One-Bond 13C-13C Spin-Coupling Constants in Saccharides: A Comparison of Experimental and Calculated Values By Density Functional Theory Using Solid-State 13C NMR and X-Ray Crystallography

18 November 2022, Version 1
This content is an early or alternative research output and has not been peer-reviewed by Cambridge University Press at the time of posting.


Methyl aldohexopyranosides were 13C-labeled at contiguous carbons, crystallized, and studied by single-crystal X-ray crystallography and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to examine the degree to which density functional theory (DFT) can calculate one-bond 13C-13C spin-coupling constants (1JCC) in saccharides with sufficient accuracy to permit their use in MA’AT analysis (J. Chem. Inf. Model., 2022, 62, 3135–3141). Experimental 1JCC values in crystalline samples of the doubly 13C-labeled compounds were measured by solid-state 13C NMR and compared to those calculated from four different DFT models: (1) 1JCC values calculated from a single structure identical to that observed in crystalline samples by X-ray crystallography; (2) 1JCC values calculated from the same single structure in (1) but allowing all C–H bonds to optimize during the DFT calculations; and (3 and 4) 1JCC values calculated in rotamers of torsion angle theta 2 (C1–C2–O2–O2H) or omega (C4–C5–C6–O6) from which either specific or generalized parameterized equations were obtained and used to calculate 1JCC values in the specific theta 2 or omega rotamer observed in crystalline samples. Good qualitative agreement was observed between calculated 1JCC values and those measured by solid-state 13C NMR regardless of the DFT model, but in no cases were calculated 1JCC values quantitative, differing on average by 4–5% from experimental values. Calculated 1JCC values were consistently larger than experimental values. These findings, and those reported in recent solution NMR studies (Tetrault et al., J. Phys. Chem. B 2022, in press), indicate that improvements in DFT calculations are needed before calculated 1JCC values can be used as reliable constraints in MA’AT analyses of saccharides in solution.


solid-state 13C NMR
DFT calculations
1JCC values
13C-labeled saccharides
MA'AT analysis


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.