The drastic differences in absorption spectra of structurally close quinoxalinone derivatives, containing electron-donor and -acceptor units, are rationalized, by means of theoretical tools. They are ascribed to the difference in the intramolecular charge-transfer character of the electronic transition corresponding to the experimental longest-wavelength absorption bands of these systems. Charge-transfer compounds are not luminescent in solutions, in contrast to their analogs with weaker charge-separation and longer π-conjugated backbone, which suggests that the main factor “switching-off” emission is related to their “push-pull” properties and the balance between the length of the π-conjugated backbone and the donor-acceptor strength. Furthermore, the protonation of the studied quinoxalinones is shown to result in a weakening of the donor-acceptor strengths and conjugation efficiency, thus limiting charge-transfer and producing the emission response in the acidified solutions.

借助于理论工具，合理化了结构紧密的喹喔啉酮衍生物的吸收光谱的巨大差异，该衍生物含有电子供体和-受体单元。它们归因于电子跃迁的分子内电荷转移特性的差异，其与这些系统的实验最长波长吸收带相对应。电荷转移化合物在溶液中不发光，相反，其电荷分离较弱且π共轭骨架更长的类似物，这表明“关断”发射的主要因素与其“推挽”性质有关。 π共轭骨架的长度和供体-受体强度之间的平衡。此外，