Melechalil Masbooth Rasa, Shimada Tetsuya, Ishida Tamao, Takagi Shinsuke
Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan.
Research Center for Hydrogen Energy Based- Society (ReHES), Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan.
Photochem Photobiol Sci. 2024 Sep;23(9):1725-1734. doi: 10.1007/s43630-024-00625-3. Epub 2024 Sep 6.
The enhanced emission properties of several cationic dye molecules on the clay surface established as a result of the strong electrostatic interaction and associated molecular flattening leading to either the suppression of non-radiative deactivation processes or the improvement of radiative deactivation processes has been verified, and it is known as surface-fixation induced emission (S-FIE). Here, the differences in the S-FIE properties as well as the self-fluorescence quenching behavior of the dimidium and propidium dyes were compared. Propidium differs from dimidium by the substitution of a propyl (diethyl methylammonium) group at the 5th position instead of the methyl group in dimidium. So, the differences induced by this substitution, which is not even in conjugation with the chromophore part of the dye molecule show a significant impact on the adsorption strength, S-FIE properties, and self-fluorescence quenching behavior. In propidium and dimidium, the suppression of k was the key factor for emission enhancement on the clay surface. Interestingly, the alkylammonium cation group in the Propidium helped for better adsorption strength as well as to reduce the self-fluorescence quenching behavior on the clay surface as compared to the dimidium. Since the trialkylammonium cation was not in conjugation with the core structure of the molecule and located at a specific distance, it did not interrupt the flattening of the molecule on the clay surface. These results could be beneficial in the construction of efficient photochemical reaction systems, where the molecule having low adsorption strengths can be modified by alkyl ammonium cations, which will not affect molecular planarization.
由于强静电相互作用以及相关的分子扁平化导致非辐射失活过程受到抑制或辐射失活过程得到改善，从而确立了几种阳离子染料分子在粘土表面的增强发射特性，这被称为表面固定诱导发射（S-FIE）。在此，比较了双咪啶和碘化丙啶染料的S-FIE特性差异以及自荧光猝灭行为。碘化丙啶与双咪啶的不同之处在于，在第5位取代了一个丙基（二乙甲基铵）基团，而不是双咪啶中的甲基。因此，这种甚至与染料分子的发色团部分不共轭的取代所引起的差异，对吸附强度、S-FIE特性和自荧光猝灭行为产生了显著影响。在碘化丙啶和双咪啶中，抑制k是粘土表面发射增强的关键因素。有趣的是，与双咪啶相比，碘化丙啶中的烷基铵阳离子基团有助于提高吸附强度，并减少粘土表面的自荧光猝灭行为。由于三烷基铵阳离子与分子的核心结构不共轭且位于特定距离，它不会干扰分子在粘土表面的扁平化。这些结果可能有利于构建高效的光化学反应体系，其中吸附强度低的分子可以通过烷基铵阳离子进行修饰，而这不会影响分子的平面化。
