Modeling Polymorphic Molecular Crystals with Electronic Structure Theory

Abstract

Interest in molecular crystals has grown thanks to their relevance to pharmaceuticals, organic semiconductor materials, foods, and many other applications. Electronic structure methods have become an increasingly important tool for modeling molecular crystals and polymorphism. This article reviews electronic structure techniques used to model molecular crystals, including periodic density functional theory, periodic second-order Møller-Plesset perturbation theory, fragment-based electronic structure methods, and diffusion Monte Carlo. It also discusses the use of these models for predicting a variety of crystal properties that are relevant to the study of polymorphism, including lattice energies, structures, crystal structure prediction, polymorphism, phase diagrams, vibrational spectroscopies, and nuclear magnetic resonance spectroscopy. Finally, tools for analyzing crystal structures and intermolecular interactions are briefly discussed.

Solid-State Testing of a Van-Der-Waals-Corrected Exchange-Correlation Functional Based on the Semiclassical Atom Theory

“…These are in fact important systems for materials science but also difficult cases for conventional DFT approaches due to the relevant role of dispersion in determining the intermolecular interactions and the crystal packing [8,18,88]. Table 4.…”

First-Principles Models for van der Waals Interactions in Molecules and Materials: Concepts, Theory, and Applications

“…7,78,276,277 More than half of the compounds in a pharmaceutically relevant data set show polymorphism, 278 and the energy differences between polymorphs are usually less than 1 kcal/mol and often even less than 1 kJ/mol (0.24 kcal/mol). The X23 database contains two polymorphs of oxalic acid, for which the experimental energy difference between the α and β forms amounts to only 0.05 kcal/mol.…”

Understanding the Influence of the Electronic Structure on the Crystal Structure of a TTF-PTM Radical Dyad

“…It must be mentioned that DFT-functionals incorporating dispersion correction has been a common method for studying polymorphism in molecular crystals. 1,[18][19][20][21][22][23][24] The minimum energy structure of the different polymorphs has been obtained by performing successive variable-cell geometry relaxations, in which the lattice parameters as well as the atomic positions are optimized simultaneously until the atomic forces are smaller than 1.0 E −5 atomic units. We have chosen to compare optimized structures (instead of the reported crystals) for two reasons.…”

“…Consequently, the modelling of crystallization processes, and polymorph-prediction techniques, have become increasingly important in the quest to improve the structure/function design capabilities. 1 Progress in this field implies great potential benefits due to their relevance to pharmaceuticals, electronics, and, virtually, all fields of chemical industry working in materials design in the solid state. Most of crystal structure prediction studies are based on the assumption that the crystal structure corresponds to the thermodynamically-favored polymorph.…”

“…[3][4] The physical properties of such advanced materials are directly related to their molecular packing in the solid state. 5 In this context, we have recently reported the radical and the non-radical analogue species based on the electron-donor tetrathiafulvalene (TTF) unit connected, through a ᴨ-conjugated phenyl-pyrrole-vinylene bridge, to the electronacceptor polychlorotriphenylmethane (PTM) radical (1), or to the corresponding HPTM non-radical derivative (2). Compounds 1 and 2 exhibit a similar molecular structure but, surprisingly, they present a different crystalline packing.…”