The Effects Of Noncovalent Interactions Studied By Ultrafast Two-Dimensional Infrared Spectroscopy
type: CreativeWork
description: Understanding how noncovalent interactions affect dynamics and energetics is essential for predicting and describing chemical reactivity and stability. In this thesis I investigate the impact of noncovalent interactions on two different types of reactive systems: fluxional metal carbonyl complexes and biological cofactors. Through varying the local environment, by changing solvents or encapsulation cages, I focus on characterizing the effects of noncovalent interactions on the ultrafast solvation dynamics, anharmonicities, and intramolecular vibrational energy redistribution (IVR) of these different types of systems by applying ultrafast two-dimensional infrared (2DIR) spectroscopy and ultrafast polarization dependent mid-IR pump-probe spectroscopy. Bis(cyclopentadienyl ruthenium dicarbonyl) dimer and bis(cyclopentadienyl iron dicarbonyl) dimer are two fluxional metal carbonyl complexes that exist as multiple isomers in dynamic equilibrium in solution. However, when encapsulated by self-assembled cages, the dynamic equilibrium is disrupted, and only one isomeric form is stabilized. Though the static picture of the trapped complexes is known from x-ray crystallography, the ultrafast equilibrium dynamics of the trapped complexes have not been well characterized. A better understanding of the equilibrium dynamics of these systems could lead to additional insight into the mechanism by which hosts tune the reactivity of trapped guest molecules. Using polarization dependent mid-IR pump-probe spectroscopy I characterized the population relaxation and molecular reorientation of the trapped complexes. I find that encapsulation results in spatial restriction – with the metal carbonyl complexes undergoing hindered molecular reorientation. In addition, encapsulation results in a faster timescale for vibrational population relaxation. Applying ultrafast 2DIR spectroscopy to the diiron complex I explore the effects of encapsulation on the intramolecular vibrational energy redistr…
abstract: Understanding how noncovalent interactions affect dynamics and energetics is essential for predicting and describing chemical reactivity and stability. In this thesis I investigate the impact of noncovalent interactions on two different types of reactive systems: fluxional metal carbonyl complexes and biological cofactors. Through varying the local environment, by changing solvents or encapsulation cages, I focus on characterizing the effects of noncovalent interactions on the ultrafast solvation dynamics, anharmonicities, and intramolecular vibrational energy redistribution (IVR) of these different types of systems by applying ultrafast two-dimensional infrared (2DIR) spectroscopy and ultrafast polarization dependent mid-IR pump-probe spectroscopy. Bis(cyclopentadienyl ruthenium dicarbonyl) dimer and bis(cyclopentadienyl iron dicarbonyl) dimer are two fluxional metal carbonyl complexes that exist as multiple isomers in dynamic equilibrium in solution. However, when encapsulated by self-assembled cages, the dynamic equilibrium is disrupted, and only one isomeric form is stabilized. Though the static picture of the trapped complexes is known from x-ray crystallography, the ultrafast equilibrium dynamics of the trapped complexes have not been well characterized. A better understanding of the equilibrium dynamics of these systems could lead to additional insight into the mechanism by which hosts tune the reactivity of trapped guest molecules. Using polarization dependent mid-IR pump-probe spectroscopy I characterized the population relaxation and molecular reorientation of the trapped complexes. I find that encapsulation results in spatial restriction – with the metal carbonyl complexes undergoing hindered molecular reorientation. In addition, encapsulation results in a faster timescale for vibrational population relaxation. Applying ultrafast 2DIR spectroscopy to the diiron complex I explore the effects of encapsulation on the intramolecular vibrational energy redistr…
author: Meloni, Stephen Lewis
language: en
date published: 2020
date modified: 2026-07-24T03:45:49Z
provider: University of Pennsylvania
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Pennsylvania