Synthesis and Characterisation of N-substituted Pyrrole Monomers and Polypyrrole Films

In this body of work, the polymerisation of N-substituted pyrrole monomers and the functionalisation of the monomers or the resulting polymers, with transition metal complexes, were performed. Polymer deposition was executed, utilising the electrochemical deposition technique, due to its facile use and the unequivocal control attained during the experimental procedure. The pyrrole monomers employed, possessed either azide, 2,2’-bipyridine or nitrile moieties, as these species have been universally exploited in cycloaddition and coordination chemistry. Firstly, N-(10-azidodecyl)pyrrole, N-(3-azidopropyl)pyrrole and N-(2- azidoethyl)pyrrole were electropolymerised in the bulk morphology and characterised. Then, employing copper(I)-catalysed azide-alkyne cycloaddition chemistry, the monomers, N-(10-azidodecyl)pyrrole and N-(2-azidoethyl)pyrrole, were reacted with the redox active molecule, ethynylferrocene, to yield the products, 1-[10-(4-ferrocenyl-1H-1,2,3-triazol-1yl)decyl]pyrrole and 1-[2-(4-ferrocenyl-1H�1,2,3-triazol-1yl)ethyl]pyrrole, which were subsequently electropolymerised and characterised. Development of a novel, template-free, electrodeposition method yielded the facile fabrication of the nanostructured poly[N-(2-azidoethyl)pyrrole] film, shown using field emission scanning electron microscopy and transmission electron microscopy. The deposition mechanism, involving a bielectrolyte co-solvent system, was investigated using nucleation and growth mechanisms, while the roles of both the ‘seed’ (LiClO4) and ‘bulk’ ((NH4)H2PO4) electrolyte were determined. Chemical post-functionalisation of the nanowire film, via copper(I)-catalysed azide-alkyne cycloaddition chemistry, permitted the covalent attachment of ethynylferrocene, which created the possibility of a very effective, mediator-less (covalently bound), nanostructured biosensor. A novel pyrrole monomer, 4,4’-bis-(N-propyl-3-pyrrole-carbamoyl)-2,2’-bipyridine was synthesised and coordinated with Group 6 metal carbonyls, producing 4,4’-bis- (N-propyl-3-pyrrole-carbamoyl)-2,2’-bipyridine tetracarbonyl chromium(0), molybdenum(0) and tungsten(0). The electroactivity of 4,4’-bis-(N-propyl-3-pyrrole�carbamoyl)-2,2’-bipyridine tetracarbonyl molybdenum(0) was determined utilising cyclic voltammetry, while the controlled release of carbon monoxide was induced by introducing acetonitrile. The 4,4’-bis-(N-propyl-3-pyrrole-carbamoyl)-2,2’- bipyridine ligand was electropolymerised and post-functionalisation with Group 6 metal carbonyls was attempted, to possibly produce medically beneficial carbon monoxide releasing polymers. Utilising the nitrile moiety, tricarbonyl cyclopentadienyl N-2-(5-tetrazolatephenyl) molybdenum(II), tricarbonyl cyclopentadienyl N-2-(5-tetrazolate-2-thiophene) molybdenum(II) and tricarbonyl cyclopentadienyl N-2-(5-tetrazolate-1-benzyl) molybdenum(II) were synthesised via cycloaddition chemistry employing sodium azide. N-(2-cyanoethyl)pyrrole, possessing the ability to be electrodeposited as a nanostructured film was employed, producing dicarbonyl cyclopentadienyl (N-2-(5- tetrazolate-2-ethylpyrrole) iron(II).

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

National University of Ireland Maynooth

Year dc:date.issued

2013

Author dc:creator

• McGuinness, Niall B.

Language dc:language

en