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(ÏR + ÏR')] 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).
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-07162013-154508 |
| Date | 16 July 2013 |
| Creators | Freitag, Roxanne |
| Contributors | Prof J Conradie |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-07162013-154508/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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