Das Sudhir Kumar, Sarkar Moloy
School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, 751005, India.
J Fluoresc. 2014 Mar;24(2):455-63. doi: 10.1007/s10895-013-1311-x. Epub 2013 Oct 26.
Rotational diffusion of two organic solutes, coumarin153 (C153) and 4-aminophthalimide (AP) has been investigated in four ionic liquids (ILs), viz. 1-ethyl-3-methylimidazolium trifluoroacetate (EMIMTFA), 1-ethyl-3-methylimidazolium ethylsulfate (EMIMESU), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMTFB) and 1-ethyl-3-methylimidazolium tetracyanoborate (EMIMTCB), as a function of temperature. Between the two probes, AP can act as hydrogen-bond-donor to the solvents having hydrogen bond acceptor ability. The results indicate that the rotational dynamics of C153 is mainly governed by the viscosity of the medium. On the other hand, the rotational motion of AP is found to be significantly hindered in the ILs depending on the nature of anions of the ILs. Rotational coupling constant values for AP in the ILs follow the order TFA > ESU > TCB > TFB. The slower rotational motion of AP in these ILs has been attributed to the specific hydrogen bonding interaction between AP and anions of ILs.
已研究了两种有机溶质香豆素153（C153）和4-氨基邻苯二甲酰亚胺（AP）在四种离子液体（ILs）中的旋转扩散，这四种离子液体分别是1-乙基-3-甲基咪唑三氟乙酸盐（EMIMTFA）、1-乙基-3-甲基咪唑硫酸乙酯（EMIMESU）、1-乙基-3-甲基咪唑四氟硼酸盐（EMIMTFB）和1-乙基-3-甲基咪唑四氰硼酸盐（EMIMTCB），其作为温度的函数。在这两种探针之间，AP可作为氢键供体与具有氢键受体能力的溶剂相互作用。结果表明，C153的旋转动力学主要受介质粘度的控制。另一方面，发现AP的旋转运动在离子液体中受到显著阻碍，这取决于离子液体阴离子的性质。AP在离子液体中的旋转耦合常数数值顺序为TFA＞ESU＞TCB＞TFB。AP在这些离子液体中较慢的旋转运动归因于AP与离子液体阴离子之间的特定氢键相互作用。
