1
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Endeward B, Bretschneider M, Trenkler P, Prisner TF. Implementation and applications of shaped pulses in EPR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 136-137:61-82. [PMID: 37716755 DOI: 10.1016/j.pnmrs.2023.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/12/2023] [Accepted: 04/26/2023] [Indexed: 09/18/2023]
Abstract
In this review, we describe the application of shaped pulses for EPR spectroscopy. Pulses generated by fast arbitrary waveform generators are mostly used in the field of EPR spectroscopy for broadband (200 MHz-1 GHz) excitation of paramagnetic species. The implementation and optimization of such broadband pulses in existing EPR spectrometers, often designed and optimized for short rectangular microwave pulses, is demanding. Therefore, a major part of this review will describe in detail the implementation, testing and optimization of shaped pulses in existing EPR spectrometers. Additionally, we review applications using such pulses for broadband inversion of longitudinal magnetization as well as for the creation and manipulation of transverse magnetization in the field of dipolar and hyperfine EPR spectroscopy. They demonstrate the great potential of shaped pulses to improve the performance of pulsed EPR experiments. We give a brief theoretical description of shaped pulses and their limitations, especially for adiabatic pulses, most often used in EPR. We believe that this review can on the one hand be of practical use to EPR groups starting to work with such pulses, and on the other hand give readers an overview of the state of the art of shaped pulse applications in EPR spectroscopy.
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Affiliation(s)
- Burkhard Endeward
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Matthias Bretschneider
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Paul Trenkler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue Str. 7, 60438 Frankfurt am Main, Germany.
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2
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Smith AJR, York R, Uhrín D, Bell NGA. 19F-centred NMR analysis of mono-fluorinated compounds. RSC Adv 2022; 12:10062-10070. [PMID: 35424946 PMCID: PMC8966657 DOI: 10.1039/d1ra08046f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/15/2022] [Indexed: 11/29/2022] Open
Abstract
Addressing limitations of the existing NMR techniques for the structure determination of mono-fluorinated compounds, we have developed methodology that uses 19F as the focal point of this process. The proposed 19F-centred NMR analysis consists of a complementary set of broadband, phase-sensitive NMR experiments that utilise the substantial sensitivity of 19F and its far reaching couplings with 1H and 13C to obtain a large number of NMR parameters. The assembled 1H, 13C and 19F chemical shifts, values of JHF, JHH, and JFC coupling constants and the size of 13C induced 19F isotopic shifts constitute a rich source of information that enables structure elucidation of fluorinated moieties and even complete structures of molecules. Here we introduce the methodology, provide a detailed description of each NMR experiment and illustrate their interpretation using 3-fluoro-3-deoxy-d-glucose. This novel approach performs particularly well in the structure elucidation of fluorinated compounds embedded in complex mixtures, eliminating the need for compound separation or use of standards to confirm the structures. It represents a major contribution towards the analysis of fluorinated agrochemicals and (radio)pharmaceuticals at any point during their lifetime, including preparation, use, biotransformation and biodegradation in the environment. The developed methodology can also assist with the investigations of the stability of fluoroorganics and their pharmacokinetics. Studies of reaction mechanisms using fluorinated molecules as convenient reporters of these processes, will also benefit. 19F is the focal point of broadband, phase-sensitive 2D NMR experiments that provide 1H, 13C and 19F chemical shifts, values of JHF, JHH, and JFC coupling constants and 13C-induced 19F isotopic shifts to elucidate structures of fluorinated molecules.![]()
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Affiliation(s)
- Alan J R Smith
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Richard York
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Dušan Uhrín
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Nicholle G A Bell
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
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3
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Verstraete JB, Foroozandeh M. Improved design of frequency-swept pulse sequences. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 336:107146. [PMID: 35144158 DOI: 10.1016/j.jmr.2022.107146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Frequency-swept pulses are extensively used in magnetic resonance spectroscopic techniques for the robust manipulation of spins across wide ranges of offset frequencies in the presence of B1 field variations. Nevertheless, designing pulse sequences consisting of multiple frequency-swept pulses can be challenging, as they often require specific timings and parameter tweaking. In the present work we discuss a simple and general approach for constructing such sequences. We present new and improved pulse sequences for applications including broadband B1-tolerant CPMG (CHORUS-CPMG), broadband chirped excitation with suppression of homonuclear J-modulation (PROCHORUS), and the further compression of frequency-swept pulse sequences by superposition of pulses which reduces pulse sequence durations by 25-40%. All sequence design strategies are accompanied by mathematical presentations, experimental results, and supporting simulations.
