Recently synthesized D-A-D system shows mechanochromic luminescence. The resulting four conformers are quasi axial – quasi axial (AA) with syn: and anti-variants, quasi axial – quasi equatorial (AE) and quasi equatorial – quasi equatorial (EE). AA shows phosphorescence and EE shows thermally activated delayed fluorescence (TADF), while AE exerts both. With lesser overlap between HOMO and LUMO in AE and EE, transitions are charge transfer in nature and decreases the singlet-triplet gap (ΔE_ST) favoring TADF, while higher ΔE_ST and lower reorganization energy of T₁ in AA boosts phosphorescence.

中文翻译：

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描述分子供体-受体-供体三联体光物理行为中的构象控制

最近合成的 DAD 系统显示出机械致变色发光。由此产生的四个构象异构体是准轴 - 准轴 (AA) 与同步：和反变体，准轴 - 准赤道 (AE) 和准赤道 - 准赤道 (EE)。AA 显示磷光，EE 显示热激活延迟荧光 (TADF)，而 AE 两者都发挥。由于 AE 和 EE 中 HOMO 和 LUMO 之间的重叠较少，跃迁本质上是电荷转移，并降低了有利于 TADF的单线态-三线态间隙 (ΔE _ST )，而AA 中较高的 ΔE _ST和较低的 T ₁重组能促进了磷光。