An Fe^II complex that features a pH-dependent spin state population, by virtue of a variable ligand protonation state, is described. This behavior leads to a highly pH-dependent ¹⁹F NMR chemical shift with a sensitivity of 13.9(5) ppm per pH unit at 37 °C, thereby demonstrating the potential utility of the complex as a ¹⁹F chemical shift-based pH sensor.

中文翻译：

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pH依赖的自旋态种群和铁（II）络合物中通过远程配体质子化作用进行的¹⁹ F NMR化学位移

描述了一种Fe ^II配合物，该配合物通过可变的配体质子化状态而具有pH依赖的自旋态种群。此行为导致高度依赖pH的¹⁹ F NMR化学位移，在37°C下每个pH单位的灵敏度为13.9（5）ppm，从而证明了该络合物作为¹⁹ F基于化学位移的pH传感器的潜在用途。