobrovetsky, Gabriel Menard
Summary: The paper discusses the facile activation of aryl E-H or ammonia N-H bonds via coordination-induced bond weakening to a redox-active boron center in the complex. Significant decreases in E-H bond dissociation free energies were observed upon substrate coordination, enabling subsequent proton-coupled electron transfer. Experimental results showed a drop of over 50 kcal mol(-1) in H2N-H bond dissociation free energy upon coordination.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Applied
Keshia Saradima Indriadi, Peijie Han, Shipeng Ding, Bingqing Yao, Shinya Furukawa, Qian He, Ning Yan
Summary: Ammonia decomposition is important in hydrogen production, and Fe-based catalysts are commonly used due to their affordability and moderate activity. However, the transformation of Fe-based catalysts into more active FexN species can be slow. Addition of Pt significantly enhances the FexN formation rate by aiding in H2 desorption via reverse spillover and exposing more Fe surface sites. The study provides insights into the formation mechanism of active species in ammonia decomposition and offers a simple strategy for improving catalytic performance.
CHINESE JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Dashui Yuan, Zongyuan Li, Xueru Chen, Jing Ding, Hui Wan, Guofeng Guan
Summary: In this study, a homodispersed S-scheme carbon nitride homojunction with enhanced photocatalytic performance was prepared through pre-doping and recalcination methods. The electron structure engineering and S-scheme homojunction construction facilitated efficient charge separation and redox reactions, resulting in significantly improved photocatalytic performance.
GREEN ENERGY & ENVIRONMENT
(2022)
Article
Chemistry, Physical
Dashui Yuan, Zongyuan Li, Xueru Chen, Jing Ding, Hui Wan, Guofeng Guan
Summary: In this study, a homodispersed S-scheme carbon nitride homojunction was successfully prepared by pre-doping and recalcination method. The rich interface and S-scheme homojunction structure led to improved photogenerated electron transfer efficiency and enhanced photocatalytic performance.
GREEN ENERGY & ENVIRONMENT
(2022)
Article
Chemistry, Multidisciplinary
Gabriele Hierlmeier, Paolo Tosatti, Kurt Puentener, Paul J. J. Chirik
Summary: This study reports a new molybdenum ligand for catalyzing the hydrogenation of benzene, which is formed by the coordination of phosphino(imino)pyridine and cyclooctadiene. The experimental results indicate that the ligand can selectively generate cyclohexane catalyst in the presence of benzene, and the formation of the insertion product is a key step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Editorial Material
Chemistry, Inorganic & Nuclear
Paul J. Chirik
Article
Chemistry, Physical
Paul O. Peterson, Matthew Joannou, Eric M. Simmons, Steven R. Wisniewski, Junho Kim, Paul J. Chirik
Summary: The synthesis and characterization of phenoxy(imine) iron(II) alkyl precatalysts for C(sp2)-C(sp3) Suzuki-Miyaura cross-coupling reaction is reported. This method utilizes mild alkoxide bases and nonpolar solvents to achieve high efficiency C(sp2)-C(sp3) bond formation with various aryl boronic esters and alkyl bromides. The study also highlights the compatibility of the precatalysts with base-sensitive functionality and the role of boronate intermediates in transmetalation.
Article
Chemistry, Multidisciplinary
Yunjung Baek, Adam Reinhold, Lei Tian, Philip D. Jeffrey, Gregory D. Scholes, Robert R. Knowles
Summary: This study reports 11 isolable singly reduced iridium chromophores. Chemical reduction of a cyclometalated iridium complex with potassium graphite yields a 19-electron species. Structural and spectroscopic characterizations reveal a ligand-centered reduction product. The reduced chromophore exhibits wide light absorption and photoinduced bimolecular electron transfer reactivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Suong T. T. Nguyen, Lydia R. R. Fries, James H. H. Cox, Yuting Ma, Brett P. P. Fors, Robert R. R. Knowles
Summary: This research presents a catalytic, light-driven method for chemically recycling thiol epoxy thermosets to their original monomer at ambient temperature. The method involves the proton-coupled electron transfer (PCET) activation of hydroxy groups within the polymer network, generating alkoxy radicals that promote polymer fragmentation. The method efficiently depolymerizes insoluble thiol epoxy thermosets into small-molecule products that can be converted back to the original monomer. This research marks an important development in the recyclability of epoxy thermosets and demonstrates the potential of PCET for sustainable end-of-life management of commercial plastics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Guanqi Qiu, Chi-Li Ni, Robert R. Knowles
Summary: We report a diagnostic framework for elucidating the mechanisms of photoredox-based hydrogen isotope exchange (HIE) reactions based on hydrogen/deuterium (H/D) fractionation. The traditional thermal HIE methods proceed by reversible bond cleavage and bond reformation steps, while light-driven HIE reactions can proceed via multiple, non-degenerate sets of elementary steps. The fractionation method presented here extracts information regarding the nature of the key bond-forming and bond-breaking steps.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Lauren N. Mendelsohn, Connor S. MacNeil, Madison R. Esposito, Tyler P. Pabst, David K. Leahy, Ian W. Davies, Paul J. Chirik
Summary: The cobalt-catalyzed asymmetric hydrogenation of indazole-containing enamides relevant to the synthesis of Zavegepant, a CGRP receptor antagonist, which is approved for the treatment of migraines, is described. Both neutral and cationic bis(phosphine)cobalt complexes were efficient precatalysts, providing excellent yield and enantioselectivities for related substrates, with key reactivity differences observed. The hydrogenation of the indazole-containing enamide was successfully scaled up to 20 g.
