Article
Chemistry, Multidisciplinary
Hochul Woo, Angela M. Devlin, Adam J. Matzger
Summary: Solvent exchange within metal-organic frameworks (MOFs) is crucial for activating coordinatively unsaturated sites (CUS) and achieving optimal surface area, enabling versatile applications of MOFs. This study quantifies the exchange behavior of a copper paddlewheel-based CUS-MOF (HKUST-1) in the presence of different solvents and reveals that solvent exchange in CUS-MOFs is not diffusion-limited, but rather determined by the solvent exchange kinetics at the metal center. The insights from this study can inform best practices for solvent exchange in various copper-paddlewheel-based MOFs.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Wencui Li, Zhi Li, Hang Zhang, Pengxiao Liu, Zean Xie, Weiyu Song, Baijun Liu, Zhen Zhao
Summary: By using magnesium hydride as a support and combining it with a Cu(I) salt solution under the synergistic action of sodium hydroxide and cupric acetate, a Cu2-block catalyst was successfully formed. This catalyst exhibits high activity and stability for the selective oxidation of methane to C1 organic oxygenates at low temperatures.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Energy & Fuels
Hao Guo, Jun Cheng, Yuxiang Mao, Lei Qian, Yang Shao, Weijuan Yang
Summary: In order to increase the efficiency of metal-organic frameworks for biodiesel production, ultrafine ZIF-67 was used to release metal atoms and create coordinatively unsaturated cobalt-nitrogen active sites. Reducing the crystal size of ZIF67 resulted in an increase in the unsaturated Co-N-x content, leading to enhanced Lewis acid-base properties. The optimized catalyst achieved high conversion efficiencies for free fatty acid and triglyceride in acidic lipids to biodiesel.
Article
Chemistry, Physical
Yuanfei Song, Shaoxia Weng, Fan Xue, Alan J. McCue, Lirong Zheng, Yufei He, Junting Feng, Yanan Liu, Dianqing Li
Summary: In this study, a synthesis approach for preparing catalysts with shape-controlled Al2O3 supports containing coordinatively unsaturated Al3+ centers is reported. These centers induce ordering in bimetallic catalysts through a simple impregnation strategy, benefiting the selective hydrogenation of acetylene. The use of nanorod Al2O3 results in a highly homogeneous and ordered Ni1Cu1 nanoalloy, attributed to the coordination effect of unsaturated Al3+ sites that promote atomic diffusion and ordering. The obtained Ni-Cu/Al2O3-rod catalyst shows both satisfactory activity and ethylene selectivity, outperforming most reported Ni-based catalysts.
Article
Chemistry, Multidisciplinary
Xiaoyue Shi, Yiqi Ling, Youcong Li, Guanhua Li, Juan Li, Lingwei Wang, Fanhong Min, Rene Huebner, Shuai Yuan, Jinhua Zhan, Bin Cai
Summary: This study presents a novel approach for achieving complete glucose electrooxidation using a Cu-based metal-hydroxide-organic framework, which exhibits significantly improved electrocatalytic activity and enables the exclusive oxidation of glucose into formate and carbonate. A high-performance nonenzymatic glucose sensor was also developed. This work provides a new molecule-level strategy for designing catalytically active sites and has potential implications for the development of next-generation electrochemical devices.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Multidisciplinary Sciences
Ji Wei Sun, Xuefeng Wu, Peng Fei Liu, Jiacheng Chen, Yuanwei Liu, Zhen Xin Lou, Jia Yue Zhao, Hai Yang Yuan, Aiping Chen, Xue Lu Wang, Minghui Zhu, Sheng Dai, Hua Gui Yang
Summary: The authors report a general method to synthesize coordinatively unsaturated metal-nitrogen sites doped within carbon nanotubes, which can mediate efficient CO2-to-CO formation in a membrane flow configuration, achieving high current density and CO selectivity. This fabrication method can be scaled up with negligible decay in CO2-to-CO activity.
NATURE COMMUNICATIONS
(2023)
Article
Agricultural Engineering
Hao Guo, Jun Cheng, Yuxiang Mao, Lei Qian, Yang Shao, Xiao Yang, Weijuan Yang
Summary: In this study, an acid-base bifunctional catalyst was successfully synthesized and its catalytic performance was improved through pyrolysis process. The pyrolysis process destroyed the coordination structure of the catalyst, releasing more active sites and increasing the Lewis acid/Bronsted acid ratio and basicity. Additionally, more mesopores were generated inside the catalyst, facilitating the transportation and conversion of lipid molecules. The use of this catalyst achieved higher conversion efficiency of microalgal lipids compared to traditional catalysts.
