Abstract by Caleb Tinsley
Chemistry and Biochemistry
Conformational Switching Upon Metal Binding: Complexes of Cucurbit(6)uril with Alkylammonium and Alkali Metal Ions
Cucurbit(6)uril (CB6) is a pumpkin-shaped host molecule that has a hollow interior. It is a component in proposed molecular machines. The oxygens ringing both portals allow CB6 to bind cations. We are studying CB6’s ability to bind n-alkylammoniums of different tail lengths when another cation is bound to one of the portals. We used Merck Molecular Force Field and IMoS collisional cross sectional modeling in Spartan to compute energies and collision cross sections of low energy conformers. We found that when binding a sodium cation and an alkylammonium, it is energetically favorable for the tail to be inside for tails up to six carbons long; longer tails go outside. There is a slight degree of metal dependence, where the same complex with a potassium ion instead allows a few conformers of hexylammonium with the tail inside. We plan further computations with other alkali metals and experiments to see how dependent on the metal the conformers are.