Mathematisch-Naturwissenschaftliche Fakultät

Institut für Organische Katalyseforschung

Fachgebiet: Koordinationschemische Katalyse

Betreuer: Prof. Dr. Uwe Rosenthal

Diplom-Chemiker Christian Godemann
(e-mail: )

Ansa-Titanocenkomplexe zur Untersuchung der fundamentalen Schritte in der lichtgetriebenen Wasserspaltung

This thesis deals with water splitting at titanocene complexes. The purpose was to gain a fundamental understanding of the oxidation and reduction processes at the metal centre and the water molecule. During this work, a series of organometallic titanocene complexes was synthesized and characterized.

The redox processes were investigated independently. For the water oxidation process, the first step was to optimize the synthesize procedure for the complex [(SiMe2C5Me4)2Ti(OH)2]. Irradiation experiments with visible light show that the reduction of this complex is possible due to an OH radical cleavage. Water reduction was studied using the complex [(SiMe2C5Me4)2Ti(OTf)]. Addition of water and subsequent oxidation using (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl resulted in the complex [(SiMe2C5Me4)2Ti(OH)(OTf)].

It was shown that formal abstraction of hydrogen radicals is possible while forming a titanium oxygen bond. In a further step the Ti-O bond could be cleaved using light thus reforming the starting complex. This represents an example for a synthetic cycle of overall water splitting.