Crystal Structures of Organic Molecules: Insights and Implications

This lecture discusses the crystal structures of various organic molecules, focusing on their packing arrangements and the impact of molecular design on solubility and electronic properties. The instructor begins by explaining the challenges associated with large discotic molecules, which are often insoluble and infusible, making them difficult to process. To address solubility issues, flexible alkyl tails are introduced, enhancing the entropy of dissolution. The lecture then explores the crystal structures of specific molecules, such as bisbenzocoronene and dihexylquaterthiophene, highlighting their unique packing arrangements, including herringbone and columnar structures. The instructor emphasizes the importance of molecular interactions, such as quadrupole moments and dispersive forces, in determining these packing patterns. Additionally, the lecture covers the implications of molecular orbital interactions on electronic properties, illustrating how these interactions can influence charge transport in organic materials. The session concludes with a discussion on the significance of understanding these structures for the development of organic electronic devices.