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dc.contributor.advisorGordon, Keith C
dc.contributor.authorHorvath, Raphael
dc.date.available2012-11-13T21:46:53Z
dc.date.copyright2012
dc.identifier.citationHorvath, R. (2012). A Photophysical Investigation of d6 Metal Polypyridyl Complexes (Thesis, Doctor of Philosophy). University of Otago. Retrieved from http://hdl.handle.net/10523/2599en
dc.identifier.urihttp://hdl.handle.net/10523/2599
dc.description.abstractA number of polypyridyl complexes based on d6 metals have been investigated using a range of spectroscopic and computational techniques. Interest in these systems stems from potential applications in molecule based devices, such as dye sensitised solar cells, as well as the potential to gain insight into fundamental photophysical properties of metal complexes and the development of techniques to probe these. Several techniques have been used and are described. The ground states of complexes have been characterised using FT-IR and FT-Raman spectroscopic techniques, which allow for verification of observable quantities obtained from density functional theory calculations. Electronic absorption and resonance Raman allow the initially excited state to be investigated, while transient absorption and transient and time resolved resonance Raman are sensitive toward excited states with the longest lifetimes. Picosecond time resolved infrared is used to bridge this gap, to provide a comprehensive description of processes post initial photoexcitation. Chapter 3 involves discussion of N3, a commonly used dye for dye sensitised solar cells, and derivatives thereof. Derivatisation was carried out to enhance the solar absorption properties of the dyes; however, it was found that the acceptor molecular orbitals do not extend over the attached units in the absorbing state. Time resolved infrared spectroscopy was carried out to probe the excited state, which showed, for an anthrylethenyl-substituted complex, an unusual charge-separated excited state based on a single ligand. In Chapters 4 and 7, investigations on complexes based on the ligand 2,2’;6’,2”-terpyridine, including multimetallic assemblies, are described. The terpyridine allows for the constructions of linear structures; however, corresponding metal complexes possess short lifetimes. Replacing two carbon of this ligand with nitrogen gives 2,6-di-2-pyridyl-1,3,5-triazine, which imbues the corresponding ruthenium complexes with extended lifetimes. Resonance Raman spectroscopy was able to show predominant population of the triazine-containing ligand when the complex is excited in the visible region. The ability of multimetallic assemblies comprised of similar ligands to quench excited state populations was probed. To that end, transient absorption and time resolved resonance Raman spectroscopic techniques have been used to show that initially populated excited state electrons return to the ground state by interacting with attached secondary metal subunits. In Chapters 5 and 6, the effects of substitution of electron donating units on well studied complexes of the ligands 2,2’-bipyridine and dipyrido[3,2-a:2’,3’-c]phenazine are investigated. Rhenium complexes of these ligands show unusual excited states that are thought to originate from the electron donating properties of the substituents. The bipyridine complexes, substituted with ethenyl-linked diphenylaniline, possess an intraligand charge transfer reaction that exists without contribution from the metal; these are well described using resonance Raman and computational methods. Complexes of the substituted dipyridophenazine ligand possess a complex system of excited states that are shown to interconvert on the picosecond and nanosecond timescales. Time resolved infrared spectroscopy was used to assign these states.
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectRaman
dc.subjectrhenium
dc.subjectruthenium
dc.subjectbipyridine
dc.subjectterpyridine
dc.subjectdppz
dc.subjectpolypyridyl
dc.subjecttriplet state calculation
dc.subjectDFT
dc.subjectTD-DFT
dc.subjectN3
dc.subjecttransient absorption
dc.subjecttransient emission
dc.subjecttime resolved resonance Raman
dc.subjecttime resolved infrared
dc.subjectinfrared
dc.subjectexcited state dynamics
dc.subjectdye sensitised solar cell
dc.subjectmetal to ligand charge transfer
dc.subjectintraligand charge transfer
dc.subjectligand centered charge transfer
dc.subjectHATN
dc.subjectoxadiazole
dc.subjecttriarylamine
dc.subjecttriphenylamine
dc.subjectmultimetallic assembly
dc.titleA Photophysical Investigation of d6 Metal Polypyridyl Complexes
dc.typeThesis
dc.date.updated2012-11-13T12:13:44Z
dc.language.rfc3066en
thesis.degree.disciplineChemistry
thesis.degree.nameDoctor of Philosophy
thesis.degree.grantorUniversity of Otago
thesis.degree.levelDoctoral
otago.interloanno
otago.openaccessAbstract Only
otago.evidence.presentYes
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