TEMPO Containing Radical Polymonothiocarbonate Polymers with Regio‐ and Stereo‐Regularities: Synthesis, Characterization, and Electrical Conductivity Studies. (11th August 2021) - Bhat, Gulzar A.
Abstract: We report the synthesis of a (2, 2, 6, 6‐tetramethylpiperidin‐1‐yl)oxidanyl) (TEMPO) appended polymonothiocarbonates through the ring‐opening copolymerization of (4‐glycidyloxy‐2, 2, 6, 6‐tetramethylpiperidine‐1‐oxyl) (GTEMPO) in the presence of carbonyl sulfide under ambient conditions. We have prepared the atactic and isotactic versions of this polymer, using enantiopure R or S forms of the GTEMPO monomer in the latter instances. Cyclic voltammetry studies revealed both oxidation and reduction events that were characteristic of TEMPO radicals. Electrical conductivity of these polymers was measured as solid‐state films after annealing the samples above their glass transition temperatures. At room temperature the isotactic polymer shows much greater conductivity (ca. 10 −4 S cm −1 ) than the atactic (ca. 10 −7 S cm −1 ), attributed to the well‐defined stereochemistry and regulated charge transport pathway of isotactic polymer chains in contrast to the irregular structure of the atactic counterpart. Abstract : The preparation of atactic and isotactic radical polymonothiocarbonates by the copolymerization of a TEMPO derived epoxide and carbonyl sulfide (COS) in the presence of the metal catalyst (salen)CrCl/PPNCl is reported. It was uncovered that there is a significant enhancement of the electrical conductivity of the isotactic copolymer (ca. 10 −4 S cm −1 ) as compared to that of the atactic copolymer (10 −7 S cm −1 ).