Ultrafast dynamics of solute-solvent complexation observed at thermal equilibrium in real time

被引：392

作者：

Zheng, JR ^{[1
]}

Kwak, K ^{[1
]}

Asbury, J ^{[1
]}

Chen, X ^{[1
]}

Piletic, IR ^{[1
]}

Fayer, MD ^{[1
]}

机构：

[1] Stanford Univ, Dept Chem, Stanford, CA 94305 USA

来源：

SCIENCE | 2005年 / 309卷 / 5739期

关键词：

D O I：

10.1126/science.1116213

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

In general, the formation and dissociation of solute-solvent complexes have been too rapid to measure without disturbing the thermal equilibrium. We were able to do so with the use of two-dimensional infrared vibrational echo spectroscopy, an ultrafast vibrational analog of two-dimensional nuclear magnetic resonance spectroscopy. The equilibrium dynamics of phenol complexation to benzene in a benzene-carbon tetrachloride solvent mixture were measured in real time by the appearance of off-diagonal peaks in the two-dimensional vibrational echo spectrum of the phenol hydroxyl stretch. The dissociation time constant tau(d) for the phenol-benzene complex was 8 picoseconds. Adding two electron-donating methyl groups to the benzene nearly tripled the value of tau(d) and stabilized the complex, whereas bromobenzene, with an electron-withdrawing bromo group, formed a slightly weaker complex with a slightly lower,tau(d). The spectroscopic method holds promise for studying a wide variety of other fast chemical exchange processes.

引用

页码：1338 / 1343

页数：6

共 21 条

[1] Dynamics of water probed with vibrational echo correlation spectroscopy [J].