Research Experience

Host-Guest Chemistry

Host-guest chemistry is a branch of supramolecular chemistry that studies the interactions between two or more molecules, where one molecule (the host) provides a cavity or a space for another molecule (the guest) to bind. The binding is usually based on non-covalent forces, such as hydrogen bonding, electrostatic interactions, van der Waals forces, or n- stacking. The host and the guest can form stable complexes with specific stoichiometry and selectivity. The properties of the complexes cah be influenced by the size, shape, charge, and polarity of the host and the guest. Host-guest chemistry can be used to create complex structures, functiónal materials, sensors, catalysts, and drug delivery.

My first undergraduate project began with Host-Guest chemistry, which I will briefly outline below.

Graphical abstract

The alkali metals have strong affinity and interactions with crown ethers. The oxygen atom at the center of the crown ether molecule creates a favorable binding site for the alkali ions like Cesium. Cs is produced as a primary fission product in the nuclear power plants. Therefore, using crown ethers (CEs) for Cs+ extraction from nuclear waste is a potential approach. However, no specific conformation of CEs has been identified for the selective separation of cesium ions. Additionally, the relationship between the cavity size and its effectiveness in different stoichiometric ratios remained unexplored in prior studies. In this study, we used DFT theory (functional: M06-2X, basis set: def2TZVP) and molecular dynamics (MD) simulations to investigate the stoichiometric host-guest complexation mechanisms between Crown Ethers and Cs+ ions.

This project is complete and is prepared for submission to a Peer Reviewed Journal. The results from this study provided theoretical guidance for the design of crown ethers to extract Cs+ ions from nuclear waste and earth minerals.

Crown EtherTrim.mp4

MD simulation in YASARA showing Cs⁺ is incorporated within Crown Ethers

Above figure illustrating the encapsulation of metals within the crown ethers in a number of simulation timelines. Nevertheless, the crown ethers were unable to capture the majority of the metals, as no clusterization occurred.

Above Figure illustrating the encapsulation of metals within the crown ethers in a number of simulation timelines. The crown ethers were captured all of the metals by forming a giant cluster due to the introduction of counter ions.

PCA biplot for CE-Cs+ using Rstudio;

PCA biplot for CE-Cs+ with counter ion using Rstudio;

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