New classes of luminescent transition metal complexes, including the systems of rhenium(I) tricarbonyl diimine, cyclometalated iridium(III) diimine, cyclometalated rhodium(III) diimine, ruthenium(II) diimine and ruthenium(II) terpyridine complexes tethered with rhodamine moieties, have been synthesized. The X-ray crystal structure of one of the cyclometalated rhodium(III) diimine complexes with rhodamine pendants, [Rh(SPLC2N2)(ppy)2](PF6) has been determined. The molecular structure of [Rh(SPLC2N2)(ppy)2](PF6) showed a distorted octahedral geometry and the rhodamine moiety was found in a spirolactam closed-ring form. All of them were found to exhibit emission in fluid solution. The emissions of rhenium(I) tricarbonyl diimine and ruthenium(II) polypyridyl complexes are derived from the triplet metal-to-ligand charge transfer (3MLCT) excited state, i.e. from dπ orbital of the rhenium(I) or ruthenium(II) metal center to the π* orbital of the diimine ligand; while that of cyclometalated iridium(III) diimine complexes is (3MLCT) [dπ(Ir) → π*(N^N)] and that of cyclometalated rhodium(III) diimine complexes involves the (3IL) [π → π*(N^C)] excited state, probably mixed with (3MLCT) [dπ(Rh) → π*(N^C)] character. The cation-binding properties of these complexes toward alkali, alkaline-earth and transition-metal cations were investigated by electronic absorption and emission spectrophotometries. Some of them were found to exhibit new low-energy absorption and emission bands, characteristic of the rhodamine absorption and emission, with high selectivity and sensitivity for certain transition metal cations. A series of rhodamine-appended Schiff base organic compounds has also been synthesized in order to explore their capability as luminescent lanthanide ion sensors. The lanthanide ion binding properties of one of the compounds in acetonitrile were examined. Upon addition of lanthanide ions, new intense low-energy electronic absorption and emission bands were also observed, characteristic of the rhodamine absorption and emission, demonstrating its lanthanide ion sensing behaviour. / published_or_final_version / Chemistry / Master / Master of Philosophy

The aim of this study was to synthesise mono-phosphite complexes of type [Rh(OX)(CO){P(OY)3}], (where Y = the different phosphites that were used and OX = 8-hydroxyquinoline) and to do a kinetic study of iodine oxidative addition to these rhodium(I) square planar complexes in order to determine the rate constants and the reaction mechanism. Part of the characterization was X-ray crystallographic structure determinations which were done on two complexes, namely the [Rh(OX)(CO){P(O(2,4-t-BuPh))3}] and the [Rh(OX)(CO){ P(O(2,6-diMePh))3}]. From the characterization methods it can be said with certainty that the synthesis of the mono-phosphite rhodium(I) complexes was successfully achieved. Table 1 - Selected crystal data as obtained for the two Rh(I) crystal structures solved in this study. [Rh(OX)(CO){P(O(2,4-t- / Prof. A. Roodt

Please refer to full text to view abstract / Prof. A. Roodt