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4
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Smith AJR, York R, Uhrín D, Bell NGA. New 19F NMR methodology reveals structures of molecules in complex mixtures of fluorinated compounds. Chem Sci 2022; 13:3766-3774. [PMID: 35432904 PMCID: PMC8966635 DOI: 10.1039/d1sc06057k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/25/2022] [Indexed: 11/24/2022] Open
Abstract
Although the number of natural fluorinated compounds is very small, fluorinated pharmaceuticals and agrochemicals are numerous. 19F NMR spectroscopy has a great potential for the structure elucidation of fluorinated organic molecules, starting with their production by chemical or chemoenzymatic reactions, through monitoring their structural integrity, to their biotic and abiotic transformation and ultimate degradation in the environment. Additionally, choosing to incorporate 19F into any organic molecule opens a convenient route to study reaction mechanisms and kinetics. Addressing limitations of the existing 19F NMR techniques, we have developed methodology that uses 19F as a powerful spectroscopic spy to study mixtures of fluorinated molecules. The proposed 19F-centred NMR analysis utilises the substantial resolution and sensitivity of 19F to obtain a large number of NMR parameters, which enable structure determination of fluorinated compounds without the need for their separation or the use of standards. Here we illustrate the 19F-centred structure determination process and demonstrate its power by successfully elucidating the structures of chloramination disinfectant by-products of a single mono-fluorinated phenolic compound, which would have been impossible otherwise. This novel NMR approach for the structure elucidation of molecules in complex mixtures represents a major contribution towards the analysis of chemical and biological processes involving fluorinated compounds. 19F-centred NMR structure determination protocol alleviates the need for compound separation. Disinfection byproducts of chloramination were unraveled by analyzing the reaction pathways of a single fluorinated molecule.![]()
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Affiliation(s)
- Alan J R Smith
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Richard York
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Dušan Uhrín
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
| | - Nicholle G A Bell
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Rd Edinburgh EH9 3FJ UK
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5
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Namyslo JC, Drafz MHH, Kaufmann DE. Durable Modification of Wood by Benzoylation-Proof of Covalent Bonding by Solution State NMR and DOSY NMR Quick-Test. Polymers (Basel) 2021; 13:2164. [PMID: 34208957 PMCID: PMC8271922 DOI: 10.3390/polym13132164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
A convenient, broadly applicable and durable wood protection was recently published by Kaufmann and Namyslo. This procedure efficiently allows for esterification of wood hydroxyl groups with (1H-benzotriazolyl)-activated functionalized benzoic acids. The result of such wood-modifying reactions is usually monitored by an increase in mass of the wood material (weight percent gain value, WPG) and by infrared spectroscopy (IR). However, diagnostic IR bands suffer from overlap with naturally occurring ester groups, mainly in the hemicellulose part of unmodified wood. In contrast to known NMR spectroscopy approaches that use the non-commonly available solid state techniques, herein we present solution state NMR proof of the covalent attachment of our organic precursors to wood. The finding is based on a time-efficient, non-uniformly sampled (NUS) solution state 1H,13C-HMBC experiment that only needs a tenth of the regular recording time. The appropriate NMR sample of thoroughly dissolved modified wood was prepared by a mild and non-destructive method. The 2D-HMBC shows a specific cross-signal caused by spin-spin coupling over three bonds from the ester carbonyl carbon atom to the α-protons of the esterified wood hydroxyl groups. This specific coupling pathway requires a covalent bonding as a conditio sine qua non. An even more rapid test to monitor the covalent bonding was achieved with an up-to-date diffusion-ordered spectroscopy sequence (Oneshot-DOSY) based on 1H or 19F as the sensitive nucleus. The control experiment in a series of DOSY spectra gave a by far higher D value of (1.22 ± 0.06)∙10-10 m2∙s-1, which is in accordance with fast diffusion of the "free" and thus rapidly moving small precursor molecule provided as its methyl ester. In the case of a covalent attachment to wood, a significantly smaller D value of (0.12 ± 0.01)∙10-10 m2∙s-1 was obtained.
