Spiropyrans are a class of photochromic compounds that feature two main isoforms, a closed spiropyran (SP) and an open merocyanine (MC), which are inter-switchable with UV and visible light. The double bond containing MC isomer has several resonance forms with different optical spectra. Consequently, the overall spectral characteristic of the spiropyran solution depends on the relative contribution of each resonance form. In addition, the reversible changes of the absorbance or fluorescence spectra of MC are dictated by the environment. By utilizing these properties, spiropyran and its derivatives have been employed to monitor a variety of molecules and ions that can alter the resonance forms of MC. In this review, we provide a comprehensive discussion on a range of species that can be detected by spiropyran including metal ions, anions, acids, solvents, and even biomolecules, the major analytical detection mechanisms involved, and the novelty of such techniques. This study establishes spiropyran as a versatile platform for the detection of both organic and inorganic target molecules.

中文翻译：

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螺吡喃及其衍生物的化学和生物传感应用——综述

螺吡喃是一类光致变色化合物，具有两种主要异构体，封闭的螺吡喃 (SP) 和开放的部花青 (MC)，它们可以通过紫外线和可见光相互切换。含有双键的 MC 异构体​​具有几种不同光谱的共振形式。因此，螺吡喃溶液的整体光谱特性取决于每种共振形式的相对贡献。此外，MC 的吸光度或荧光光谱的可逆变化是由环境决定的。通过利用这些特性，螺吡喃及其衍生物已被用于监测可以改变 MC 共振形式的各种分子和离子。在这篇综述中，我们全面讨论了螺吡喃可检测的一系列物种，包括金属离子、阴离子、酸、溶剂，甚至生物分子，所涉及的主要分析检测机制，以及此类技术的新颖性。该研究将螺吡喃确立为检测有机和无机目标分子的多功能平台。