Huang Jianjun, Chung Pham Thanh, Coenen Daan, Vandenwijngaerden Jonathan, Gong Jing, Minh Thi Nguyen Hue, Van Meervelt Luc, Van der Auweraer Mark, Escudero Daniel, Dehaen Wim
Sustainable Chemistry for Metals and Molecules, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
Quantum Chemistry and Physical Chemistry, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
Chemistry. 2024 Nov 4;30(61):e202401837. doi: 10.1002/chem.202401837. Epub 2024 Oct 16.
A novel category of asymmetric boron chromophores with the attachment of two BF moieties denoted as BOPAM has been successfully synthesized via a one-pot three-step reaction starting from N-phenylbenzothioamide. This synthetic route results in the production of [a] and [b]benzo-fused BOPAMs along with post-functionalization of the [a]benzo-fused BOPAMs. The photophysical properties of these compounds have been systematically investigated through steady-state absorption and fluorescence emission measurements in solvents at both ambient and cryogenic temperatures, as well as in the solid state. Computational methods have been employed to elucidate the emissive characteristics of the benzo-fused BOPAMs, revealing distinctive photophysical attributes, including solvent-dependent fluorescence intensity. Remarkably, certain BOPAM derivatives exhibit noteworthy photophysical phenomena, such as the induction of off-on fluorescence emission under specific solvent conditions and the manifestation of intermolecular charge transfer states in solid-state matrices. Through post-functionalization strategies involving the introduction of electron-donating groups onto the [a]benzo-fused BOPAM scaffold, an intramolecular charge transfer (ICT) pathway is activated, leading to substantial fluorescence quenching via non-radiative decay processes. Notably, one [a]benzo-fused BOPAM variant exhibits a pronounced fluorescence enhancement upon exposure to acidic conditions, thereby underscoring its potential utility in pH-sensing applications.
一类新型的不对称硼发色团已成功合成，这类发色团带有两个BF部分，记为BOPAM，它是从N-苯基苯硫酰胺开始通过一锅三步反应合成的。这条合成路线产生了[a]和[b]苯并稠合的BOPAM，以及[a]苯并稠合的BOPAM的后功能化产物。通过在环境温度和低温下的溶剂中以及固态下的稳态吸收和荧光发射测量，系统地研究了这些化合物的光物理性质。已采用计算方法来阐明苯并稠合的BOPAM的发射特性，揭示了独特的光物理属性，包括溶剂依赖性荧光强度。值得注意的是，某些BOPAM衍生物表现出值得关注的光物理现象，例如在特定溶剂条件下诱导开-关荧光发射以及在固态基质中表现出分子间电荷转移态。通过涉及在[a]苯并稠合的BOPAM支架上引入供电子基团的后功能化策略，激活了分子内电荷转移（ICT）途径，导致通过非辐射衰变过程产生大量荧光猝灭。值得注意的是，一种[a]苯并稠合的BOPAM变体在暴露于酸性条件时表现出明显的荧光增强，从而突出了其在pH传感应用中的潜在用途。
