One-dimensional nuclear magnetic resonance spectroscopy

I. J. Kosir, J. Kidric 2001, (Identification of amino acids in wines by one- and two-dimensional nuclear magnetic resonance spectroscopy), J. Agric. Food Chem. 49, 50—56. 

The structure and identity of such compounds that are of practical relevance as com-plexing agents may be elucidated unequivocally by both one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy of the isotopes H-l, C-13, and P-31. Sufficiently high concentrations also render possible their quantitative analysis [87-91]. However, because of the low sensitivity, especially of the phosphorus nucleus, problems are encountered with the limits of detection in practical applications. 

This well-rounded introduction features updated spectra, a modernizedpresentation of one-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy, the introduction of biological molecules in mass spectrometry, and inclusion of modern techniques alongside DEPT, COSY, and HECTOR. Count on this book s exceptional presentation to provide the comprehensive coverage needed to truly understand today s spectroscopic techniques. 

The structures of vanicosides A (1) and B (2) and hydropiperoside (3) were established primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy techniques and fast atom bombardment (FAB) mass spectrometry (MS).22 The presence of two different types of phenylpropanoid esters in 1 and 2 was established first through the proton (4H) NMR spectra which showed resonances for two different aromatic substitution patterns in the spectrum of each compound. Integration of the aromatic region defined these as three symmetrically substituted phenyl rings, due to three p-coumaryl moieties, and one 1,3,4-trisubstituted phenyl ring, due to a feruloyl ester. The presence of a sucrose backbone was established by two series of coupled protons between 3.2 and 5.7 ppm in the HNMR spectra, particularly the characteristic C-l (anomeric) and C-3 proton doublets... 

Buddrus, J., Burba, P., Herzog, H., and Lambert, J. (1989). Quantitation of partial structures of aquatic humic substances by one-dimensional and two-dimensional solution 13C nuclear magnetic-resonance spectroscopy Anal. Chem. 61, 628-631. 

Dugat, D., Gramain, J.-C., and Dauphin, G. (1990) Structure, stereochemistry, and conformation of diastereoisomeric cis- and trons-3-ethyl-l,2,3,4,4a,9a-hexa-hydrocarbazol-4-ones by means of 13C and two-dimensional JH nuclear magnetic resonance spectroscopy. An example of diastereoselection in a photocyclisation reaction. Journal of the Chemical Society, Perkin Transactions 2, 605-611. 

Reprinted with permission from Buddrus et al. Quantitation of Partial Structures of Aquatic Humic Substances by One- and Two-Dimensional Solution Nuclear Magnetic Resonance Spectroscopy," Anal. Chem. 61, 628-631. Copyright 1989, American Chemical Society. 

As a qualitative means to investigate the ionic nature of acid-base systems, various techniques have been employed such as one- or two-dimensional nuclear magnetic resonance (NMR) spectroscopy [31], infrared (IR) spectroscopy [32], the Walden plot [33], the ratio of molar conductivities AjmpMNMR (determined by electrochemical impedance spectroscopy and pulse-field-gradient spin-echo NMR, respectively) [34], Some of these will be discussed below. 

Nuclear Magnetic Resonance Spectroscopy Part Four Other Topics in One-Dimensional NMR... 

Generally, the most powerful method for stmctural elucidation of steroids is nuclear magnetic resonance (nmr) spectroscopy. There are several classical reviews on the one-dimensional (1-D) proton H-nmr spectroscopy of steroids (267). C-nmr, a technique used to observe individual carbons, is used for stmcture elucidation of steroids. In addition, C-nmr is used for biosynthesis experiments with C-enriched precursors (268). The availability of higher magnetic field instmments coupled with the arrival of 1-D and two-dimensional (2-D) techniques such as DEPT, COSY, NOESY, 2-D J-resolved, HOHAHA, etc, have provided powerful new tools for the stmctural elucidation of complex natural products including steroids (269). 

Porphyrin is a multi-detectable molecule, that is, a number of its properties are detectable by many physical methods. Not only the most popular nuclear magnetic resonance and light absorption and emission spectroscopic methods, but also the electron spin resonance method for paramagnetic metallopor-phyrins and Mossbauer spectroscopy for iron and tin porphyrins are frequently used to estimate the electronic structure of porphyrins. By using these multi-detectable properties of the porphyrins of CPOs, a novel physical phenomenon is expected to be found. In particular, the topology of the cyclic shape is an ideal one-dimensional state of the materials used in quantum physics [ 16]. The concept of aromaticity found in fuUerenes, spherical aromaticity, will be revised using TT-conjugated CPOs [17]. 

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