| Summary: | 碩士 === 國立成功大學 === 化學系碩博士班 === 94 === Bond orbital analysis performed on EMI+ and various Lewis bases reveals that the Weinhold’s “counterbalance effects of rehybridization and hyperconjugation” are valid for the most polar C-H (EMI+) bonding orbitals and are not suitable for the lone-pair bonding orbital of the bases. Only when alkyl C-H BOs are involved in hyperconjugative interactions with the base, chloride or bromide anions under this research, the hyperconjugation effect prevails over rehybridization effect and H-bonding results in a strengthened C(3)-H bond.
The self-diffusing BMI-PF6 in neat ionic liquid (IL) state have been found, in the presence of aprotic organic solvent (AOS), associated to different extents, which can be explained by B3LYP/3-21G* calculated binding energies for the adducts of AOS and PF6 anion. These results are consistent with the very recent nitrogen NMR studies performed on ionic liquids, which infer that solvent-anion interactions dominate modified physical properties. The NBO second-order perturbation energy analysis provides orbital-based explanations for the unusually up-field shifts of 19F NMR resonances in propylene carbonate and the relative solvent-IL effects .
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