Facile Synthesis of Functional Polytrithiocarbonates from Multicomponent Tandem Polymerizations of CS2, Thiols, and Alkyl Halides

Abstract

Polytrithiocarbonates have attracted significant attention recently because of their good thermal stability, light refractivity, crystallinity, and mechanical properties; however, the exploration of their structures and functionalities has been limited by their synthetic approaches. Multicomponent polymerization featuring simple monomers, mild conditions, diversified product structures, and high efficiency could provide a powerful and versatile tool to synthesize various polytrithiocarbonates from commercially available monomers. Herein, a robust and efficient multicomponent tandem polymerization (MCTP) of CS₂, dithiols, and alkyl halides was developed in DMF with K₂CO₃ at room temperature in air to synthesize 12 polytrithiocarbonates with diversified and systematically tuned structures, high molecular weights (M_ns up to 37900 g/mol), and high yields (up to 93%). Depending on the different polymer backbone structures, amorphous polytrithiocarbonates showed excellent breaking elongations, and crystallinic polytrithiocarbonates possessed a large process temperature window (about 200 °C) and good mechanical performance (σ_B of 23.6 MPa and ε_B of 858%), whose tensile strength could be dramatically enhanced to 87.5 MPa after uniaxial extension deformation. The upper critical solution temperature (UCST) in organic solvents, together with nonconventional luminescence, were observed for the crystallinic polytrithiocarbonates, even without any aromatic ring. This efficient, robust, mild, and economic MCTP of CS₂ thus opened up an avenue for the facile construction of polytrithiocarbonates with structural diversity, bringing modulable mechanical, thermal, luminescent, and thermal-responsive properties, which would greatly broaden the scope of structures and applications of sulfur-containing polymers.