Synthesis and analysis of π-conjugated europium(III) complexes for phosphoanion sensing
The development of luminescent lanthanide complexes, particularly those based on europium(III), has garnered significant attention due to their exceptional photophysical properties, including sharp emission lines, long luminescence lifetimes, and distinct spectral fingerprints. These characteristics make europium complexes invaluable in various scientific and industrial applications, such as optical imaging, sensing, and developing responsive materials for environmental and biomedical uses. This thesis explores synthesising and characterising a series of novel europium(III) complexes, focusing on enhancing their photophysical properties and anion sensing capabilities through strategic ligand design and advanced analytical techniques.
The research begins with the EXAFS analysis of the [Eu.1]+ complex, providing a comprehensive understanding of its structural properties in different phases and conditions, particularly in interactions with ATP and ADP. This analysis established a reliable model for understanding the coordination environment of the europium ion, revealing significant structural changes upon anion binding. Subsequent chapters detail synthesising and characterising six novel macrocyclic lanthanide complexes, each featuring extended conjugation in their quinoline antennae. Despite the challenges encountered during synthesis, particularly in purification, the work successfully laid the groundwork for future studies to optimise the synthesis of water-soluble, luminescent lanthanide complexes.
The photophysical properties of these newly synthesized complexes were systematically explored, revealing significant differences in luminescence efficiency and stability across the series. Notably, discovering an intraligand charge transfer (ILCT) state in [Eu-4-Ph]+ opens new possibilities for enhancing the luminescence efficiency of europium-based probes. The anion sensing capabilities of these complexes were also extensively studied, with [Eu-6-OMe]+ exhibiting a remarkable 30-fold increase in emission intensity upon binding to ADP, highlighting its potential as a selective anion sensor. However, challenges related to solubility and stability were identified, underscoring the need for further ligand optimization to enhance practical applicability.
The thesis concludes with a detailed analysis of these complexes' structural and energetic properties using Density Functional Theory (DFT) calculations. The findings provide valuable insights into how ligand environment and anion binding influence the geometry and stability of europium(III) complexes, guiding the design of future complexes with enhanced anion-sensing capabilities.
Overall, this thesis significantly advances the understanding of europium(III) complexes and their application in anion sensing and luminescent imaging. The research provides a strong foundation for future work to develop more selective, efficient, and versatile luminescent probes for various scientific and industrial applications.
Funding
Engineering and Physical Sciences Research Council
History
School
- Science
Department
- Chemistry
Publisher
Loughborough UniversityRights holder
© Hannah Kathleen PylePublication date
2025Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of the degree of Doctor of Philosophy of Loughborough University.Language
- en
Supervisor(s)
Stephen J. ButlerQualification name
- PhD
Qualification level
- Doctoral
This submission includes a signed certificate in addition to the thesis file(s)
- I have submitted a signed certificate