Jarroux N, Guégan P, Cheradame H, Auvray L
Laboratoire Matériaux Polymères aux Interfaces, UMR CNRS 7581, University of Evry, bld. Mitterrand, 91025 Evry Cedex, France.
J Phys Chem B. 2005 Dec 22;109(50):23816-22. doi: 10.1021/jp054908t.
We describe the quantitative synthesis of new pyrene labeled cyclodextrin-based polyrotaxane starting from pseudopolyrotaxane of alpha,omega-dimethacrylate poly(ethylene oxide) (PEO) and alpha-cyclodextrins (alpha-CDs). Using a solvent mixture (H2O/dimethyl sulfoxide (DMSO)), an almost quantitative conversion in polyrotaxane can be achieved using the coupling reaction between methacrylic functions and 1-pyrene butyric acid N-hydroxysuccinimide ester. This result is due to the fast blocking reaction of the pseudopolyrotaxane telechelic functions. The polyrotaxanes are characterized by NMR, size exclusion chromatography (SEC), and small-angle neutron scattering (SANS). A rodlike structure of the polyrotaxane is evidenced by SANS, and a persistence length of 70 A is determined. This result corresponds to an almost completely stretched PEO chain of 1000 g.mol(-1) molecular weight. We furthermore studied the opposite case of low packing density polyrotaxanes that were also silylated to suppress interactions between cyclodextrins. We observed a random coil structure only for silylated low packed polyrotaxane. This result demonstrates that both hydrogen bonding and packing density can explain the rodlike structure of cyclodextrin-based polyrotaxane.
我们描述了一种新型芘标记的基于环糊精的聚轮烷的定量合成方法，该方法从α,ω-二甲基丙烯酸酯聚环氧乙烷（PEO）与α-环糊精（α-CD）的准聚轮烷开始。使用混合溶剂（水/二甲基亚砜（DMSO）），通过甲基丙烯酸官能团与1-芘丁酸N-羟基琥珀酰亚胺酯之间的偶联反应，可实现聚轮烷几乎定量的转化。这一结果归因于准聚轮烷遥爪官能团的快速封端反应。通过核磁共振（NMR）、尺寸排阻色谱（SEC）和小角中子散射（SANS）对聚轮烷进行了表征。SANS证实了聚轮烷的棒状结构，并确定其持久长度为70 Å。这一结果对应于分子量为1000 g·mol⁻¹的几乎完全伸展的PEO链。我们还研究了低堆积密度聚轮烷的相反情况，这些聚轮烷也进行了硅烷化处理以抑制环糊精之间的相互作用。我们仅观察到硅烷化的低堆积聚轮烷呈现无规卷曲结构。这一结果表明，氢键和堆积密度都可以解释基于环糊精的聚轮烷的棒状结构。
