Hu Pengcheng, Zhang Rui, Meng Xianghai, Liu Haiyan, Xu Chunming, Liu Zhichang
State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Beijing 102249, China.
Inorg Chem. 2016 Mar 7;55(5):2374-80. doi: 10.1021/acs.inorgchem.5b02744. Epub 2016 Feb 5.
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 (27)Al 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.
通过一步法，以三种不同结构的酰胺作为供体分子，合成了几种基于酰胺 - AlCl₃的离子液体（IL）类似物。通过对这些IL类似物进行²⁷Al NMR、拉曼光谱、原位红外光谱和紫外 - 可见光谱，研究了N原子上取代甲基的空间效应和诱导效应对AlCl₃不对称分裂以及酰胺配位位点的影响。由于甲基的诱导效应，在基于N - 甲基乙酰胺 - AlCl₃和N，N - 二甲基乙酰胺 - AlCl₃的IL类似物中，通过O和N原子的双齿配位占主导地位。相比之下，基于乙酰胺 - AlCl₃的IL类似物主要以通过O原子的单齿配位形式存在。与单齿配位相比，在相同的酰胺 - AlCl₃摩尔比下，双齿配位有利于AlCl₃的不对称分裂。在甲基的空间效应和诱导效应的影响下，这些IL类似物中的离子物种百分比按以下顺序排列：N - 甲基乙酰胺＞N，N - 二甲基乙酰胺＞乙酰胺。
