A strategy for improving CO2 capture by new anion-functionalized ionic liquids (ILs) making use of multiple site cooperative interactions is reported. An extremely high capacity of up to 1.60 mol CO2 per mol IL and excellent reversibility were achieved by introducing a nitrogen-based interacting site on the phenolate and imidazolate anion. Quantum-chemical calculations, spectroscopic investigations, and calorimetric data demonstrated that multiple-site cooperative interactions between two kinds of interacting sites in the anion and CO2 resulted in superior CO2 capacities, which originated from the π-electron delocalization in the pyridine ring.

3He NMR spectrometry has been used to examine bisaddition to C60 containing an encapsulated 3He atom (3He@C60) using three types of reactions:  (1) cyclopropanation with diethyl bromomalonate and base to give dicarbethoxymethanofullerenes (Bingel−Hirsch reaction), (b) addition of azomethine ylides to give N-methylfulleropyrrolidines (Prato−Wudl reaction), and (c) reduction to give C60H4. 3He NMR spectra of crude reaction mixtures in all three series showed well-separated resonances for each of the bisadducts, spread out over more than 2 ppm. The major isomeric bisadducts from the first two reactions were separated and characterized, and the 3He NMR spectra of the individual major bisadducts from 3He@C60 were obtained (five isomers from reaction 1, four isomers from reaction 2). Although the absolute chemical shifts in the two series of bisadducts differ, the relative chemical shifts are significantly but not perfectly correlated. Bisadducts with appended ligands on opposite hemispheres of C60 (7, 6, and 5) tend to have 3He NMR resonances downfield of the bisadducts with appended ligands on the same hemisphere (bisadducts 2 and 3). Unfortunately, the equatorial isomer 4, a major product from the Hirsch addition reaction, was not obtained in sufficient quantity for study from the Prato reaction. Well-separated resonances were also seen for the isomeric compounds of composition 3He@C60H4 from reaction of the fullerene with diimide, but the individual isomers were not separated. The very large differences in the 3He NMR chemical shifts of the isomeric bisadducts in all three reactions demonstrate that the magnetic field felt by the 3He atom due to the ring currents in the residual π-system is extremely sensitive to the pattern of ligation on the C60 surface. These results provide further support for the assertion that 3He NMR is a very sensitive probe of patterns of chemical addition to fullerenes, and suggest that this technique will prove to be generally useful in determining the ratio as well as the identity of isomeric fullerene bisadducts.

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A strategy for improving CO 2 capture by new anionfunctionalized ionic liquids (ILs) making use of multiple site cooperative interactions is reported. An extremely high capacity of up to 1.60 mol CO 2 per mol IL and excellent reversibility were achieved by introducing a nitrogen-based interacting site on the phenolate and imidazolate anion. Quantum-chemical calculations, spectroscopic investigations, and calorimetric data demonstrated that multiple-site cooperative interactions between two kinds of interacting sites in the anion and CO 2 resulted in superior CO 2 capacities, which originated from the p-electron delocalization in the pyridine ring.