Novel bonding motifs in low-valent nickel complexes : Dewar, Chatt, and Duncanson revisited
department or school: Science, Faculty of
department or school: Chemistry, Department of
data provider: DSpace
degree campus: UBCV
creator: He, Weiying
issued: 2022-05-31T07:00:00Z
issued: 2021
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The classic Dewar-Chatt-Duncanson (DCD) model describes the bonding in transition metal-olefin complexes. In this framework, electron density can be bidirectionally relocated through binary frontier orbital interactions: σ donation and π back donation. Modern spectroscopic and theoretical methods have allowed us to probe the boundary of the framework of this bonding pattern, indicative of the existence of unique DCD model metal complex derivatives. The introduction of this thesis is developed in Chapters 1 & 2, illustrating both the historical context for the development of the DCD model, and its utility in investigating catalyst transfer polycondensation with Ni(0) catalysts in polymer science. Chapter 3 & 4 describe our initial studies using advanced synchrotron-based X-ray absorption spectroscopic methods to comprehensively re-examine this classic electronic structure and provide a framework for the interpretation of synchrotron spectroscopy of nickel complexes. These studies reveal the importance of ancillary ligands to enable strong metal-olefin bonding via ligand-induced backbonding. Insights from these systematic studies afforded the opportunity to examine its relevance in catalytically-relevant systems. Chapter 5 reveals how these insights could be leveraged to stabilize previously elusive analogs of the previously proposed Ni(0) π intermediate in catalyst transfer polycondensation of polythiophenes. The dynamic behaviour of these π -intermediates along the delocalized polymer backbone, i.e. so-called ring-walking along the polymer chain , is explored both via experimental and computational methods. An additional example of DCD-like bonding with unique properties is explored in Chapter 6, where a unique agostic interaction is identified and explained in some low-valent linear Ni(I) complexes, whose electronic structure provides a previously unreported mode of agostic bonding. The application of advanced physical methods to classic problems in organometallic …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/78299
note: Novel Bonding Motifs in Low-valent Nickel Complexes: Dewar, Chatt, and Duncanson revisited by Weiying He B.Sc., Sichuan University, 2016 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Chemistry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) May 2021 © Weiying He, 2021 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Novel Bonding Motifs in Low-valent Nickel Complexes: Dewar, Chatt, and Duncanson revisited Submitted by Weiying He in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry. Examining Committee: Pierre Kennepohl, Affiliate Professor, Department of Chemistry, UBC Associate Professor, Department of Chemistry, Ucalgary Co-Supervisor Parisa Mehrkhodavandi, Professor, Department of Chemistry, UBC Co-Supervisor Michael Wolf, Professor& Head, Department of Chemistry, UBC Supervisory Committee Member Keng Chou Professor, Department of Chemistry, UBC Supervisory Committee Member Laurel Schafer Professor, Department of Chemistry, UBC Supervisory Committee Member Mark Thachuk Associate Professor, Department of Chemistry, UBC University Examiner Eric Cytrynbaum Associate Professor, Department of Mathematics, UBC University Examiner iii Abstract The classic Dewar-Chatt-Duncanson (DCD) model describes the bonding in transition metal-olefin complexes. In this framework, electron density can be bidirectionally relocated through binary frontier orbital interactions: σ donation and π back donation. Modern spectroscopic and theoretical methods have allowed us to probe the boundary of the framework of this bonding pattern, indicative of the existence of unique DCD model metal complex derivatives. The introduction of this thesis is developed in Chapters 1 & 2, illustrating both the historical context for the development of …
has type: Thesis/Dissertation
date issued: 2021-11
is shown at: 10.14288/1.0397434
language: eng
degree discipline: Chemistry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Kennepohl, Pierre
contributor: Mehrkhodavandi, Parisa
type: Text
identifier URI: http://hdl.handle.net/2429/78299