Unexpected reactivity of sulfur chelators

Synthesis of novel sulfur chelators such as dithiocarbamates (DTCs), thiomaltol (Htma) and dithiomaltol (Httma) have been of interest to the Farmer lab for the last 8 years. These complexes exhibit a wide spectrum of biological activities in the antibacterial, antifungal, antimicrobial and anticancer fields. However it is their selective toxicity to melanoma which is of interest to our lab. One hypothesis that has been explored is that the specific anti-melanoma activity depends on the complexes' ability to undergo sulfur oxidation and sulfur extrusion. Studies have shown that sulfur oxygenation of thiones yield sulfine intermediates which are susceptible to sulfur atom extrusion. These findings motivated us to investigate the sulfur oxygenation and extrusion ability of our sulfur chelators.;Chapter 2 of this dissertation introduces a third generation of metal complexes containing sulfur chelators, Zn(II)bis(perthiobenzoate) and Zn(II)bis(dithiobenzoate). We report the conversion of these complexes to form novel sulfur oxygenated and sulfur extruded species when treated with peroxides. In Chapter 3, peroxidations of the model complexes [Ru(bpy)2(tma)]+ [Ru(bpy) 2(ttma)]+ and [Ru(bpy)2(ettma)]+ are investigated. The two latter complexes, unexpectedly generated products of C-H activation at their pendant methyl groups to form aldehyde and ketone products and the pathway of this unusual reaction has been explored. In addition, the C-H activation of [Ru(bpy)2(ttma)]+ has been analyzed through photo initiation in the presence of an electron acceptor, yielding the 2 electron oxidized [Ru(bpy)2(ttma-alcohol)] +. These findings are described in Chapter 4, including photochemical studies of additional metal dithiomaltol complexes such as Zn(ttma)2 , In(ttma)3 and Ga(ttma)3.