Chemistry in silico: Organic Reactions, Ionic Liquids, Tautomerization

Abstract

Computational chemistry is a collection of methods that seek to interpret and predict chemical phenomena. In this work, three distinct areas of chemistry are investigated: (1) the reactive pathways of UVA irradiated N-chlorohydantoins; (2) alternative methods for calculating long-range electrostatics in room temperature ionic liquids; (3) benchmarking implicit solvent models and cavity sizes to experimentally determined free energies of protomerization in solution phase. Chapter 1 presents a brief introduction to these three subjects. Chapter 2 presents the methodologies used in this research. Chapter 3 reports the results of a joint experimental and computational investigation into the UVA stabilities of the N-chlorohydantoins 1-chloro-3,5,5-trimethyhydantoin and 3-chloro-1,5,5-trimethylhydantoin. Chapter 4 details the exhaustive testing of pair-wise Ewald alternatives on a wide range of ionic liquids reveals that shifted forces, shifted potentials, and Coulombic interactions all damped by 0.2 Å-1 with an interaction cutoff of 15 Å consistently accurately reproduce Ewald sum electrostatics. Additionally, a new methodology is presented, SF3, whose accuracy is on par with the above-mentioned methods, yet at a much-reduced computational cost. Finally, chapter 5 details the findings of the tautomerization benchmarking work.