Anila Sebastian, Suresh Cherumuttathu H
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala, 695 019, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Phys Chem Chem Phys. 2022 Sep 21;24(36):22144-22153. doi: 10.1039/d2cp03464f.
The reaction of C fullerene with '' molecules ( = 1 to 6) of 1,3-dimethyl-2,3-dihydro-2-cyano-imidazole (IMCN) results in the exothermic formation of imidazolium cation-polyanionic fulleride complexes, (IM)⋯((C(CN))). The binding energy of IM with (C(CN)) in the imidazolium-fulleride ionic complexes increased from -69.6 kcal mol for = 1 to -202.9 kcal mol for = 6. The energetics of the complex formation and cation-anion interaction energy data suggest the formation of imidazolium-fulleride ionic liquid (IL) systems. Furthermore, the dimer formation of such ionic complexes showed more exergonic nature due to multiple cooperative electrostatic interactions between oppositely charged species and suggested improved energetics for higher order clusters. The molecular electrostatic potential (MESP) analysis has revealed that the extra '' electrons in the ionic complex as well as that in the bare (C(CN)) are delocalized mainly on the unsaturated carbon centers of the fullerene unit, while the CN groups remain as a neutral unit. The MESP minimum () values of (C(CN)) on the carbon cage have shown that the addition of each CN unit on the cage enhances the negative character of by ∼54.7 kcal mol. This enhancement in MESP is comparable to the enhancement observed when one electron is added to C to produce (62.5 kcal mol) and suggests that adding '' CN groups to the fullerene cage is equivalent to supplying '' electrons to the carbon cage. Also the high capacity of the fullerene cage to hold several electrons can be attributed to the spherical delocalization of them onto the electron deficient carbon cage. The interactive behavior of CO molecules with (IM)⋯(C(CN)) systems showed that the interaction becomes stronger from -2.3 kcal mol for = 1 to -18.6 kcal mol for = 6. From the trianionic fulleride onwards, the C⋯CO noncovalent (nc) interaction changes to C-CO covalent (c) interaction with the development of carboxylate character on the adsorbed CO. These results prove that cyano-fullerides are promising candidates for CO capture.
C富勒烯与1,3 - 二甲基 - 2,3 - 二氢 - 2 - 氰基咪唑（IMCN）的“n”个分子（n = 1至6）反应会放热形成咪唑鎓阳离子 - 多阴离子富勒烯化物配合物，即(IM)⋯((C(CN))n)。在咪唑鎓 - 富勒烯化物离子配合物中，IM与(C(CN))n的结合能从n = 1时的 - 69.6千卡/摩尔增加到n = 6时的 - 202.9千卡/摩尔。配合物形成的能量学以及阳离子 - 阴离子相互作用能数据表明形成了咪唑鎓 - 富勒烯化物离子液体（IL）体系。此外，由于带相反电荷的物种之间存在多种协同静电相互作用，这种离子配合物的二聚体形成表现出更强的放能性质，并且表明高阶簇的能量学有所改善。分子静电势（MESP）分析表明，离子配合物以及裸(C(CN))n中的额外“n”个电子主要离域在富勒烯单元的不饱和碳中心上，而CN基团保持为中性单元。碳笼上(C(CN))n的MESP最小值（Vmin）表明，笼上每添加一个CN单元，Vmin的负性增加约54.7千卡/摩尔。这种MESP的增强与向C60添加一个电子形成C60−时观察到的增强相当（62.5千卡/摩尔），这表明向富勒烯笼添加“n”个CN基团相当于向碳笼提供“n”个电子。此外，富勒烯笼容纳多个电子的高能力可归因于电子在缺电子碳笼上的球形离域。CO分子与(IM)⋯(C(CN))n体系的相互作用表明，相互作用从n = 1时的 - 2.3千卡/摩尔增强到n = 6时的 - 18.6千卡/摩尔。从三阴离子富勒烯化物开始，C⋯CO非共价（nc）相互作用随着吸附的CO上羧酸盐性质的发展转变为C - CO共价（c）相互作用。这些结果证明氰基富勒烯化物是有前途的CO捕获候选物。
