A simple meso-pyrrolyl BODIPY-Schiff base conjugate was synthesized by reacting (α-formylpyrrolyl) BODIPY with 2-aminophenol in ethanol at reflux followed by recrystallization from CH₂Cl₂/petroleum ether, affording the conjugate in 72% yield. The conjugate was thoroughly characterized by HR-MS, 1D and 2D NMR and X-ray crystallographic techniques. The X-ray structure of the meso-pyrrolyl BODIPY-Schiff base conjugate revealed that the meso-pyrrole and the phenyl substituents were deviated by an angle of 35∘ and 49∘, respectively, from the plane of the BF₂-dipyrrin core. The absorption spectrum of the conjugate was similar to the (α-formylpyrrolyl) BODIPY with a strong absorption band at 508 nm, whereas the fluorescence of the (α-formylpyrrolyl) BODIPY was completely quenched in the BODIPY-Schiff base conjugate. Furthermore, cation sensing studies revealed that the conjugate has a specific sensing ability for the Cu(II) ion even in the presence of the other metal ions, as verified by the visual, absorption and mass spectral studies. The DFT optimized structure revealed that the Cu(II) ion was bound to pyrrolic nitrogen, imine nitrogen, phenolic oxygen and two water molecules in a distorted square pyramidal fashion. TD-DFT studies accounted well for the absorption spectra of the BODIPY-Schiff base conjugate and its Cu2+ bound complex.

中文翻译：

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基于 Meso-pyrrolyl BODIPY 的 Cu2+ 离子比色光学传感器

一个简单的中观-吡咯基 BODIPY-席夫碱共轭物通过反应合成 (α-甲酰基吡咯基)BODIPY与2-氨基苯酚在乙醇中的回流，然后从CH ₂ Cl ₂ /石油醚中重结晶，以72％的产率提供缀合物。通过 HR-MS、1D 和 2D NMR 以及 X 射线晶体学技术彻底表征了缀合物。X射线结构中观-吡咯基 BODIPY-席夫碱共轭物表明中观-吡咯和苯基取代基偏离的角度为35∘和49∘，分别来自BF ₂ -dipyrrin核心的平面。共轭物的吸收光谱与（α-formylpyrrolyl) BODIPY 在 508 nm 处有强吸收带，而 (α-甲酰基吡咯基) BODIPY在BODIPY-席夫碱偶联物中完全淬灭。此外，阳离子传感研究表明，即使在存在其他金属离子的情况下，该共轭物也对 Cu(II) 离子具有特定的传感能力，这已通过视觉、吸收和质谱研究得到证实。DFT 优化结构表明，Cu(II) 离子以扭曲的方锥体方式与吡咯氮、亚胺氮、酚氧和两个水分子结合。TD-DFT 研究很好地解释了 BODIPY-Schiff 碱共轭物及其 Cu 的吸收光谱2+束缚复合体。