Cappello Daniela, Maar Ryan R, Staroverov Viktor N, Gilroy Joe B
Department of Chemistry, and Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Chemistry. 2020 Apr 24;26(24):5522-5529. doi: 10.1002/chem.202000533. Epub 2020 Apr 15.
The creation of dimeric boron difluoride complexes of chelating N-donor ligands is a proven strategy for the enhancement of the optoelectronic properties of fluorescent dyes. We report dimers based on the boron difluoride hydrazone (BODIHY) framework, which offer unique and sometimes unexpected substituent-dependent absorption, emission, and electrochemical properties. BODIHY dimers have low-energy absorption bands (λ =421 to 479 nm, ϵ=17 200 to 39 900 m cm ) that are red-shifted relative to monomeric analogues. THF solutions of these dimers exhibit aggregation-induced emission upon addition of water, with emission enhancement factors ranging from 5 to 18. Thin films of BODIHY dimers are weakly emissive as a result of the inner-filter effect, attributed to intermolecular π-type interactions. BODIHY dimers are redox-active and display two one-electron oxidation and two one-electron reduction waves that strongly depend on the N-aryl substituents. These properties are rationalized using density-functional theory calculations and X-ray crystallography experiments.
生成具有螯合氮供体配体的二聚体二氟化硼配合物是增强荧光染料光电性能的一种行之有效的策略。我们报道了基于二氟化硼腙（BODIHY）框架的二聚体，其具有独特的、有时甚至出乎意料的依赖于取代基的吸收、发射和电化学性质。BODIHY二聚体具有低能吸收带（λ = 421至479 nm，ϵ = 17200至39900 m cm ），相对于单体类似物发生红移。这些二聚体的四氢呋喃溶液在加入水后表现出聚集诱导发光，发射增强因子在5至18之间。由于内滤效应，BODIHY二聚体薄膜的发射较弱，这归因于分子间π型相互作用。BODIHY二聚体具有氧化还原活性，显示出两个单电子氧化波和两个单电子还原波，这强烈依赖于N - 芳基取代基。利用密度泛函理论计算和X射线晶体学实验对这些性质进行了合理解释。
