离子液体1-乙基-3-甲基咪唑三氟甲基磺酸盐与水之间的氢键作用(英文)

Hydrogen-Bonding Interactions between Ionic Liquid 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate and Water

通过衰减全反射红外(ATR-IR)光谱、二维红外相关谱结合量子化学计算研究了1-乙基-3-甲基咪唑三氟甲基磺酸盐([emim][OTf])和水之间的氢键作用.结果表明,在[emim][OTf]-水体系中,当水的浓度较低时(0.1<x(D2O)<0.3),水分子的主要存在形式是包裹在离子液体中的没有缔合的单体.水分子优先填充到[emim][OTf]的空隙中,并且与[emim][OTf]的阴离子形成"[OTf]-…HOH…[OTf]-"结构,水分子与[emim][OTf]的阳离子的相互作用位点是烷基氢而不是芳香氢;当水分子浓度较高时,水分子倾向于自身缔合形成小团簇结构,水分子与[emim][OTf]的阳离子的相互作用位点是芳香氢而不是烷基氢.

Attenuated total reflectance infrared （ATR-IR） spectroscopy, two-dimensional correlation spectroscopy, and quantum chemical calculations were used to elucidate the hydrogen-bonding interactions between an ionic liquid （IL）, namely 1-ethyl-3-methylimidazolium trifluoromethanesulfonate （[emim][OTf]）, and water over a wide concentration range. It was found that water molecules are isolated from each other and embedded in the IL environment at low water concentrations （0. 1〈x（D20）〈0.3）. The water molecules occupy the IL interstices, and one water molecule forms two hydrogen bonds, with two [OTf]- anions. ＂[OTf]^-…HOH…… [OTf]-＂ hydrogen-bonded complexes exist in the [emim][OTf]- water system. In this concentration range, the hydrogen-bonding interaction sites between the cation and water is the alkyl C--H rather than the aromatic C-- H. At higher water concentrations, the water molecules form hydrogen bonds with themselves, producing water clusters in the mixture. The hydrogen-bonding interaction site between the cation and water is the aromatic C-- H rather than the alkyl C--H.