"Synthesis and Investigation of Unusual Polycyclic Conjugated Hydrocarbon and Polymer"
I am Ke Zheng, a sixth-year PhD candidate in Professor Yan Xia's laboratory. My research focuses on the synthesis and characterization of novel polycyclic conjugated hydrocarbons and polymers with unique structural features.
Polycyclic conjugated hydrocarbons (PCHs) have garnered significant attention in organic synthesis and materials science due to their applications in organic electronics. Ladder-type PCHs, such as oligoacenes, play an important role in organic electroluminescent devices and organic photovoltaic systems. However, PCHs incorporating antiaromatic cyclobutadienoid (CBD) units remain largely unexplored, with limited knowledge of their electronic structures, chemical reactivity, and solid-state properties. This gap stems from the synthetic challenges and inherent instability of these systems. Understanding antiaromaticity is essential for elucidating electron delocalization mechanisms and enabling rational design of molecular systems with tailored electronic properties.
Our laboratory has developed catalytic arene-norbornene annulation (CANAL) as an efficient synthetic approach to access conjugated molecules containing antiaromatic CBD units, allowing systematic investigation of their bonding, electronic properties, and chemical behavior.
In my thesis defense, I will present three key research areas: First, the modular synthesis and characterization of linear ladder-type CBD-containing PCHs that function as stable yet flexible molecular wires. Second, the chemical transformations of CBD-containing PCHs through regioselective activation, enabling modular construction of helically curved PCH architectures. Finally, I will discuss my work on degradable polymers, specifically the synthesis of high molecular weight semicrystalline substituted polycyclohexene via alternating copolymerization of butadiene and methacrylate, and the successful demonstration of its ambient depolymerization.