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Chemical reactions that mimic the function of ATP hydrolysis in biochemistry are of current interest in nonequilibrium systems chemistry. The formation of transient bonds from these reactions can drive molecular machines or generate materials with time-dependent properties. While the behavior of these systems can be complicated, the underlying chemistry is often simple: they are therefore potentially interesting topics for undergraduate introductory organic chemistry students, combining state-of-the-art advances in systems chemistry with straightforward reactions. Here, a teaching experiment has been developed that explores the transient assembly of benzoic acid derivatives driven by carbodiimide hydration. Working in teams, students examine the formation and decomposition of anhydrides from two benzoic acids using a carbodiimide “fuel”. The students examine classic reaction kinetics of anhydride hydrolysis using two independent methods, NMR and IR spectroscopies. They then explore how the amount of carbodiimide affects the lifetimes of precipitates of benzoic anhydride as a simple example of out-of-equilibrium self-assembly.more » « less
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Abstract ortho ‐Phenylenes are one of the simplest classes of aromatic foldamers, adopting helical geometries because of aromatic stacking interactions. The folding and misfolding of ortho ‐phenylenes are slow on the NMR timescale at or below room temperature, allowing detection of folding states using 1 H NMR spectroscopy. Herein, an ortho ‐phenylene hexamer is coupled with a RAFT chain transfer agent (CTA) on each repeat unit. A variety of acrylic monomers are polymerized onto the CTA‐functionalized ortho ‐phenylene using PET‐RAFT to yield functionalized star polymers with ortho‐ phenylene cores. The steric bulk of the acrylate monomer units as well as the chain length of each arm of the star polymer is varied. 1 H NMR spectroscopy shows that the folding of the ortho ‐phenylenes do not vary, providing a robust helical core for star polymer systems.more » « less
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