论文总字数：25011字

摘 要

在有机催化中，（硫）脲/胺氢键催化取得了巨大的成功。尤其是在聚合反应中，氢键与质子酸结合催化几乎从来没有过。本文我们公开了在室温下用1,3-双-（3,5-双（三氟甲基）苯基）硫脲（TU）作为氢键供体（HBD），用三氟乙酸（TFA）作为质子酸（BA），两者结合促进δ-戊内酯（δ-VL）和ε-己内酯（ε-CL）高效可控/活性开环聚合反应（ROP）。δ-VL和ε-CL的开环聚合反应以苄醇（BnOH）作为引发剂，生成聚（δ-戊内酯）（PVL，M_{n, NMR}=1900-9900g mol^–1，M_w/M_n=1.28-1.34）和聚（ε-己内酯）（PCL，M_{n, NMR}=2400-11600g mol^–1，M_w/M_n=1.19-1.35），并且聚合物具有可预测的分子量和较窄的分散度。本轮文还提出了一种可能的机制，就是TU通过双氢键与TFA结合，从而稳定羧酸根阴离子和增加质子酸度，使得TU-TFA催化开环聚合反应可行。¹ H NMR和MALDI-ToF 质谱测量证实了引发剂存在于聚合物链末端。动力学和链延伸实验证明了聚合的可控性和活性。嵌段共聚物PVL-b-PCL和PCL-b-PVL的合成再次验证了开环聚合反应的可控性和活性，这表明氢键供体与质子酸结合催化是一个普遍适用的方法。

关键词：1,3-双-（3,5-双（三氟甲基）苯基）硫脲 开环聚合 有机催化

Thiourea Binding with Carboxylic Acid Promoted Cationic Ring-Opening Polymerization

Abstract

H-bonding organocatalysis using (thio)urea/amine achieved massive success. H-bonding binding with Brønsted acid catalysis, especially in polymerizations, was scarcely explored. Here we disclosed 1,3-bis-(3,5-bis(trifluoromethyl)phenyl)thiourea (TU) as hydrogen bond donor (HBD), combined with trifluoroacetic acid (TFA) as a Brønsted acid (BA), promoted efficient controlled/living ring-opening polymerization (ROP) of δ-valerolactone (δ-VL) and ε-caprolactone (ε-CL) at room temperature. The ROPs of δ-VL and ε-CL with benzyl alcohol (BnOH) as the initiator yielded poly(δ-valerolactone) (PVL, M_{n, NMR} = 1,900-9,900 g mol^–1, M_w/M_n = 1.28-1.34) and poly(ε-caprolactone) (PCL, M_{n, NMR} = 2,400-11,600 g mol^–1, M_w/M_n = 1.19-1.35) with predicted molecular weights and narrow dispersities. A plausible mechanism of the ROP by associations of TU with TFA through double hydrogen bonding was suggested, in which stabilizing of the carboxylate anion and enhancing of the Brønsted acidity made the catalytic ROPs by TU-TFA viable. The quantitative incorporation of the initiator into the polymer chains was demonstrated by ¹H NMR and MALDI-ToF MS measurements. The controlled/living fashion of the polymerization was supported by the kinetics and chain extension experiments. Synthesis of well-defined block copolymers of PVL-b-PCL and PCL-b-PVL verified again the ROPs were in controlled/living manner, and suggested the hydrogen bond donor binding with Brønsted acid catalysis to be a generally applicable method.

Key Words: 1,3-bis-(3,5-bis(trifluoromethyl)phenyl)thiourea; ROP; organocatalysis

目录

摘要 I

Abstract II

目录 III

第一章 前言 1

1.1 背景 1

1.2 氢键-布朗斯特酸共催化环酯开环聚合 2

1.3 氢键结合布朗斯特酸催化开环聚合机理 3

第二章 实验部分 5

2.1 实验内容 5

2.1.1 实验仪器 5

2.1.2 实验试剂 5

2.1.3 检测及表征方法 7

2.1.4 反应步骤 7

2.2结果与讨论 8

2.2.1 用苄醇和1,3-双-（3,5-双（三氟甲基）苯基）硫脲和三氟乙酸结合催化开环聚合 8

2.2.2 PVL和PCL的特征描述 13

2.2.3 开环聚合反应的活性/可控的特征 15

2.2.4 PVL-b-PCL和PCL-b-PVL的嵌段共聚 17

第三章 总结 20

参考文献 21

致谢 26

第一章 前言

1.1 背景

氢键（HB）是一个在自然界中无处不在的非共价相互作用，在化学和生物学中发挥重要作用，主要负责蛋白质的结构，核酸的稳定性，晶体结构的形成，以及软物质的功能。^[1-3]氢键供体和受体之间的氢键相互作用在分子和超分子认可、阴离子结合、自组装体和催化生物化学转化中广泛存在。^[4-8]

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