3,4-ethylenedioxythiophene derivatives with tuned properties & precursors for solid-state oxidative preparation of polythiophenes

Conductive polymers prepared under oxidative conditions whether via chemical or electrochemical avenues are often insoluble as a result of their rigid conjugated polymeric backbones. A new avenue to their processability developed by the Sotzing group is the “precursor approach”. Here, electroactive units are appended to conventional polymeric backbone that can be solution processed into desired forms. Upon attaining their designated form, they are conveniently converted into their conductive form in their solid state. Different polythiophenes were prepared under this protocol with polynorbornene and polyvinylpyrrolidinone backbones and their key optical and electrochemical properties compared to their respective linear analogs. ^ Similarly, in-chain precursors that incorporated sacrificial dimethylgermane and dimethylsilane bridges in controlled proportions on the conjugated polymer backbone in an alternating fashion were explored. More importantly, they underwent oxidative conversion into their conductive form in their solid state with release of the inorganic entities. In addition, the optical properties of the resultant conductive polymers were dictated by the ratio of the two inorganic bridges in the parent precursor.^ Related to this, novel highly versatile synthons based on the most popular polythiophene, poly(3,4-ethylenedioxythiopnene) (PEDOT) were prepared in good yields. These materials possessed unique optical and electrochemical properties in comparison to PEDOT. In addition, they possessed reactive functionalities that are amenable to further functionalization to form new monomeric units.