Fluorescence and chemiluminescence properties of indolylmaleimides: experimental and theoretical studies
作者:Manabu Nakazono、Ai Jinguji、Shinkoh Nanbu、Ryoichi Kuwano、Zilong Zheng、Kenichiro Saita、Yuji Oshikawa、Yuta Mikuni、Tatsuhiro Murakami、Yi Zhao、Shigeki Sasaki、Kiyoshi Zaitsu
DOI:10.1039/c003021j
日期:——
Various indolylmaleimides (IMs) were synthesized, and their fluorescence (FL) and chemiluminescence (CL) were measured. The substitution at the 2-position of the indole ring and the 3- or 4-position of the maleimide moiety caused an obvious change in the FL and CL of the IMs. An almost on–off switching of the FL of the IMs was observed. The intramolecular charge transfer from the indole moiety to the maleimide moiety occurred in 3-(1H-3-indolyl)-2,5-dihydro-1H-2,5-pyrroledione. In the FL of the IMs, CASPT2 calculations showed deprotonation of the NH group of the indole ring and the maleimide moiety at the excited state. The CC bond in the maleimide moiety was needed for strong CL in the IMs without substitution at the 2-position of the indole ring. The relationships between the FL or CL properties and the structures of the IMs were clarified. These results provide significant information on the rational design of IMs as FL and CL probes.
合成了多种吲哚马来酰亚胺(IMs),并测量了它们的荧光(FL)和化学发光(CL)。在吲哚环的 2 位和马来酰亚胺分子的 3 位或 4 位上进行取代会导致 IMs 的 FL 和 CL 发生明显变化。我们观察到 IM 的 FL 几乎可以开关切换。在 3-(1H-3-吲哚基)-2,5-二氢-1H-2,5-吡咯烷二酮中,分子内电荷从吲哚分子转移到马来酰亚胺分子。在 IM 的 FL 中,CASPT2 计算显示吲哚环的 NH 基团和马来酰亚胺基团在激发态发生了去质子化反应。马来酰亚胺分子中的 CC 键是 IMs 在吲哚环 2 位没有取代的情况下实现强 CL 的必要条件。FL 或 CL 特性与 IM 结构之间的关系也得到了澄清。这些结果为合理设计作为 FL 和 CL 探针的 IMs 提供了重要信息。