Synthesis and characterisation of ligand-bridged tungsten and chromium penta- and tetra-carbonyl complexes
| dc.contributor.advisor | Kolawole, G.A. | |
| dc.contributor.author | Sinuka, Ludwe | |
| dc.date.accessioned | 2011-09-27T10:50:29Z | |
| dc.date.available | 2011-09-27T10:50:29Z | |
| dc.date.issued | 2002 | |
| dc.description | Submitted to the Faculty of Science and Agriculture In fulfilment of the requirement for the award of the degree of Master of Science in the Department of Chemistry University of Zululand, South Africa, 2002. | en_US |
| dc.description.abstract | Ligand bridged metal carbonyl complexes of the form [5(CO)MLM(CO)5], [4(CO)MLM(CO)4] and [4(CO)ML], where M is either tungsten or chromium and L is either trans-l,2-(bis-4-pyridyl)ethylene(TBE) or 3,6-di-2-pyridyl-l,2,4,5-tetrazine (DPT) have been synthesised. They were characterised using IR, UV-Vis and NMR, MS, TLC and microanalysis. Electronic spectral studies showed that both the dinuclear, [4(CO)CrDPTCr(CO)4] and mononuclear, [4(CO)CrDPT] complexes have MLCT transitions at 900.88 nm and 652.52 nm respectively. The dinuclear MLCT is more intense and broad and is deemed to have overlapped with the d-d transitions observed in the mononuclear complex at 909.45 nm. However, intra-ligand transitions were observed at 279.97 nm, 303.53 nm and 382.75 nm for both mononuclear and dinuclear complexes. Photoluminescence spectra showed two emissions for [TBE{W(CO)5}2]; with the emission at 530 nm originating from an MLCT transition, and the one at 353 nm originating from an intra-ligand transition. For [4(CO)CrDPTCr(CO)4] and [4(CO)CrDPT], a single broad emission was observed at 523 nm and 460 nm respectively. A small peak at 400 nm in the dinuclear complex is observed and is tentatively attributed to an intra-ligand transition. A structure of distorted octahedron is proposed for pentacarbonyl/ro^-l^-(bis-4-pyridyl) emyIenetungsten. | en_US |
| dc.description.sponsorship | National Research Foundation in South Africa and the Royal Society in the United Kingdom. | en_US |
| dc.identifier.other | 268174 | |
| dc.identifier.uri | https://hdl.handle.net/10530/900 | |
| dc.language.iso | en | en_US |
| dc.subject | Ligand field theory | en_US |
| dc.title | Synthesis and characterisation of ligand-bridged tungsten and chromium penta- and tetra-carbonyl complexes | en_US |
| dc.type | Thesis | en_US |
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