Converting Non‐strained γ‐Valerolactone and Derivatives into Sustainable Polythioesters via Isomerization‐driven Cationic Ring‐Opening Polymerization of Thionolactone Intermediate

Abstract

This contribution reports the efficient conversion of γ-valerolactone and its derivatives, abundant but unexplored renewable feedstocks, into sustainable and degradable polythioesters via the establishment of the first isomerization-driven ring-opening polymerizations (IROPs) of corresponding thionolactone intermediates. The key to this success relies on the development of a new simple and robust [Et 3 O] + [B(C 6 F 5 ) 4 ] À cationic initiator which possesses high activity, exclusive selectivity, living nature, and broad scope of thionolactones. A complete inversion of configuration during IROP of enantiopure γ-thionovalerolactone is also disclosed, affording isotactic semicrystalline polythioesters (T m = 87.0 °C) with mechanical property compared well to the representative commodity polyolefins. The formation of a highly crystalline supramolecular stereocomplex with enhanced thermal property (T m = 117.6 °C) has also been revealed.

Emerging Trends in the Chemistry of End-to-End Depolymerization

“…16 In another recent interesting contribution, irreversible ROP of biomass-derived thionolactones was discovered, which proceeded at industrially relevant temperatures of 80−100 °C to produce high-molar-mass polythiolactones (Figure 7e). 104,105 Computational studies revealed that the selective irreversible ROP of γ-thionobutyrolactones was thermodynamically driven by S/O isomerization during the ring-opening process. Notably, poly(γ-thionobutyrolactone) with a high molar mass up to 162.6 kg/mol could undergo depolymerization within only 15 s upon treatment with 0.2 mol % of TBD at room temperature, quantitatively converting into γ-thiobutyrolactone, a structural isomer of the initial monomer, although at a relatively low concentration.…”

“…Alternatively, a geminal disubstitution strategy was applied to high T c thiolactone monomers to enhance depolymerizabiity of the corresponding polymers (Figure c). , The geminal disubstitution site proved to be important, as substitution led to changes in conformation of the thiolactones, leading to unpredictable shifts in T c . On the other hand, direct O-to-S substitution from lactones emerged as another promising approach to access depolymerizable polythioesters (Figure d). ,− For example, diverse low-strain dithiolactones bearing different side chains were synthesized and then polymerized into polythioesters with molar masses up to 100.5 kg/mol, which could undergo efficient thermolysis or catalytic depolymerization at room temperature to regenerate monomers …”

Designing Polymer Electrolytes via Ring‐Opening Polymerization for Advanced Lithium Batteries

“…Copyright 2023, Wiley. [170] formal Fe(II) and Fe(III) oxidation states of bis(imino)pyridinium ferritol salt complexes became possible, leading to the activation of the complexes with the ability to be used in ROP reactions (Figure 24b). In addition to acting as a redox trigger, an electrochemical toggle switch was developed in which the chemoselectivity of the polymerization of propargyl esters and epoxides was altered in situ.…”

“…The polymerization of fourteen five‐membered cyclic thiocarbonyl lactone monomers is highly efficient and controllable, and a series of polysulfide materials with molecular weights (M n ) up to 252.0 kg mol −1 and glass transition temperatures in the range from −56.7 to 3.4 °C have been successfully obtained. [ 170 ] In conclusion, the research team has developed simple and efficient initiators for isomerization‐driven ROP, which provides a new pathway for the conversion of previously “unpolymerizable” but abundant and inexpensive biobased monomers and their derivatives into new high‐performance sustainable functional polymers. The development of new initiators provides new ideas for the design and synthesis of high‐performance SPEs at a later stage, while these new polymers obtained on the basis of new initiators are expected to be used as SPEs, which provides the possibility of the development of low‐cost and high‐performance SPEs.…”

Copolymerization Involving Sulfur-Containing Monomers

“…Notably, the ring-opening homopolymerization of cyclic S-containing monomers is an efficient strategy for obtaining S-containing polymers in a controlled manner. ,,− However, this review focuses primarily on the synthesis of S-containing polymers via copolymerization; therefore, the progress made in the ring-opening homopolymerization of S-containing monomers is not included in this review. Furthermore, the scope of the copolymerization described here refers to those with different functional groups generated from the reaction of two or more monomers.…”