Quantifying Cooperativity in Non-Covalent Networks
type: CreativeWork
description: Non-covalent interactions are important in biological, material, systems, and supramolecular chemistry. Some quantification of cooperativity in networks of non-covalent interactions has been done in the literature, but these experiments are often complex and not easily applicable to many different types of functional group. The work in this thesis builds on previous work in the Hunter group on quantifying the cooperativity in functional groups capable of forming two H-bonds by expanding it to new functional groups. A cooperativity parameter, κ, that measures the relationship between two H-bonds to the same functional group was introduced previously in studies of phenols. The values of κ can be determined by using an intramolecular and intermolecular H-bond to the functional group of interest and measuring the relationship between them. The stabilisation due to cooperativity is equal to the strength of a H-bond between the intramolecular and intermolecular groups multiplied by κ. The methodology was first used in this thesis on amides with an intramolecular H-bond to a phenol and an intermolecular H-bond to a phosphine oxide, the stabilisation from cooperativity was found to be worth up to 6 kJ mol-1 . Amides with an intramolecular H-bond to a pyridine and an intermolecular H-bond to perfluoro-tert-butanol (PFTB) were also studied. In both cases κ for an amide was found to be +0.20. Density-functional theory (DFT) calculations were used to predict the cooperativity, and provided a good match to the data, showing that the cooperativity from the intramolecular H-bond arises from properties of the isolated, individual molecules. The DFT calculations capture both changes in polarity of the amide group and through-space electrostatic interactions with the intramolecular H bonding group (phenol or pyridine). The same scaffold with an intramolecular H-bond to a pyridine was used to study anilines and sulfonamides. The value of κ for the anilines when H-bonding intermolecula…
abstract: Non-covalent interactions are important in biological, material, systems, and supramolecular chemistry. Some quantification of cooperativity in networks of non-covalent interactions has been done in the literature, but these experiments are often complex and not easily applicable to many different types of functional group. The work in this thesis builds on previous work in the Hunter group on quantifying the cooperativity in functional groups capable of forming two H-bonds by expanding it to new functional groups. A cooperativity parameter, κ, that measures the relationship between two H-bonds to the same functional group was introduced previously in studies of phenols. The values of κ can be determined by using an intramolecular and intermolecular H-bond to the functional group of interest and measuring the relationship between them. The stabilisation due to cooperativity is equal to the strength of a H-bond between the intramolecular and intermolecular groups multiplied by κ. The methodology was first used in this thesis on amides with an intramolecular H-bond to a phenol and an intermolecular H-bond to a phosphine oxide, the stabilisation from cooperativity was found to be worth up to 6 kJ mol-1 . Amides with an intramolecular H-bond to a pyridine and an intermolecular H-bond to perfluoro-tert-butanol (PFTB) were also studied. In both cases κ for an amide was found to be +0.20. Density-functional theory (DFT) calculations were used to predict the cooperativity, and provided a good match to the data, showing that the cooperativity from the intramolecular H-bond arises from properties of the isolated, individual molecules. The DFT calculations capture both changes in polarity of the amide group and through-space electrostatic interactions with the intramolecular H bonding group (phenol or pyridine). The same scaffold with an intramolecular H-bond to a pyridine was used to study anilines and sulfonamides. The value of κ for the anilines when H-bonding intermolecula…
author: Hanna, Fergal
language: eng
keywords: Organic Chemistry, Chemistry, Physical Organic Chemistry, Non-covalent interactions, Supramolecular Chemistry, H-bonding, Hydrogen bonds
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/126f985a-bacc-4652-99f9-4bba68c2b90f/download
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2024-06-13
date modified: 2026-07-22T22:24:04Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.115422