How important are H...H intermolecular interactions in single crystals of distyrylbenzene derivatives?

Crystal engineering is a fast-developing discipline with applications in the hi-tech field for the study of semiconductors or in the pharmaceutical field for pharmacokinetic and solubility studies. This includes the study of organic distyrylbenzene crystals, whose utility is already proven as a semiconductor, in the construction of OLED systems or in the field of sensor technology. The knowledge of intermolecular interactions is, therefore, essential for understanding crystal structures. During my thesis preparation at the University of Antwerp, in the research group of Professor Frank Blockhuys, I studied several crystal structures based on a distyrylbenzene skeleton in which the hydrogens on the aromatic rings are symmetrically replaced by methoxy. Despite the presence of these groups, however, it has been observed through computational experiments, that in addition to C-H...O type intermolecular interactions, which can be expected due to the inclusion of heteroatoms in the structure, C-H...H type intermolecular interactions are ubiquitously present. This type of interaction is still under-investigated and for this reason it was decided to investigate the topic further. The aim of the activity carried out during the training was to study, characterize and finally classify intermolecular interactions of the C-H...H type into three different categories. This was achieved by carrying out various computations and selecting suitable structures for further study. The interactions were categorized using the number of atoms involved, the shape of the interaction and other variables such as electronic density and the curvature of the interaction line as parameters. In addition to the study and understanding of distyrylbenzene crystal structures, future studies on this type of interaction could be essential for the general understanding of crystal structures. But could also pave the way for the explanation of chemical phenomena such as the self-assembly mechanism.