Article
Chemistry, Physical
Haolin Zhan, Mengyou Hao, Ye Feng, Shuohui Cao, Zhikai Ni, Yuqing Huang, Zhong Chen
Summary: Diffusion-ordered NMR spectroscopy (DOSY) is a noninvasive method for studying intact mixtures and identifying individual components based on their diffusion behaviors. The strategy of spatially selective pure shift-based DOSY can help eliminate inhomogeneous line broadening and extract pure shift singlets, facilitating diffusion analyses on complex mixtures and potentially monitoring electrochemical reactions. This study demonstrates the potential of DOSY in complex mixture analysis and its applications in various fields.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Ye Tian, Xiaomeng Chong, Shangchen Yao, Mingzhe Xu
Summary: A method utilizing NMR spectroscopy and mass spectrometry was established for determining the chemical structure of vancomycin hydrochloride. The study successfully identified the compound and concluded that the method is accurate and applicable for production and structural elucidation of vancomycin hydrochloride.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Analytical
Bin Yuan, Zhiming Zhou, Bin Jiang, Ghulam Mustafa Kamal, Xu Zhang, Conggang Li, Xin Zhou, Maili Liu
Summary: CORDY is a novel approach for NMR spectroscopy that utilizes concentration order to separate and quantify components in complex samples, by utilizing prior information of chemical shift distribution and line shape characteristics to shrink the solution space, it generates a pseudo-two-dimensional spectrum. The combination of CORDY and DOSY (CORDY-DOSY) has been found to be more efficient in resolving molecules with similar concentrations or self-diffusion coefficients.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Alexander G. Martynov, Marina A. Polovkova, Gayane A. Kirakosyan, Evgeny N. Zapolotsky, Sergey P. Babailov, Yulia G. Gorbunova
Summary: This study investigates the structural assignments of Ln(2)[(15C5)4Pc]3 complexes using NMR relaxation and paramagnetic lanthanide induced shifts (LIS) data. The analysis reveals isostructurality in the complete series of triple-decker complexes in solution. DFT calculations for model complexes with methoxy-substituted ligands show good agreement with experimental NMR data.
Article
Biochemical Research Methods
Julian Ilgen, Jens Nowag, Lukas Kaltschnee, Volker Schmidts, Christina M. Thiele
Summary: NMR experiments like NOESY, ROESY, and EXSY have been used in solution to elucidate molecular structure and dynamics by providing interatomic distance restraints or rates for chemical exchange. Pure shift methods are becoming popular to improve spectral resolution in order to reduce signal overlap.
JOURNAL OF MAGNETIC RESONANCE
(2021)
Article
Chemistry, Multidisciplinary
Manuel Cordova, Pinelopi Moutzouri, Bruno Simoes de Almeida, Daria Torodii, Lyndon Emsley
Summary: A deep learning approach is introduced to determine pure isotropic proton spectra from a two-dimensional set of magic-angle spinning spectra acquired at different spinning rates. The model is applied to 8 organic solids, yielding high-resolution H-1 solid-state NMR spectra with isotropic linewidths in the 50-400 Hz range.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Qi Zhao, Christian Marcus Pedersen, Jiamin Wang, Rui Liu, Yuanli Zhang, Xiuyin Yan, Zhenzhou Zhang, Xianglin Hou, Yingxiong Wang
Summary: The article introduces a high-resolution diffusion-related NMR technique that can effectively separate and identify individual compounds in complex mixtures of biomass. The technique can be applied to model and genuine mixture samples from cellulose, hemicellulose, and lignin, successfully separating isomers, homologous compounds, model compounds, and genuine reaction systems. The results show that this method can detect and separate the mixture components of C5/C6 sugar conversion products and their derivative hydrogenation/hydrogenolysis from lignocellulosic biomass.
GREEN ENERGY & ENVIRONMENT
(2023)
Article
Multidisciplinary Sciences
Juan M. Lopez, Vanessa Leyva, Helena Maruenda
Summary: Nuclear Magnetic Resonance (NMR) is a powerful tool in metabolomics for quantitative data and structural identification of metabolites. However, signal overlapping and J-coupling multiplicities present challenges in spectra analysis, limiting the application of classical H-1 NMR profiling.
