fig. 1 molecular structures of 1 and 2. atomic labeling used for geometric description

2017在organic electronic上发表的一篇文章

题目是：how does a little different in structure determine whether molecules have thermally activated delayed fluorescence characteristic or not?

结构上的小小改变，致使分子的TADF性质发生重大改变，原因是什么？

分子1不具有TADF性质，而分子2具有TADF性质。

摘要部分指出，ΔEst, SOC and MECP between S1 and T1 are fairly important factors determining the TADF characteristic of 1 and 2.

选材来源于2015年的一篇JMCC

light blue and green thermally activated delayed fluorescence from 10H-phenoxaborin-derivatives and their application to organic light-emitting diodes

文章摘要中指出：however, compound 9 exhibited only a prompt emission and no delayed component. photoluminescence studies and quantum chemical calculation based on DFT and TD-DFT revealed that in comparison with compound 9, the HOMO and LUMO for compounds 10 and 11 are well separated, resulting in lowering of ΔEst and effective RISC between a lowest triplet excited state(T1) and a lowest singlet excited state(S1).

 化合物9（对应17年文章中的化合物1）仅具有即时发光，没有延迟发光。而化合物10（对应17年文章中化合物2）和11是具有延迟发光性质（也就是TADF性质）。

在2017年organic electronic那篇文章摘要的第一句就指出: DFT calculation was performed to analyze the critical factors determining whether molecule has a TADF characteristic by comparing two similar molecules(1 and 2), which have a little difference in structure but opposite TADF performance.

1和2具有相反的TADF性质表现。