New electrochromic organometallic materials for light modulation
Creators: name: Grelaud, Guillaume
Publisher: name: The Australian National University
Year: 2012
Subjects: subject: Organometallic compounds Optical properties
subject: Nonlinear optics Materials
subject: Optical materials
subject: Electrochromic devices

description: Group 8 metal alkynyl complexes are particularly attractive as building blocks for nonlinear optical materials for two reasons: the high efficiency of the resulting materials, especially for large complexes such as dendrimers, and the possibility of switching the nonlinear activity using various stimuli. The work reported in this thesis focuses on the second aspect, using an already existing complex as starting point and optimizing its properties by various structural modifications. In the Introduction, the theory of nonlinear optics, its various effects, and experimental methods for measuring NLO responses are presented. The effect of structural variations on the NLO activities of group 8 metal alkynyl complexes is reviewed to contextualize the present work. A new type of heterobimetallic complex is studied as potential redox end-group in the first chapter, with a special focus on its properties in the mixed-valent state. In a second part of this chapter, the possibility of using a more extended analogue of the ferrocenyl end{u00AD}group is explored, with a report on the third-order NLO activity of a model complex bearing this extended end-group. The second and third chapter share the same topic, concerned with the use of triphenylpnictogen as connecting cores for octupolar complexes. The use of triphenylamine is covered in the second chapter, the aim being to increase the number of redox states obtainable within a given octupolar complex as a result of the unique properties of triphenylamine-type compounds. In the third chapter, triphenylphosphine and its P(V) derivatives are investigated. This study, which led to the use of extended triphenylphosphine oxide is detailed in the first part of this third chapter. In a second part, the synthesis and characterization of the physicochemical properties of complexes bearing this extended triphenylphosphine core is discussed. Lastly, in the fourth chapter, the search for new types of redox-switchable end-group is pursued. After judicious structural modification of a simple starting complex, two new and different types of functionalities have been developed. In the first part of this last chapter, functionalization of the model complex with a pendant alkyne group is demonstrated to allow for the grafting of this complex on silicon surfaces, giving the opportunity of obtaining a redox-switchable material out of these air-stable ferrocenyl ruthenium alkynyl complexes via a simple modification. The synthesis of potentially Si-graftable precursors related to these complexes is also presented. In the second part, the possibility of using ferrocenyl allenylidene as redox-switchable groups is presented. It is demonstrated that these complexes might lead to systems possessing a dual type of redox switching, namely using either oxidation or reduction, leading to new possibilities in the design of NLO-active multi{u00AD}redox-stable molecules.