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Affiliation(s)
| | | | - Dieter E. Kaufmann
- Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstr. 6, 38678 Clausthal-Zellerfeld, Germany; (J.C.N.); (M.H.H.D.)
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6
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Coote P, Bermel W, Arthanari H. Optimization of phase dispersion enables broadband excitation without homonuclear coupling artifacts. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 325:106928. [PMID: 33652210 PMCID: PMC8012116 DOI: 10.1016/j.jmr.2021.106928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
In NMR spectroscopy, many specialized shaped pulses are available for broadband excitation, beyond the bandwidth of conventional high-powered hard pulses. These shaped pulses typically have long duration. However, long-duration pulses are unsuitable for spectra containing significant homonuclear couplings, such as polyfluorinated compounds in 19F NMR. J-coupling evolution during the excitation pulse leads to spectral artifacts and incorrect peak integrals. Here, we report an approach to optimal control pulse design which significantly reduces the pulse length required to excite large bandwidths of chemical shift frequencies. The target state phase is not chosen beforehand but is instead only constrained to be linearly dependent on offset frequency. The first-order phase of the target state is then treated as a free-variable, to be optimized at the same time as the RF waveform itself. The resulting spectra are easily phased using standard NMR processing software. We observe that the required pulse length is significantly shorter than for currently available in-phase excitation schemes. Spectral artifacts from homonuclear couplings are avoided. We also demonstrate that pure in-phase excitation can be obtained over the same bandwidth by appending two inversion pulses, at the expense of increased overall duration.
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Affiliation(s)
- Paul Coote
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Dana Farber Cancer Institute, Boston, MA, USA
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Dana Farber Cancer Institute, Boston, MA, USA.
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7
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Verstraete JB, Myers WK, Foroozandeh M. Chirped ordered pulses for ultra-broadband ESR spectroscopy. J Chem Phys 2021; 154:094201. [PMID: 33685137 DOI: 10.1063/5.0038511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recently, applications of swept-frequency pulses proved to be a useful approach to circumvent the problem of limited excitation bandwidth in pulsed ESR posed by conventional pulses. Here, we present a chirped excitation sequence, CHirped ORdered pulses for Ultra-broadband Spectroscopy (CHORUS), for ultra-broadband ESR spectroscopy. It will be demonstrated that the application of this sequence can address the problems of excitation non-uniformity and sensitivity to instrumental instabilities to a greater extent compared to the current state of the art. This sequence is highly promising for finding applications beyond single excitation in many ESR experiments. Theoretical and experimental results for the proposed method are presented along with calibration strategies for experimental implementation.
