The Synthesis Of Ctnnamate-bashd Photoresponsive Ionic Liquids And Their Aggregation Behavior In Solutions

Ionic liquids (ILs) have attracted considerable attention in the past decade because of their uniquephysicochemical properties. Their inherent properties, such as generally negligible vapor pressures, wideliquid ranges, wide electrochemical windows, considerable electric conductivities, and good thermalstabilities, are advantageous for a large number of applications. Ionic liquids are composed of distinctcations and anions, which renders them tunable. They may be designed for specific applications byincorporation of functionalities in one or both ions and by the choice of cation–anion combination.Incorporating ILs with photochromism/photoisomerism functionality will give the so-calledphotoresponsive ILs or photochromism/ILs systems. Recently, a few such ILs or composite systems havebeen developed and exhibited attractive features. But the species is relatively rare and further developmentis necessary for in-depth investigation of their physicochemical properties and enhancement of theirperformance. As a part of the project supported by the Key Programme of National Natural ScienceFoundation of China (No.21133009), the main contents of the works are as follows.1. A series of cinnamate-based ionic liquids have been synthesized and confirmed by NMR, DSC andTGA techniques, and the effects of melting point and thermal stability of the ionic liquids such asmethylene linkage and the structure of anionic are also investigated.2. The UV-Vis absorption spectrum of these cinnamate-based ionic liquids were measured．Theimpacts of the polarity of solvent, methylene linkage and the structure of anionic on the maximumabsorption wavelength were studied. The effects of photochromism properties of these cinnamate-basedionic liquids are also investigated.3. Conductivities for solutions of cinnamate-based ionic liquids in four kinds of organic slovents(Methanol, Ethanol, Dichloromehtane and Chloroform) have been determined at298.15K. The criticalaggregation concentrations(CAC) of the ionic liquids and the physical-chemical properties have beendeliberated. It is indicated that the aggregation of ILs is related to the relative dielectric constant of solventsand the structure of the ionic liquids.4. Photoresponsive conductivities for dilution solutions of cinnamate-based ionic liquids in four kindsof organic solvents (Methanol, Ethanol, Dichloromehtane and Chloroform) have been determined, All ILs show distinct solvent-dependent photoresponsive conductivity, which could be related tophotoisomerism-induced change of aggregation behavior of ionic clusters. The result demonstrates thepossibility of in-depth investigation of the aggregation behavior of ILs.