Star-shaped trithiophene and hexathiophene functionalized truxenes: synthesis, electropolymerization, and electrochromism

The porous structure produced by star-shaped molecules via electrochemical polymerization provides a number of transport channels, which will be beneficial for ions migration and improving electrochemical and electrochromic performance. Two novel star-shaped trithiophene and hexathiophene functionalized truxenes, Tr-3Th and Tr-6Th, were successfully synthesized. The corresponding porous polymers PTr-3Th and PTr-6Th, prepared by the electrochemical polymerization of the Tr-3Th and Tr-6Th, have provided compatible ion transport channels, which performed high electrochemical stability (maintain 99% electrochemical activity after 5000 cycles). PTr-3Th revealed colour change from light gray-green to dark gray-green upon oxidation, meanwhile, PTr-6Th presented the colour variations from light yellow to green. The result provides a new insight into the design of electrochromic polymers with good stability.