Naphthazarin esters (C1–C4) isolated from the roots of Arnebia euchroma are found as skilled dual chemosensors for Ni²⁺ and Cu²⁺ among Pb²⁺, Na²⁺, K²⁺, Hg²⁺, Mg²⁺, and Ca²⁺ metal ions. C1–C4 esters exhibited a red shift of 54 nm with Ni²⁺ and 30 nm with Cu²⁺ metal ions in absorption. There is a formation of red‐shifted bands between 517 and 613 nm in the absorption spectrum of C1–C4 sensors on binding with Ni²⁺ and Cu²⁺ ions. The addition of Ni²⁺ and Cu²⁺ ions to sensors C1–C4 stimulates a remarkable color change from reddish pink to purple and light blue, respectively. These color changes can be identified with the naked eye. The significant downfield shifts of CO and OH peaks in nuclear magnetic resonance (NMR) spectrum confirm the chelation as binding mechanism. With ultraviolet–visble and NMR studies, it is found that C1–C4 esters possessed notable selectivity and sensitivity toward Ni²⁺ and Cu²⁺ over other metal ions.

中文翻译：

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Ni2+ 和 Cu2+ 金属离子与从 Arnebia euchroma 中分离的萘甲素酯的选择性结合。

从Arnebia euchroma 根中分离出的萘甲素酯 (C1–C4)被发现是 Pb ²⁺、Na ²⁺、K ²⁺、Hg ²⁺、Mg ²⁺和Ni ²⁺和 Cu ^{2+ 的}熟练双化学传感器Ca ²⁺金属离子。C1–C4 酯在吸收中表现出 54 nm 的红移 Ni ²⁺和 30 nm 的 Cu ²⁺金属离子吸收。在与 Ni ²⁺和 Cu ²⁺离子结合时，C1-C4 传感器的吸收光谱在 517 和 613 nm 之间形成红移带。Ni ²⁺和Cu ^{2+ 的添加}传感器 C1-C4 的离子分别刺激从红粉色到紫色和浅蓝色的显着颜色变化。这些颜色变化可以用肉眼识别。核磁共振 (NMR) 光谱中 CO 和 OH 峰的显着低场位移证实了螯合是结合机制。通过紫外-可见光和核磁共振研究，发现C1-C4 酯对Ni ²⁺和Cu ²⁺比其他金属离子具有显着的选择性和敏感性。