Two ultrastable luminescent covalent organic frameworks (COFs), PyTA‐BC and PyTA‐BC‐Ph, are synthesized through polycondensations of 4,4′,4″,4′″‐pyrene‐1,3,6,8‐tetrayl)tetraaniline (PyTA‐4NH₂) with two carbazole‐based derivatives having different degrees of conjugation. The PyTA‐BC and PyTA‐BC‐Ph COFs exhibit ultrahigh thermal stabilities (up to 421 °C), excellent crystallinity, and high Brunauer–Emmett–Teller surface areas (up to 1445 m² g⁻¹). These COFs display strong fluorescence emissions in various solvents, with their emission maxima gradually red‐shifting upon increasing the polarity of the solvent (solvatochromism). Upon exposure to HCl, they respond very rapidly and sensitively in terms of changing their colors and fluorescence emission maxima. In the presence of a sacrificial electron donor, these COFs mediate the highly efficient photocatalytic evolution of H₂ from water. In the absence of a noble metal cocatalyst, the COFs and ascorbic acid provide a photocatalytic H₂ production of up to 1183 µmol g⁻¹ h⁻¹ (λ ≥ 420 nm); this value is the highest reported to date for a COF. Such COFs appear to be potentially useful as chemosensors for the naked‐eye and sensitive spectroscopic detection of HCl and as cocatalysts for the sustainable photocatalytic production of H₂ from water.

中文翻译：

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双重功能的荧光共价有机框架：HCl感测和光催化水中H2的释放

通过4,4'，4''，4'''-py-1,3,6,8-四基）四苯胺的缩聚反应合成了两种超稳定的发光共价有机骨架（COF）PyTA-BC和PyTA-BC-Ph （PyTA-4NH ₂）与两种具有不同结合度的咔唑基衍生物。PyTA-BC和PyTA-BC-Ph COF表现出超高的热稳定性（高达421°C），出色的结晶度和高的Brunauer-Emmett-Teller表面积（高达1445 m ² g ^-1））。这些COF在各种溶剂中均显示出强烈的荧光发射，随着溶剂极性的增加，其发射最大值会逐渐发生红移（溶剂变色）。暴露于HCl后，它们在改变其颜色和最大荧光发射方面反应非常灵敏。在牺牲电子供体的存在下，这些COF介导了H ₂从水中的高效光催化放出。在没有贵金属助催化剂的情况下，COF和抗坏血酸可提供高达1183 µmol g ^-1 h ^-1的光催化H ₂产生（λ≥420 nm）; 该值是迄今为止COF报告的最高值。此类COF可能用作肉眼的化学传感器和HCl的灵敏光谱检测，以及用作从水中可持续光催化生产H _2的助催化剂。