Polycarbonates Derived from Glucose via an Organocatalytic Approach
Polycarbonates Derived from Glucose via an Organocatalytic Approach
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DOI：
10.1021/ja402319m
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发表时间：
2013-05-08
影响因子：
15
通讯作者：
Wooley, Karen L.
中科院分区：
文献类型：
--
作者：
Mikami, Koichiro;Lonnecker, Alexander T.;Wooley, Karen L.
以天然产物葡萄糖为原料，采用有机催化开环聚合法制备聚碳酸酯。由市售的葡萄糖衍生物分三步制备具有1、2和3位甲基保护的葡萄糖的环状4，6-碳酸酯单体，并通过NMR和IR光谱、电喷雾电离质谱（MS）和单晶X射线分析确认结构。在作为有机催化剂的1，5，7-三氮杂双环[4.4.0]癸-5-烯的存在下，由4-甲基苄醇引发的单体的聚合以受控的方式有效地进行，以提供具有可调聚合度、窄分子量分布和明确限定的端基的聚碳酸酯，如通过NMR光谱、凝胶渗透色谱、和MALDI-TOF MS。通过NMR光谱和通过电子转移解离的串联MS分析确定头对头、头对尾和尾对尾区域化学的分布。这些聚碳酸酯作为工程材料是令人感兴趣的，因为它们来源于可再生资源，结合它们的无定形特性和相对高的玻璃化转变温度，如通过X射线衍射和差示扫描量热法研究所确定的。
An organocatalyzed ring-opening polymerization methodology was developed for the preparation of polycarbonates derived from glucose as a natural product starting material. The cyclic 4,6-carbonate monomer of glucose having the 1, 2, and 3 positions methyl-protected was prepared in three steps from a commercially available glucose derivative, and the structure was confirmed by means of NMR and IR spectroscopies, electrospray ionization mass spectrometry (MS), and single-crystal Xray analysis. Polymerization of the monomer, initiated by 4-methylbenzyl alcohol in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene as the organocatalyst, proceeded effectively in a controlled fashion to afford the polycarbonate with a tunable degree of polymerization, narrow molecular weight distribution, and well-defined end groups, as confirmed by a combination of NMR spectroscopy, gel-permeation chromatography, and MALDI-TOF MS. A distribution of head-to-head, head-to-tail, and tail-to-tail regiochemistries was determined by NMR spectroscopy and tandem MS analysis by electron transfer dissociation. These polycarbonates are of interest as engineering materials because of their origination from renewable resources combined with their amorphous character and relatively high glass transition temperatures as determined by X-ray diffraction and differential scanning calorimetry studies.