磷腈催化β-硫代丁内酯的开环聚合,Polymer Chemistry

当前位置： X-MOL 学术 › Polym. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

磷腈催化β-硫代丁内酯的开环聚合
Polymer Chemistry ( IF 4.1 ) Pub Date : 2023-07-26 , DOI: 10.1039/d3py00707c
Hui Li ₁ , Sophie M. Guillaume ₁ , Jean-François Carpentier ₁

Affiliation

通过开环聚合（ROP）获得聚硫酯（PTE）的硫内酯最近引起了越来越多的关注，特别是由于它们的生物相容性和改善的可降解性等特性。我们在此报道了最简单的四元环硫代内酯，即外消旋β-硫代丁内酯（rac -TBL），由市售磷腈碱介导，提供相应的聚（3-硫代丁内酯）（P3TB）。反应在室温、甲苯或 THF 中进行，表观反应活性随着磷腈的碱度和空间位阻单调增加 (BEMP ∼ t Bu-P ₁ < t Bu-P ₂ < t Bu-P₄ ). 这一趋势表明，ROP 的引发至少在某种程度上是通过从单体中提取一个酸性亚甲基氢来进行的，最终生成磷腈鎓-硫代羧酸盐离子对物质，该物质接下来充当引发/链增长物质。在 THF 中进行的 ROP 受到动力学控制，提供具有确定摩尔质量和公平分散性的 P3TB，这是活体 ROP 的一些特征。对使用t Bu-P₄生产的聚合物进行的详细¹ H、¹³ C、³¹ P 和 DOSY NMR 光谱、MALDI-ToF/ESI 质谱和 TGA 研究支持了 {[ t Bu-P₄ ]H}的伴随形成⁺基本上是α-硫代巴豆酸酯，ω-[硫代羧酸酯] ^-封端的线性P3TB；然而，不能排除周期性 P3TB 的存在。通过 NMR 分析从该硫代巴豆酸酯端基 ( M _n,NMR ) 确定的摩尔质量值随着单体转化率线性增加，但截距非零，表明引发较慢。传播。回收的 P3TB 的摩尔质量受到适度控制（M _n,SEC = 7.5–18.5 kg mol ⁻¹ , M _n,NMR = 5.2–22.4 kg mol ⁻¹），显示出相对较窄的分散度（Đ _M= 1.39–1.52（四氢呋喃））。这项工作提供了P3TB化学合成的第二个例子。

"点击查看英文标题和摘要"

Ring-opening polymerization of β-thiobutyrolactone catalyzed by phosphazenes

Thiolactones that give access to polythioesters (PTEs) upon ring-opening polymerization (ROP) have recently attracted increasing attention especially due to their biocompatibility and improved degradability among other properties. We report herein on the ROP of the simplest four-membered ring thiolactone, namely racemic β-thiobutyrolactone (rac-TBL), mediated by commercially available phosphazene bases, affording the corresponding poly(3-thiobutyrolactone) (P3TB). The reactions proceeded at room temperature, in toluene or in THF, with the apparent reactivity increasing monotonously with the basicity and steric hindrance of the phosphazene (BEMP ∼ tBu-P₁ < tBu-P₂ < tBu-P₄). This trend suggests that initiation of the ROP proceeds, at least to some extent, by abstraction of one acidic methylene hydrogen from the monomer, to generate eventually a phosphazenium–thiocarboxylate ion-pair species that next acts as the initiating/chain-propagating species. ROP performed in THF was kinetically controlled affording P3TBs with defined molar mass and fair dispersity, some features of a living ROP. Detailed ¹H, ¹³C, ³¹P and DOSY NMR spectroscopic, MALDI-ToF/ESI mass spectrometric and TGA studies conducted on the polymers produced using tBu-P₄ supported the concomitant formation of {[tBu-P₄]H}⁺ and essentially α-thiocrotonate,ω-[thiocarboxylate]⁻ end-capped linear P3TBs; yet, the presence of cyclic P3TBs could not be excluded. The molar mass values, as determined by NMR analysis from this thiocrotonate end-group (M_n,NMR), increased linearly with the monomer conversion, yet with a nonzero intercept, suggesting slow initiation vs. propagation. The molar mass of the recovered P3TBs was moderately controlled (M_n,SEC = 7.5–18.5 kg mol⁻¹, M_n,NMR = 5.2–22.4 kg mol⁻¹), displaying relatively narrow dispersities (Đ_M = 1.39–1.52 in THF). This work provides the second example of chemical synthesis of P3TB.

更新日期：2023-07-26

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南