Replacement of the carbon–carbon bonds of antiaromatic compounds with polar boron–nitrogen bonds often provides isoelectronic BN compounds with excellent thermodynamic stability and interesting photophysical properties. By this element-substitution strategy, we synthesized a new B₄N₄-heteropentalene derivative, 1, which is fully substituted with mesityl groups. Owing to kinetic protection by the sterically bulky substituents, 1 is remarkably stable toward air and even water. Single-crystal X-ray analysis of 1 revealed the bonding characteristics of the B₄N₄-heteropentalene structure. In a glassy matrix, 1 emitted short-wavelength phosphorescence with an onset at 350 nm, indicating that the triplet energy is substantially high. DFT calculations reasonably explained the ground- and excited-state electronic structures of 1 as well as its emission properties. Motivated by the high-energy triplet state of 1, we used it as a host material to fabricate a phosphorescent organic light-emitting diode with an external quantum efficiency of 15 %.

中文翻译：

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空气和水稳定的 B4N4-杂戊烯用作磷光 OLED 的主体材料

用极性硼-氮键取代抗芳族化合物的碳-碳键通常可以提供具有优异热力学稳定性和有趣的光物理性质的等电子 BN 化合物。通过这种元素取代策略，我们合成了一种新的 B ₄ N _{4 -}杂戊烯衍生物1，它完全被甲基苯取代。由于空间庞大的取代基的动力学保护，1对空气甚至水非常稳定。的单晶X射线分析1揭示了B的粘合特性₄ Ñ ₄ -heteropentalene结构。在玻璃矩阵中，1发射短波长磷光，起始波长为 350 nm，表明三线态能量相当高。DFT 计算合理地解释了1 的基态和激发态电子结构及其发射特性。受1的高能三重态的启发，我们用它作为主体材料制造了外量子效率为 15% 的磷光有机发光二极管。