Aniline tetramer groups

Polythiophene randomly grafted with alkyl and aniline tetramer groups (157) was synthesized. The tetramer was chosen because it is the minimum oligomer size that mimics the electrochemical behavior of polyaniline, which shows semiconduction and conduction behavior depending on its state of oxidation and the pH. Transition from one structure to the other is illustrated in equation 23, where the electron mobility of quinonoid states (158) rearranging to isolated free radicals (159) is precluded after reduction to 160. A correlation was found between the electrochemical behavior and the UVV-NIR spectra of the 157 polymers255. 

These facts are perfectly matched with our above-mentioned desired requirements. In addition, alkyl zinc is known to be less basic and deprotonation of ketone-aniline 36 by zinc reagent is highly unlikely. However, one of the issues for this reaction was the requirement for two alkyl groups on the zinc metal since the product ends up as tetramer 61, where the zinc atom still has one alkyl group, recalling that our cyclopropylacetylene (37) is not easy to obtain. 

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