Dublin City University. School of Chemical Sciences
Abstract
Zeolites can act as hosts for supramolecular organization of molecules and complexes. A key objective in supramolecular chemistry is the development of donor acceptor systems capable of controlled photoinduced electron and energy transfer. This thesis focuses on a fundamental study of the capacity of zeolite materials to accommodate dipolar communication between metal complex guest species as well as exploring the effect of zeolite materials on the photophysical properties of guest molecules.
Chapter 1 and 2 outline the current state of zeolite host-guest chemistry and the experimental procedures and instrumentation ultilised in this work.
Chapter 3 investigates the ability of Y-zeolite to accommodate energy transfer processes between co-doped donors and acceptors. A series of [Ru(bpy)3]2+ (where bpy is 2,2’-bipyridine) doped Zeolite Y materials co-doped with iron polypyridyl complexes [Fe(bpy)3]2+ and [Fe(tpy)2]2+ were prepared via the ‘ship in a bottle’ syntesis. The co-encapsulated [Ru(bpy)3]2+ complex undergoes efficient energy transfer to both iron polypyridyl complexes over distances of between of 32 Å and 27 Å.
Chapter 4 examines the influence of zeolite-Y entrapment upon the photophysical properties of the Iridium (III) polypyridyl complexes [Ir(bpy)3]3+ and [Ir(tpy)2]3+. Their preparation and photophysical characterization is described. Dramatic changes in the emission spectra of the complexes were observed due to both the polarity of the zeolite interior as well as distortions caused by tight steric confinement.
Chapter 5 quantifies the extent of the excited state distortion of guest molecules entrapped within the pores of zeolite-Y by Huang-Rhys analysis. It was found that the zeolite environment impacts on the excited state geometry of the complexes generally limiting the amount of structural distortion the complex can undergo.
In Chapter 6, iridium polypyridyl complexes in a zeolite-Y matrix were codoped with europium bis-bipyridine. The photophysical properties of these materials were studied and indicated that sensitisation of the zeolite included europium acceptor by a co-included iridium polypyridyl energy donor complex occurred.
Chapter 7 offers conclusions on this thesis and outlines future work
