Synthesis and Characterization of Novel Side-Chain Pseudopolyrotaxanes Containing Cucurbituril
Synthesis and Characterization of Novel Side-Chain Pseudopolyrotaxanes Containing Cucurbituril
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DOI：
10.1021/ma020534f
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发表时间：
2002-08
期刊：
影响因子：
5.5
通讯作者：
Yebang Tan;Soowhan Choi;Jaewook Lee;and Young Ho Ko;Kimoon Kim
中科院分区：
文献类型：
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作者：
Yebang Tan;Soowhan Choi;Jaewook Lee;and Young Ho Ko;Kimoon Kim
近年来，其组分通过机械键结合在一起的聚合物受到了广泛的关注，这不仅是因为它们独特的结构，而且还因为它们不寻常的性能。1这种机械连接的聚合物包括（假）聚轮烷，其中许多环状单元被连接到聚合物主链或侧链上。1，2虽然主链（假）聚轮烷已被广泛研究，但对侧链（假）聚轮烷的研究却很有限。3-8 Ritter 3合成了一系列侧链聚轮烷，其含有在各种聚合物主链的侧链上螺旋的环糊精（CD）珠。Osakada和Yamamoto 4还制备了侧链聚轮烷，其中含有CD的半轮烷单元连接到聚（苯并咪唑）主链上。最近，Takata 5报道了通过将含有冠醚的半轮烷单体聚合在丙烯酸酯衍生物上合成的侧链聚轮烷。葫芦脲（CB [6]）是一种大环，包含六个甘脲单元，具有疏水空腔，可通过两个相同的羰基边缘门户进入。[9]在入口处的极性羰基和疏水空腔允许CB [6]与小分子如质子化氨基烷烃形成稳定的主客体复合物。特别地，它与质子化的二氨基烷烃如二氨基丁烷形成非常稳定的络合物（K> 105）。9利用这一事实，我们10和其他人11，12已经成功地合成了各种机械联锁分子，包括轮烷和（假）聚轮烷。然而，尚未报道含有CB [6]作为分子珠的侧链（伪）聚轮烷。在这里，我们报告了新的侧链假聚轮烷，其中CB [6]珠串在连接到主聚合物链的（质子化）二氨基丁烷侧基上（方案1）。假聚轮烷的独特特征是CB [6]珠的穿线和脱线可以通过溶液的pH可逆地控制。
Polymers whose components are held together by mechanical bonds have received much attention in recent years not only because of their unique structures but also because of their unusual properties. 1 Such mechanically linked polymers include (pseudo) polyrotaxanes in which a number of cyclic units are threaded onto a polymer main chain or side chains. 1, 2 While mainchain (pseudo) polyrotaxanes have been studied quite extensively, studies on side-chain (pseudo) polyrotaxanes are limited. 3-8 Ritter3 synthesized a series of side-chain polyrotaxanes containing cyclodextrin (CD) beads threaded on side chains of various polymer backbones. Osakada and Yamamoto4 also prepared side-chain polyrotaxanes in which CD containing semirotaxane units are attached to a poly (bezimidazole) backbone. More recently, Takata5 reported side-chain polyrotaxanes synthesized by polymerization of a semirotaxane monomer containing crown ether threaded on an acrylate derivative.Cucurbituril (CB [6]) is a macrocycle comprising six glycoluril units with a hydrophobic cavity that is accessible through two identical carbonyl-fringed portals. 9 The polar carbonyl groups at the portals and the hydrophobic cavity allow CB [6] to form stable hostguest complexes with small molecules such as protonated aminoalkanes. In particular, it forms very stable complexes (K> 105) with protonated diaminoalkanes such as diaminobutane. 9 Taking advantage of this fact, we10 and others11, 12 have successfully synthesized various mechanically interlocked molecules, including rotaxanes and (pseudo) polyrotaxanes. However, no sidechain (pseudo) polyrotaxane containing CB [6] as a molecular bead has been reported yet. Here we report novel side-chain pseudopolyrotaxanes in which CB [6] beads are threaded on (protonated) diaminobutane pendants attached to a main polymer chain (Scheme 1). A unique feature of the pseudopolyrotaxanes is that threading and dethreading of the CB [6] beads can be reversibly controlled by the pH of the solution.