BIORESOURCE TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
S. Rajasekaran, B. S. Reghunath, K. R. Sunaja Devi, D. Pinheiro
Summary: A bimetallic electrocatalyst MOF using Ni and Cu has been synthesized and evaluated for oxygen evolution reaction. Bimetallic MOFs show higher activity in electrocatalysis due to the abundance of active sites, local crystallinity, and lower long-range disorder. Ni-Cu MOFs exhibit a low overpotential of 340 mV at 10 mA/cm2 and a low Tafel slope of 65 mV/dec when used as oxygen evolution catalysts. The study paves the way for efficient catalyst development in water splitting applications.
MATERIALS TODAY CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Yangpei Li, Hao Han, Aodong Xu, Yanming Fu, Chengfeng Zhu, Lanjun Cheng, Yougui Li
Summary: Integrating inorganic oxygen evolution cocatalysts with photoanodes is a viable strategy to increase the photogenerated charge utilization. In this study, a cobalt-organic complex was constructed and applied to the photoelectrochemical water oxidation. The synthesized photoanode exhibited high photocurrent density and excellent photostability.
INORGANIC CHEMISTRY
(2023)
Article
Engineering, Environmental
He Liang, Ruiping Liu, Xiaoqiang An, Chengzhi Hu, Xiwang Zhang, Huijuan Liu
Summary: Recently, a new Fenton-like catalyst, CUMSs/MIL-101(Fe, Cu), with mixed valence of Fe(II)/Fe(III) and Cu(I)/Cu(II) as coordinatively unsaturated metal sites has been successfully synthesized and demonstrated enhanced degradation performance for ciprofloxacin compared to single iron catalyst in the neutral pH range. This work provides a new strategy for designing highly efficient, stable, and eco-friendly Fenton-like catalysts for superior environmental remediation efficiency across a wide pH range.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Green & Sustainable Science & Technology
Jian Sun, Tao Xue, Liying Cui, Juan Liu
Summary: This study presents a controllable bibonding method to construct coordinatively unsaturated Zni+ (0 < i < 2) active sites by forming N(g-C3N4)-Zn-N-(imidazole) under mild experimental conditions. The catalysts with Zni+ are utilized for the photo-Fenton degradation of methylene blue (MB) without any oxidant, and the degradation efficiency is positively correlated with Zni+. Zni+ improves the Fe2+/Fe3+ conversion efficiency and H2O2 generation ability of the catalysts. The optimized catalysts with 2.27% of Zni+ exhibit photo-Fenton degradation efficiency of MB as 73.45 mg g(-1) at pH 7 and 78.54 mg g(-1) at pH 4. This strategy can be applied to construct coordinatively unsaturated metal sites for a series of narrow bandgap semiconductor materials containing nitrogen atoms.
ADVANCED SUSTAINABLE SYSTEMS
(2023)
Article
Engineering, Environmental
Jia Deng, Xiaobao Zeng, Feng Wu, Zheng Fang, Yitao Dai, Li-Zhi Huang
Summary: In this study, a biomimetic Hemin catalyst was used for the electrochemical dechlorination of trichloroethylene (TCE). It was found that lowering the applied potential generated coordinatively unsaturated FeI sites, which showed higher reactivity towards TCE reduction.
JOURNAL OF ENVIRONMENTAL ENGINEERING
(2022)
Article
Chemistry, Physical
Halil Durak, Salih Genel
Summary: This study investigates the impact of NaF/Al2O3 catalysts on hydrothermal liquefaction of cellulose. The results show that NaF/Al2O3 catalysts effectively enhance the liquid product yield and generate high-energy-value products. The optimal NaF loading is found to be 30%.
