Computational protocols for calculating 13C NMR chemical shifts

Recent advances in computational 31P NMR: Part 1. Chemical shifts

“…Indeed, it requires evaluation of the parameters that are defined as the second and third derivatives of the electronic potential energy together with corresponding gradients and Hessians with respect to the Cartesian displacement coordinates. This aspect of chemical shift calculation is discussed in more detail in our recent review …”

“…Theoretical aspects of the calculation of nuclear magnetic resonance (NMR) parameters are thoroughly reviewed in a fundamental handbook of molecular electromagnetism by Stephan Sauer and in a number of related reviews on theoretical and computational aspects of NMR parameters, together with those evaluated on relativistic level . The present review covers computational aspects of 31 P NMR and is written in continuation of our four recent reviews published in Progress in NMR Spectroscopy and three reviews that appeared in Magnetic Resonance in Chemistry very recently dealing with computation of 1 H, 13 C, and 15 N NMR chemical shifts and spin–spin coupling constants involving those nuclei.…”

The 1H and 13C NMR chemical shifts of Strychnos alkaloids revisited at the DFT level

“…[8][9][10][11][12][13][14][15][16][17][18] In view of the large molecular size, severe proton deficiency, strong intramolecular stereoelectronic effects, and characteristic of Strychnos alkaloids, such as calculations, require a substantial computational effort and present a challenging task for modern computational NMR. [19][20][21][22][23][24][25][26][27][28][29][30] In this respect, calculation of 1 H and 13 C NMR chemical shifts of Strychnos alkaloids is of the utmost importance in view of their prospective application to chemical identification, spectral assignment, and structural elucidation of biochemical pathways.…”

“…Herewith, we do not give references on the numerous publications in this area, forwarding the reader to a couple of most recent comprehensive reviews on this topic. [30,31] The statistical quality of calculated 1 H and 13 C NMR chemical shifts published in the numerous papers is excellent and trustworthy, which means that the current theoretical methods (mostly those based on the density functional theory [DFT] calculations) are capable of predicting chemical shifts that numerically match the experiment. In general, experimental data supported by the DFT calculation of 1 H and 13 C NMR chemicalshifts, often together with the computer-assisted structure elucidation, [32,33] result in numerous structural elucidations and reestablishments of a number of natural products, as an example of those performed by Buevich et al [2,7,[34][35][36][37][38][39][40] However, in the recent publication by Bagno and Saielli, [41] it was stated that even though the accuracy of such calculations is outstanding, it may still not be sufficient for the simple reason that very often calculated 1 H and 13 C NMR chemical shifts differ by an amount smaller than the statistical error of the fit.…”

Recent advances in computational 31P NMR: Part 2. Spin–spin coupling constants

“…Calculation of nuclear magnetic resonance (NMR) parameters in a wide variety of chemical compounds and biochemical species has become very popular in the past 10–15 years, providing a breakthrough into theoretical and stereochemical aspects of chemical structure . In particular, calculation of 31 P NMR chemical shifts and heteronuclear spin–spin coupling constants, involving phosphorous in a wide series of different organophosphorus compounds and phosphorus‐containing complexes and clusters together with different bioorganic phosphorus compounds like phosphorus containing nucleosides and nucleotides, natural and synthetic peptides, DNA, and RNA, is of utmost importance in view of the structural information that could be gained from these calculations.…”