Studies on Halogen Bonding in Solution, the Solid State, and the Calculated Gas Phase: Towards a Hexameric Halogen Bonding-Based Capsule

This works targets the understanding and improvement of halogen bonding (XB) in solution, and the synthesis of an XB-based capsule. Based on DFT and Coupled Cluster calculations, in the first chapter a series of single and combined parameters are evaluated towards their potential to predict XB binding strength better than the sigma-hole. Secondly, a study on halogenated vinylogous bipyridines is presented, in which we aimed to trigger XB by electrochemical oxidization and reduction. Furthermore, to not only predict XB in the gas phase but in solution the computational Solvent Model based on Charge Density (SMD) was optimized for iodine and bromine based on isothermal calorimetric titrations. As a side project, iodine(III) containing biphenyls (iodolium compounds) were tested towards their performance in XB catalysis. To increase the XB strength in neutral complexes attempts were made to synthesize polycyano substituted aromatic XB donors by nucleophilic substitutions with a variety of cyanide sources in a single step and by conventional multistep nitrile synthesis. At last, two different neutral XB-based capsules are presented, their properties calculated by DFT methods and synthetic strategies developed.