Article
Chemistry, Physical
Zean Xie, Zhi Li, Peng Tang, Yangyang Song, Zhen Zhao, Lian Kong, Xiaoqiang Fan, Xia Xiao
Summary: Recent studies have shown that coordinatively unsaturated metal-O Lewis acid-base pairs of metal oxides can efficiently activate the C-H bond of light alkanes, and the surface oxygen vacancy amount of Al2O3 plays a crucial role in propane dehydrogenation (PDH) reaction.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Applied
Zekun Li, Zhao Wang
Summary: Metal-organic frameworks (MOFs) are considered as promising catalyst candidates for oxygen evolution reaction (OER). This study successfully tuned the coordinatively unsaturated metal sites (CUMSs) of nickel-based MOF (Ni-BTC) using glow discharge plasma at room temperature. The electrochemical activity of Ni-BTC was correlated with the abundance of CUMSs.
Article
Biochemistry & Molecular Biology
Tomasz Ratajczyk, Gerd Buntkowsky, Torsten Gutmann, Bartlomiej Fedorczyk, Adam Mames, Mariusz Pietrzak, Zuzanna Puzio, Piotr Grzegorz Szkudlarek
Summary: The biorelevant PyFALGEA oligopeptide ligand has been successfully utilized in SABRE experiments for signal amplification, with its interaction with the iridium catalyst influencing the efficiency of hyperpolarization. Steric hindrance caused by the bulky phenylalanine in the PyFALGEA oligopeptide can hinder hyperpolarization, highlighting the importance of optimizing the molecular structures for efficient hyperpolarization. Additionally, a unique NMR pattern in the hydride region observed during SABRE experiments with PyFALGEA and IMesBn can serve as a fingerprint for this oligopeptide.
Article
Physics, Atomic, Molecular & Chemical
Laura Wienands, Franziska Theiss, James Eills, Lorenz Roesler, Stephan Knecht, Gerd Buntkowsky
Summary: Parahydrogen-induced polarization is a hyperpolarization method that enhances nuclear magnetic resonance signals through chemical reactions involving the para spin isomer of hydrogen gas. This method allows for biomolecules to be hyperpolarized for real-time in vivo metabolic imaging. Current research on the efficient hyperpolarization of fumarate has not been thoroughly investigated, leading to inconsistencies in chosen reaction conditions in previous work seeking higher reaction rates and yields.
APPLIED MAGNETIC RESONANCE
(2022)
Article
Chemistry, Inorganic & Nuclear
Wei Mao, Yanbo Bai, Zhaohua Jia, Yue Qin, Bo Wang, Wei Zhang, Jian Lu, Erhard Kemnitz
Summary: Nano AlF3 prepared by the ethylene glycol-mediated sol-gel process shows improved thermal stability compared to conventionally prepared HS-AlF3, but exhibits weaker acidity.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Jonathan Bould, Michael G. S. Londesborough, Miroslava Litecka, Ramon Macias, Suzanne L. Shea, Thomas D. McGrath, William Clegg, John D. Kennedy
Summary: High yields of novel macropolyhedral selenaboranes have been synthesized and characterized. These selenaboranes exhibit unique structural features, including different numbers of vertices, connectivity between subclusters, and the presence of special structural motifs within the subclusters.
INORGANIC CHEMISTRY
(2022)
Article
Thermodynamics
Markus M. Hoffmann, Joseph D. Kealy, Torsten Gutmann, Gerd Buntkowsky
Summary: The study investigated the physical properties of polyethylene glycol (PEG) and its binary mixtures, finding a linear relationship between temperature and density, while viscosity and self-diffusion coefficients followed the Arrhenius law. Calculated molar volumes largely agreed with measured values, viscosities were mostly within a few percent, and self-diffusion coefficients were generally within 20% of measurement uncertainty.
JOURNAL OF CHEMICAL AND ENGINEERING DATA
(2022)
Article
Chemistry, Multidisciplinary
Shirin M. Usmani, Linn Voss, Ina Stephan, Thomas Huebert, Erhard Kemnitz
Summary: The decay protection of wood using low-water soluble metal fluorides was evaluated. The study found that nano metal fluorides were more effective in preventing fungal decay than stand-alone metal fluorides. Metal fluorides were present in treated wood, both unleached and leached. The combination of MgF2 and CaF2 reduced the mass losses of wood to below 3%. These findings suggest that nano metal fluorides can provide full protection to wood in outdoor environments.
