Article
Chemistry, Multidisciplinary
Oleg G. Salnikov, Alexandra Svyatova, Larisa M. Kovtunova, Nikita Chukanov, Valerii Bukhtiyarov, Kirill Kovtunov, Eduard Y. Chekmenev, Igor Koptyug
Summary: This study presents H-1 hyperpolarized diethyl ether, which can be imaged on any clinical MRI scanner, achieving up to 1.3% nuclear spin polarization through heterogeneous hydrogenation and prolonging its lifetime. This approach has potential applications in anatomy and functional studies.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Multidisciplinary Sciences
Yanyan Zhao, Sheng Dai, Ke R. Yang, Sufeng Cao, Kelly L. Materna, Hannah M. C. Lant, Li Cheng Kao, Xuefei Feng, Jinghua Guo, Gary W. Brudvig, Maria Flytzani-Stephanopoulos, Victor S. Batista, Xiaoqing Pan, Dunwei Wang
Summary: Atomically dispersed catalysts have shown high activity for selective oxidation of carbon monoxide with excess hydrogen, but their stability is not ideal. This study demonstrates that introducing a structural component to minimize the diffusion of the active metal center significantly improves stability without compromising activity. By using a dinuclear iridium heterogeneous catalyst as a study platform, two types of oxygen species, interfacial and bridge, are identified to work together for both activity and stability. This work provides important insights into the synergistic effect between the active metal center and the supporting substrate, with potential broad applications for atomically dispersed catalysts.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Chemistry, Multidisciplinary
Grazia Bencivenni, Diana Salazar Illera, Maria Moccia, K. N. Houk, Joseph A. Izzo, Johanna Novacek, Paolo Grieco, Mathew J. Vetticatt, Mario Waser, Mauro F. A. Adamo
Summary: Through H-1 NMR titration experiments, it was found that chiral ammonium salts interact with substrates through specific C-H positions, providing a new rationale for rationalizing the enantioselectivity in chiral phase-transfer catalysis.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Oleg G. Salnikov, Nikita Chukanov, Larisa M. Kovtunova, Valerii Bukhtiyarov, Kirill Kovtunov, Roman Shchepin, Igor Koptyug, Eduard Y. Chekmenev
Summary: The efficiency of H-1 and C-13 hyperpolarization of acetate and pyruvate esters using heterogeneous hydrogenation and parahydrogen over Rh/TiO2 catalysts was investigated. Acetate esters surpassed pyruvates in hyperpolarization, and esters with a double bond in unsaturated alcoholic moieties were more efficient than those with a triple carbon-carbon bond. Among the compounds studied, propyl acetate yielded the maximum H-1 and C-13 NMR signal intensities.
Review
Chemistry, Physical
Ekaterina V. Pokochueva, Dudari B. Burueva, Oleg G. Salnikov, Igor V. Koptyug
Summary: HET-PHIP has attracted significant research attention in recent years, showing major prospects for applications in biomedical MRI and industrial catalytic studies, despite the current need for further improvement in NMR signal enhancements.
Article
Chemistry, Physical
Juan Camilo Arango-Daza, Carles Lluna-Galan, Luis Izquierdo-Aranda, Jose R. Cabrero-Antonino, Rosa Adam
Summary: A heterogeneous catalytic system for the acceptorless dehydrogenative condensation between N,N'-disubstituted ureas and 1,2-diols to produce imidazolones was developed. The designed palladium nanoaggregates on an alumina matrix showed good activity and selectivity, with wide applicability and moderate to good yields. Mechanistic studies and characterization were performed, revealing the key factors for the catalyst's activity. Furthermore, a Pd-Zn cooperation effect was described, and bimetallic materials were also designed and characterized properly.
Article
Chemistry, Physical
Luca Deiana, Elham Badali, Abdolrahim A. Rafi, Cheuk-Wai Tai, Jan-E Backvall, Armando Cordova
Summary: This article describes efficient nanogold-catalyzed cycloisomerization reactions of alkynoic acids and allenynamides, resulting in the formation of enol lactones and dihydropyrroles, respectively. The gold nanoparticles were immobilized on thiol-functionalized microcrystalline cellulose and exhibited robust catalytic activity for multiple cycles.
