LAQV-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
Research Institute for Medicine (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal.
Int J Mol Sci. 2023 Feb 9;24(4):3533. doi: 10.3390/ijms24043533.
In this work, the design and synthesis of a series of photochromic gemini diarylethene-based ionic liquids (GDILs) with different cationic motifs is reported. Several synthetic pathways were optimized for the formation of cationic GDILs with chloride as the counterion. The different cationic motifs were achieved through the -alkylation of the photochromic organic core unit with different tertiary amines, including different aromatic amines such as imidazole derivatives and pyridinium, and other non-aromatic amines. These novel salts present surprising water solubility with unexplored photochromic features that broaden their known applications. The covalent attachment of the different side groups dictates their water solubility and differences upon photocyclization. The physicochemical properties of GDILs in aqueous and in imidazolium-based ionic liquid (IL) solutions were investigated. Upon irradiation with ultraviolet (UV) light, we have observed changes in the physico-chemical properties of distinct solutions containing these GDILs, at very low concentrations. More specifically, in aqueous solution, the overall conductivity increased with the time of UV photoirradiation. In contrast, in IL solution, these photoinducible changes are dependent on the type of ionic liquid used. These compounds can improve non-ionic and ionic liquids' solutions since we can change their properties, such as conductivity, viscosity or ionicity, only by UV photoirradiation. The electronic and conformational changes associated with these innovative stimuli GDILs may open new opportunities for their use as photoswitchable materials.
在这项工作中，报道了一系列具有不同阳离子结构单元的光致变色双子二芳基乙烯基离子液体（GDILs）的设计和合成。优化了几种合成途径，以形成带有氯离子的阳离子 GDIL。通过将光致变色的有机核心单元与不同的叔胺进行 - 烷基化，得到了不同的阳离子结构单元，包括不同的芳基胺如咪唑衍生物和吡啶𬭩，以及其他非芳基胺。这些新型盐具有令人惊讶的水溶性和探索性的光致变色特性，拓宽了它们的已知应用。不同侧基的共价连接决定了它们的水溶性和光环化后的差异。研究了 GDIL 在水相和咪唑基离子液体（IL）溶液中的物理化学性质。用紫外线（UV）光照射时，我们观察到含有这些 GDIL 的不同溶液的物理化学性质发生了变化，浓度非常低。更具体地说，在水溶液中，整体电导率随 UV 光照射时间的增加而增加。相比之下，在 IL 溶液中，这些光致诱导的变化取决于所使用的离子液体的类型。这些化合物可以改善非离子和离子液体溶液的性能，因为我们可以通过 UV 光照射来改变它们的性质，如电导率、粘度或离子性。这些新型刺激 GDILs 相关的电子和构象变化可能为它们作为光致变色材料的应用开辟新的机会。
