In this paper, we present for the first time an efficient method for synthesizing three novel tetra–coordinated BF2 complexes, specifically 6,6-difluoro-2,4-dimethyl-6H-5λ4,6λ4-benzo [4,5]imidazo(oxazolo/thiazolo)[3,2-c]pyrimido [2,1-f][1,3,5,2]triazaborinines (4a–c). These compounds were synthesized via the reaction of selected N-(4,6-dimethylpyrimidin-2-yl)-benzo[d]imidazo(oxazolo/thiazolo)-2-amines (3a–c) with BF3·OEt2, employing Et3N as a base. Optimized yields ranging from 64 to 69 % were achieved when the reactions were conducted in anhydrous CHCl3 at room temperature for 24 h. The structural elucidation of BF2 complexes 4a-c was performed through multinuclear NMR, FTIR, SC-XRD, and HRMS techniques. These compounds demonstrated thermal stability up to 150 °C as evidenced by thermogravimetric analysis. The spectroscopic properties (in both solution and solid states) and the electrochemical properties of the synthesized derivatives were thoroughly investigated using UV–Vis spectroscopy, steady-state, time-resolved fluorescence emission, TD-DFT calculations, and redox potential measurements. The results of this study highlighted a dependence of the compounds’ properties on the heteroatom (NH, O, or S) present within the heterocyclic skeleton.

中文翻译：

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1,1-二氟-1,3,5,2-三氮杂硼啉，含有苯并稠合咪唑基、恶唑基-和噻唑基-嘧啶基作为新的发光框架


在本文中，我们首次提出了一种合成三种新型四配位 BF2 配合物的有效方法，特别是 6,6-二氟-2,4-二甲基-6H-5λ4,6λ4-苯并[4,5]咪唑（恶唑并/噻唑)[3,2-c]嘧啶并[2,1-f][1,3,5,2]三氮杂硼啉(4a–c)。这些化合物是通过选定的 N-(4,6-二甲基嘧啶-2-基)-苯并[d]咪唑(恶唑并/噻唑)-2-胺 (3a–c) 与 BF3·OEt2 反应合成的，使用 Et3N 作为一个基地。当反应在无水 CHCl3 中于室温下进行 24 小时时，优化收率范围为 64% 至 69%。通过多核NMR、FTIR、SC-XRD 和HRMS 技术对BF2 配合物4a-c 进行了结构解析。热重分析证明，这些化合物在高达 150 °C 的温度下表现出热稳定性。使用紫外-可见光谱、稳态、时间分辨荧光发射、TD-DFT 计算和氧化还原电位测量，对合成衍生物的光谱性质（溶液和固态）和电化学性质进行了彻底研究。这项研究的结果强调了化合物的性质取决于杂环骨架中存在的杂原子（NH、O 或 S）。