A combined first principles computational and solid-state NMR study of a molecular crystal: flurbiprofen

Abstract

The 1H, 13C and 19F magic-angle spinning NMR spectra have been recorded for Form 1 of flurbiprofen. In the case of 19F, spinning sideband analysis has produced data for the components of the shielding tensor. The chemical shift of the hydrogen-bonded proton was found to be 14.0 ppm. Shielding parameters for all three nuclei have been calculated using Density Functional Theory (DFT) together with the Gauge Including Projector Augmented Wave (GIPAW) method which takes full allowance for the repetition inherent in crystalline structures. Such computations were made for the reported geometry, for a structure with all the atomic positions relaxed using DFT, and with only the hydrogen positions relaxed. The relationships of the computed shifts to those observed are discussed. In general, the correlations are good.

13C shielding tensors of crystalline amino acids and peptides: Theoretical predictions based on periodic structure models

“…[29][30][31][33][34][35][36] Moreover, by including the short-range (hydrogen bonding) and the long-range (electrostatic effect) interactions in the Madelung potential for crystalline lattice, accurate predictions of the NMR parameters at different carbon sites can be obtained, as depicted in Table 2 for various crystalline amino acids and peptides. Comparing with the results calculated based on MM model, it is obvious that the values predicted by the GIPAW method based on PM1 derived from the crystallographic (XRD) data (in absence of structure optimization) are in close resemblance with the experimental values.…”

Powder crystallography of pharmaceutical materials by combined crystal structure prediction and solid-state 1H NMR spectroscopy

“…For small molecules, however, an approach based on the analysis of chemical shifts would be most attractive. There are today many examples of chemical shifts being combined with density functional theory (DFT) calculations for structure validation in organic molecular compounds with respect to known structures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . However, there are very few examples of ab initio structure determination from powders by NMR without a structural hypothesis.…”

Synthesis, Crystal Structure, and Solid-State NMR Investigations of Heteronuclear Zn/Co Coordination Networks — A Comparative Study

“…28 In this paper, we report on the synthesis and detailed structural elucidation of two Zn MOFs together with their corresponding protonated ligands by means of X-ray structure analysis, 1 32 which has already been proven to be a reliable tool in characterizing the NMR properties of crystalline solids. [33][34][35][36][37][38][39][40] Heteronuclear MOFs with varying percentage of paramagnetic Co 2+ were also investigated with 1 H and 13 C NMR to study the influence of paramagnetic metal ions on the parent framework.…”