Dr. A. Kumar at IIT B Department of Chemistry has devised a way to novelly synthesize 3,4-propylenedioxyhiophene derivatives with pendant functional groups capable of being processed. The devised way can also help synthesize their oligo-, polymeric and copolymeric derivatives. These polymers are intrinsically capable of conducting electrons because of their ?-electrons are along the main chain exhibiting non-linear optical properties and after oxidation and reduction they are good electrical conductors. These synthesized compounds show promise in uses such as, data storage, optical signal processing, suppression of EMI and solar energy conversion. The synthesized molecules can also be used in rechargeable batteries, light-emitting diodes, electrochromic windows, display panels, field-effect transistors, print circuit boards, chemical biosensor and antistatic materials.
In one of the synthesis processes, Diethyl malonate is reacted with ethyl haloformate in dry organic solvent in presence of a base to produce 2-ethoxycarbioyl-malonic acid diethyl ester. The ester produced initially is reacted with alkyl halides or alkyl tosylate in a solvent to produce
alkyl 2-ethoxycarbonyl-malonic acid diethyl ester. This new ester is reduced in solvent by a reducing agent to give alkyl tiols. The alkyl thiol is further reacted with 3,4-dialkoxythiophene in dry organic solvent and catalyst acid to give (3-alkyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-3-yl)-methanol which is further reacted with alkyl halides, alkyl tosylates or alkane sultones in presence of a catalyst and base in dry organic solvent to give a 3,4-propylenedioxyhiophene derivative. Two alternative routes have also been developed with differing starting material and reagents also help to novelly synthesize other 3,4-propylenedioxyhiophene derivatives. With the help of chemical, oxidative or reductive reactions polymers or copolymers can be made from the resultant drivatives.
Indian patent application no. 347/MUM/2005 Patent grant no.
Inventors: A Kumar and S P Mishra