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.T he resultant poly(monothiocarbonate)s have main-chain chirality and more than 99 %i sotacticity. Notably,the stereoregular copolymers are typical semicrystalline thermoplastics with high melting temperatures up to 232 8 8C. Additionally,t hese sulfur-containing polymers have good optical properties with refractive indices of up to 1.56 and Abbesn umbers of up to 43.

Heterocycle/Heteroallene Ring‐Opening Copolymerization: Selective Catalysis Delivering Alternating Copolymers

“…styrene/butadiene SBS (28 MPa stress-, 800% elongation at break) or polyurethanes PU (25 to 75 MPa stress-, 500% elongation at break), it serves as proof of potential. [164] Lu and co-workers employed an assymetric catalyst to make semicrystalline poly(monothio carbonates) from achiral meso-epoxides and COS. [165] For COS/CHO surprising given that the same systems fail in CO2 ROCOP. [169] 10.1002/anie.202104495…”

Non-Isocyanate and Catalyst-Free Synthesis of a Recyclable Polythiourethane with Cyclic Structure

“…Excessive industrial activities cause the increase of COS’s concentration in the atmosphere to become an aerial pollutant . Recently, successful copolymerization of COS with epoxides has provided a variety of well-defined polymonothiocarbonates, indicating that COS is an excellent building block for synthesizing sulfur-containing polymers. − ,− We expect to construct sulfur and nitrogen-containing polythiourethanes through the copolymerization of COS and aziridines (Scheme ), and we speculate that the weaker acidity of COS compared to CO 2 may be beneficial to weaken the homopolymerization of aziridines and achieve well-defined and alternating aziridine–COS copolymer.…”

“…Introducing heteroatoms (such as sulfur and nitrogen) into polymer structures, depending on the kind of functional groups, can endow enhanced or special characteristics to the materials. These include enhanced thermal and mechanical properties such as higher toughness and thermal stability, − metal absorption capability, − self-healing or reprocessable abilities, − and crystalline and optical properties. − Polythiourethanes are typical heteroatom-containing polymers containing both sulfur and nitrogen atoms in their structures. Unlike their oxygen analogue polyurethanes, detailed studies related to the synthesis of polythiourethanes are relatively scarce. − In fact, polythiourethanes find their utilization in optical materials, coatings, and medical technology because of their enhanced properties such as refractive index, adhesive strength, biocompatibility, and mechanical characteristics. − Polythiourethanes can be synthesized by a type of base-catalyzed nucleophilic addition of dithiols to diisocyanates (Scheme ).…”

Zwitterionic Alternating Polymerization to Generate Semicrystalline and Recyclable Cyclic Polythiourethanes

“…Structure regularity is the primary cause of polymer crystallization, which significantly improves the polymer’s thermal properties. − Our goal is to design a catalyst-free polymerization system to achieve cyclic and semicrystalline polymers with very regular structures through the ZAP of COS and aziridine compounds. COS has proven to be an excellent building block for synthesizing sulfur-containing polymers. − It has been chosen as one monomer because it is nucleophilic and less acidic. Comonomer’s acidity is an important factor affecting the alternating property in aziridine-involved copolymerization systems.…”