Computational, structural and electrochemical properties of metal (III) tris-betadiketonato complexes
| dc.contributor.advisor | Conradie, J | |
| dc.contributor.author | Freitag, Roxanne | |
| dc.date.accessioned | 2015-08-17T08:48:44Z | |
| dc.date.available | 2015-08-17T08:48:44Z | |
| dc.date.issued | 2012 | |
| dc.description.abstract | English: A series of MnIII(β-diketonato)3 complexes (β-diketonato = acac, ba, dbm, tfaa, tfth, tffu, tfba and hfac) were synthesized and characterized with the aid of mass spectroscopy, elemental analysis, X-ray diffraction (crystallography) and melting point measurements. The electrochemical study (cyclic voltammetry) showed that for MnIII(β-diketonato)3 complexes with more electron withdrawing R and R' groups on the β-diketonato ligands (RCOCHCOR')-, the redox potential of the [MnIII(β-diketonato)3] + e- [MnII(β-diketonato)3] redox reaction was found to shift to more positive potentials. The reduction potential of the the MnIII/MnII couple was correlated to electronic parameters (acid dissociation constant (pKa) of the uncoordinated b- diketones (RCOCH2COR'), the total group electronegativities [Σ(cR + cR')] and total Hammett sigma meta constant [Σ(σR + σR')] of the R and R' side groups of the b-diketonato ligands (RCOCHCOR') and the calculated electron affinity of Mn(β-diketonato)3 complexes. DFT computational studies were done on the Mn(acac)3 and Mn(dbm)3 complexeto understand the Jahn-Teller distortion that that MnIII(β-diketonato)3 complexes undergo. Electrochemical (cyclic voltammetry) studies were done on M(acac)3 complexes where M = V, Cr, Mn, Fe and Co. The reduction potential of the MIII/MII couple was correlated to electronic parameters such as the metal electronegativity (cPauling and cMulliken), calculated electron affinity and LUMO energy. DFT computational studies were done on the symmetry of V(acac)3 to investigate the Jahn-Teller distortion of the V(acac)3 complex. A DFT computational study was used to illustrate the d-orbital occupations of the M(acac)3 complexes ( M = V, Cr, Mn, Fe and Co). | en_ZA |
| dc.description.abstract | Afrikaans: ‘n Reeks van MnIII(β-diketonato)3 komplekse (β-diketonato = asas, ba, dbm, tfaa, tfth, tffu, tfba en hfac) is gesintetiseer en gekarakteriseer met behulp van massa spektroskopie, element analise, X-straal diffraksie (kristallografie) en smeltpunt metings. Die elektrochemiese studie met behulp van sikliese voltammetrie het gewys dat die MnIII(β-diketonato)3 komplekse met meer electrononttrekkende R en R' groepe van die b-diketonato ligand (RCOCHCOR')-, se reduksie potensiaal van die [MnIII(β-diketonato)3] + e- [MnII(β-diketonato)3] redoks reaksie na meer positiewe potensiale verskuif het. Die MnIII/MnII redoks koppel is chemies en elektrochemies onomkeerbaar. Die reduksie potensiaal van die MnIII/MnII koppel was gekorreleer met elektroniese parameters (suurdissosiasie konstante (pKa) van die vrye b-diketoon (RCOCH2COR'), die totale groepelektronegatiwiteite en totale sigma meta Hammett konstante van die R en R' groepe van die b-diketonato ligande (RCOCHCOR')- en die berekende elektronaantrekking van die Mn(β-diketonato)3 komplekse. Kwantum-berekeningschemie studies was uitgevoer om die Jahn-Teller distorsie van Mn(acac)3 en Mn(dbm)3 beter te verstaan. Elektrochemiese studies van die M(acac)3 komplekse waar M = V, Cr, Mn, Fe en Co was uitgevoer met behulp van sikliese voltammetrie. Die reduksie potensiaal van die MIII/MII koppel was gekorreleer met the metal se elektronegatiwiteit (cPauling en cMulliken), berekende elektronaantrekking en the energie van die laagste ongevulde molekulêre orbitale. Kwantumberekeningschemie studies was gedoen om die simmetrie van V(acac)3 om die Jahn-Teller distorsie van die kompleks te ondersoek. Kwantum-berekeningschemie studies was uitgevoer om die d-orbitaal opvulling van die M(acac)3 komplekse (M = V, Cr, Mn, Fe en Co) te illustreer. | |
| dc.identifier.uri | http://hdl.handle.net/11660/879 | |
| 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 | Voltammetry | en_ZA |
| dc.subject | Crystallography | en_ZA |
| dc.subject | Electrochemistry | en_ZA |
| dc.subject | Mass spectrometry | en_ZA |
| dc.subject | Metal complexes | en_ZA |
| dc.subject | Catalysis | en_ZA |
| dc.subject | Manganese | en_ZA |
| dc.subject | B-diketonato | en_ZA |
| dc.subject | Tris(acetylacetonato)metal | en_ZA |
| dc.subject | Dissertation (M.Sc. (Chemistry))--University of the Free State, 2012 | en_ZA |
| dc.title | Computational, structural and electrochemical properties of metal (III) tris-betadiketonato complexes | en_ZA |
| dc.type | Dissertation | en_ZA |