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Wong, Ngaisum (2023) Investigation of Rhenium (I) Tri-, Di-, Tetra- Carbonyl Diimine Complexes. MRes thesis, University of Nottingham.

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Abstract

Chapter 1

This Chapter provides an introduction to the photophysical and photochemical properties of the complexes of interest in this Thesis highlighting their different excitedstates. A brief background of well-studied rhenium (I) tricarbonyl diimine complex is presented to allow comparison to the much less explored rhenium (I) di- and tetracarbonyl diimine complex which are the subject of this work. A brief outline is given of techniques used within this Thesis namely UV-visible, luminescence and timeresolved infrared (TRIR) spectroscopy. The latter technique is a pump-probe method that has been utilised to investigate the photophysical and photochemical properties of the complexes of interest.

Chapter 2

This chapter focuses on Rhenium dicarbonyl bis-diimine complex and presents new complexes with the form of [Re(CO)2(dppp2)2]+. [Re(CO)2(dppp2)2]PF6 which have been characterized by FTIR, 1 H NMR, and HRMS. During the synthesis of [Re(CO)2(dppp2)2]+, four new tricarbonyl complex intermediates have been synthesized which are [(OTf)Re(CO)3(dppp2)], [(CH3CN)Re(CO)3(dppp2)]OTf, [(OTf)Re(CO)3(phdo)] and [(CH3CN)Re(CO)3(phdo)]OTf and have been characterized by FTIR, 1H NMR, 19F NMR and HRMS. Preliminary emission measurements are reported. Two completely new synthetic routes/methodologies for the synthesis of Rhenium (I) dicarbonyl bis-diimine complex are reported namely to facial-meridianal isomerization and direct CO substitution route. Both methods have been developed and demonstrated that both routes can be used to synthesise bis-diimine complexes.

Chapter 3

This chapter presents the study of temperature effect on photochemistry and photophysics of the Rhenium tetracarbonyl diimine complexes. Five complexes [Re(CO)4(4,4’-R2-bpy)]PF6 (R= NH2, CH3, H, Br or CF3) have been prepared and probed by temperature-dependent emission measurement. The photophysics and photochemistry of these complexes are governed by the formation of two mixed excited states, namely State I and State II. The State II excited-state, decays on the microsecond timescale and results in the photodissociation of a CO ligand and the interplay between these states governs both the decay. The result suggests that the temperature effect that the CO photodissociation reaction of the complexes may have two reaction barriers, the first barrier is in between state II 3 ILCT and 3 MLCT state and the second barrier is in the 3 MLCT state and the photoproduct. The temperature effect and the solvent effect affected both barriers. The substituents on the bpy ligand affected the energy of 3MLCT state which will enhance or inhibit the temperature effect and CO dissociation.

Chapter 4

The experimental methods and spectroscopic techniques used throughout this Thesis are described in this Chapter. This includes detailed descriptions of the equipment used, along with procedures and materials used.

Item Type:	Thesis (University of Nottingham only) (MRes)
Supervisors:	Michael, George
Keywords:	transition metal complexes, metal-to-ligand charge transfer, MLCT, rhenium
Subjects:	Q Science > QD Chemistry > QD146 Inorganic chemistry Q Science > QD Chemistry > QD450 Physical and theoretical chemistry
Faculties/Schools:	UK Campuses > Faculty of Science > School of Chemistry
Item ID:	74253
Depositing User:	Wong, Ngai
Date Deposited:	12 Dec 2023 04:40
Last Modified:	12 Dec 2023 04:40
URI:	https://eprints.nottingham.ac.uk/id/eprint/74253

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