APPLIED SCIENCES-BASEL
(2022)
Article
Biochemistry & Molecular Biology
Nargiz B. Asanbaeva, Larisa Yu Gurskaya, Yuliya F. Polienko, Tatyana Rybalova, Maxim S. Kazantsev, Alexey A. Dmitriev, Nina P. Gritsan, Nadia Haro-Mares, Torsten Gutmann, Gerd Buntkowsky, Evgeny Tretyakov, Elena G. Bagryanskaya
Summary: This study investigates the feasibility of using ferrocene-substituted 1,3-diazetidine-2,4-diimine couplers as DNP agents. The results show that the spiro-substituted nitroxyl biradicals have a higher DNP gain compared to the methyl-substituted biradicals. The difference in temperature dependence of the EPR spectra is explained using DFT calculations. The effects of nucleophiles and substituents on the ring-opening reaction and the influence of ring opening on the exchange interaction are also examined.
Article
Chemistry, Physical
Markus M. Hoffmann, Matthew D. Too, Nathaniel A. Paddock, Robin Horstmann, Sebastian Kloth, Michael Vogel, Gerd Buntkowsky
Summary: In this study, molecular dynamics simulations were performed to investigate polyethylene glycol (PEG)200. Force fields for describing ethylene glycol oligomers were tested and adjusted to improve the agreement with experimental properties. The simulations revealed that PEG200 is a random mixture of its ethylene glycol oligomer components.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Sonja C. Doeller, Torsten Gutmann, Markus Hoffmann, Gerd Buntkowsky
Summary: This study investigates the behavior of four different commercially available polarizing agents using 1-octanol as the analyte. By establishing a relative method to compare the direct and indirect polarization transfer pathways, it is possible to directly compare the polarization efficacy for different radicals and different parts of the 1-octanol molecule. The results highlight the importance of hydrophilicity in the polarization transfer process.
SOLID STATE NUCLEAR MAGNETIC RESONANCE
(2022)
Article
Biochemistry & Molecular Biology
Nargiz B. B. Asanbaeva, Sergey A. A. Dobrynin, Denis A. A. Morozov, Nadia Haro-Mares, Torsten Gutmann, Gerd Buntkowsky, Elena G. G. Bagryanskaya
Summary: This paper reports on the DNP efficiency at a high magnetic field for two water-soluble biradicals resistant to reducing media. The radicals were obtained in the form of quaternary ammonium salts to achieve water solubility. The influence of hyperfine interaction and exchange interaction on the DNP effect was determined through EPR spectroscopy.
Article
Chemistry, Inorganic & Nuclear
Jonathan Bould, Michael G. S. Londesborough, Jiri Brus, Oleg Tok, Pablo J. Sanz Miguel, Ramon Macias
Summary: The [PSH](+) decaborane salt can react with ethanol to form [PSH][B9H14], providing a simple method for synthesizing the arachno-nonaborate anion. The properties of the new polyhedral salt are characterized using NMR spectroscopy and X-ray diffraction. DFT calculations reveal insights into the low-energy dynamic behavior involving hydrogen atoms.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Melissa-Jane Monks, Christian Wuerth, Erhard Kemnitz, Ute Resch-Genger
Summary: A fluorolytic sol-gel method was used to synthesize small cubic-phase SrF2:Yb3+,Er3+ upconversion nanocrystals (UCNC) of different compositions at room temperature. It was found that doping with 13.5% Yb3+ and 1.3% Er3+ resulted in the highest upconversion luminescence (UCL) performance in the studied conditions. The UCL quantum yields of the UCNC were similar to that of popular β-NaYF4:Yb3+,Er3+ nanocrystals. The UCL quenching pathway in the unshelled SrF2:Yb3+,Er3+ UCNC was different from the commonly accepted pathway in β-NaYF4:Yb3+,Er3+ UCNC. The results emphasize the complexity of the upconversion processes and the importance of the crystal phase and symmetry of the host lattice.
Article
Chemistry, Physical
Niels Rothermel, Hans-Heinrich Limbach, Iker del Rosal, Romuald Poteau, Gabriel Mencia, Bruno Chaudret, Gerd Buntkowsky, Torsten Gutmann
Summary: Ruthenium nanoparticles stabilized with dppb and hydrogen were exposed to (NH3)-N-15 gas, leading to the formation of surface-bound urea. The pressure of hydrogen gas affects the chemical shifts of RuNH2 on the surface.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
