Date of Award
2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry
Department
Chemistry
First Advisor
Daniel Thomas
Abstract
Intermolecular interactions such as hydrogen bonding, strongly influence the physicochemical properties of multi-component molecular systems such as deep eutectic solvents (DESs). These properties in turn dictate the utility of a given solvent for applications including liquid/liquid extraction, nanomaterial synthesis, gas capture, and biomolecule preservation. Identifying the prominent structural motifs and intermolecular interactions is crucial for connecting fundamental attributes to the macroscopic properties of the system, especially in multi-component solvents that involve hydrogen bond donors and acceptors.
Chapter 1 of this work details the synthesis and solvation capability of selected deep eutectic solvents, (DESs). The solvation capability of DESs is evaluated by measuring the partitioning of polycyclic sulfur compounds between heptane and the DES phase. Electronic structure calculations were utilized to probe the intermolecular interactions that govern the extraction of polycyclic thiophene compounds.
Chapter 2 describes the structural characterization of DES clusters in vacuum condition using helium nanodroplet isolation infrared (HENDI IR) action spectroscopy to probe the condensed phase interactions by comparing the respective DES HENDI IR spectra with the FT-IR spectra.
Chapter 3 describes the design and construction of a modified atmospheric pressure interface for the ion infrared action spectroscopy instrument at the University of Rhode Island. The revised design of the interface is intended to facilitate the preservation of weakly bound clusters, such as those featuring CH-p interactions, during the transfer of ions to vacuum. Additionally, this chapter describes preliminary studies of benzethonium, which can adopt conformations featuring intramolecular CH-p or p-p interactions. This molecule may serve as a test case for examining the competition between these interaction motifs under vacuum conditions.
Lastly, the Appendix describes custom instrumentation implemented for ion detection in infrared action spectroscopy experiments.
Recommended Citation
Madduma Wellalage, Miyuru Madusanka, "PROBING INTERMOLECULAR INTERACTIONS OF DEEP EUTECTIC SOLVENTS VIA INFRARED ACTION SPECTROSCOPY & CONDENSED-PHASE ANALYSIS" (2026). Open Access Dissertations. Paper 4568.
https://digitalcommons.uri.edu/oa_diss/4568