Poly(thioester) by Organocatalytic Ring-Opening Polymerization.
Poly(thioester) by Organocatalytic Ring-Opening Polymerization.
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通过有机催化环的聚合聚合聚合（硫酯）。
DOI：
10.1021/acs.macromol.5b01463
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发表时间：
2015-08-25
期刊：
影响因子：
5.5
通讯作者：
Kiesewetter MK
中科院分区：
文献类型：
--
作者：
Bannin TJ;Kiesewetter MK
通常用于环酯单体开环聚合的有机催化剂应用于硫代内酯，ε-硫代己内酯(TCL)。在没有氢键给体的情况下，提出了亲核聚合机理。尽管硫代酯和硫醇(相对于酯和醇)对氢键的能力降低，氢键有机催化剂-硫脲和氢键接受碱的组合-仍然对TCL的ROP有效。硫醇(相对于醇)的亲核性增加与聚(硫代己内酯)相对聚己内酯的Mw/mN增加有关，但有害的酯交换反应在硫脲存在下被抑制。硫酯单体TCL在热力学上与ε-己内酰胺相似，但在动力学上与ε-己内酯相似。
Organocatalysts typically used for the ring-opening polymerization (ROP) of cyclic ester monomers are applied to a thiolactone, ε-thiocaprolactone (tCL). In the absence of an H-bond donor, a nucleophilic polymerization mechanism is proposed. Despite the decreased ability of thioesters and thiols (versus esters and alcohols) to H-bond, H-bonding organocatalysts—a thiourea in combination with an H-bond accepting base—are also effective for the ROP of tCL. The increased nucleophilicity of thiols (versus alcohols) is implicated in the increased Mw/Mn of the poly(thiocaprolactone) versus poly(caprolactone), but deleterious transesterification is suppressed in the presence of a thiourea. The thioester monomer, tCL, is shown to be thermodynamically similar to ε-caprolactam but kinetically similar to ε-caprolactone.