The incorporation of cyano-based acceptor 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) in phenothiazine based derivatives via [2+2] cycloaddition-electrocyclic ring-opening reaction led to a red-shifted absorption band and low optical band gaps, which facilitated the donor-acceptor strength to a greater extent.

中文翻译：

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基于供体-受体的 1,8-萘酰亚胺取代吩噻嗪：调节 HOMO-LUMO 间隙

氰基受体1,1,4,4-tetracyanobuta-1,3-diene (TCBD)通过[2+2] 环加成-电环开环反应在吩噻嗪基衍生物中引入导致红移吸收带和低光学带隙，这在更大程度上促进了供体 - 受体强度。