Understanding the effects of targeted modifications on the 1 : 2 Choline And GEranate structure.
Understanding the effects of targeted modifications on the 1 : 2 Choline And GEranate structure.
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了解靶向修饰对 1:2 胆碱和 GEranate 结构的影响。
DOI：
10.1039/d3cp05271k
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发表时间：
2024
期刊：
影响因子：
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通讯作者：
Dobre A
中科院分区：
文献类型：
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作者：
Dobre A
1：2胆碱-锗烷（CAGE）是一种离子液体，因其生物医学应用而被广泛研究。 然而，它的工业规模制备和长期储存都存在问题，因此找到更合适的候选物并保留其有利特性至关重要。作为实现这一目标的第一步，我们进行了有针对性的修饰研究，以了解特定官能团对CAGE性能的影响。合成了1：2胆碱-辛酸酯和1：2丁基三甲基铵-辛酸酯，并将它们的热性能和流变性能与CAGE进行了比较。 使用差示扫描量热法和偏光显微镜，模型化合物被发现是一个各向同性的液体，而类似物是室温下的液晶，加热时过渡到各向同性的液体。动态力学分析表明，所研究的系统的热行为更加复杂，与离子液体也经历了热激活松弛过程。此外，我们还使用了电子顺磁共振（EPR）光谱，沿着各种不同的功能团的自旋探针，以了解在每个系统中的溶质所经历的化学环境。EPR谱表明，自由基经历两个不同的环境（极性和非极性）在液晶相，但只有一个平均环境中的各向同性相。液晶相的实验还表明，这两个域的相对人口取决于溶质的性质，极性或强氢键的溶质更喜欢极性域。对于带电的溶质，EPR谱线变宽，这表明它们的离子性质导致复杂的，未解决的相互作用。
1 : 2 Choline-and-geranate (CAGE) is an ionic liquid (IL) widely studied for its biomedical applications. However, both its industrial-scale preparation and its long-term storage are problematic so finding more suitable candidates which retain its advantageous properties is crucial. As a first step towards this we have conducted a targeted modification study to understand the effects of specific functional groups on the properties of CAGE. 1 : 2 Choline-and-octanoate and 1 : 2 butyltrimethylammonium-and-octanoate were synthesised and their thermal and rheological properties examined in comparison to those of CAGE. Using differential scanning calorimetry and polarising microscopy, the model compound was found to be an isotropic liquid, while the analogues were room-temperature liquid-crystals which transition to isotropic liquids upon heating. Dynamic mechanical analysis showed that the thermal behaviour of the studied systems was even more complex, with the ILs also undergoing a thermally-activated relaxation process. Furthermore, we have used electron paramagnetic resonance (EPR) spectroscopy, along with a variety of spin probes with different functional groups, in order to understand the chemical environment experienced by solutes in each system. The EPR spectra indicate that the radicals experience two distinct environments (polar and nonpolar) in the liquid-crystalline phase, but only one average environment in the isotropic phase. The liquid-crystalline phase experiments also showed that the relative populations of the two domains depend on the nature of the solutes, with polar or strongly hydrogen-bonding solutes preferring the polar domain. For charged solutes, the EPR spectra showed line-broadening, suggesting that their ionic nature leads to complex, unresolved interactions.