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Affiliation(s)
- Jean-Baptiste Verstraete
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - William K Myers
- Centre for Advanced ESR, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | - Mohammadali Foroozandeh
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
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8
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Dal Poggetto G, Soares JV, Tormena CF. Selective Nuclear Magnetic Resonance Experiments for Sign-Sensitive Determination of Heteronuclear Couplings: Expanding the Analysis of Crude Reaction Mixtures. Anal Chem 2020; 92:14047-14053. [PMID: 32924438 PMCID: PMC7660590 DOI: 10.1021/acs.analchem.0c02976] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
State-of-the-art nuclear magnetic resonance (NMR) selective experiments are capable of directly analyzing crude reaction mixtures. A new experiment named HD-HAPPY-FESTA yields ultrahigh-resolution total correlation subspectra, which are suitable for sign-sensitive determination of heteronuclear couplings, as demonstrated here by measuring the sign and magnitude for proton-fluorine couplings (JHF) from major and minor isomer products of a two-step reaction without any purification. Proton-fluorine couplings ranging from 51.5 to -2.6 Hz could be measured using HD-HAPPY-FESTA, with the smallest measured magnitude of 0.8 Hz. Experimental JHF values were used to identify the two fluoroketone intermediates and the four fluoroalcohol products. Results were rationalized and compared with the density functional theory (DFT) calculations. Experimental data were further compared with the couplings reported in the literature, where pure samples were analyzed.
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Affiliation(s)
- Guilherme Dal Poggetto
- Institute of Chemistry, University of Campinas (UNICAMP), PO BOX 6154, Campinas, São Paulo CEP 13083-970, Brazil
| | - João Vitor Soares
- Institute of Chemistry, University of Campinas (UNICAMP), PO BOX 6154, Campinas, São Paulo CEP 13083-970, Brazil
| | - Cláudio F Tormena
- Institute of Chemistry, University of Campinas (UNICAMP), PO BOX 6154, Campinas, São Paulo CEP 13083-970, Brazil
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9
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Foroozandeh M. Spin dynamics during chirped pulses: applications to homonuclear decoupling and broadband excitation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 318:106768. [PMID: 32917298 DOI: 10.1016/j.jmr.2020.106768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/27/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Swept-frequency pulses have found applications in a wide range of areas including spectroscopic techniques where efficient control of spins is required. For many of these applications, a good understanding of the evolution of spin systems during these pulses plays a vital role, not only in describing the mechanism of techniques, but also in enabling new methodologies. In magnetic resonance spectroscopy, broadband inversion, refocusing, and excitation using these pulses are among the most used applications in NMR, ESR, MRI, and in vivo MRS. In the present survey, a general expression for chirped pulses will be introduced, and some numerical approaches to calculate the spin dynamics during chirped pulses via solutions of the well-known Liouville-von Neumann equation and the lesser-explored Wei-Norman Lie algebra along with comprehensive examples are presented. In both cases, spin state trajectories are calculated using the solution of differential equations. Additionally, applications of the proposed methods to study the spin dynamics during the PSYCHE pulse element for broadband homonuclear decoupling and the CHORUS sequence for broadband excitation will be presented.
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10
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Howe PWA. Recent developments in the use of fluorine NMR in synthesis and characterisation. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 118-119:1-9. [PMID: 32883447 DOI: 10.1016/j.pnmrs.2020.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 06/11/2023]
Abstract
A review of developments in fluorine NMR of relevance to synthesis, characterisation and industrial applications of small organic molecules. Developments considered include those in spectrometer technology, computational methods and pulse sequences. The review of 80 references outlines applications in areas of identification, quantitation, mixture analysis, reaction monitoring, environmental studies and fragment-based drug design.
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Affiliation(s)
- Peter W A Howe
- Syngenta, Jealott's Hill Research Centre, Bracknell, Berkshire RG42 6EY, UK.
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11
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Evans R. The interpretation of small molecule diffusion coefficients: Quantitative use of diffusion-ordered NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:33-69. [PMID: 32471534 DOI: 10.1016/j.pnmrs.2019.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 06/11/2023]
Abstract
Measuring accurate molecular self-diffusion coefficients, D, by nuclear magnetic resonance (NMR) techniques has become routine as hardware, software and experimental methodologies have all improved. However, the quantitative interpretation of such data remains difficult, particularly for small molecules. This review article first provides a description of, and explanation for, the failure of the Stokes-Einstein equation to accurately predict small molecule diffusion coefficients, before moving on to three broadly complementary methods for their quantitative interpretation. Two are based on power laws, but differ in the nature of the reference molecules used. The third addresses the uncertainties in the Stokes-Einstein equation directly. For all three methods, a wide range of examples are used to show the range of chemistry to which diffusion NMR can be applied, and how best to implement the different methods to obtain quantitative information from the chemical systems studied.