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS
(2021)
Article
Spectroscopy
Hongpeng Wang, Yingjian Xin, Xiong Wan
Summary: This paper reports on the spectral characterization of porphyrins and terpenoids in different vegetable oils, classifying them using a PCA-SVM model. The study analyzed the effects of oil types and processing technology on spectral differences, finding that chlorophyll and β-carotene were the main contributors to the fingerprint information in the spectral techniques. Extra virgin olive oil obtained by physical cold pressing had the highest content of porphyrins and terpenoids, indicating the strongest activity.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Multidisciplinary
Pinelopi Moutzouri, Manuel Cordova, Bruno Simoes de Almeida, Daria Torodii, Lyndon Emsley
Summary: One key bottleneck of solid-state NMR spectroscopy is the broadness of H-1 NMR spectra of organic solids due to dipolar couplings. A new approach called PIP was suggested to address this problem by mapping errors leading to dipolar broadening and removing them in a correlation experiment. By extending the PIP approach to a second dimension using deep learning, high resolution H-1-H-1 double-quantum/single-quantum dipolar correlation and spin-diffusion spectra were obtained with significantly higher resolution than the corresponding spectra at 100 kHz MAS, allowing the identification of previously overlapped isotropic correlation peaks.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Analytical
Qianjin Wang, Pengshuai Sun, Zhirong Zhang, Lewen Zhang, Tao Pang, Bian Wu, Hua Xia, Qiang Guo, Markus W. Sigrist, Brian Culshaw
Summary: This paper introduces a dual-gas sensor using tunable diode laser absorption spectroscopy for the measurement of multi-component gas mixture, and a novel multi-component gas measurement aliasing spectral demodulation method for interference separation. The experiments have shown that this method can provide accurate measurement results with fast response time and good repeatability.
SENSORS AND ACTUATORS B-CHEMICAL
(2022)
Article
Chemistry, Analytical
Marshall J. Smith, Laura Castanar, Ralph W. Adams, Gareth A. Morris, Mathias Nilsson
Summary: Many interesting problems in chemistry, biology, and pharmacy involve mixtures. However, analyzing such mixtures using NMR can be challenging, especially when the components overlap. This study proposes a new method that exploits the relaxation properties of selected nuclei and uses pure shift methods to increase spectral resolution, allowing for accurate differentiation of mixture components.
ANALYTICAL CHEMISTRY
(2022)
Article
Engineering, Electrical & Electronic
Hong Li, Yu Yang, Haolin Zhan, Xiaoqing Lin, Zhong Chen
Summary: Pure shift techniques are a rapidly developing frontier in nuclear magnetic resonance fields that enhance resolution by removing splittings induced by scalar couplings. This study introduces a signal model for pure shift data and proposes an artifact-suppression method based on constraints on the low-rank property of pure shift NMR data, which enables reconstruction of a clean spectrum and accelerates experiment time while maintaining accuracy. The proposed method is demonstrated to effectively suppress periodic artifacts on complex samples and shows potential for practical applications.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Engineering, Electrical & Electronic
Ge Zhang, Shaohui Mei, Yan Feng, Qian Du
Summary: This study introduces a spectral-spatial constrained unmixing method based on nonnegative matrix factorization (NMF), which improves the performance of unmixing by imposing spatial and spectral constraints. Experimental results on synthetic and real-world datasets demonstrate the effectiveness of the proposed method in comparison to state-of-the-art NMF-based unmixing algorithms.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2021)
Article
Multidisciplinary Sciences
Ajin Joy, M. Albert Thomas
Summary: Covariance transformation and Inner Product can significantly increase the resolution of 2D COSY spectrum without affecting the spectral width, leading to a reliable measure of unsaturation index for malignant breast cancer.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Jan-Patrick Steitz, Leonhard Krug, Lydia Walter, Karel Hernandez, Caroline Roehr, Pere Clapes, Michael Mueller
Summary: Thiamine diphosphate (ThDP) dependent enzymes play an important role in asymmetric C-C bond formation through benzoin-type condensation reactions. In this study, a subclass of (myco)bacterial ThDP-dependent enzymes with an extended donor substrate range was identified. The introduction of functionalized alpha-keto acids, accessible by known aldolase-catalyzed transformations, greatly broadens the donor substrate range of ThDP-dependent enzymes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Physical
Virgil Helaine, Cedric Gastaldi, Marielle Lemaire, Pere Clapes, Christine Guerard-Helaine
Summary: Aldolases are powerful enzymes for C-C bond formation in biocatalysis due to their outstanding stereoselectivity, ease of setting up reactions without cofactor recycling, availability of various types and families, and feasibility under mild operating conditions. Recent major discoveries have expanded the scope of both nucleophile and electrophile substrates, leading to significant advancements in the field.
Article
Chemistry, Multidisciplinary
Laura Hernandez-Lopez, Alba Cortes-Martinez, Teodor Parella, Arnau Carne-Sanchez, Daniel Maspoch
Summary: In this study, a novel supramolecular strategy based on the use of metal-organic polyhedron (MOP) as a capture agent is reported for removing nitrogenous organic micropollutants from water, even at low concentrations. This approach is achieved by coordinatively sequestering pollutants through the exohedral coordination positions of Rh-II-MOP and controlling their aqueous solubility through acid/base reactions of the exposed surface carboxyl groups. The method has been validated for the removal of benzotriazole, benzothiazole, isoquinoline, and 1-napthylamine from water.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Analytical
Marshall J. Smith, Laura Castanar, Ralph W. Adams, Gareth A. Morris, Mathias Nilsson
Summary: Many interesting problems in chemistry, biology, and pharmacy involve mixtures. However, analyzing such mixtures using NMR can be challenging, especially when the components overlap. This study proposes a new method that exploits the relaxation properties of selected nuclei and uses pure shift methods to increase spectral resolution, allowing for accurate differentiation of mixture components.
ANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Coral Mycroft, Mathias Nilsson, Gareth A. Morris, Laura Castanar
Summary: A general pure shift method is presented for obtaining ultra-high resolution H-1 NMR spectra by suppressing both homonuclear and heteronuclear J-couplings. Its usefulness is demonstrated in the analysis of fluorine- and phosphorus-containing compounds of pharmaceutical and biochemical interest.
Article
Biochemical Research Methods
Runchao Li, Laura Castanar, Mathias Nilsson, Gareth A. Morris
Summary: Quantitative NMR is widely used, but the errors introduced by soft pulses are not well understood. This study shows that relaxation on resonance during shaped soft refocusing pulses can be represented by biexponential decay, allowing for correction of relaxational losses in experiments.
JOURNAL OF MAGNETIC RESONANCE
(2023)
Article
Chemistry, Applied
Mathias Pickl, Markus Ebner, Samantha Gittings, Pere Clapes, Wolfgang Kroutil
Summary: Although optical pure amino alcohols are highly demanded, their synthesis remains challenging due to the requirement of elaborate protection strategies. This study presents a multi-enzymatic methodology that allows the synthesis of enantioenriched 1,3-amino alcohols from commodity chemicals. By utilizing a Type I aldolase and enzymatic transamination, both diastereomers of the 1,3-amino alcohol motif were accessible, resulting in the desired amino alcohols with high enantioselectivity.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Carlos J. Moreno, Karel Hernandez, Samantha Gittings, Michael Bolte, Jesu's Joglar, Jordi Bujons, Teodor Parella, Pere Clapes
Summary: This study presents a tandem biocatalytic stereodivergent route for the preparation of chiral 2-hydroxy acids and 2-hydroxy-4-butyrolactone derivatives using simple and achiral starting materials. The strategy involves aldol addition reactions and subsequent reduction reactions, utilizing aldolases and ketoreductases from E. coli, Pseudomonas putida, and Pseudomonas syringae pv. tomato DSM 50315. A total of 29 structurally diverse compounds were synthesized with high enantiomeric excess and isolated yields.
Article
Chemistry, Multidisciplinary
Daniel A. Taylor, Peter Kiraly, Paul Bowyer, Mathias Nilsson, Laura Castanar, Gareth A. Morris, Ralph W. Adams
Summary: Selective 1D COSY can identify coupled spins but has limitations in selectivity and multiplet lineshapes. This study combines ultra-selective GEMSTONE excitation with CLIP-COSY to provide through-bond correlations for overlapping NMR signals. The method is demonstrated using the drugs lasalocid and cyclosporin.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Elsa Caytan, Howard M. Foster, Laura Castanar, Ralph W. Adams, Mathias Nilsson, Gareth A. Morris
Summary: This study reveals that practical pure shift NMR experiments using cryoprobes may result in signal loss, and proposes a simple adjustment to recover the lost signal.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Grayson J. Ford, Christopher R. Swanson, Ruth T. Bradshaw Allen, James R. Marshall, Ashley P. Mattey, Nicholas J. Turner, Pere Clapes, Sabine L. Flitsch
Summary: This study presents a three-component strategy for the stereoselective enzymatic synthesis of amino-diols and amino-polyols. Through biocatalytic aldol reactions and reductive aminations, stereoselective formation of amino-polyols was achieved without the need for intermediates isolation.
Article
Chemistry, Multidisciplinary
Grayson J. Ford, Christopher R. Swanson, Ruth T. Bradshaw Allen, James R. Marshall, Ashley P. Mattey, Nicholas J. Turner, Pere Clapes, Sabine L. Flitsch
Summary: A three-component strategy was developed for the stereoselective enzymatic synthesis of amino-diols and amino-polyols. The strategy utilized a diverse set of prochiral aldehydes, hydroxy ketones, and amines as starting materials, combining biocatalytic aldol reactions and reductive aminations. Stereoselective formation of the desired enantiomers of amino-polyols was observed and confirmed by X-ray crystallography.
Article
Food Science & Technology
Gabriel Rossetto, Peter Kiraly, Laura Castanar, Gareth A. Morris, Mathias Nilsson
Summary: The complexity of food makes analysis by H-1 NMR difficult, but the recently introduced DISPEL experiment can suppress satellite peaks and improve the accuracy of minor signals, making it a potential method for analyzing olive oil.
ACS FOOD SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Miriam Pujals, Tania Pelachs, Carles Fuertes-Espinosa, Teodor Parella, Marc Garcia-Borras, Xavi Ribas
Summary: This study utilizes tetragonal prismatic nanocapsules for regioselective Diels-Alder functionalization of I-h-C-60, allowing the synthesis of either e,e-bis-anthracene-C-60 or trans-1-bis-pentacene-C-60 by changing acene length. The supramolecular mask strategy also enables the formation of unprecedented equatorial hetero-tris-functionalized-C-60 adducts. Computational modeling and MD simulations provide insights into the regioselective control exerted by the supramolecular mask.
CELL REPORTS PHYSICAL SCIENCE
(2022)
