Facile Access to Functionalized Poly(thioether)s via Anionic Ring-Opening Decarboxylative Polymerization of COS-Sourced α-Alkylidene Cyclic Thiocarbonates

Herein, a series of alpha-alkylidene cyclic thiocarbonates (alpha CTCs) have been selectively synthesized from carbonyl sulfide (COS) and primary propargylic alcohols and polymerized via anionic ring-opening decarboxylative polymerization (ARODP) in the presence of alkali metal alkoxides as initiating systems. The generated polymers have exclusive thioether units as evidenced by H-1 and C-13 NMR spectroscopy, Fourier transform infrared spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. Both the glass transition temperatures and degradation temperatures at 5% weight loss of these polymers were in ranges of -15.6 to 149.3 and 188.3-307.1 degrees C, respectively, strongly dependent on the side chain structure. Moreover, poly(thioether)s bearing naphthalenyl groups possess a high refractive index of 1.752. By simply incorporating an aggregation-induced emission (AIE) moiety of tetraphenylethylene into the side chains, the corresponding polymers exhibit typical AIE features. Furthermore, Pearson's hard-soft acid-base theory and computational studies were performed to rationalize the ARODP process. This research furnishes an original and effective strategy for utilizing COS-sourced monomers as a sulfur feedstock in polymer synthesis.

Automated summary

In this study, a series of alpha-alkylidene cyclic thiocarbonates (α CTCs) were selectively synthesized from carbonyl sulfide (COS) and primary propargylic alcohols, and polymerized via anionic ring-opening decarboxylative polymerization (ARODP) using alkali metal alkoxides as initiating systems. The resulting polymers showed exclusive thioether units and demonstrated varying glass transition temperatures and degradation temperatures based on their side chain structures, with poly(thioether)s bearing naphthalenyl groups exhibiting a high refractive index. Additionally, incorporation of tetraphenylethylene into the side chains led to aggregation-induced emission (AIE) features in the polymers, further rationalized through Pearson's hard-soft acid-base theory and computational studies. This research presents a novel and effective approach for utilizing COS-sourced monomers in polymer synthesis.