Design and synthesis of dithiolene based biomimetic compounds for metal ion sensors and oxo-transfer catalytic applications

Because heavy metal ions prefer to bind sulfur, inspired by molybdopterin the main goal of this work was combining dithiolene binding moieties with optically active substituents with the aim to detect/capture metal ions, which could preferably bind to the dithiolene moiety of for instance MPT. Therefore a number of dithiolene based molecules mimicking the natural immediate coordination sphere composition of Mo and W dependent oxidoreductase enzymes were synthesized and characterized by NMR, MS, IR, X-ray crystallography, UV-Vis, EPR and electrochemical methods. In order to work at the lowest possible base concentration due to potentially base sensitive substituents and reaction partners, the procedure for the de-protection of the ligand precursors and the in situ complexation reaction was first optimized in course of the work and interim we explored the surprising fact that the ring opening reaction of the 1,3- dithiol-2-one system is fully reversible and can be controlled simply by adjusting the pH-value of the solution. Then, the coordination behavior of the de-protected ligands towards different metal ions, including biologically relevant ions like Cu+, Cu2+, Fe3+ was tested. As the optically active substituents necessarily possess interesting electronic properties, a second focus of this work was to utilize the developed ligand systems for MoCo and WCo models and to investigate their potential catalytic activity in the model oxotransfer reaction between DMSO and PPh3 in order to evaluate the substituent’s effect on the dithiolene binding moiety.Da Schwermetalle Schwefel als Bindungspartner bevorzugen, war das Hauptziel der Arbeit, inspiriert von Molybdopterin, die Kombination von Dithiolen-Bindungsmotiven mit fluoreszierenden Substituenten, um Metallionen zu detektieren, die an das Diothiolen-Motiv binden. Daher wurden eine Reihe dithiolenbasierter Moleküle synthetisiert, die die unmittelbare Koordinationssphäre in Mo bzw. W-basierten Oxidoreduktasen imitieren. Diese wurden dann durch spektroskopische und elektrochemische Methoden untersucht. Durch die interessanten elektrischen Eigenschaften von fluoreszierenden Substituenten war ein weiterer Fokus dieser Arbeit, Ligandesysteme für MoCo und WCo Modelle zu entwickeln und deren potentielle katalytische Aktivität in der Modellreaktion mit DMSO und PPh3 zu testen, um den Effekt der Substituenten auf die Dithiolen-Gruppe zu untersuchen