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Licensed Unlicensed Requires Authentication Published by Oldenbourg Wissenschaftsverlag February 18, 2011

The use of dispersion-corrected DFT calculations to prevent an incorrect structure determination from powder data: the case of acetolone, C11H11N3O3

Jürgen Brüning, Edith Alig, Jacco van de Streek and Martin U. Schmidt

Abstract

The crystal structure of acetolone (5-(acetoacetylamino)benzimidazolone, C11H11N3O3), was determined from X-ray powder data. Despite strong preferred orientation effects, the structure could be solved with real-space methods and refined by the Rietveld method using restraints. The resulting structure gave a good Rietveld fit with reasonable confidence values; the structure looked chemically sensible and passed all tests including a CSD check and the checkCIF procedure. But dispersion-corrected density functional theory (DFT) calculations revealed that this structure was actually wrong, and further work showed that the terminal acetyl group had to be rotated by 180°. The correct crystal structure led to a better Rietveld refinement with improved R-values. This structure was confirmed by dispersion-corrected DFT calculations. The compound crystallises in P-1 with two molecules per unit cell. The molecules are connected by a 2-dimensional hydrogen bond network.


* Correspondence address: Goethe University, Institute of Inorganic and Analytical Chemistry, Max-von-Laue-Str. 7, 60438 Frankfurt, Deutschland

Published Online: 2011-02-18
Published in Print: 2011-05

© by Oldenbourg Wissenschaftsverlag, Frankfurt, Germany