文摘
Several amide–AlCl3-based ionic liquid (IL) analogues were synthesized through a one-step method using three different structure amides as donor molecules. The effects of the steric and inductive effects of the methyl group substituted on the N atom on the asymmetric splitting of AlCl3 and the coordination site of the amide were investigated by 27Al NMR, Raman, in situ IR, and UV–vis spectra for these IL analogues. Bidentate coordination through both the O and N atoms was dominant in the N-methylacetamide–AlCl3- and N,N-dimethylacetamide–AlCl3-based IL analogues because of the inductive effect of the methyl group. By contrast, the acetamide–AlCl3-based IL analogue presented mainly in the form of monodentate coordination via the O atom. Compared with monodentate coordination, bidentate coordination was favorable to the asymmetric splitting of AlCl3 with the same amide–AlCl3 molar ratio. Under the influence of the steric and inductive effects of the methyl group, the ionic species percentages in these IL analogues ranked in the following order: N-methylacetamide > N,N-dimethylacetamide > acetamide.