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Mycroft C, Smith MJ, Nilsson M, Morris GA, Castañar L. Pure shift FESTA: An ultra-high resolution NMR tool for the analysis of complex fluorine-containing spin systems. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:606-614. [PMID: 37688573 DOI: 10.1002/mrc.5393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 09/11/2023]
Abstract
NMR measurements of molecules containing sparse fluorine atoms are becoming increasingly common due to their prevalence in medicinal chemistry. However, the presence of both homonuclear and heteronuclear scalar couplings severely complicates their analysis by NMR. In complex systems, FESTA, a heteronuclear spectral editing method, allows simplified 1 H NMR spectra to be obtained containing only 1 H signals from the same spin system as a chosen 19 F. Despite spectral simplification, signal overlap due to the presence of scalar couplings is often a problem in FESTA spectra. Here, we report a new experiment that combines FESTA and pure shift methods to provide fully decoupled ultra-high resolution FESTA spectra showing a single signal for each 1 H chemical environment. The utility of the method is demonstrated for the analysis of two complex fluorine-containing mixtures of pharmaceutical and biochemical interest.
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Affiliation(s)
- Coral Mycroft
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Marshall J Smith
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Mathias Nilsson
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Gareth A Morris
- Department of Chemistry, University of Manchester, Manchester, UK
| | - Laura Castañar
- Department of Chemistry, University of Manchester, Manchester, UK
- Department of Organic Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Madrid, Spain
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2
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Mycroft C, Dal Poggetto G, Barbosa TM, Tormena C, Nilsson M, Morris GA, Castañar L. Rapid Measurement of Heteronuclear Coupling Constants in Complex NMR Spectra. J Am Chem Soc 2023; 145:19824-19831. [PMID: 37650656 PMCID: PMC10510310 DOI: 10.1021/jacs.3c05515] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Indexed: 09/01/2023]
Abstract
The NMR analysis of fluorine-containing molecules, increasingly widespread due to their importance in pharmaceuticals and biochemistry, poses significant challenges. Severe peak overlap in the proton spectrum often hinders the extraction of critical structural information in the form of heteronuclear scalar coupling constants, which are crucial for determining pharmaceutical properties and biological activity. Here, a new method, IPAP-FESTA, is reported that drastically simplifies measurements of the signs and magnitudes of proton-fluorine couplings. Its usefulness is demonstrated for the structural study of the steroidal drug fluticasone propionate extracted from a commercial formulation and for assessing solvent effects on the conformational equilibrium in a physically inseparable fluorohydrin mixture.
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Affiliation(s)
- Coral Mycroft
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United
Kingdom
| | - Guilherme Dal Poggetto
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
- Analytical
Research & Development, Merck &
Co., Inc., 126 Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Thaís M. Barbosa
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
- Nanalysis
Corp., 1-4600 5 Street NE, Calgary, Alberta, Canada T2E 7C3
| | - Cláudio
F. Tormena
- Chemistry
Institute, University of Campinas −
UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
| | - Mathias Nilsson
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Gareth A. Morris
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Laura Castañar
- Department
of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Department
of Organic Chemistry, Faculty of Chemical Science, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
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3
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Mishra SK, Suryaprakash N. Pure shift edited NMR methodologies for the extraction of Homo- and heteronuclear couplings with ultra-high resolution. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 136-137:1-60. [PMID: 37716754 DOI: 10.1016/j.pnmrs.2023.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 01/20/2023] [Accepted: 02/01/2023] [Indexed: 09/18/2023]
Abstract
The scalar couplings that result in the splitting of the signals in the NMR spectrum arise due to the interaction of the nuclear spins, whereby the spin polarization is transmitted through chemical bonds. The interaction strengths depend inter alia on the number of consecutive chemical bonds intervening between the two interacting spins and on the molecular conformation. The pairwise interaction of many spins in a molecule resulting in a complex spectrum poses a severe challenge to analyse the spectrum and hence the determination of magnitudes and signs of homo- and heteronuclear couplings. The problem is more severe in the analysis of 1H spectra than the spectra of most of the other nuclei due to the often very small chemical shift dispersion. As a consequence, the straightforward analysis and the accurate extraction of the coupling constants from the 1H spectrum of a complex spin system continues to remain a challenge, and often may be a formidable task. Over the years, the several pure shift-based one-dimensional and two-dimensional methodologies have been developed by workers in the field, which provide broadband homonuclear decoupling of proton spectra, removing the complexity but at the cost of the very informative scalar couplings. To circumvent this problem, several one-dimensional and two-dimensional NMR experiments have been developed for the determination of homonuclear and heteronuclear couplings (nJHX, where n = 1,2,3) while retaining the high resolution obtained by implementing pure shift strategies. This review attempts to summarize the extensive work reported by a large number of researchers over the years for the accurate determination of homo- and heteronuclear scalar couplings.
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Affiliation(s)
- Sandeep Kumar Mishra
- Department of Physics and NMR Research Centre, Indian Institute of Science Education and Research, Pune 411008, India.
| | - N Suryaprakash
- NMR Research Centre and Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India.
