An attempt to analyze the orientation behavior of ionic liquids through observation of electron transfer reactions

溶剂分子的旋转重定向发生在大多数化学反应的激活过程中，因为分子在基态和过渡态的偶极矩通常是不同的。另一方面，从基态形成过渡态的电子弛豫应该是非常迅速的。然而，这种电子弛豫不能实现，除非实现更慢的溶剂旋转弛豫。因此，活化能与溶剂分子重定向（旋转松弛）的难易程度密切相关。然而，对于具有小粘度的普通分子液体，这种旋转弛豫是快速的（10^<-12> s）。另一方面，离子液体具有较大的粘度，由于静电相互作用，其组分离子的运动在很大程度上受到限制，有望成为观察化学活化过程中缓慢旋转弛豫的理想候选者。我们试图观察反应活化能的变化，这对应于离子液体组分离子的缓慢取向弛豫。

Rotational re-orientations of solvent molecules take place during the activation processes of most chemical reactions, since the dipole moments of a molecule in the ground state and in the transition state are usually different. On the other hand, electronic relaxation that forms the transition state from the grounds state should be very rapid. However, such an electronic relaxation cannot be achieved unless much slower solvent rotational relaxation is achieved. Therefore, activation energy is strongly related to the easiness of the re-orientation (rotational relaxation) of solvent molecules. However, such a rotational relaxation is rapid (10^<-12> s) for ordinary molecular liquids with small viscosity. On the other hand, ionic liquid, that has relatively large viscosity and the movement of the component ions of which are largely restricted because of the electrostatic interactions, is expected to be an excellent candidate for the observation of slow rotational relaxation during the chemical activation process. We attempted to observe changes of the activation energy of a reaction that corresponds to the slow orientation relaxation of the component ions of ionic liquids.