Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
J Phys Chem A. 2011 Jun 23;115(24):6481-7. doi: 10.1021/jp201537k. Epub 2011 May 18.
Time-resolved emission techniques were employed to study the nonradiative process of thioflavin-T (ThT) in 1-propanol, 1-butanol, and 1-pentanol as a function of the hydrostatic pressure. Elevated hydrostatic pressure increases the alcohol viscosity, which in turn strongly influences the nonradiative rate of ThT. A diamond-anvil cell was used to increase the pressure up to 2.4 GPa. We found that the nonradiative rate constant, k(nr), decreases with pressure. We further found a remarkable linear correlation between a decrease in k(nr) (increase in the nonradiative lifetime, τ(nr)) and an increase in the solvent viscosity. The viscosity was varied by a factor of 1000 and k(nr) was measured at high pressures, at which the nonradiative rate constant of the molecules decreased from (7 ps)(-1) to (13 ns)(-1), (13 ps)(-1) to (17 ns)(-1) and (17 ps)(-1) to (15 ns)(-1) for 1-propanol, 1-butanol, and 1-pentanol, respectively. The viscosity-dependence of k(nr) is explained by the excited-state rotation rate of the two-ring systems, with respect to each other.
采用时间分辨荧光技术，研究了噻唑橙（ThT）在 1-丙醇、1-丁醇和 1-戊醇中的非辐射过程，作为静压的函数。升高静压会增加醇的粘度，从而强烈影响 ThT 的非辐射速率。使用金刚石压腔将压力提高到 2.4 GPa。我们发现，非辐射速率常数 k(nr)随压力降低。我们进一步发现，k(nr)的降低（非辐射寿命 τ(nr)的增加）与溶剂粘度的增加之间存在显著的线性相关性。粘度变化了 1000 倍，在高压下测量了 k(nr)，此时分子的非辐射速率常数从（7 ps）（-1）降低到（13 ns）（-1）、（13 ps）（-1）降低到（17 ns）（-1）和（17 ps）（-1）降低到（15 ns）（-1），分别用于 1-丙醇、1-丁醇和 1-戊醇。k(nr)的粘度依赖性可以通过两个环系相对于彼此的激发态旋转速率来解释。
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