Department of Chemistry, Indian Institute of Technology , Kanpur 208016, India.
J Org Chem. 2016 Sep 2;81(17):7741-50. doi: 10.1021/acs.joc.6b01361. Epub 2016 Aug 9.
The fluoride-mediated desilylation reaction has been exploited, for the first time, to trigger ring-opening of photochromic diarylbenzo-/naphthopyrans into highly colored anionic merocyanine dyes with high molar absorptivities to permit naked-eye sensing. The absorption spectral shifts, i.e., differences in the absorption maxima of colorless and colored forms, observed for a rationally designed set of silyloxy-substituted diarylpyrans subsequent to fluoride-induced ring opening are remarkably high (330-480 nm), and are unknown for any colorimetric probe. In particular, the disilyloxy-substituted diphenylnaphthopyran and its analog, in which the diphenyl groups are fused in the form of fluorene, allows "naked-eye" detection of fluoride in subppm levels (<1.0 ppm) in THF as well as in DMSO-H2O. The sensing is specific for fluoride among various other anions. This approach for colorimetric sensing of fluoride by ring-opening of the otherwise photochromic benzo-/naphthopyrans is heretofore unprecedented.
氟介导的去硅反应首次被利用，引发光致变色二芳基苯并-/萘并吡喃开环，生成高摩尔吸光率的阴离子型螺噁嗪染料，具有高可见颜色，可用于裸眼传感。在合理设计的一组硅氧基取代的二芳基吡喃中，观察到氟化物诱导开环后无色和有色形式的吸收光谱位移（吸收最大值的差异）非常大（330-480nm），这在任何比色探针中都是未知的。特别是二硅氧基取代的二苯基萘并吡喃及其类似物，其中二苯基基团以芴的形式融合，允许在 THF 和 DMSO-H2O 中以亚 ppm 级（<1.0ppm）的水平进行“裸眼”检测氟。该传感对各种其他阴离子中的氟具有特异性。通过光致变色的苯并-/萘并吡喃的开环来进行氟离子比色传感的方法在此之前是前所未有的。
