光谱学研究离子液体与氟罗沙星的相互作用  

Spectral Study on the Interaction between Ionic Liquid and Fleroxacin

作　　者：江涛[1] 张婧[1] 赵文岩[1] 张春玲[1] 贾瑞梅[1] 

机构地区：[1]内蒙古大学化学化工学院,内蒙古呼和浩特010021

出　　处：《光谱学与光谱分析》2017年第4期1211-1214,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21167008);内蒙古自然科学基金项目(2015MS0203)资助

摘　　要：离子液体可以有效地萃取水相中的喹诺酮类药物,为了探讨其萃取机理,通过荧光、紫外和红外光谱法等手段研究了离子液体1-己基-3-甲基咪唑六氟磷酸盐([C_6mim]PF_6)与喹诺酮药物氟罗沙星(fleroxacin,FLX)间的相互作用。由荧光发射谱图可知,随[C_6mim]PF_6加入量的增大,FLX体系的荧光强度发生有规律的猝灭。Stern-Volmer猝灭常数随温度的升高而降低。另外,相同条件时FLX的紫外吸收光谱随着[C_6mim]PF_6的加入逐渐降低并发生红移,表明两者在基态时形成了不发射荧光的复合物,确定猝灭类型为静态猝灭。15,25和35℃时,[C_6mim]PF_6与FLX相互作用的表观结合常数Ka分别为130.0,198.3和170.6L·mol^(-1)。计算热力学参数,ΔG<0,表明萃取是自发过程,而ΔS和ΔH均大于零,推测萃取的主要驱动力可能为疏水作用。[C_6mim]PF_6在水中可较为有序地排布,亲水性咪唑环指向外部水相,疏水性的烷基链一起构成疏水内腔。在疏水内腔中,咪唑环中的—CH与电负性大的N原子相邻,C更强烈地吸引H原子上的电子,使H成为潜在的氢键供体。而FLX上的π电子比较密集,使得其整体电负性较大,可作为氢键的受体,咪唑环中的—CH与FLX上的π电子形成—CH…π键,FLX可进入疏水内腔,从而被包接萃取。另外,红外谱图分析表明,FLX分子中的—COOH基团可能取代了原本与PF_6^-结合的水分子而发生了氢键缔合的疏水相互作用。Ionic liquid can effectively extract quinolones medicines from aqueous phase.In order to explore the extraction mechanism,the interaction between ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate（[C6mim]PF6）and fleroxacin（FLX）were studied by using fluorescence,UV-VIS absorption and infrared spectrometry.With the increasing addition of[C6mim]PF6,inerratic fluorescence quenching of FLX solution could be observed from fluorescence spectra.Stern-Volmer constant had negative correlation with temperature.Besides,the addition of[C6mim]PF6caused a decrease and red-shift of absorption peak in UV-VIS absorption spectra of FLX,which indicated the fluorescence quenching of FLX by[C6mim]PF6 was due to the formation of[C6mim]PF6-FLX complex in the ground state through static quenching procedure.Apparent affinity binding constants Kaof interaction between[C6mim]PF6 and FLX were 130.0,198.3,170.6L·mol^（-1） at 15,25,35℃,respectively.Calculating of thermodynamics parameters,ΔG0,ΔS0,ΔH 0,demonstrated extraction was a spontaneous process,and hydrophobic interaction probably was the major driving force of extraction.[C6mim]PF6 could orderly distribute in water with the hydrophilic imidazole ring pointing out to the aqueous phase and the hydrophobic alkyl chains together arranging into hydrophobic cavities.In these hydrophobic cavities,the H of—CH— adjacent to N of imidazole rings is a potential H-bond donor,and intensiveπelectrons in FLX could act as H-bond acceptor,so the FLX entered the hydrophobic cavities of[C6mim]PF6due to the interaction of—CH…πtype bonds between—CH of[C6mim]＋andπelectrons included in FLX.Furthermore,based on infrared spectra,it suggested that the hydrophobic interaction might be the result of FLX replacing the H2O molecular combined with PF6^-through the hydrogen bonding interaction between PF6^-and —COOH groups of FLX.

关 键 词：氟罗沙星 1-己基-3-甲基咪唑六氟磷酸盐 荧光猝灭 光谱 相互作用 

分 类 号：O657.3[理学—分析化学]