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Affiliation(s)
- Robert Evans
- Aston Institute of Materials Research, School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, United Kingdom.
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12
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Day IJ. Matrix-assisted DOSY. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:1-18. [PMID: 32130955 DOI: 10.1016/j.pnmrs.2019.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/30/2019] [Accepted: 09/01/2019] [Indexed: 06/10/2023]
Abstract
The analysis of mixtures by NMR spectroscopy is challenging. Diffusion-ordered NMR spectroscopy enables a pseudo-separation of species based on differences in their translational diffusion coefficients. Under the right circumstances, this is a powerful technique; however, when molecules diffuse at similar rates separation in the diffusion dimension can be poor. In addition, spectral overlap also limits resolution and can make interpretation challenging. Matrix-assisted diffusion NMR seeks to improve resolution in the diffusion dimension by utilising the differential interaction of components in the mixture with an additive to the solvent. Tuning these matrix-analyte interactions allows the diffusion resolution to be optimised. This review presents the background to matrix-assisted diffusion experiments, surveys the wide range of matrices employed, including chromatographic stationary phases, surfactants and polymers, and demonstrates the current state of the art.
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Affiliation(s)
- Iain J Day
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, UK.
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13
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Foroozandeh M, Nilsson M, Morris GA. Improved ultra-broadband chirp excitation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 302:28-33. [PMID: 30939336 DOI: 10.1016/j.jmr.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/20/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
The design and application of ultra-broadband excitation pulses have been among the most interesting and timely areas in NMR and EPR methodology in recent years, due especially to advances in hardware design in EPR, the advent and popularity of high- and ultrahigh-field NMR, and the application of numerical methods like optimal control theory to the design and optimization of radiofrequency pulses and pulse sequences. In this communication, we present a short, robust, and flexible version of the CHORUS family of constant-phase, very broadband excitation sequences. We demonstrate that more than 0.5 MHz excitation with uniform amplitudes and phases can be achieved with this excitation sequence.
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Affiliation(s)
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gareth A Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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14
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Nieland E, Topornicki T, Kunde T, Schmidt BM. [2+2] Halogen-bonded boxes employing azobenzenes. Chem Commun (Camb) 2019; 55:8768-8771. [DOI: 10.1039/c9cc03061a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Herein, we report the synthesis and crystal structures of three [2+2] supramolecular boxes assembled by halogen bonding.
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Affiliation(s)
- Esther Nieland
- Institut für Organische Chemie und Makromolekulare Chemie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Thomas Topornicki
- Institut für Organische Chemie und Makromolekulare Chemie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Tom Kunde
- Institut für Organische Chemie und Makromolekulare Chemie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Bernd M. Schmidt
- Institut für Organische Chemie und Makromolekulare Chemie
- Heinrich-Heine-Universität Düsseldorf
- D-40225 Düsseldorf
- Germany
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15
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Dal Poggetto G, Castañar L, Foroozandeh M, Kiraly P, Adams RW, Morris GA, Nilsson M. Unexploited Dimension: New Software for Mixture Analysis by 3D Diffusion-Ordered NMR Spectroscopy. Anal Chem 2018; 90:13695-13701. [DOI: 10.1021/acs.analchem.8b04093] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guilherme Dal Poggetto
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Laura Castañar
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Mohammadali Foroozandeh
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Peter Kiraly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Ralph W. Adams
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Gareth A. Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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16
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Moutzouri P, Kiraly P, Foroozandeh M, Phillips AR, Coombes SR, Nilsson M, Morris GA. Suppression of 13C satellites in 1H DOSY spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 295:6-11. [PMID: 30081299 DOI: 10.1016/j.jmr.2018.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Diffusion-ordered spectroscopy (DOSY) is a valuable tool for the analysis of intact mixtures, since it can separate the signals of components according to their apparent diffusion coefficients. However, DOSY experiments are acutely sensitive to spectral quality, and especially to signal overlap, which can lead to misleading apparent diffusion coefficients. Here, we introduce a new NMR experiment to reduce signal overlap in mixtures with a wide range of concentrations, by removing one-bond 13C satellites. In such high dynamic range mixtures, 13C isotopomer signals from major components can overlap with signals from minor components, causing problematic distortions in the diffusion domain of a DOSY spectrum. The new method, Oneshot-iDISPEL, is a combination of the Oneshot and DISPEL experiments, and its performance has been demonstrated on a Greek alcoholic beverage, ouzo, which contains small amounts of anise flavour components and sucrose. Ethanol is a major component, and the suppression of its 13C satellites reduces signal overlap with minor components, offering significant improvement in DOSY spectra.
