Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
J Fluoresc. 2013 Mar;23(2):283-91. doi: 10.1007/s10895-012-1146-x. Epub 2012 Nov 15.
The photophysical properties of chlorin e6 (Ce6) in twelve different protic, aprotic and non-polar solvents were investigated using ultraviolet-visible and fluorescence spectroscopic methods. Solvatochromic effects were determined by the changes in quantum yield, Stokes shift, fluorescence half-life and excited state dipole moments of Ce6 in the different solvents. The absorption shifts observed in different solvents were further analyzed using the Kamlet-Abboud-Taft model and the nature of solute-solvent interactions between Ce6 and different protic and aprotic solvents was elucidated. The quantum yields were found highest in protic solvents (except water), followed by aprotic and non-polar solvents. Solvent polarity parameters showed a linear increasing trend with Stokes shift and fluorescence half-life, which indicated the presence of Ce6-solvent interaction. Using the Kamlet-Abboud-Taft model, a direct correlation between the solvent polarity parameters and absorption shift was observed, which substantiated the existence of Ce6-solvent interaction by hydrogen bond formation. The excited state dipole moments in specific protic and aprotic solvents were found to be higher than the ground state dipole moments, implying a more polar nature of Ce6 during excited state transition.
使用紫外-可见和荧光光谱法研究了氯卟啉 e6（Ce6）在 12 种不同质子性、非质子性和非极性溶剂中的光物理性质。通过 Ce6 在不同溶剂中的量子产率、Stokes 位移、荧光半衰期和激发态偶极矩的变化来确定溶剂化效应。进一步使用 Kamlet-Abboud-Taft 模型分析了在不同溶剂中观察到的吸收位移，并阐明了 Ce6 与不同质子性和非质子性溶剂之间的溶质-溶剂相互作用的性质。量子产率在质子性溶剂（水除外）中最高，其次是非质子性和非极性溶剂。溶剂极性参数与 Stokes 位移和荧光半衰期呈线性增加趋势，表明存在 Ce6-溶剂相互作用。使用 Kamlet-Abboud-Taft 模型，观察到溶剂极性参数与吸收位移之间存在直接相关性，这通过氢键形成证实了 Ce6-溶剂相互作用的存在。在特定的质子性和非质子性溶剂中，激发态偶极矩高于基态偶极矩，这意味着 Ce6 在激发态跃迁过程中具有更极性的性质。
