Polymer Mechanochemistry Enhanced with Mechanically Interlocked Molecules

机械力是一种强大的能量来源，具有扭曲、弯曲和拉伸化学键的能力，在激活化学反应的方式上是独一无二的。在聚合物机械化学中，聚合物用于将机械力朝向机械响应官能团（“机械基团”），然后机械响应官能团经历机械化学转化。虽然机械力在促进反应途径方面具有特殊的能力，但到目前为止，它仅限于涉及键断裂或重排的转化。这些限制的起源是由于这样的事实，即致动聚合物必须连接到机械载体以激活它，这到目前为止使得不可能：重复激活易分裂的机械载体或构建分子。解决这个问题的一个办法是找到一种方法，让聚合物“抓住”机械基团，而不是共价连接到它。互锁分子，这在分子机器的发展中起到了重要作用，非常适合这项任务，因为它们的子组件在空间中纠缠，但不是共价连接。因此，它们可以经历大幅度的内部位移，例如大环沿着轮烷的轴沿着穿梭，这使得它们成为吸引力致动器。在这个项目中，我们想展示如何使用轮烷结构来重复激活易分裂的机械载体并构建分子。

Mechanical force is a formidable source of energy that, with its ability to distort, bend and stretch chemical bonds, is unique in the way it activates chemical reactions. In polymer mechanochemistry, polymers are used to transduce mechanical force towards a mechanoresponsive functional group (a "mechanophore") that then undergoes a mechanochemical transformation. Although mechanical force is exceptional in its ability to promote reaction pathways that are otherwise inaccessible, it has so far been limited to transformations involving bond cleavage or rearrangements. The origin of these limitations is due to the fact that the actuating polymers have to be linked to the mechanophore to activate it, which has so far made impossible to: repetitively activate scissile mechanophores or to build molecules. A solution to that problem would be to find a way for the polymer to 'grab' the mechanophore without being covalently attached to it. Interlocked molecules, which have been instrumental in the development of molecular machines, are ideally suited for that task because their subcomponents are entangled in space but not covalently linked. As a result, they can undergo large amplitude internal displacements, such as a macrocycle shuttling along the axle of a rotaxane, which makes them attractive force actuators. In this programme, we want to demonstrate how a rotaxane architecture can be used to repetitively activate scissile mechanophores and to build molecules.