Computational modeling is a central component in two projects that share the common aim of an improved structural understanding but for distinctly different systems, ranging from refined structures of cocrystals of pharmaceuticals to the amorphous structures of inorganic borosilicate glasses.
1.The KAW-funded project “Access to potent medical drugs through polymorph-specific crystallization enabled by ionic liquids” aims at steering the crystallization of polymorphic pharmaceuptical compounds for obtaining a specifically targeted form. Here we utilize a very recently developed solid-state NMR crystallography method, which enables estimates of entire sets of 13C-1H and 1H-1H interatomic distances from polycrystalline powders. In conjunction with structural refinements by plane-wave DFT calculations along with computations of 1H and 13C chemical shifts by the gauge including projector augmented wave (GIPAW) method for assisting NMR-peak assignments, we will refine the structures of various cocrystals of pharmaceuticals, such as paracetamol and caffeine, with small organic molecules.
2.Similar DFT/GIPAW calculations will also be utilized for predicting NMR parameters from glass models obtained by atomistic MD simulations within the project "Harnessing Exotic Structural Motifs in Borosilicate Glasses for Improved Structural Models", funded by the Swedish Research Council. Here we will explore minor structural motifs, which have hitherto been considered “forbidden” in traditional glass theories/models, but which are consistently predicted by MD-generated glass models. Yet we recently proved the existence of some of these local glass motifs by advanced 2D NMR experiments [Yu, Stevensson, Edén, J. Phys. Chem. Lett. (2018)]. The computational work will primarily target the prediction of 11B and 17O NMR parameters for assisting NMR spectral analyses, as well as advancing the understanding of the potential bearings of the “exotic structural motifs” on the physical properties of borosilicate glasses that have diverse applications from biomedical implants to nuclear-waste immobilization.