Département de chimie moléculaire

Different N-substituted phenothiazines have been synthesized and their electrochem. behavior has been investigated in CH3CN in order to design the best polyphenothiazine based cathodic material candidate for lithium batteries. These compds. exhibit two successive reversible one-electron oxidn. processes. Ab initio calcns. demonstrate that the potential of the first process is a result of both the hybridization effects between the substituent and the phenothiazine unit as well as the change of conformation of the phenothiazine heterocycle during the oxidn. process. More specifically, we show that an asym. MO spreading throughout an external cycle of the phenothiazine unit and the alkyl fragment is formed only if the alkyl fragment is long enough (from the Me moiety onwards) and is at the origin of the bent conformation for N-substituted phenothiazines during oxidn. Electrochem. investigations supported by ab initio calcns. allow the selection of a phenothiazinyl unit which is then polymd. by a Suzuki coupling strategy to avoid the common solubilization issue in carbonate-based liq. electrolytes of lithium cells. The first electrochem. measurements performed show that phenothiazine derivs. pave the way for a promising family of redox polymers intended to be used as org. positives for lithium batteries. [on SciFinder(R)]