scholarly journals Dudley Howard Williams. 25 May 1937 — 3 November 2010

2017 ◽  
Vol 63 ◽  
pp. 567-583
Author(s):  
Jeremy K. M. Sanders ◽  
Dame Carol V. Robinson

Dudley Williams was a pioneer in using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) to solve important structural problems in Chemistry and Biology. His 35-year quest to understand the structure and mode of action of the vancomycin antibiotics led him to fundamental thinking about the nature and thermodynamics of molecular recognition, in particular the roles of solvation, flexibility, entropy, enthalpy and cooperativity. He was always keen that his expertise be used for practical benefit through his academic research and industrial consulting. His legacy also includes a set of textbooks that transformed the use of spectroscopic methods in organic chemistry, and a school of former PhD students and postdoctoral colleagues who have themselves made major contributions across a broad swathe of science.

Author(s):  
Peter Atkins

Physical chemistry lies at the heart of one of chemistry's principal applications and achievements: the identification of the substances present in a sample and the determination of their abundances and structures. ‘Investigating matter’ considers how the laser and computer have elaborated and refined classical techniques. Various forms of investigative technique are explained including absorption spectroscopy and nuclear magnetic resonance. Mass spectrometry is widely used in organic chemistry to help identify compounds and photoelectron spectroscopy is used both to explore the energies with which electrons are bound inside molecules and to identify species on surfaces. The study of surfaces has been transformed by scanning tunnelling microscopy, which relies on quantum mechanics.


Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Daniel J. van de Pas ◽  
Bernadette Nanayakkara ◽  
Ian D. Suckling ◽  
Kirk M. Torr

Abstract Mild hydrogenolysis has been compared with thioacidolysis as a method for degrading lignins in situ and in isolated form before analysis by gas chromatography/mass spectrometry and quantitative 31P nuclear magnetic resonance (NMR) spectroscopy. Both degradation methods gave similar levels of β-aryl ether-linked phenylpropane units that were released as monomers. Degradation by hydrogenolysis generally gave lower levels of total phenylpropane units when analyzed by 31P NMR, especially in the case of lignins with high levels of condensed units. Overall, these results indicate that mild hydrogenolysis could offer an alternative to thioacidolysis for probing lignin structure.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3283
Author(s):  
Miriam Pérez-Trujillo ◽  
Toby J. Athersuch

Nuclear magnetic resonance (NMR) spectroscopy remains one of the core analytical platforms for metabolomics, providing complementary chemical information to others, such as mass spectrometry, and offering particular advantages in some areas of research on account of its inherent robustness, reproducibility, and phenomenal dynamic range [...]


1968 ◽  
Vol 22 (2) ◽  
pp. 115-120 ◽  
Author(s):  
R. W. Warren ◽  
Abraham Schneider ◽  
E. J. Janoski

A combination of gas chromatography, infrared and nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry was used to characterize the products obtained from aluminum halide-catalyzed isomerizations of tricyclic saturated hydrocarbons. Six compounds were isolated and identified as methyl and ethyl bridgehead-substituted adamantane derivatives. In addition to supplying evidence pertinent to the structural proof of these derivatives, the data provide useful correlations between infrared, NMR, and mass spectra and methyl and ethyl bridgehead substitution of the adamantane nucleus. A complex splitting pattern which was observed in the NMR spectra of the ethyl-substituted derivatives was shown to be due to the unique A2B3 splitting of the bridgehead-ethyl group.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
R. Mogana ◽  
K. Teng-Jin ◽  
C. Wiart

Bioassay guided fractionation of an ethanol extract of leaves ofCanarium patentinerviumMiq. (Burseraceae Kunth.) led to the isolation of scopoletin. The structure of this coumarin was elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D) and mass spectrometry. Scopoletin inhibited the enzymatic activity of 5-lipoxygenase and acetyl cholinesterase with an IC50equal to1.76±0.01 μM and0.27±0.02 mM, respectively, and confronted oxidation in the ABTS, DPPH, FRAP, andβ-carotene bleaching assay with EC50values equal to5.62±0.03 μM,0.19±0.01 mM,0.25±0.03 mM and0.65±0.07 mM, respectively. Given the aforementioned evidence, it is tempting to speculate that scopoletin represents an exciting scaffold from which to develop leads for treatment of neurodegenerative diseases.


2019 ◽  
Vol 5 (5) ◽  
pp. 19-24
Author(s):  
V. Shvannikov

The paper deals with the main components of NMR spectroscopy, namely: terminology (chemical shift, multiplicity, and so on) and some examples of software additions (COSY, HECTOR). The theme of this work is aimed at students in the profile of organic chemistry, it allows you to get acquainted with the phenomenon of NMR (in General terms) and decoding spectra without deepening into quantum chemistry and physics. This improves communication and minimizes misunderstandings between the synthetic chemist and the spectroscopic chemist, as this method is one of the most commonly used in determining the structure of organic matter (does not violate the integrity of the carbon skeleton and prevents fragmentation).


2021 ◽  
Author(s):  
◽  
Wem Turupadang

<p>Marine algae are an important and historically rich source of new marine-based natural products. This thesis describes the screening of 40 Indonesian macroalgal samples using liquid chromatography-mass spectrometry (LC-MS) based molecular networking, and the subsequent nuclear magnetic resonance (NMR)-guided isolation and structural elucidation of a 6-deoxy-6-aminoglycoglyrecolipid (60). Molecular networking was performed using LC-MS/MS data through the online Global Natural Product Social Molecular Networking (GNPS) platform directly from crude extracts. NMR spectroscopy-guided screening was also employed targeting unique peaks detected by 1H NMR to validate any hits from GNPS. Out of 40 macroalgae specimens collected from West Timor waters, six samples were prioritised by the molecular networking screening. Proton NMR revealed three specimens with significantly interesting peaks but only one specimen, Laurencia snackeyi was purified further, which yielded compound 60.</p>


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