López-Bueno Carlos, Bittermann Marius R, Dacuña-Mariño Bruno, Llamas-Saiz Antonio Luis, Del Carmen Giménez-López María, Woutersen Sander, Rivadulla Francisco
CIQUS, Centro de Investigación en Química Biolóxica e Materiais Moleculares, Universidade de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Phys Chem Chem Phys. 2020 Sep 23;22(36):20524-20530. doi: 10.1039/d0cp02633f.
Self-assembled ionic liquid crystals are anisotropic ionic conductors, with potential applications in areas as important as solar cells, battery electrolytes and catalysis. However, many of these applications are still limited by the lack of precise control over the variety of phases that can be formed (nematic, smectic, or semi/fully crystalline), determined by a complex pattern of different intermolecular interactions. Here we report the results of a systematic study of crystallization of several imidazolium salts in which the relative contribution of isotropic coulombic and directional H-bond interactions is carefully tuned. Our results demonstrate that the relative strength of directional H-bonds with respect to the isotropic Coulomb interaction determines the formation of a crystalline, semi-crystalline or glassy phase at low temperature. The possibility of pinpointing H-bonding directionality in ionic liquids make them model systems to study the crystallization of an ionic solid under a perturbed Coulomb potential.
自组装离子液晶是各向异性离子导体，在太阳能电池、电池电解质和催化等重要领域具有潜在应用。然而，这些应用中的许多仍受到限制，因为难以精确控制由不同分子间相互作用的复杂模式所决定的可形成的各种相（向列相、近晶相或半/全晶相）。在此，我们报告了对几种咪唑鎓盐结晶的系统研究结果，其中对各向同性库仑相互作用和定向氢键相互作用的相对贡献进行了仔细调整。我们的结果表明，相对于各向同性库仑相互作用，定向氢键的相对强度决定了在低温下形成结晶相、半结晶相或玻璃相。在离子液体中确定氢键方向性的可能性使其成为研究在扰动库仑势下离子固体结晶的模型体系。
