Sulfur Analog of Spirocyclic Orthocarbonate Capable of Undergoing Tandem Double Ring-Opening Polymerization: Synthesis, Structure, and Cationic Polymerization of Dibenzo[3,4;10,11]-1,6,8,13-tetrathiaspiro[6.6]tridecane, Property of the Polymer, and Volume Change on Polymerization

Abstract

The sulfur analog of spiroorthocarbonate (SOC) capable of undergoing tandem double ring-opening polymerization (dibenzo[3,4;10,11]-1,6,8,13-tetrathiaspiro[6.6]tridecane, 4) was synthesized, and its polymerization behavior was studied. Some properties of the polymers obtained and the volume change on polymerization of 4 were also examined. The synthesis of 4 was performed by the acid-catalyzed ester-exchange reaction of tetrakis(methylthio)methane with o-xylenedithiol and was obtained in 98% yield. The structure of 4 was determined by the spectral and elemental analysis data. Cationic polymerization of 4 with latent thermal initiator benzyl tetrahydrothiophenium hexafluoroantimonate in nitrobenzene proceeded efficiently at more than 150 °C to give the corresponding poly(thioethertrithiocarbonate) 5. The polymer structure was determined by the spectral data and further confirmed by the structures of the decomposition products formed by the reductive cleavage of the trithiocarbonate bond of with LiA1H 4 . The mechanism of the polymerization was postulated from the results obtained. Thermal properties of such as T g and T m were examined and compared with those of its oxygen analog (13). The volume change was studied in the polymerizations of4 and its oxygen analog (2), during which 5.2 and 6.7% volume expansions were observed, respectively.