Expanded cyclophanes for switchable capture/release of metal complexes

Abstract

The thesis, entitled ‘Expanded Cyclophanes for Switchable Capture/Release of Metal Complexes’ is separated into four main chapters. The first chapter focuses on the introduction of cyclophane receptors and the use of cyclophanes in molecular machines and some other potential applications. Then, an introduction of molecular logic-based computation is presented.

The second chapter presents the design and synthesis of three novel water-soluble redox-switchable anionic triangular cyclophane receptors with pentamethylene chains. Ru(II) polypyridine complexes Ru(II)(bpy)3 and Ru(II)(phen)3, which have similar D3 symmetry conformation to cyclophane receptors, can be encapsulated into the cavity of the receptors to form inclusion complexes in water. The switchability of cyclophane receptors is achieved by the capturing behavior of trialcohol cyclophane and releasing action of triketone cyclophane. This is demonstrated by 1 H NMR spectroscopy, 2D ROESY and luminescence emission spectroscopy. This chemically redox-switchable system with luminescence outcomes can be regarded as an all-chemical RS Flip-Flop, integrating with a downstream PASS 1 gate or an IMPLICATION gate. Besides, two cyclophane receptors can also provide strong protection ability to Ru(II) polypyridine complexes from external environments in water.

In chapter 3, three analogous cyclophane receptors with tetramethylene chains are synthesized. These smaller cyclophane receptors can selectively capture and release Ru(II)(bpy)3, but cannot bind Ru(II)(phen)3. The spectral results and luminescence quenching experiments indicate the complex between Ru(II)(bpy)3 and receptor is inclusive but off-central.

In chapter 4, the general conclusion of the research projects is given, with some discussion of further development. Chapter 5 presents the experimental procedures for synthesis work in chapters 2 and 3.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Amilra De Silva (Supervisor) & Cristina Lagunas-Castedo (Supervisor)