Li Bo, Sathishkumar Palanivel, Gu Feng Long
Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry of South China Normal University, Guangzhou 510006, People's Republic of China.
Phys Chem Chem Phys. 2021 Apr 14;23(14):8489-8499. doi: 10.1039/d1cp00170a. Epub 2021 Mar 25.
In the satisfactory design and synthesis of high-performance nonlinear optical (NLO) materials, for meeting the rapidly expanding demands of optoelectronic devices, a deeper understanding of the relationship between the structures and NLO properties has become a key issue. Herein, five novel mislinked expanded hexaphyrins with different connections of pyrrole units are selected to study the relationship between the structures and NLO properties. These five mislinked expanded hexaphyrins are neo-fused, neo-confused hexaphyrins, singly, doubly, and triply N-confused hexaphyrins. From theoretical results, the order of the static first hyperpolarizability (β) values is found to be: neo-fused hexaphyrin (β = 4163 a.u.) < neo-confused hexaphyrin (β = 5494 a.u.) < singly N-confused hexaphyrin (β = 6510 a.u.) < doubly N-confused hexaphyrin (β = 15 130 a.u.) < triply N-confused hexaphyrin (β = 26 095 a.u.). Furthermore, β values of the doubly and triply N-confused hexaphyrins are improved 2.1 and 3.7 times over that of their usual parent hexaphyrin (β = 7120 a.u.), respectively. It is worth noting that increasing mislinked connection numbers and changing mislinked connection ways of the pyrrole units in these mislinked expanded hexaphyrins plays a crucial role in the tune of their second-order NLO responses.
在高性能非线性光学（NLO）材料的满意设计与合成中，为满足光电器件迅速增长的需求，深入理解结构与NLO性质之间的关系已成为关键问题。在此，选择了五种具有不同吡咯单元连接方式的新型错连扩展六卟啉，以研究结构与NLO性质之间的关系。这五种错连扩展六卟啉分别是新稠合、新混杂六卟啉、单、双、三重氮混杂六卟啉。从理论结果来看，静态第一超极化率（β）值的顺序为：新稠合六卟啉（β = 4163 a.u.）＜新混杂六卟啉（β = 5494 a.u.）＜单重氮混杂六卟啉（β = 6510 a.u.）＜双重氮混杂六卟啉（β = 15130 a.u.）＜三重氮混杂六卟啉（β = 26095 a.u.）。此外，双重和三重氮混杂六卟啉的β值分别比其通常的母体六卟啉（β = 7120 a.u.）提高了2.1倍和3.7倍。值得注意的是，在这些错连扩展六卟啉中增加错连连接数和改变吡咯单元的错连连接方式在其二阶NLO响应的调谐中起着关键作用。
