Rajput Swati Singh, Zaleśny Robert, Alam Md Mehboob
Department of Chemistry, Indian Institute of Technology Bhilai, GEC Campus, Sejbahar, Raipur, Chhattisgarh 492015, India.
Faculty of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland.
J Phys Chem A. 2023 Sep 28;127(38):7928-7936. doi: 10.1021/acs.jpca.3c04288. Epub 2023 Sep 18.
In this work, we have employed electronic structure theories to explore the effect of the planarity of the chromophore on the two-photon absorption properties of bi- and ter-phenyl systems. To that end, we have considered 11 bi- and 7 ter-phenyl-based chromophores presenting a donor-π-acceptor architecture. In some cases, the planarity has been enforced by bridging the rings at ortho-positions by -CH and/or -BH, -O, -S, and -NH moieties. The results presented herein demonstrate that in bi- and ter-phenyl systems, the planarity achieved a -CH bridge increases the 2PA activity. However, the introduction of a bridge with the -BH moiety perturbs the electronic structure to a large extent, thus diminishing the two-photon transition strength to the lowest electronic excited state. As far as two-photon absorption activity is concerned, this work hints toward avoiding -BH bridge(s) to enforce planarity in bi- and ter-phenyl systems; however, one may use -CH bridge(s) to achieve the enhancement of the property in question. All of these conclusions have been supported by in-depth analyses based on generalized few-state models.
在这项工作中，我们运用电子结构理论来探究发色团的平面性对双苯基和三苯基体系双光子吸收性质的影响。为此，我们考虑了11种具有供体-π-受体结构的双苯基和7种三苯基发色团。在某些情况下，通过-CH和/或-BH、-O、-S和-NH基团在邻位桥接环来增强平面性。本文给出的结果表明，在双苯基和三苯基体系中，通过-CH桥实现的平面性提高了双光子吸收活性。然而，引入含-BH基团的桥会在很大程度上扰乱电子结构，从而降低到最低电子激发态的双光子跃迁强度。就双光子吸收活性而言，这项工作表明在双苯基和三苯基体系中应避免使用-BH桥来增强平面性；不过，可以使用-CH桥来实现所讨论性质的增强。所有这些结论都得到了基于广义少态模型的深入分析的支持。
