Synthesis and properties of a [2.2.2]-diazabicyclic polymer

Polymers represent a general class of molecules consisting of many repeated units, or monomers. Traditionally, polymers consist of hydrocarbon monomers and can vary drastically in complexity and functionality. Due to their high molecular weight and chain-like structure, polymers have unique properties that differ significantly from their monomer counterparts, including durability and malleability. For this reason, polymers are used in many everyday products.

Polymeric chains can be efficiently synthesized via Ring-Opening Metathesis Polymerization (ROMP). ROMP consists of three steps: Initiation, propagation, and termination. Initiation begins with the coordination of a metal complex with the cyclic olefin of interest, followed by a cycloaddition and cycloreversion to effectively activate the complex for propagation. Once the chain achieves the desired length, a reagent is added to terminate this process by exchanging the metal complex with an appropriate functional group.

This summer, I will explore metathesis polymerization on strained polycyclic structures. These [2.2.2] systems are of particular interest due to several unique features:

  1. They contain a strained alkene within a [2.2.1] ring system. This strain can be utilized for efficient ring polymerization.
  2. The [2.2.2] diazabicyclic ring systems are composed of Lewis basic lactam and lactim ether functionalities. This adjoining system contains ring strain that can be utilized to modify these positions.
  3. They contain an aryl group that can be easily modified, diversifying the pool of potential polymeric products.

My coworker and I have already established a reliable method to create the [2.2.2]-diazabicyclic monomer. This summer, studies will be carried out to probe which catalyst best promotes polymerization of this system. Additionally, other conditions including solvent type, temperature, and reaction duration will be tested in order to develop the optimal synthesis of the [2.2.2] polymer. Once this synthesis is successful, the product will be analyzed for size via its polydispersity index and molecular weight range.

After a reliable polymeric synthesis for the current [2.2.2] system is established, the focus of this project will turn to adjusting the aryl substituent on the monomer, as well as the modification of the structure’s lactam and lactim bridges. If this modified synthesis can be established, this project has the potential to create hundreds of polymeric products with diverse properties.

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