Computational NMR of charged systems

Abstract

This review covers NMR computational aspects of charged systemscarbocations, heterocations, and heteroanions, which were extensively studied in a number of laboratories worldwide, first of all, at the Loker Hydrocarbon Research Institute in California directed for several decades by a distinguished scientist, the Nobel laureate George Andrew Olah. The first part of the review briefly outlines computational background of the modern theoretical methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the historical results, advances, and perspectives of the computational NMR of classical carbocations like methyl cation, CH 3 + , and protonated methane, CH 5 + , together with their numerous homologs and derivatives. The third and the forth parts of this survey are focused on the NMR computational aspects of accordingly, heterocations and heteroanions, the organic and inorganic ions with a charge localized mainly on heteroatoms like boron, oxygen, nitrogen, and heavier elements.

Gefapixant Citrate (MK-7264) Sulfonamide Step Speciation Study: Investigation into Precipitation–Dissolution Events during Addition of Chlorosulfonic Acid

“…Although chemical shift calculations are most commonly done by comparing with NMR data for compounds dissolved in deuterated chloroform (CDCl 3 ), accurate predictions have also been reported for compounds dissolved in CD 3 CN, CD 3 OD, CD 2 Cl 2 , and DMSO- d 6 . Importantly, computational chemistry applied to NMR of charged compounds was recently reviewed by Krividin . In addition, we found good prediction accuracy for assigning δ C signals of highly polar, charged carbapenems dissolved in D 2 O …”

“…7 Importantly, computational chemistry applied to NMR of charged compounds was recently reviewed by Krividin. 8 In addition, we found good prediction accuracy for assigning δ C signals of highly polar, charged carbapenems dissolved in D 2 O. 9 To ascertain the protonation states of the various diaminopyridine 1 species, test structures were initially proposed based on the observed two-dimensional (2D) NMR correlations from the COSY, HSQC, and HMBC spectra as well as the measured scalar coupling constants (see the Supporting Information).…”

Tritium NMR: A compilation of data and a practical guide

“…Expanded regions of (a) 1 H NMR, (b) proton-coupled 3 H NMR, and (c) proton decoupled 3 H NMR spectra of (S)-10-bromoacetamidomethylcamptothecin in DMSO-d 6 recorded at 400 and 426 MHz for proton and tritium NMR, respectively. Reproduced with minor editing privilege from Shu et al [33] with the permission of John Wiley and Sons possesses a rather unique azaspiro [4,5]decane-7,9-dione structural moiety. This spectrum documents the exclusive tritium labeling of the product in the central methylene groups of the alkyl chain.…”

“…In continuation of our recent survey of computational and experimental NMR of the magnetic isotopes of chemical elements across three small periods of Periodic Table—hydrogen, [ 1–3 ] lithium, [ 4 ] boron, [ 5 ] carbon, [ 6–9 ] the latter dealing in particular with natural products [ 10 ] and carbohydrates, [ 11 ] nitrogen, [ 12 ] fluorine, [ 13 ] silicon, [ 14 ] and phosphorus [ 15,16 ] together with heavier p ‐elements—selenium, [ 17–19 ] tungsten, [ 20 ] tellurium, [ 17,18,20 ] thallium, [ 20 ] lead, [ 20 ] and d ‐elements—silver, [ 20 ] cadmium, [ 20 ] platinum, [ 20 ] and mercury, [ 20,21 ] in the present review we turn to tritium, the heaviest isotope of hydrogen.…”

Structural applications of the isotropic liquid‐phase deuterium nuclear magnetic resonance

“…The present review is written in continuation of our recent survey of the computational and experimental NMR of magnetic isotopes across three small periods, namely, hydrogen, 12–14 tritium, 15 helium, 16 lithium, 17 boron, 18 carbon, 19–24 nitrogen, 25 oxygen 26 fluorine, 27 silicon, 28 phosphorus, 29,30 and sulfur 31 together with selected heavier p ‐elements like selenium, 32–34 tungsten, 35 tellurium, 32,33,35 thallium, 35 and lead 35 together with most interesting d ‐elements involving silver, 35 cadmium, 35 platinum, 35 and mercury 35,36 …”