Article
Chemistry, Applied
Paul J. Chirik, Keary M. Engle, Eric M. Simmons, Steven R. Wisniewski
Summary: Earth-abundant metal (EAM) catalysis has significant impact on the sustainability and cost improvement in the pharmaceutical industry. It replaces precious metals like palladium and utilizes the reactivity of first-row metals to enable more efficient routes to clinical candidates. This article describes the strategy for building these capabilities within the process group, including the development of a reaction screening platform, scalability demonstration, and increasing mechanism understanding.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2023)
Article
Chemistry, Inorganic & Nuclear
Boran Lee, Tyler P. Pabst, Gabriele Hierlmeier, Paul J. Chirik
Summary: Cobalt complexes with 2,6-diaminopyridinesubstituted PNP pincer ligand were synthesized and studied. The PNP pincer ligand showed higher rigidity and electron-donating properties compared to the iPrPNP ligand. The coordination sphere of the metal was completed by a fourth ligand, resulting in planar, diamagnetic, four-coordinate complexes. Computational studies indicated that the increased rigidity of the pincer ligand led to a higher barrier for C-H oxidative addition. The reduced reactivity of (iPrPNMeNP)CoMe enabled it to be an efficient precatalyst for alkene hydroboration.
Article
Chemistry, Multidisciplinary
L. Reginald Mills, Francesca Di Mare, David Gygi, Heejun Lee, Eric M. Simmons, Junho Kim, Steven R. Wisniewski, Paul J. Chirik
Summary: The relative rates of the cobalt-catalyzed C(sp(2))-C(sp(3)) Suzuki-Miyaura cross-coupling were evaluated, and it was found that smaller N-alkyl substituents on the phenoxyimine ligand accelerated the reaction. This inspired the design of optimal cobalt catalysts with phenoxyoxazoline and phenoxythiazoline ligands. The catalyst lifetime was improved by adding excess KOMe•B(O-iPr)3, which attenuated alkoxide basicity and prevented demetallation of the ligand.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Eric P. Geunes, Jonathan M. Meinhardt, Emily J. Wu, Robert R. Knowles
Summary: We report a light-driven method for the intermolecular anti-Markovnikov hydroamination of alkenes with primary heteroaryl amines. This method exhibits broad functional group tolerance and good reactivity. The reported method has important application value for pharmaceutically relevant heteroaryl amines.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Benjamin G. Hejna, Jacob M. Ganley, Huiling Shao, Haowen Tian, Jonathan D. Ellefsen, Nicholas J. Fastuca, Kendall N. Houk, Scott J. Miller, Robert R. Knowles
Summary: We present a highly enantioselective radical-based hydroamination of enol esters with sulfonamides using an Ir photocatalyst, Bronsted base, and tetrapeptide thiol. The reaction produces 23 protected β-amino-alcohol products with selectivities up to 97:3 er. Experimental and computational studies reveal that hydrogen bonding, π-π stacking, and London dispersion interactions play important roles in substrate recognition and enantioinduction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Coralie Duchemin, Amelia I. Liu, Junho Kim, Paul J. Chirik
Summary: This study describes the synthesis, characterization, and reactivity of a series of quinoline pyridine(imine) iron dichloride complexes. The complexes were found to be effective catalysts for the hydrovinylation reaction of butadiene with ethylene, showing high selectivity for the hexa-1,4-diene isomer.
Article
Chemistry, Multidisciplinary
Coralie Duchemin, Junho Kim, Paul J. J. Chirik
Summary: A series of C-S-symmetric (aryl,alkyl)-substituted pyridine(dimine) iron methyl ((Cy)ARPDI)FeCH3 complexes have been synthesized and used as precatalysts for [2+2] cycloaddition. The chemoselectivity of the reaction is affected by the stability and resting state of the catalyst, leading to the formation of vinylcyclobutane and (Z)-hexa-1,4-diene.
Article
Chemistry, Inorganic & Nuclear
Junho Kim, Yoonsu Park, Paul J. Chirik
Summary: Piano-stool iridium hydride complexes with phenylpyridine ligands are effective in promoting element-hydrogen bond formation using H-2 as a H-atom source. Blue light irradiation enhances the catalyst turnover for iridium-catalyzed hydrogenation of aryloxyl radicals. The reaction involves proton-coupled electron transfer and formation of an iridium compound. Blue light irradiation with H-2 releases a free heterocycle and regenerates the iridium hydride precatalyst, leading to increased turnover.
INORGANIC CHEMISTRY
(2023)