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Mycroft C, Nilsson M, Morris GA, Castañar L. Simultaneous Broadband Suppression of Homonuclear and Heteronuclear Couplings in 1 H NMR Spectroscopy. Chemphyschem 2022; 23:e202200495. [PMID: 35994208 PMCID: PMC10099583 DOI: 10.1002/cphc.202200495] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/16/2022] [Indexed: 01/05/2023]
Abstract
The 1 H NMR analysis of species containing NMR-active heteronuclei can be difficult due to signal overlap caused by the combined effects of homonuclear and heteronuclear scalar (J) couplings. Here, a general pure shift method is presented for obtaining ultra-high resolution 1 H NMR spectra where spectral overlap is drastically reduced by suppressing both homonuclear and heteronuclear J-couplings, giving one single signal per 1 H chemical environment. Its usefulness is demonstrated in the analysis of fluorine- and phosphorus-containing compounds of pharmaceutical and biochemical interest.
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Affiliation(s)
- Coral Mycroft
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Mathias Nilsson
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Gareth A Morris
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
| | - Laura Castañar
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
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5
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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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Lin Y, Zeng Q, Lin L, Chen Z, Barker PB. High-resolution methods for the measurement of scalar coupling constants. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:135-159. [PMID: 30527134 DOI: 10.1016/j.pnmrs.2018.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 06/09/2023]
Abstract
Scalar couplings provide important information regarding molecular structure and dynamics. The measurement of scalar coupling constants constitutes a topic of interest and significance in NMR spectroscopy. However, the measurement of J values is often not straightforward because of complex signal splitting patterns and signal overlap. Many methods have been proposed for the measurement of scalar coupling constants, both for homonuclear and heteronuclear cases. Different approaches to the measurement of scalar coupling constants are reviewed here with several applications presented. The accurate measurement of scalar coupling constants can greatly facilitate molecular structure elucidation and the study of molecule dynamics.
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Affiliation(s)
- Yanqin Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China.
| | - Qing Zeng
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Liangjie Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Peter B Barker
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F. M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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7
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Dumez JN. Spatial encoding and spatial selection methods in high-resolution NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:101-134. [PMID: 30527133 DOI: 10.1016/j.pnmrs.2018.08.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
A family of high-resolution NMR methods share the common concept of acquiring in parallel different sub-experiments in different spatial regions of the NMR tube. These spatial encoding and spatial selection methods were for the most part introduced independently from each other and serve different purposes, but they share common ingredients, often derived from magnetic resonance imaging, and they all benefit from a greatly improved time-efficiency. This review article provides a description of several spatial encoding and spatial selection methods, including single-scan multidimensional experiments (ultrafast 2D NMR, DOSY, Z spectroscopy, inversion recovery and Laplace NMR), pure shift and selective refocusing experiments (including Zangger-Sterk decoupling, G-SERF and PSYCHE), a Z filter, and fast-pulsing slice-selective experiments. Some key elements for spatial parallelisation are introduced and when possible a common framework is used for the analysis of each method. Sensitivity considerations are discussed, and a selection of applications is analysed to illustrate which questions can be answered thanks to spatial encoding and spatial selection methods, and discuss the perspectives for future developments and applications.
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Affiliation(s)
- Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Univ. Paris Sud, Université Paris-Saclay, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
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8
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Mishra SK, Suryaprakash N. Orchestrated approaches using pure shift NMR: Extraction of spectral parameters, ultra-high resolution, and sensitivity enhancement. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:893-909. [PMID: 29230870 DOI: 10.1002/mrc.4696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 06/07/2023]
Abstract
The limited chemical shift range of protons and pairwise interaction among all the abundant nuclear spins of a molecule makes 1 H spectrum too complicated. As a consequence, the straightforward analysis and the accurate extraction of their interaction strengths from the 1 H spectrum of a complex spin system are formidably difficult or often impossible. This problem persists in the determination of scalar couplings be it between two abundant homonuclear spins or between 1 H and an abundant heteronuclear spin (viz., 19 F and 31 P). Such problems are encountered in many situations where the determination of homonuclear and heteronuclear couplings is challenging. The several pure shift based one-dimensional and two-dimensional NMR strategies recently developed in our laboratory for the straightforward extraction of homonuclear and heteronuclear interaction parameters in diverse situations are discussed. Initially, the unique application of pure shift technique that paves the way for easy and straightforward extraction of magnitudes of heteronuclear couplings, namely, n JHX (where X stands for 19 F, 31 P, etc.), is discussed. Subsequently, several pure shift edited one-dimensional and two-dimensional NMR strategies that are developed for the direct extraction of homonuclear and heteronuclear couplings and for achieving ultra-high-resolved 1 H spectra with complete eradication of zero frequency peaks and the evolution of unwanted couplings. The enhancement in the sensitivity has also been achieved in the slice-selective pure shift experiments by the rapid acquisition of proton spectrum where the polarization from the adjacent protons is transferred to the selectively excited proton.