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Affiliation(s)
- Pinelopi Moutzouri
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Peter Kiraly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | | | - Andrew R Phillips
- Early Product Development, Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield SK10 2NA, UK
| | - Steven R Coombes
- Pharmaceutical Technology and Development, AstraZeneca, Silk Road Business Park, Macclesfield SK10 2NA, UK
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gareth A Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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17
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Castañar L, Moutzouri P, Barbosa TM, Tormena CF, Rittner R, Phillips AR, Coombes SR, Nilsson M, Morris GA. FESTA: An Efficient Nuclear Magnetic Resonance Approach for the Structural Analysis of Mixtures Containing Fluorinated Species. Anal Chem 2018; 90:5445-5450. [DOI: 10.1021/acs.analchem.8b00753] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Laura Castañar
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Pinelopi Moutzouri
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Thaís M. Barbosa
- Chemistry Institute, University of Campinas − UNICAMP, P.O. Box. 6154, 13083-970 Campinas, São Paulo, Brazil
| | - Claudio F. Tormena
- Chemistry Institute, University of Campinas − UNICAMP, P.O. Box. 6154, 13083-970 Campinas, São Paulo, Brazil
| | - Roberto Rittner
- Chemistry Institute, University of Campinas − UNICAMP, P.O. Box. 6154, 13083-970 Campinas, São Paulo, Brazil
| | - Andrew R. Phillips
- Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield SK10 2NA, United Kingdom
| | - Steven R. Coombes
- Pharmaceutical Technology and Development, AstraZeneca, Silk Road Business Park, Macclesfield SK10 2NA, United Kingdom
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Gareth A. Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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18
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Moutzouri P, Kiraly P, Phillips AR, Coombes SR, Nilsson M, Morris GA. 13C Satellite-Free 1H NMR Spectra. Anal Chem 2017; 89:11898-11901. [PMID: 29083868 DOI: 10.1021/acs.analchem.7b03787] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new NMR experiment (Destruction of Interfering Satellites by Perfect Echo Low-pass filtration, DISPEL) is introduced that facilitates the analysis of low-level components in high dynamic range mixtures by suppressing one-bond 13C satellite signals in 1H spectra. Since the natural abundance of 13C is around 1.1%, these satellites appear at 0.54% of the intensity of a parent peak, mimicking and often masking impurity signals. The new experiment suppresses one-bond 13C satellite signals, with high efficiency, at negligible cost in signal-to-noise ratio, and over a wide range of one-bond coupling constants, without the need for broadband 13C decoupling.
