טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentDomeshek Elena
SubjectGold Corroles
DepartmentDepartment of Chemistry
Supervisor Professor Zeev Gross
Full Thesis textFull thesis text - English Version


Abstract

In this thesis we describe the expansion of the 5d corrole complexes family, which hitherto was limited to iridium and rhenium. Based on the interesting chemistry of gold complexes with other ligands and their utility in many fields, our focus was on the synthesis of gold corroles, exploration of their structural and photophysical properties, and their possible utility as catalysts in various processes.

The first attempts to insert gold into corrole via their reaction with Au(Cl)PPh3 and Au(Me)PPh3 led to changes in the corrole skeleton, mainly chlorination and oxidation of the β-pyrrole moieties.  This was prevented by utilizing a corrole in which all the β-pyrrole H atoms are substituted by bromines. Two isomeric gold(I) corrole, which differ in the kind of N-atom coordinated to a AuPPh3 moiety, were isolated from the reaction with MeAuPPh3. The more desired gold(III) complex was synthesized by two methods: a) oxidation of the corresponding gold(I) corrole; b) by the reaction of the free base corrole with chloro(tetrahydrothiophene)gold. Gold(III) acetate was also found to serve well as auration agent, which allowed for the synthesis of the gold(III) complexes of both non-brominated and bis-sulfonated corroles.

 The gold(III) complexes of both brominated and non-brominated corroles were found to display long lived photo-excited life-time and quite respectable phosphoresce quantum yields. To elucidate the effect that gold has on these luminescent properties, a comparison with analogues gold(III) and gallium(III) corroles was performed. This disclosed that: a) the non-brominated gallium corrole is only fluorescent; b) the brominated gallium corrole displays only very weak phosphorescenc. This is strong evidence that the introduction of gold into the corrole core is responsible for the remarkable changes in photophysical properties. Regarding redox chemistry, the issue of stable gold(II) corroles was addressed by electrochemical and chemical reduction of the corresponding gold(III) corrole and characterization of the obtained species by means of UV-Vis, NMR and EPR techniques.

Very promising results were obtained when the anti-cancer activity of several corroles was examined. The bis-sulfonated water soluble gold(III) corrole was found to be up to ten times more cytotoxic and cytostatic to cancer cells than the analogues gallium corrole studied before, and also more than the approved drug cis-platin. Initial investigation on a much more lipophilic corrole with a piperazine moiety revealed a further increase in cytotoxicity of up to three times greater than the amphipolar gold(III) corrole and up to five times greater than cis-platin in four different cancer cells lines.