The characterisation and kinetic study of rhodium(I) and iridium(I) triazole complexes
| dc.contributor.advisor | Basson, S. S. | |
| dc.contributor.advisor | Purcell, W. | |
| dc.contributor.author | Muller, Alfred Johannes | |
| dc.date.accessioned | 2017-06-15T06:33:00Z | |
| dc.date.available | 2017-06-15T06:33:00Z | |
| dc.date.issued | 2000-11 | |
| dc.description.abstract | English: A number of triazolecyclooctadienemetal(l) complexes of the type [M(LL')(cod)] (where M = Ir or Rh and LL' represents the different bidentate N-N'- donor atom ligands, such as bpt-Nl+ and bpt) as well as their oxidative addition products [M(LL')(cod)(Me)(I)] have been prepared and characterised by IR, ¹H NMR and elemental analyses. It was found that in general these complexes are monomeric containing one LL' and cod ligand respectively. The oxidative addition between CH31 and the studied metal(l) complexes have been investigated on a UVNis . spectrophotometer. Under pseudo-first order conditions linear relationships were found indicating second order kinetics. All of the kinetic data had zero intercepts (within experimental error) indicating that no reverse reactions occur. The reactions were carried out in different solvents to study the influence of solvent properties on the reaction rate. The reactions were also conducted at different temperatures to calculate the activation parameters. These indicated an associative mechanism as what is usually expected from these types of complexes. The ability of the LL' bidentate ligands to increase the Lewis basicity of the metal center are reflected in the values of the second order rate constants. From this we can compile the following series indicating the different bidentate ligands' donating capabilities: macsm> AnMetha > hpt > bpt-Nl+ > sacac> tfaa > cupf > bpt' The activation ability of the bpt-Nl+ ligand for oxidative addition to the metal center is better than that of the bpt ligand given the correct solvent and metal center are chosen. It seems that in the case of the [M(bpt-NH)( cod)] complexes the rhodium analogue is more reactive, while the opposite case' is observed for the- [M(bpt)(cod)] complexes. Thus the bpt-Nl+ ligand is the better 0- donor in the rhodium complex, while the bpt ligand is the better 0- donor in the iridium complex. | en_ZA |
| dc.description.abstract | Afrikaans: 'n Aantal triasoolsiklooktadiëenmetaal(l) komplekse van die tipe [M(LL')(cod)] (waar M = Ir of Rh en LL' verskillende bidentate ligande met N-N'- donoratome soos byvoorbeeld bpt-Nl+ en bpt) sowel as hulle oksidatiewe produkte [M(LL')(cod)(Me)(I)], is berei en gekarakteriseer met behulp van IR, ¹H KMR en element analises. In die algemeen -is die bestudeerde komplekse monomenes met een bidentate ligand en 'n siklooktadiëenmolekuul. Die oksidatiewe addisie van CH31 aan die metaal(l) komplekse is bestudeer op 'n UV/Sigbare spektrofotometer. Onder pseudo- eerste-orde kondisies word 'n reglynige verband gevind, kenmerkend van tweede-orde kinetika. AI die kinetiese data het binne eksperimentele fout nulafsnitle wat daarop dui dat geen terugwaartse reaksie plaasvind nie. Die reaksie is ook in verskillende oplosmiddels gedoen om die effek van oplosmiddeleienskappe op die reaksietempo te bestudeer. Die reaksies is ook by verskillende temperature gedoen om die aktiveringsparameters te bepaal. Die eksperimentele waardes is kenmerkend van 'n assosiatiewe meganisme soos verwag word vir hierdie tipe komplekse. Die vermoë van die bidentate ligande om die Lewisbasisiteit van die metaalsentrum te verhoog word in die waardes van die tweede-ordetempokonstantes weerspiëel en op grond daarvan is die ligande volgens hul doneringsvermoë in die volgende ordereeks geplaas: macsm> AnMetha > hpt > bot-Nl+ > sasas> tfaa > kupf > bpt Die aktiveringsvermoë van bpt-Nlf vir oksidatiewe addisie van die metaalsentrum is beter as die van die bpt ligand, gegewe die korrekte oplosmiddel en metaalsentrum. Dit blyk dat in die geval van die [M(bpt-NH)( cod)]-komplekse die rodiumanaloog meer reaktief is, terwyl die teenoorgestelde waargeneem word vir [M(bpt)(cod)]-komplekse. Dus is die bot-Nl+ ligand die beter adonor in die rodiumkompleks, terwyl die bpt in die iridiumkompleks die beter a-donor is. | af |
| dc.identifier.uri | http://hdl.handle.net/11660/6369 | |
| dc.language.iso | en | en_ZA |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Rhodium | en_ZA |
| dc.subject | Iridium | en_ZA |
| dc.subject | Triazoles | en_ZA |
| dc.subject | Dissertation (M.Sc. (Chemistry))--University of the Free State, 2000 | en_ZA |
| dc.title | The characterisation and kinetic study of rhodium(I) and iridium(I) triazole complexes | en_ZA |
| dc.type | Dissertation | en_ZA |