Synthesis of Chiral Sulfur-Containing Polymers: Asymmetric Copolymerization of meso-Epoxides and Carbonyl Sulfide

Abstract

Synthesis of chiral sulfur-containing polymers was realized for the first time by the asymmetric alternating copolymerization of achiral meso-epoxides with carbonyl sulfide (COS) using catalyst systems based on enantiopure binaphthol-linked dinuclear Co^III complexes under mild reaction conditions. The resultant poly(monothiocarbonate)s have main-chain chirality and more than 99 % isotacticity. Notably, the stereoregular copolymers are typical semicrystalline thermoplastics with high melting temperatures up to 232 °C. Additionally, these sulfur-containing polymers have good optical properties with refractive indices of up to 1.56 and Abbe's numbers of up to 43.

Keywords: carbonyl sulfide; cobalt; desymmetrization; polymers; synthetic methods.