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Affiliation(s)
- Sandeep Kumar Mishra
- NMR Research Centre, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India
| | - N Suryaprakash
- NMR Research Centre, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, 560012, India
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Kakita VMR, Rachineni K, Hosur RV. Fast and simultaneous determination of 1 H- 1 H and 1 H- 19 F scalar couplings in complex spin systems: Application of PSYCHE homonuclear broadband decoupling. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:1043-1046. [PMID: 28731512 DOI: 10.1002/mrc.4635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 06/07/2023]
Abstract
The present manuscript focuses on fast and simultaneous determination of 1 H-1 H and 1 H-19 F scalar couplings in fluorinated complex steroid molecules. Incorporation of broadband PSYCHE homonuclear decoupling in the indirect dimension of zero-quantum filtered diagonal experiments (F1-PSYCHE-DIAG) suppresses 1 H-1 H scalar couplings; however, it retains 1 H-19 F scalar couplings (along F1 dimension) for the 19 F coupled protons while preserving the pure-shift nature for 1 H resonances uncoupled to 19 F. In such cases, along the direct dimensions, 1 H-1 H scalar coupling multiplets deconvolute and they appear as duplicated multiplets for the 19 F coupled protons, which facilitates unambiguous discrimination of 19 F coupled 1 H chemical sites from the others. Further, as an added advantage, data acquisition has been accelerated by invoking the known ideas of spectral aliasing in the F1-PSYCHE-DIAG scheme and experiments demand only ~10 min of spectrometer times.
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Affiliation(s)
- Veera Mohana Rao Kakita
- UM-DAE-Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Santa Cruz, Mumbai, 400 098, India
| | - Kavitha Rachineni
- UM-DAE-Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Santa Cruz, Mumbai, 400 098, India
| | - Ramakrishna V Hosur
- UM-DAE-Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Santa Cruz, Mumbai, 400 098, India
- Department of Chemical Sciences, Tata Institute of Fundamental Research (TIFR), 1-Homi Bhabha Road, Colaba, Mumbai, 400 005, India
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10
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Berger S. A quarter of a century of SERF: The progress of an NMR pulse sequence and its application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 108:74-114. [PMID: 30538049 DOI: 10.1016/j.pnmrs.2018.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 06/09/2023]
Abstract
SERF, an NMR pulse sequence for selectively measuring a spin coupling constant without interference from other couplings, was published by the current author almost 25 years ago in 1995. Since then, about 35 modifications and extensions of the original have been published by other groups and applied to many chemical problems. This review discusses these modifications and provides pertinent examples. A comparative and critical evaluation of these developments is given in tabular form. The last part focuses on the chemical results.
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Affiliation(s)
- Stefan Berger
- Institute of Analytical Chemistry, University Leipzig, Johannisallee 29, D-04103 Leipzig, Germany.
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11
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Buchberger K, Walenta M, Zangger K. Extracting unresolved coupling constants from complex multiplets by a real-time J-upscaled SERF experiment. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:934-940. [PMID: 29240255 PMCID: PMC6175170 DOI: 10.1002/mrc.4699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 05/08/2023]
Abstract
The measurement of small homonuclear coupling constants is often prevented by either their small size and/or overlap with other signal splittings. Here, we present a real-time method to extract such couplings without interference from other splittings, with a resolution that is beyond conventional NMR spectra. In this real-time J-upscaled SERF experiment, homonuclear coupling is removed by slice-selective pure shift NMR, whereas scalar coupling to only one selected signal is reintroduced by selective refocusing. The remaining couplings are enhanced by real-time J-upscaling during interruptions of the FID data acquisition. The resulting spectrum is not only simplified by the restriction of the scalar coupling but also its resolution enhanced. This improved resolution results from a reduction of signal broadening due to magnetic field inhomogeneities from 2 different sources: slice-selective excitation and the spin-echo type J-upscaling element.
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Affiliation(s)
- Kathrin Buchberger
- Institute of Chemistry/Organic and Bioorganic ChemistryUniversity of GrazHeinrichstrasse 28A‐8010GrazAustria
| | - Martin Walenta
- Institute of Chemistry/Organic and Bioorganic ChemistryUniversity of GrazHeinrichstrasse 28A‐8010GrazAustria
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic ChemistryUniversity of GrazHeinrichstrasse 28A‐8010GrazAustria
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Parella T. Current developments in homonuclear and heteronuclear J-resolved NMR experiments. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:230-250. [PMID: 29314247 DOI: 10.1002/mrc.4706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
Two-dimensional J-resolved (Jres) NMR experiments offer a simple, user-friendly spectral representation where the information of coupling constants and chemical shifts are separated into two orthogonal frequency axis. Since its initial proposal 40 years ago, Jres has been the focus of considerable interest both in improving the basic pulse sequence and in its successful application to a wide range of studies. Here, the latest developments in the design of novel Jres pulse schemes are reviewed, mainly focusing on obtaining pure absorption lineshapes, minimizing strong coupling artifacts, and also optimizing sensitivity and experimental measurements. A discussion of several Jres versions for the accurate measurement of a different number of homonuclear (JHH ) and heteronuclear (JCH ) coupling constants is presented, accompanied by some illustrative examples.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
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