New pyrimidine-containing β-iminoenolates and their difluoroboron complexes were synthesized. It was found that the ligand and the complex bearing tert-butyl could self-assemble into organogels in methylcyclohexane/1,4-dioxane and other solvents, but no organogel could be formed from the carbazole derivatives. This suggested that tert-butyl played a key role in the gel formation. It should be noted that no traditional gelation moiety was involved in the fully conjugated TCPPA ((Z)-2-(6-chloropyrimidin-4-yl)-1-(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)et-hen-1-ol) and TCPPAB (6-chloro-3-(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)phenyl)-1,1-diflu-oro-1H-1l4,9l4-pyrimido[1,6-c][1,3,2]oxazaborinine), and π–π interactions were found to be the main driving forces for the gelation. Moreover, the xerogel-based film of TCPPAB emitting strong yellow light could be used as a “turn-off” fluorescent sensor to detect TFA vapor with the decay time and detection limit of 0.8 s and 260 ppb, respectively. On the other hand, the β-iminoenolate difluoroboron complexes exhibited reversible mechanofluorochromic behavior. The as-synthesized crystals of TCPPAB emitted strong green light and could be transformed into powders emitting orange light upon grinding, and the fluorescence could be recovered when the ground powders were fumed with CH₂Cl₂. Such reversible MFC processes for TCPPAB were suggested to have resulted from the transformation between crystalline and amorphous states. Herein, we provide a strategy for designing new multi-stimuli-responsive soft materials.

中文翻译：

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含嘧啶的β-亚氨基磺酸二氟硼配合物，充当非传统的π-胶凝剂和机械氟致变色染料†

合成了新的含嘧啶的β-亚氨基丙烯酸酯及其二氟硼配合物。发现该配体和带有叔丁基的配合物可以在甲基环己烷/ 1,4-二恶烷和其他溶剂中自组装成有机凝胶，但是咔唑衍生物不能形成有机凝胶。这表明叔丁基在凝胶形成中起关键作用。应当指出，完全偶联的TCPPA（（Z）-2-（6-氯嘧啶-4-基）-1-（4-（3,6-二叔丁基-9）H-咔唑-9-基）苯基] et-hen-1-ol）和TCPPAB（6-氯-3-（4-（3,6-二叔丁基-9 H-carbazol-9-yl）phenyl）-1,1-diflu-oro-1 H -1l4,9l4-pyrimido [1,6- c ] [1,3,2] oxazaborinine），并发现π–π相互作用成为凝胶化的主要动力。此外，发出强黄光的TCPPAB的基于干凝胶的薄膜可以用作“关闭”荧光传感器，以检测TFA蒸气，其衰变时间和检测极限分别为0.8 s和260 ppb。另一方面，β-亚氨基酚二氟硼配合物表现出可逆的机械氟致变色行为。刚合成的TCPPAB晶体发出强烈的绿光，研磨后可转变为散发出橙色光的粉末，当研磨的粉末与CH ₂一起熏蒸时可回收荧光。Cl ₂。这种用于TCPPAB的可逆MFC工艺被认为是晶态和非晶态之间的转换所致。在此，我们提供了设计新的多刺激响应性软材料的策略。