A novel Schiff-base derivative containing polydentate ligands, N-2′-hydroxyl-1′-naphthyl methylene-3-hydroxyl-2-amino pyridine (NNAP), was identified and developed. After its structure was characterized by FTIR, ¹H NMR, mass spectra and element analyses, it was noted that NNAP displayed multi-wavelength colorimetric responses to Fe²⁺ and Fe³⁺, accompanied by differentiable color changes, i.e., from yellow to brown in the presence of Fe²⁺ but to colorless upon addition of Fe³⁺. Importantly, the multi-wavelength colorimetric responses to trace Fe²⁺ and Fe³⁺, i.e., at 522 nm, 448 nm and 389 nm for Fe²⁺ detection, and at 448 nm and 389 nm for Fe³⁺ detection, could efficiently eliminate system error. Their different action mechanisms, a 1 : 1 complex mode for NNAP–Fe²⁺ and 1 : 2 for NNAP–Fe³⁺, were proposed and confirmed by means of a Job's plot and theoretical calculation. NNAP would be a practical probe for multi-wavelength colorimetric differentiation of trace Fe²⁺ from Fe³⁺.

中文翻译：

---

开发了一种新型多齿席夫碱衍生物，用于痕量Fe ²⁺与Fe ^3+的多波长比色区分。

鉴定并开发了一种新型的包含多齿配体的席夫碱衍生物，N -2'-羟基-1'-萘基亚甲基-3-羟基-2-氨基吡啶（NNAP）。通过FTIR，¹ H NMR，质谱和元素分析对其结构进行表征后，注意到NNAP显示出对Fe ²⁺和Fe ^3+的多波长比色响应，并伴随着可区分的颜色变化，即从黄色变为棕色。在Fe ²⁺存在下，但在加入Fe ³⁺后变为无色。重要的是，对痕量Fe ²⁺和Fe ³⁺的多波长比色响应，即，在522纳米，448纳米和389的Fe纳米²⁺检测，并且在448 nm和389的Fe纳米³⁺检测，能有效地消除系统误差。提出了它们不同的作用机理，并通过Job's图和理论计算证实了NNAP –Fe ²⁺的1：1复杂模式和NNAP –Fe ^3+的1：2复杂模式。NNAP将是一种实用的探针，用于从痕量Fe ²⁺到Fe ^3+的多波长比色鉴别。