Shoetan, Ibrahim
2021.
Applications of N-heterocyclic carbenes.
PhD Thesis,
Cardiff University.
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Abstract
This study is on the synthesis and metal coordination of N-heterocyclic carbenes and their application as antimicrobial agents and as catalysts in hydrosilylation reaction. Chapter 2 discusses the synthesis and characterisation of surface-active proligands (imidazolium salts). Three sets of monocationic amphiphilic salts bearing methyl-imidazole, mesityl-imidazole and imidazolyl-propane-1-sulfonate head group and three sets of Gemini dicationic amphiphilic salts with head group comprising of methyl-imidazole-tethered-to-imidazole, mesityl-imidazole-tethered-to-imidazole and trimethylamine-tethered-to-imidazole with a propyl linker respectively. The hydrophobic/lipophilic part of all the amphiphilic salts are made up of alkyl chains with lengths ranging from 8 – 16 and with bromide ion as a counter anion. The critical micelle concentrations (CMC) of these amphiphilic proligands were determined by conductometric method. The synthesis of five series of Ag(I)-NHC complexes of general composition [NHC-Ag-Br] and Na+[NHC-Ag-Cl]- derived from the amphiphilic proligands and their characterisation by 1H and 13C NMR spectroscopy and High-Resolution Mass Spectrometry (HRMS) are described in chapter 3 while their in vitro antimicrobial activity against Escherichia coli NCTC 12923, Staphylococcus aureus NCTC 6571, Staphylococcus aureus NCIMB 9518, Pseudomonas aeruginosa ATCC 15692, Staphylococcus epidermidis ATCC 14990, Staphylococcus epidermidis ATCC RP62A and Candida albicans ATCC 90028 are reported in chapter 4. Chapter 5 describes the synthesis of novel metallosurfactant bearing NHC ligand systems with Pt(II) metal centre as the head group and hydrophobic tail comprising of hydrocarbon chain. These complexes were characterised by 1H and 13C NMR spectroscopy, HRMS and their application as catalysts for the hydrosilylation of terminal alkenes and an alkyne with three different hydrosilanes in water are discussed. These metallosurfactants provide extended functionality beyond their amphiphilic nature. They achieved excellent conversions and regioselectivity for the synthesis of organosilanes in a sustainable way.
Item Type: | Thesis (PhD) |
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Date Type: | Completion |
Status: | Unpublished |
Schools: | Chemistry |
Funders: | Commonwealth Scholarship Commission |
Date of First Compliant Deposit: | 10 February 2022 |
Last Modified: | 10 Feb 2023 02:30 |
URI: | https://orca.cardiff.ac.uk/id/eprint/147381 |
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