Photochromism of Spiropyran in Ionic Liquids: Enhanced Fluorescence and Delayed Thermal Reversion

CORC > 兰州化学物理研究所 > 中国科学院兰州化学物理研究所 > 绿色化学研究发展中心

	Photochromism of Spiropyran in Ionic Liquids: Enhanced Fluorescence and Delayed Thermal Reversion
	Deng YQ(邓友全); Zhang QH(张庆华); Deng YQ(邓友全)
刊名	J. Phys. Chem. B
	2009
卷号	113 期号:17 页码:6012-6019
ISSN号	1520-6106
通讯作者	邓友全
中文摘要	Photochromism of spiropyran and thermal reversion of MC in a series of imidazolium-based ionic liquids (ILs) were investigated via fluorescence and UV-vis absorption spectra. The fluorescence emission maxima (λem) of the colored merocyanine (MC) form is polarity dependent in all ILs and fluorescence intensity enhancement was first observed in ILs with respect to that observed in organic solvents (e.g., in [HOMIm][PF6], nearly 32-fold enhancement than ethanol). Moreover, the thermal decay of MC in all ILs is uniformly first order, and in comparison with polar solvents possessing comparable polarity (such as ethanol and acetonitrile), a significant retardation of the decay rate and increase of half-lifetime of MC form was observed, in particular at elevated temperature (e.g., at 313 K, MC decay with k of 5.19 × 10-4 and 34.7 × 10-4 s-1 in [BMMIm][BF4] and ethanol, respectively). Abnormal thermodynamics of the thermal decay of MC in ILs were observed, activation energies in less polar ILs (88-97 kJ mol-1) have a larger value than in polar ILs (70-82 kJ mol-1), opposite that in organic solvents (70-80 kJ mol-1 in nonpolar solvents and around 100 kJ mol-1 in polar solvents), and all ILs exclusively exhibit minus activation entropies (-85.4 to -24.5 J K-1 mol-1), similar to that of nonpolar solvents. Desolvation due to the conformational change during the thermal reversion between MC and the transition state may be the key to interpret this experimental result.
学科主题	物理化学
收录类别	SCI
资助信息	the National Natural Science Foundation of China (No. 20533080;20225309;50421502)
语种	英语
WOS记录号	WOS:000265529900043
公开日期	2012-12-01
内容类型	期刊论文
源URL	[http://210.77.64.217/handle/362003/2302]
专题	兰州化学物理研究所_绿色化学研究发展中心
通讯作者	Deng YQ(邓友全); Deng YQ(邓友全)
推荐引用方式 GB/T 7714	Deng YQ,Zhang QH,Deng YQ. Photochromism of Spiropyran in Ionic Liquids: Enhanced Fluorescence and Delayed Thermal Reversion[J]. J. Phys. Chem. B,2009,113(17):6012-6019.
APA	邓友全,张庆华,&邓友全.(2009).Photochromism of Spiropyran in Ionic Liquids: Enhanced Fluorescence and Delayed Thermal Reversion.J. Phys. Chem. B,113(17),6012-6019.
MLA	邓友全,et al."Photochromism of Spiropyran in Ionic Liquids: Enhanced Fluorescence and Delayed Thermal Reversion".J. Phys. Chem. B 113.17(2009):6012-6019.