Thesis
Investigations of s-block organoelement (nitrogen, oxygen) chemistry
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2024
- Thesis identifier
- T16923
- Person Identifier (Local)
- 202092937
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- It is an exciting time to be researching main group chemistry, especially s-block chemistry, as recent years have witnessed the opening up of several new fronts in the development of the Group 1 and Group 2 chemistry. Partly industrial (sponsored by Innospec Ltd) and partly fundamental, this project reflects such diversity. The industrial part considered a negative aspect of these metal compounds, that sodium carboxylate salt deposits cause a range of problems in diesel engines including misfiring, injector malfunction and failure, causing increased fuel consumption and emissions. Following up previous work by the group determining the structures of relevant long chain sodium carboxylates, here the focus turned to one possible contamination source of them in ammonium carboxylates, the structural chemistry of which has been enhanced by 16 crystal structures of one-dimensional zig-zag polymeric chains constructed of 12-, 26-, or 34-membered ring systems. Much of the project's work was devoted to preparing tripodal modifications of the common NacNacH (Me, Dipp) molecule derived from 2,6-diisopropylphenyl-βmethyldiketimine. Lithiation of NacNacH, followed by reactions with isocyanates, isothiocyanates and a carbodiimide, and aqueous work-up accessed tripodal NacNac variants with N,N,N,O; N,N,N,S; or N,N,N,N potential dentation sites. Many were crystallographically characterised, while distinct ligating modes of these new ligands were elucidated through crystal structures of their lithiated precursors. Surprisingly, literature searches revealed that LiNacNac and NacNacMg(TMP) (tetramethylpiperidide) have rarely been reported in reactions with common carbonyl substrates. Therefore, metal products from reactions with benzaldehyde and assorted ketones were synthesised and crystallographically characterised. Extended to rubidium and caesium via reaction of their HMDS (hexamethyldisilazide) complexes with benzaldehyde and acetophenone, revealed a diversity of eye-catching structural outcomes in an enolate with a hexagonal prismatic network, two dienolates with distinct ladder motifs, and two β-imino-alkoxides comprising zig-zag chains of metal– oxygen bonds in infinite cages.
- Advisor / supervisor
- Robertson, Stuart
- Mulvey, Robert
- Barker, Jim
- Resource Type
- Note
- Previously held under moratorium from 14/05/2024 to 14/05/2026.
- DOI
- Funder
- Embargo Note
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File | 2024-08-27 | Embargo |