Review
Chemistry, Multidisciplinary
Kangkang Sun, Hongbin Shan, Guo-Ping Lu, Chun Cai, Matthias Beller
Summary: N-heterocycles are important building blocks for organic chemistry and the fine-chemical industry. Recent attention has been given to the use of catalytic borrowing hydrogen and acceptorless dehydrogenative coupling reactions for their synthesis. Metal-based heterogeneous catalysts have been developed to achieve these transformations with good yields and selectivity, overcoming issues with product separation and catalyst reusability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Francesco Ferlin, Ioannis Anastasiou, Nihad Salameh, Takeru Miyakoshi, Olivier Baudoin, Luigi Vaccaro
Summary: A heterogeneous catalyst has been prepared for the intramolecular activation/cyclization reaction to synthesize indolines. The catalyst showed high efficiency through a release and catch mechanism, facilitated by iodide ligands. The heterogeneous nature of the catalyst was further utilized in the design of a continuous-flow protocol, enabling efficient recovery and reuse.
Article
Chemistry, Multidisciplinary
Irina Ritsch, Elisabeth Lehmann, Leonidas Emmanouilidis, Maxim Yulikov, Frederic Allain, Gunnar Jeschke
Summary: The interaction between hnRNP A1 and specific RNA induces liquid-droplet formation, which depends on RNA concentration and sequence. Additionally, point mutations in RNA affect local protein dynamics.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Huanhuan Jia, Rong Xie, Guangpeng Lu, Huanfeng Jiang, Min Zhang
Summary: In this study, we developed a hierarchically porous ZrO2-supported iridium catalyst derived from MOF, which exhibits sufficient accessible catalytic sites. This catalyst was successfully used for the selective and direct construction of julolidines via catalytic reductive annulation. It shows good substrate and functional group compatibility, can be reused, has high step and atom efficiency, and is easy to apply for the fabrication of functional molecules.
Article
Chemistry, Physical
Huanhuan Jia, Rong Xie, Guangpeng Lu, Huanfeng Jiang, Min Zhang
Summary: In this study, a hierarchically porous ZrO2-supported iridium catalyst was developed, which exhibited sufficient catalytic activity even with a low iridium loading. This catalyst was successfully used for the selective and direct construction of julolidines, showing good substrate and functional group compatibility, reusability, high step and atom efficiency, and applicability for the fabrication of functional molecules.
Article
Chemistry, Multidisciplinary
Kavyasripriya K. Samudrala, Winn Huynh, Rick W. Dorn, Aaron J. Rossini, Matthew P. Conley
Summary: This study discovers an effective approach to prepare aluminum-silicon oxide catalysts with well-defined structures. Through experimental and theoretical calculations, it is demonstrated that the catalyst exhibits strong Lewis acidity and can react with organometallic compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Ezzat Khan
Summary: Alkenylsilanes with chlorosilyl and boryl groups attached to a carbon atom were synthesized through hydroboration of alkynylsilanes. They reacted with N-trimethylsilylpyrazole and N-2-(trimethylsilylamino)pyridine to form Si-N bonds, resulting in heterocycles containing Si, N, and B atoms. Treatment of a dichlorosilane with trimethylsilylpyrazole yielded a bis(pyrazolyl)silane.
APPLIED ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Chao Wang, Yueying Chu, Danfeng Xiong, Haifeng Wang, Min Hu, Qiang Wang, Jun Xu, Feng Deng
Summary: We investigate the role of water in benzene methylation over ZSM-5 zeolite using solid-state NMR experiments and theoretical simulations. We find that water competes with benzene for the active sites of the zeolite and facilitates the reaction mechanism. The growth of water clusters induces a micro-hydrophobic effect in zeolite pores, which reorients benzene molecules and promotes their interactions with surface methoxy species on the zeolite.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Md Shahabuddin Alam, Xinlin Li, Drew O. O. Brittin, Saiful Islam, Pravas Deria, Eduard Y. Y. Chekmenev, Boyd M. M. Goodson
Summary: A novel phenomenon is described in which large antiphase o-H-2 signals are observed when using an intact heterogeneous catalyst constructed using a metal-organic framework (MOF), and this effect is qualitatively independent of substrate nature.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
James Eills, Dmitry Budker, Silvia Cavagnero, Eduard Y. Chekmenev, Stuart J. Elliott, Sami Jannin, Anne Lesage, Joerg Matysik, Thomas Meersmann, Thomas Prisner, Jeffrey A. Reimer, Hanming Yang, Igor V. Koptyug
Summary: Magnetic resonance techniques, especially medical magnetic resonance imaging, are widely used in various scientific disciplines and practical applications. The development of spin hyperpolarization has greatly boosted both fundamental and applied magnetic resonance. Hyperpolarization techniques significantly enhance the signal intensity of magnetic resonance, overcoming its low sensitivity and opening up new possibilities for applications.
Article
Biochemistry & Molecular Biology
Bryce. E. E. Kidd, Max. E. E. Gemeinhardt, Jamil. A. A. Mashni, Jonathan. L. L. Gesiorski, Liana. B. B. Bales, Miranda. N. N. Limbach, Roman. V. V. Shchepin, Kirill. V. V. Kovtunov, Igor. V. V. Koptyug, Eduard. Y. Y. Chekmenev, Boyd. M. M. Goodson
Summary: This study examines the potential for enhancing NMR signals of DNA nucleobases using parahydrogen-based hyperpolarization. Signal amplification by reversible exchange (SABRE) and SABRE in Shield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) are demonstrated for selected DNA nucleobases. Low H-1 epsilon values (<10) were obtained for solutions of the standard SABRE catalyst and a given nucleobase, likely indicating weak catalyst binding. However, significant natural-abundance enhancement of N-15 signals was achieved for 3-methyladenine and cytosine. These findings provide insight into nucleobase tautomerization and may facilitate the investigation of cellular function and dysfunction.
Article
Biochemistry & Molecular Biology
Isaiah Adelabu, Md Raduanul H. Chowdhury, Shiraz Nantogma, Clementinah Oladun, Firoz Ahmed, Lukas Stilgenbauer, Marianna Sadagurski, Thomas Theis, Boyd M. Goodson, Eduard Y. Chekmenev
Summary: Efficient C-13 hyperpolarization of ketoisocaproate was achieved using SABRE-SHEATH. By undergoing simultaneous chemical exchange with an Ir-IMes-based complex, parahydrogen atoms transferred their polarization to the C-13 nucleus of ketoisocaproate, resulting in high polarization values. The polarization build-up was possible due to favorable relaxation dynamics. Evaluation: 8 points.
Article
Chemistry, Analytical
Keilian MacCulloch, Austin Browning, Patrick TomHon, Soeren Lehmkuhl, Eduard Y. Chekmenev, Thomas Theis
Summary: Hyperpolarization modalities, particularly SABRE, are employed to enhance 15N polarization of nitrile-containing anticancer drugs. Optimal parameters, including temperature, magnetic field, and field profile, are fine-tuned for different substrates. Over 10% hyperpolarization and 280,000-fold signal enhancement are achieved for letrozole and anastrozole. Prolonged polarization storage and signal detection are enabled by the nitrile 15N sites.
ANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
David O. Guarin, Sameer M. Joshi, Anna Samoilenko, Mohammad S. H. Kabir, Erin E. Hardy, Atsush M. Takahashi, Jan H. Ardenkjaer-Larsen, Eduard Y. Chekmenev, Yi-Fen Yen
Summary: We present the first report of dissolution Dynamic Nuclear Polarization (d-DNP) of [N-15(3)]metronidazole ([N-15(3)]MNZ). Metronidazole, a clinically approved antibiotic, shows potential as a hypoxia-sensing molecular probe using N-15 hyperpolarized (HP) nucleus. The d-DNP process using trityl radical achieves efficient hyperpolarization of [N-15(3)]MNZ with long-lasting signal and high polarization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Boyd M. Goodson, Qingfeng Ge, Lichang Wang
Summary: In the past 20 years, there has been significant effort to advance the modular approach to teaching chemistry laboratory courses. This article presents the development and implementation of two modules for a second-semester physical chemistry laboratory course: an inquiry-based module on proteins and a project-based module on organic small molecules. These modules focus on specific molecular systems and allow students to choose and apply different methods to study them, based on each method's advantages and disadvantages. The main goals of the modules are to develop students' critical thinking skills, provide real-world applications for their knowledge, encourage them to emulate scientists, and inspire them to pursue research opportunities. The article provides details on how this modular approach has been implemented in teaching the second-semester physical chemistry laboratory over the past 11 years. Assessment results indicate that this two-level modular approach has achieved its goals and helped students choose research-based careers.
JOURNAL OF CHEMICAL EDUCATION
(2023)
Article
Chemistry, Physical
Mohammad S. H. Kabir, Sameer M. Joshi, Anna Samoilenko, Isaiah Adelabu, Shiraz Nantogma, Juri G. Gelovani, Boyd M. Goodson, Eduard Y. Chekmenev
Summary: Efficient hyperpolarization of [N-15(3)]metronidazole was achieved using the SABRE-SHEATH technique. The functionalization of [N-15(3)]metronidazole with a fluorine-19 moiety was also successful, resulting in efficient hyperpolarization of all three N-15 sites. The spin-relayed polarization transfer between N-15 and F-19 was found to be less efficient.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Nuwandi M. Ariyasingha, Anna Samoilenko, Jonathan R. Birchall, Md Raduanul H. Chowdhury, Oleg G. Salnikov, Larisa M. Kovtunova, Valerii I. Bukhtiyarov, David C. Zhu, Chunqi Qian, Michael Bradley, Juri G. Gelovani, Igor V. Koptyug, Boyd M. Goodson, Eduard Y. Chekmenev
Summary: Hyperpolarized MRI contrast agents are revolutionizing biomedical imaging. Researchers have demonstrated a low-cost, handheld device for producing hyperpolarized protonated propane gas, which has potential applications in clinical settings.
Article
Optics
Lars Lohmann, Soeren Lehmkuhl, Simon Fleischer, Matthew S. Rosen, Eduard Y. Chekmenev, Thomas Theis, Alina Adams, Stephan Appelt
Summary: A nuclear-spin-based RASER is used to explore nonlinear interaction phenomena of nuclear spins coupled via virtual photons to a resonator. The experiment shows various nonlinear phenomena in the parahydrogen-pumped two-compartment proton RASER, including mode oscillations, frequency shifts, frequency combs, period doublings, and chaos. The mode separation in the RASER is precisely controlled by a magnetic field gradient to select the observed nonlinear phenomena.
Article
Chemistry, Physical
Austin Browning, Keilian Macculloch, Patrick TomHon, Iuliia Mandzhieva, Eduard Y. Chekmenev, Boyd M. Goodson, Soeren Lehmkuhl, Thomas Theis
Summary: Hyperpolarization of C-13-pyruvate via Signal Amplification By Reversible Exchange (SABRE) is an important recent discovery due to the simplicity of hyperpolarization and the relevance of pyruvate as a biomolecular probe. This study analyzes the [1,2-C-13(2)]pyruvate-SABRE spin system theoretically and experimentally, providing insights into spin state mixing, dynamics, and resulting spectra. The results are compared to systematic experiments, enhancing our understanding of the [1,2-C-13(2)]pyruvate-SABRE system.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Iuliia Mandzhieva, Isaiah Adelabu, Shiraz Nantogma, Eduard Y. Chekmenev, Thomas Theis
Summary: This study presents a new pulse sequence approach that allows the use of hyperpolarized MRI for molecular imaging of metabolic diseases on clinical MRI scanners. The approach transfers C-13 hyperpolarization to methyl protons for detection and is robust to magnetic field inhomogeneities.