Spectroscopic alterations by mechanical bonds in supramolecular systems

Abstract

Mechanically interlocked molecules (MIMs) represent a unique class of supramolecular architectures in which component parts are linked not by covalent connectivity but by spatial entanglement. These systems provide an opportunity to probe how molecular topology influences physical properties and reactivity. This thesis explores how the introduction of a mechanical bond can fundamentally reshape spectroscopic behaviour, particularly in the context of photoswitching and nuclear magnetic resonance.
The chapter 1 establishes the conceptual framework by surveying the origins, applications, and photochemical principles of MIMs and photoswitches, highlighting their intersection as platforms for controllable function. Chapter 2 describes the synthesis of indigo-derived [2]rotaxanes, the first examples of their kind, laying the foundation for spectroscopic analysis. Chapter 3 demonstrates how mechanical bonding modulates photoswitching, with redshifts in absorption, stabilisation of metastable isomers, and dramatic extensions of thermal half-lives. These findings establish the mechanical bond as a robust design principle for tuning photochemical behaviour. Chapter 4 extends the mechanical bonds to nuclear singlet order, detailing the synthesis of 13C₂-labelled cyclodextrin [2]rotaxanes designed to exploit symmetry breaking for singlet generation and prolonged lifetimes.

More information

Identifiers

ORCID for George Williams: orcid.org/0000-0001-6162-8895

ORCID for Ali Tavassoli: orcid.org/0000-0002-7420-5063

Catalogue record

Export record

Altmetrics