Electrochromic materials represent a class of highly promising smart materials in contemporary research. Viologen, as a prevalent organic small molecule in smart chromic materials, has garnered extensive attention due to its tunable intermediate structure involving pyridine units and diverse nitrogen atom substituents. In this investigation, the molecular structure of dinaphthoviologen (DNV) were modified, and various groups were introduced to ionize nitrogen atoms. This structural modification aimed to decrease the molecular energy gap and enhance the electron acceptability of nitrogen atoms. The results demonstrate robust redox ability in DNV. To explore the practical applications, a straightforward DNV-based electrochromic device was fabricated, incorporating ferrocene as an electronic supplement. This device exhibited commendable cycling performance (exceeding 1000 cycles) and rapid response times (8 s for coloring and 10 s for fading) without the need for additional electrolytes. Additionally, the transmittance changes by more than 45 %. Moreover, owing to the presence of conjugated structures, DNV exhibited noteworthy fluorescence properties. In fluorescence-based picric acid detection experiments, the synthesized molecules exhibited high selectivity and sensitivity, as evidenced by the determined Stern–Volmer constants ( = 2.17 × 10 L/mol, = 3.87 × 10 L/mol). The findings highlight the potential of the developed dinaphthoviologen derivatives for advanced applications in electrochromic devices and sensitive detection of picric acid.

中文翻译：

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用于增强电致变色性能和苦味酸检测的桥联二萘紫精衍生物的合成

电致变色材料代表了当代研究中一类极具前景的智能材料。紫精作为智能变色材料中常见的有机小分子，由于其包含吡啶单元和多种氮原子取代基的可调中间结构而受到广泛关注。在这项研究中，对二萘紫精（DNV）的分子结构进行了修饰，并引入了各种基团来电离氮原子。这种结构修饰的目的是减少分子能隙并增强氮原子的电子可接受性。结果表明 DNV 具有强大的氧化还原能力。为了探索实际应用，我们制造了一种简单的基于 DNV 的电致变色器件，并加入二茂铁作为电子补充剂。该设备表现出值得称赞的循环性能（超过 1000 次循环）和快速响应时间（着色 8 秒，褪色 10 秒），无需额外的电解质。此外，透射率变化超过45%。此外，由于共轭结构的存在，DNV 表现出值得注意的荧光特性。在基于荧光的苦味酸检测实验中，合成的分子表现出高选择性和灵敏度，正如确定的 Stern-Volmer 常数 (= 2.17 × 10 L/mol，= 3.87 × 10 L/mol) 所证明的那样。这些发现凸显了所开发的二萘紫精衍生物在电致变色器件和苦味酸灵敏检测方面的高级应用的潜力。