One new series of boron difluoride complexes 1 derived from heterocyclic benzoxazoles 2 was reported, and their mesomorphic and optical properties were also investigated. One single crystal of the mesogenic BF₂ complex 1a (m = 12, n = 8) was obtained, and its single crystal and molecular structure were resolved. The geometry coordination at the central boron atom is tetrahedral. It crystallizes in a triclinic space group P with Z = 4. The overall molecular shape was described as slightly bent Z-shapes, and the molecular length was ca. 34.06 Å. Weak intramolecular and intermolecular H-bonds observed in the crystal lattice were attributed to the formation of mesophases. The results indicated that benzoxazoles 2a (n = 6, 8, 12) formed monotropic SmA phases, while boron difluoride complexes 1a (n = 6, 8, 12, 16) exhibited monotropic SmC mesophases. In contrast, all compounds of 2b and 1b (m = 1, n = 12 for all) were not mesogenic. Boron complexes 1 emitted a pronounced violet emission at λ_max = 399 nm in solution at room temperature.

中文翻译：

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杂环苯并恶唑衍生的荧光介晶二氟化硼配合物

报道了一系列新的衍生自杂环苯并恶唑2的二氟化硼配合物1，并且还研究了它们的介晶和光学性质。获得了一个介晶BF _2配合物1a（m = 12，n = 8）的单晶，并解析了其单晶和分子结构。中心硼原子的几何配位为四面体。该晶体三斜空间群P与Ž = 4的总体分子形状被描述为略微弯曲Z-形状，和分子长度为约34.06Å。在晶格中观察到的弱分子内和分子间氢键归因于中间相的形成。结果表明，苯并恶唑2a（n = 6、8、12）形成单向SmA相，而二氟化硼配合物1a（n = 6、8、12、16）呈现单向SmC中间相。与此相反，所有的化合物2B和图1b（米= 1，Ñ = 12为全部）不介晶。硼络合物1在发射的显着的紫光发射λ_最大在室温下在溶液= 399纳米。