Synthetic, kinetic and electrochemical aspects of betadiketonato titanium(IV) complexes

English: In this study, phenyl-containing β-diketones, phenyl-containing and biphen-containing titanium(IV) complexes were synthesised. Seven of these compounds are new and five are previously reported complexes. The keto-enol isomerisation kinetics of β-diketone PhCOCH2COCH3 has been studied by 1H NMR spectroscopy in CDCl3. The temperature study of the isomer distribution biphen-containing titanium(IV) Ti(ba)2biphen complex has been studied by 1H NMR spectroscopy in CDCl3. Electrochemical studies were conducted in dichloromethane in the presence of [NBu4][B(C6F5)4] non-coordinating supporting electrolyte. Electrochemical studies in dichloromethane utilising cyclic voltammetry of both [Ti(β-diketonato)2Cl2] and [Ti(β-diketonato)2(biphen)] complexes revealed a chemical reversible Ti4+/Ti3+ couple. Electrochemically quasi-reversible behaviour was observed: for [Ti(β-diketonato)2Cl2] and for [Ti(β-diketonato)2(biphen)] with β-diketonato = acac, dbm, tfba and irreversible for Ti(PhCOCHCOCH3)2(biphen). The substitution reaction of two Cl' ions with 2,2'-biphenyldiolato-2 from the [Ti(acac)2Cl2] is reported. The substitution reaction reveals a small negative value of entropy which suggests a dissociative mechanism.