{"id":{"repo_id":"zulu","oai_identifier":"oai:uzspace.unizulu.ac.za:10530/900"},"canonical_url":"https://search.dev.ndltd.org/etd/zulu/oai:uzspace.unizulu.ac.za:10530/900","repository":{"repo_id":"zulu","name":"University of Zululand","base_url":"https://uzspace.unizulu.ac.za/server/oai/request"},"display":{"title":"Synthesis and characterisation of ligand-bridged tungsten and chromium penta- and tetra-carbonyl complexes","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.","abstract_html":"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.","abstract_has_math":false,"creators":["Sinuka, Ludwe"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Kolawole, G.A."],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002","date_published":"2002","updated_at":"2026-07-24T06:17:19Z","subjects":["Ligand field theory"],"languages":[],"rights":[],"rights_urls":["https://devspace.unizulu.ac.za/bitstreams/7215a473-3cae-497a-a421-0ee73d7f54ce/download"],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Kolawole, G.A."]},{"key":"dc:contributor.sponsor","label":"Sponsor","values":["National Research Foundation in South Africa and the Royal Society in the United Kingdom."]},{"key":"dc:creator","label":"Author","values":["Sinuka, Ludwe"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2002"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["http://hdl.handle.net/10530/900"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ligand field theory"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["https://devspace.unizulu.ac.za/bitstreams/7215a473-3cae-497a-a421-0ee73d7f54ce/download"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://devspace.unizulu.ac.za/bitstreams/625ab76c-0a91-492c-9d0d-95240f2b512e/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["135188b41241026a61ae1bfc68b8ecf2","8a4605be74aa9ea9d79846c1fba20a33","8b7a58a460bbaed5091cc67bc4ecad5d"]},{"key":"dc:title","label":"Title","values":["Synthesis and characterisation of ligand-bridged tungsten and chromium penta- and tetra-carbonyl complexes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Kolawole, G.A."],"dc:contributor.sponsor":["National Research Foundation in South Africa and the Royal Society in the United Kingdom."],"dc:creator":["Sinuka, Ludwe"],"dc:date.issued":["2002"],"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."],"dc:format.checksum.md5":["135188b41241026a61ae1bfc68b8ecf2","8a4605be74aa9ea9d79846c1fba20a33","8b7a58a460bbaed5091cc67bc4ecad5d"],"dc:identifier.uri":["https://devspace.unizulu.ac.za/bitstreams/625ab76c-0a91-492c-9d0d-95240f2b512e/download"],"dc:relation.isreferencedby":["http://hdl.handle.net/10530/900"],"dc:rights":["https://devspace.unizulu.ac.za/bitstreams/7215a473-3cae-497a-a421-0ee73d7f54ce/download"],"dc:subject":["Ligand field theory"],"dc:title":["Synthesis and characterisation of ligand-bridged tungsten and chromium penta- and tetra-carbonyl complexes"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T06:17:19Z"}