The impact of cation–π, anion–π, and CH–π interactions on the photophysical properties of quinizarin have been investigated using the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at the M06-2X/6-311++G(d,p) level in the gas phase and solution. The complexation of quinizarin with some mono- and divalent ions (including Na⁺, K⁺, Mg²⁺, Ca²⁺, F⁻, Cl⁻, and Br⁻) and the CF₃H molecule leads to unfavorable proton transfers in the ground state. Excitation reinforces the intramolecular hydrogen bond in the complexes and facilitates proton transfer in the first excited state. The complexes exhibit exothermic excited-state proton transfer in the solution. The cation–π, anion–π, and CH–π interactions affect the absorption and emission bands and provide a wide tunable range of fluorescence emission. The large Stokes shift is an important property of the complexes that indicates their desirable fluorescence properties. The complexes involved in anion–π interactions possess the largest Stokes shift in the solution.

中文翻译：

---

阳离子-π，阴离子-π和CH-π相互作用对1,4-二羟基蒽醌的激发态分子内质子转移的影响

在M06-2X上使用密度泛函理论（DFT）和时变密度泛函理论（TD-DFT）研究了阳离子-π，阴离子-π和CH-π相互作用对奎尼扎林光物理性质的影响。气相和溶液中的/ 6-311 ++ G（d，p）水平。醌茜与一些单-和二价离子（包括钠络合⁺，K ⁺，Mg的²⁺，钙²⁺，F ^{- ，}氯^-和Br ^-和CF）₃H分子在基态下导致质子转移不利。激发增强了配合物中的分子内氢键，并促进了在第一激发态下的质子转移。络合物在溶液中表现出放热的激发态质子转移。阳离子-π，阴离子-π和CH-π相互作用会影响吸收带和发射带，并提供宽范围的可调荧光发射。较大的斯托克斯位移是复合物的重要性质，表明它们具有理想的荧光性质。阴离子-π相互作用涉及的络合物在溶液中具有最大的斯托克斯位移。