Revisiting the Blind Tests in Crystal Structure Prediction: Accurate Energy Ranking of Molecular Crystals

Abstract

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Molecule VI, a Benchmark Crystal‐Structure‐Prediction Sulfonimide: Are Its Polymorphs Predictable?

“…The results presented herein, taken together with other results obtained with the DFT(d) approach, [3,5,[15][16][17] suggest that a purely thermodynamic approach can predict the likely structures resulting from a crystallization experiment, at least for small molecules and provided that a sufficiently accurate method of calculating the lattice energy is used. However, despite the excellent prediction results achieved with the DFT(d) method, it is not yet possible to predict the outcome of a specific crystallization experiment.…”

“…[4] Recently, we used the same methodology to re-evaluate the lattice energies and energy rankings of the experimental structures and all submitted predictions in the 1999, 2001, and 2004 blind tests, with very encouraging results. [5] None of the 2001 blind-test participants had predicted the then only known experimental structure (form I, a Z' = 1 structure) of molecule VI (6-amino-2-phenylsulfonylimino-1,2-dihydropyridine, see Scheme 1). [6] Two additional polymorphs, forms II [7] (a Z' = 2 structure) and III [8] (a Z' = 1 structure), were discovered after the 2001 blind test.…”

“…[11] However, our previous work indicated that the DFT(d) method is capable of representing forms I and II of molecule VI correctly in terms of lattice energy, as well as in terms of geometry, although a full DFT(d) CSP study had not been performed. [5] To evaluate the relative stability of the new form III and to consider the validity of the previous comments on the predictability of the polymorphs of molecule VI, [7][8][9] we have conducted a full CSP of molecule VI using the GRACE software. [12] The computational procedure used in this study and its limitations are described in the Supporting Information.…”

Structural and energetic aspects of the differences between real and predicted polymorphs

“…The advent of better energy models will be a necessary first step towards reliable prediction and stability ranking of polymorphs [3], and the improvement achieved using dispersion-corrected Density-Functional Theory and a tailor-made force field, although computationally still out of reach for routine work today, is significant [5,8,9]. However, whether a purely thermodynamic improvement will lead to any significant reduction in the number of energetically accessible minima on the potential energy hypersurface, corresponding to potential polymorphs, is less certain.…”

Morphology prediction of crystals grown in the presence of impurities and solvents — An evaluation of the state of the art

“…Due to the work of e.g. Hartman and Bennema [4], Clydesda et al [5], Asmadi et al [6] modern software packages allow an easy handling and applications of those methods for a broad range of users. The list of symbols and abbreviations are given in Table 1.…”