| The investigation of detailed chemical structures and intermolecular interactions in the solid state provides a means of improving our understanding of a variety of fundamental chemical concepts. This in turn offers the opportunity to modify desired physical and chemical properties for select materials. In recent years, the use of experimental and theoretical charge density studies have been shown to be a powerful tool for the interpretation of chemical bonding in both the solid and gas-phase states. In this regard, the investigation of strong and weak interactions have reached a level, where the rational design of crystalline material can be achieved.;This Ph.D. thesis will entail the identification and characterization of a number of varying chemical systems through experimental and/or theoretical charge density studies. A number of weak interactions are often shown to significantly contribute to the formation and stabilization of molecular organic crystals (C-H···O, C-Hdelta+··· delta+H-C, etc...). However, the exact chemical nature of C-H delta+···delta+H-C interactions (H-H bonds) has been rather elusive, since these interactions have traditionally been considered as repulsive. Nevertheless, a topological analysis of a several H-H bonds in different chemical environments has shown evidence of the contrary. These studies provide support for a bonding (attractive) interaction between the two H atoms of similar charge. The similarities and differences between these H-H interactions and those of other weak interactions have also been highlighted in their topological properties of the electron density. In addition, the electronic structure and inter-ion interaction networks for a variety of organic salts have been investigated based on experimental charge density studies and the concepts involved in the theory of atoms in molecules . |
