Synthesis, crystal structure and electrochemistry of tetrahedral mono-β-diketonato titanocenyl complexes

The synthesis of a variety of tetrahedral β-diketonato titanium(IV) complexes of the type View the MathML source[(C5H5)2Ti(CH3COCHCOR)]+ClO4- with R = CF3, OCH3, C6H5, CH3 and Fc is described. The TiIII/TiIV couples and the Fc/Fc+ couple exhibited chemically and electrochemically reversible cyclic voltammetric behaviour. The formal reduction potential of the TiIII/IV couple increased as the group electronegativity of the R group of the β-diketonato ligand increased. Bulk electrolysis showed that one electron was transferred in the TiIII/IV couple and one electron in the ferrocenyl/ferrocenium redox couple in the ligand. The crystal structure for the R = OCH3 complex showed that this β-keto-ester binds through the carbonyl oxygen of the ester group and not the ether oxygen.