Spectroscopic Evidence for Unusual Microviscosity in Imidazolium Ionic Liquid and Tetraethylene Glycol Dimethyl Ether Cosolvent Mixtures

doi:10.1021/jp304914e

CORC > 化学研究所 > 中国科学院化学研究所

	Spectroscopic Evidence for Unusual Microviscosity in Imidazolium Ionic Liquid and Tetraethylene Glycol Dimethyl Ether Cosolvent Mixtures
	Li, Boxuan ; Wang, Yingying ; Wang, Xuefei ; Vdovic, Silvije ; Guo, Qianjin ; Xia, Andong 1
刊名	JOURNAL OF PHYSICAL CHEMISTRY B
	2012-11-08
卷号	116 期号:44 页码:13272-13281
ISSN号	1520-6106
DOI	10.1021/jp304914e
英文摘要	The rotational dynamics of coumarin 153 (C153) in imidazolium-based ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and tetraethylene glycol dimethyl ether (TEGDME) mixtures across all mole fractions have been investigated to determine the local viscosity of the microenvironment surrounding the probe molecules. The excimer-to-monomer fluorescence emission intensity ratio (I-E/I-M) of a well-known microviscosity probe, 1,3-bis(1-pyrenyl)propane (BPP), is also employed to study the microviscosity of the mixtures as a complementary measurement. The rotational dynamics of C153 show that there are incompact and compact domains within the heterogeneous structural [bmim][PF6], resulting in fast and slow components of C153 rotational dynamics. The microviscosity in different structural domains of [bmim][PF6] before and after adding cosolvent TEGDME with different mole fractions is further investigated by studying the fluorescence anisotropy decay of probe molecules. The obtained average rotation time constants show that the microviscosity of [bmim] [PF6] is enhanced after mixing with a certain amount of TEGDME, although the bulk viscosity of TEGDME itself is much lower than that of the ionic liquid. This unusual behavior of microviscosity enhancement is further proven by the steady state fluorescence measurement with the microviscosity probe of BPP. The microviscosity enhancement is reasonably demonstrated by the fast time constant of C153 rotational dynamics and the departure between the experimentally observed and calculated ratio of I-E/I-M of BPP, which shows that this effect is most pronounced at intermediate mole fractions of the [bmim][PF6] and TEGDME mixtures. The strengthening effects caused by the molecular interactions between TEGDME and structural heterogeneous ionic liquid [bmim][PF6] are proposed to interpret the unusual microviscosity behaviors.
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000310768600014
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/48021]
专题	中国科学院化学研究所
通讯作者	Xia, Andong
作者单位	1.Chinese Acad Sci, State Key Lab Mol React Dynam, Inst Chem, Beijing 100190, Peoples R China 2.Chinese Acad Sci, BNLMS, Inst Chem, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Li, Boxuan,Wang, Yingying,Wang, Xuefei,et al. Spectroscopic Evidence for Unusual Microviscosity in Imidazolium Ionic Liquid and Tetraethylene Glycol Dimethyl Ether Cosolvent Mixtures[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2012,116(44):13272-13281.
APA	Li, Boxuan,Wang, Yingying,Wang, Xuefei,Vdovic, Silvije,Guo, Qianjin,&Xia, Andong.(2012).Spectroscopic Evidence for Unusual Microviscosity in Imidazolium Ionic Liquid and Tetraethylene Glycol Dimethyl Ether Cosolvent Mixtures.JOURNAL OF PHYSICAL CHEMISTRY B,116(44),13272-13281.
MLA	Li, Boxuan,et al."Spectroscopic Evidence for Unusual Microviscosity in Imidazolium Ionic Liquid and Tetraethylene Glycol Dimethyl Ether Cosolvent Mixtures".JOURNAL OF PHYSICAL CHEMISTRY B 116.44(2012):13272-13281.