Progress in Our Understanding of 19F Chemical Shifts
Dahanayake, Jayangika Niroshani
Karnes, Joseph P.
Steinert, Ryan M.
Hull, Olivia A.
Ellis, Jonathan M.
Mitchell-Koch, Katie R.
MetadataShow full item record
Dahanayake, Jayangika & Kasireddy, Chandana & Karnes, Joseph & Verma, Rajni & M. Steinert, Ryan & Hildebrandt, Derek & Hull, Olivia & Ellis, Jonathan & Mitchell-Koch, Katie. (2017). Progress in Our Understanding of 19 F Chemical Shifts. Annual Reports on NMR Spectroscopy. 10.1016/bs.arnmr.2017.08.002.
Fluorine NMR spectroscopy has diverse applications, including characterization of chemical reaction mechanisms, protein structure-function studies, and solid-state NMR characterization of crystalline, amorphous, and soft materials. Computational methods have aided in assigning and interpreting chemical shifts, with wide use in solid-state NMR spectroscopy. Work to understand fluorine chemical shifts has been aided by computational methods. So-called "normal" chemical shift behaviour can be understood to arise from ground-state electron density, in which diamagnetic or Lamb shielding dominates. Meanwhile, electronic structure methods indicate that many instances of "reverse" chemical shift behaviour can be understood to be dominated by paramagnetic shielding effects, which arise from the coupling of occupied and unoccupied molecular orbitals in the presence of a magnetic field. Calculations using natural chemical shielding analysis are used to delineate contributions from diamagnetic and paramagnetic shielding of fluorine nuclei in a set of aromatic molecules and aliphatic compounds, some of which exhibit reverse chemical shift behaviour. An overview of recent advances to assign and interpret chemical shifts in complex environments is presented.
Click on the DOI link to access the article (may not be free).
Showing items related by title, author, creator and subject.
Demystifying fluorine chemical shifts: electronic structure calculations address origins of seemingly anomalous F-19-NMR spectra of fluorohistidine isomers and analogues Kasireddy, Chandana; Bann, James G.; Mitchell-Koch, Katie R. (Royal Society of Chemistry, 2015-10-23)Fluorine NMR spectroscopy is a powerful tool for studying biomolecular structure, dynamics, and ligand binding, yet the origins of F-19 chemical shifts are not well understood. Herein, we use electronic structure calculations ...
Mechanical properties improvement of polymeric nanocomposites reinforced with chemically treated helical carbon nanotubes: Influence of sonication time and molarities of nitric-sulfuric-hydrochloric acids Sritharan, Ramanan; Taklimi, Sean Reza; Ghazinezami, Ali; Askari, Davood (Composites and Advanced Materials Expo (CAMX), 2018-10)Polymer-based composites are widely used for structural applications, predominantly in the aerospace and renewable energy industries. One of the main disadvantages is their failure/delamination due to interlaminar strength ...
From the color-magnitude diagram of omega centauri and (super-) asymptotic giant branch stellar models to a galactic plane passage gas purging chemical evolution scenario Herwig, Falk; VandenBerg, Don A.; Navarro, Julio F.; Ferguson, Jason W.; Paxton, Bill (IOP Publishing, 2012-10-01)We have investigated the color-magnitude diagram of omega Centauri and find that the blue main sequence (bMS) can be reproduced only by models that have a helium abundance in the range Y = 0.35-0.40. To explain the faint ...