Controlled stacking and unstacking of peripheral chlorophyll units drives the spring-like contraction and expansion of a semi-artificial helical polymer.
Controlled stacking and unstacking of peripheral chlorophyll units drives the spring-like contraction and expansion of a semi-artificial helical polymer.
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DOI：
10.1002/chem.201203569
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发表时间：
2013-01
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影响因子：
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通讯作者：
Munenori Numata;Daiki Kinoshita;Naoya Hirose;T. Kozawa;H. Tamiaki;Y. Kikkawa;M. Kanesato
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文献类型：
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作者：
Munenori Numata;Daiki Kinoshita;Naoya Hirose;T. Kozawa;H. Tamiaki;Y. Kikkawa;M. Kanesato
开发通过精确的分子识别来控制聚合物构象的新策略可能会产生依赖于分子信息的类似机器的运动-在聚合物化学和传统超分子科学之间的领域中，这是制备新型智能纳米材料(例如，基于聚合物的纳米机器)的重要过程。在这里，我们提出了一种策略，通过外围两亲分子的一维自组装(聚集/解聚)来赋予螺旋高分子链动态弹簧状(收缩/膨胀)运动。在这个开发系统中，我们使用了一种呈现外围两亲性叶绿素单元的半人工螺旋多糖作为动力装置，它在水介质中经历收缩运动，受到其叶绿素单元之间强烈的π-π相互作用或通过对叶绿素单元对联吡啶型配体的合作分子识别的驱动，从而将分子信息转化为弹簧的调节运动。此外，该体系还通过吡啶的配位作用发生膨胀运动。我们预计这一策略将适用于药物载体(例如纳米注射器)、致动器(刺激响应膜)和定向运输器(纳米铁路)的开发(当与已建立的螺旋多糖的包裹化学相结合时)，从而扩展超分子科学的前沿。
Developing new strategies for controlling polymer conformations through precise molecular recognition can potentially generate a machine-like motion that is dependent on molecular information-an important process for the preparation of new intelligent nanomaterials (e.g., polymer-based nanomachines) in the field bordering between polymer chemistry and conventional supramolecular sciences. Herein, we propose a strategy to endow a helical polymer chain with dynamic spring-like (contraction/expansion) motion through the one-dimensional self-assembly (aggregation/disaggregation) of peripheral amphiphilic molecules. In this developing system, we employed a semi-artificial helical polysaccharide presenting peripheral amphiphilic chlorophyll units as a power device that undergoes contractive motion in aqueous media, driven by strong π-π interactions of its chlorophyll units or by cooperative molecular recognition of bipyridyl-type ligands through pairs of chlorophyll units, thereby converting molecular information into the regulated motion of a spring. In addition, this system also undergoes expansive motion through coordination of pyridine. We anticipate that this strategy will be applicable (when combined with the established wrapping chemistry of the helical polysaccharide) to the development of, for example, drug carriers (e.g., nano-syringes), actuators (stimuli-responsive films), and directional transporters (nano-railways), thereby extending the frontiers of supramolecular science.