St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Chemistry (School of)
  • Chemistry
  • Chemistry Theses
  • View Item
  •   St Andrews Research Repository
  • Chemistry (School of)
  • Chemistry
  • Chemistry Theses
  • View Item
  •   St Andrews Research Repository
  • Chemistry (School of)
  • Chemistry
  • Chemistry Theses
  • View Item
  • Register / Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Peri-substituted phosphorus-selenium and -tin acenaphthenes : syntheses, reactivities and radical species

View/Open
Thesis-Lu-Tao-Zhang-complete-version.pdf (6.565Mb)
Date
30/06/2021
Author
Zhang, Lu-Tao
Supervisor
Kilian, Petr
Woollins, J.D. (J. Derek)
Funder
China Scholarship Council (CSC)
University of St Andrews. St Leonard's College
University of St Andrews. School of Chemistry
Metadata
Show full item record
Abstract
The investigation of 𝘱𝘦𝘳𝘪-substitution has yielded fascinating approaches to unusual chemical bonds and interactions involving two or more atoms forced to close proximity. In this thesis, we discuss the syntheses and reactivities of a series of 𝘱𝘦𝘳𝘪-substituted P-Se and P-Sn species. Several dialkylphosphino-arylselanyl acenaphthenes Acenap (P𝘪Pr₂)(SeAr) (Ar = Mes, TRIP, Mes*), along with their transition metal complexes [M(Acenap(P𝘪Pr₂)(SeAr))ₙ] (M = Mo, Pd, Hg, Ag), have been prepared. Crystal structures and NMR properties (e.g. 𝘑MP and 𝘑MSe couplings) of these compounds have also been examined. We aimed to develop stable 𝘱𝘦𝘳𝘪-substituted systems that contain a captodative P-Se hemibond (2c-3e bond). We used P-Se acenaphthenes as radical candidates, investigating potential single-electron oxidation reactions with nitrosonium and silver (I) salts, expecting the formation of respective radical cations. The -P𝘪Pr₂ substituent is strongly electron-donating, and the bulky -SeAr groups are relatively electron-withdrawing. Therefore, the two captodative motifs were expected to form a stable P-Se hemibond. The stability of the radical centre was expected to be increased by steric shielding from the vicinal bulky arylselanyl groups and the presence of a large AI(ORꟳ)₄ weakly coordinated anion. The redox properties of the phosphine-selanes have been tested via electrochemical methods (e.g., cyclic voltammetry). The products of the potential single-electron oxidation reactions have been characterised by EPR spectroscopy. Despite all our efforts, the isolation of the desired cation radicals was not successful. In a separate project, we have investigated P-Sn acenaphthenes Acenap (P𝘪Pr₂)(SnHR₂) (R=Me, Ph) to get insight into their potential use as C-H coupling precursors. We have shown that the thermally induced reaction of these generates a phosphine-stabilised stannylene via elimination of benzene. Our observations have been supported by NMR spectroscopy; also, a gas trapping experiment indicates that benzene is formed as one of the products from fermal decomposition.
DOI
https://doi.org/10.17630/sta/406
Type
Thesis, PhD Doctor of Philosophy
Rights
Embargo Date: 2023-04-09
Embargo Reason: Thesis restricted in accordance with University regulations. Restricted until 9th April 2023
Collections
  • Chemistry Theses
URI
http://hdl.handle.net/10023/27420

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter