Chemistry PhD Defense — Matthew Hurlock
About the event
Title: The Design, Synthesis, and Properties of Tetraphenylethene-Based Coordination Polymers
Abstract: Materials with tunable properties are needed to address issues, such as the capture of greenhouse gases, the detection of hazardous chemicals, and the storage of energy. Coordination polymers are a type of hybrid polymeric crystalline material formed from the connection of organic ligands and metal ions or clusters through coordination bonds. The wide array of building blocks that can be used enables coordination polymers to be rationally designed and tuned to possess specific properties. Amongst coordination polymers, Metal–Organic Frameworks (MOFs) stand out due to their porosity, large internal surface areas, and diversity of structures. These features can be achieved through direct synthesis as well as through directed modification of the framework post-synthetically. The study of the structures of MOFs and how they relate to the properties of the material is important to help gain a deeper understanding and to facilitate the development of new materials with desired functionality.
Luminescent MOFs are of particular interest due to their potential as selective chemical sensors. Ligand-based fluorescence is one of the most common forms of luminescence in MOFs. Ligands built from the molecule tetraphenylethene (TPE) are ideal candidates for these systems. The aggregation-induced emission properties of TPE molecules can be enhanced through rigidification within a coordination network. This work seeks to further understand how the structures of TPE MOFs relate to the properties of the framework. To accomplish this, TPE ligands with varying functionalities are explored and a variety of new coordination polymers have been synthesized from these ligands. This work demonstrates that TPE ligands can be utilized to form a variety of fluorescent frameworks with unique structures and properties, and these properties can be further tuned. Through this work, a better understanding of how TPE ligands and their conformations influence the structure and properties of coordination polymers is gained, which will aid in the rational design of these types of materials.