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Affiliation(s)
- Pinelopi Moutzouri
- School of Chemistry, University of Manchester , Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Peter Kiraly
- School of Chemistry, University of Manchester , Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Andrew R Phillips
- Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca , Silk Road Business Park, Macclesfield, SK10 2NA, United Kingdom
| | - Steven R Coombes
- Pharmaceutical Technology and Development, AstraZeneca , Silk Road Business Park, Macclesfield, SK10 2NA, United Kingdom
| | - Mathias Nilsson
- School of Chemistry, University of Manchester , Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Gareth A Morris
- School of Chemistry, University of Manchester , Oxford Road, Manchester, M13 9PL, United Kingdom
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19
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Mykhailiuk PK, Kishko I, Kubyshkin V, Budisa N, Cossy J. Selective19F-Labeling of Functionalized Carboxylic Acids with Difluoromethyl Diazomethane (CF2HCHN2). Chemistry 2017; 23:13279-13283. [DOI: 10.1002/chem.201703446] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Pavel K. Mykhailiuk
- Taras Shevchenko National University of Kyiv; Chemistry Department; Volodymyrska 64 01601 Kyiv Ukraine
| | - Igor Kishko
- Taras Shevchenko National University of Kyiv; Chemistry Department; Volodymyrska 64 01601 Kyiv Ukraine
- Enamine Ltd.; Chervonotkatska 78 02094 Kyiv Ukraine
| | - Vladimir Kubyshkin
- Institute of Chemistry; Technical University of Berlin; Müller-Breslau-Str., 10 10623 Berlin Germany
| | - Nediljko Budisa
- Institute of Chemistry; Technical University of Berlin; Müller-Breslau-Str., 10 10623 Berlin Germany
| | - Janine Cossy
- Laboratoire de Chimie Organique, Institute of Chemistry, Biology and Innovation (CBI); ESPCI Paris/ (UMR 8231) CNRS/PSL Research University; 10 rue Vauquelin Paris 75231 Cedex 05 France)
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20
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Pagès G, Gilard V, Martino R, Malet-Martino M. Pulsed-field gradient nuclear magnetic resonance measurements (PFG NMR) for diffusion ordered spectroscopy (DOSY) mapping. Analyst 2017; 142:3771-3796. [DOI: 10.1039/c7an01031a] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The advent of Diffusion Ordered SpectroscopY (DOSY) NMR has enabled diffusion coefficients to be routinely measured and used to characterize chemical systems in solution. Indeed, DOSY NMR allows the separation of the chemical entities present in multicomponent systems and provides information on their intermolecular interactions as well as on their size and shape.
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Affiliation(s)
- G. Pagès
- INRA
- AgroResonance – UR370 Qualité des Produits Animaux
- Saint Genès Champanelle
- France
| | - V. Gilard
- Groupe de RMN Biomédicale
- Laboratoire de Synthèse et Physicochimie de Molécules d'Intérêt Biologique
- UMR CNRS 5068
- Université de Toulouse
- 31062 Toulouse cedex 9
| | - R. Martino
- Groupe de RMN Biomédicale
- Laboratoire de Synthèse et Physicochimie de Molécules d'Intérêt Biologique
- UMR CNRS 5068
- Université de Toulouse
- 31062 Toulouse cedex 9
| | - M. Malet-Martino
- Groupe de RMN Biomédicale
- Laboratoire de Synthèse et Physicochimie de Molécules d'Intérêt Biologique
- UMR CNRS 5068
- Université de Toulouse
- 31062 Toulouse cedex 9
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21
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Moutzouri P, Kiraly P, Phillips AR, Coombes SR, Nilsson M, Morris GA. Clearing the undergrowth: detection and quantification of low level impurities using 19F NMR. Chem Commun (Camb) 2016; 53:123-125. [PMID: 27904900 DOI: 10.1039/c6cc08836h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new method for the analysis of low level impurities in sparsely fluorinated species allows measurement of clean high dynamic range 19F spectra, fully decoupled and free of interfering signals from 13C isotopomers.
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Affiliation(s)
- Pinelopi Moutzouri
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Peter Kiraly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Andrew R Phillips
- Pharmaceutical Sciences, AstraZeneca, Silk Road Business Park, Macclesfield, SK10 2NA, UK
| | - Steven R Coombes
- Pharmaceutical Technology and Development, AstraZeneca, Silk Road Business Park, Macclesfield, SK10 2NA, UK
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Gareth A Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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