Switching of polymerization activity of cinnamoyl-alpha-cyclodextrin.
Switching of polymerization activity of cinnamoyl-alpha-cyclodextrin.
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DOI：
10.1039/b818241h
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发表时间：
2009-04
影响因子：
3.2
通讯作者：
Motofumi Osaki;Y. Takashima;H. Yamaguchi;A. Harada
中科院分区：
文献类型：
--
作者：
Motofumi Osaki;Y. Takashima;H. Yamaguchi;A. Harada
已发现肉桂酰基α-环糊精（α-CD）引发δ-戊内酯（δ-VL）的聚合以高产率得到聚合物。红外光谱分析表明，由于肉桂酰基的存在，δ-VL的羰基氧与CD的羟基之间形成了氢键，从而活化了单体。然而，在α-CD的C（3）-和C（6）-位上的肉桂酰基不影响聚合能力。只有C（2）-位的催化剂具有较高的聚合活性。聚合活性可以通过连接到α-CD边缘的肉桂酰基的光异构化来切换。通过光异构化改变了α-CD空腔活性位点中的特定单体识别和聚合。
Cinnamoyl alpha-cyclodextrin (alpha-CD) has been found to initiate polymerization of delta-valerolactone (delta-VL) to give a polymer in high yield. By the presence of the cinnamoyl group, hydrogen bond was formed between the carbonyl oxygen of delta-VL and the hydroxyl group of CD to activate the monomer, which was observed by FT-IR measurements. However, the cinnamoyl group at the C(3)- and C(6)-positions of alpha-CD did not affect the polymerization ability. Only that of the C(2)-position showed high polymerization activity. The polymerization activity could be switched by the photoisomerization of the cinnamoyl group attached to the rim of alpha-CD. Specific monomer recognition and polymerization in the active site of the alpha-CD cavity was changed by the photoisomerization.