We have developed novel aldazine-based colorimetric chemosensors for Cu²⁺ and Fe³⁺. The aldazine ligands were synthesized by simple condensation of 4-diethylamino-salicylaldehyde and 8-hydroxyjulolidinal with hydrazine. The (4-diethylamino)-salicylaldehyde-azine (SA) showed high selectivity and sensitivity towards Cu²⁺ over the other alkali and transition metal ions. In the presence of Cu²⁺, absorption band of SA at 425 nm red shifted to 545 nm. The color of solution changed from pale yellow to purple color. Interestingly, 8-hydroxyjulolidinal-azine (JA) showed selectivity towards Fe³⁺ over alkali and transition metal ions. In the presence of Fe³⁺, the color of the ligand solution changed from pale yellow to violet. The absorption band of JA at 445 red shifted to 575 nm. The fluorescence of ligands SA and JA was completely quenched in the presence of Cu²⁺ and Fe³⁺, respectively. However, the quenched fluorescence of JA–Fe³⁺ complex can be reversibly restored using cysteine.

我们已经开发了新颖的基于aldazine的比色化学传感器，用于Cu ²⁺和Fe ³⁺。通过使4-二乙氨基-水杨醛和8-羟基朱螺啶与肼简单缩合来合成醛嗪配体。（4-二乙基氨基）-水杨醛-嗪（SA）对其他碱金属和过渡金属离子具有较高的选择性和对Cu ^2+的敏感性。在Cu ²⁺的存在下，SA在425 nm处的吸收带红移至545 nm。溶液的颜色从浅黄色变为紫色。有趣的是，8-羟基金鸡嗪（JA）对Fe ³⁺具有选择性碱金属和过渡金属离子。在Fe ³⁺的存在下，配体溶液的颜色从浅黄色变为紫色。JA在445红色处的吸收带移至575nm。分别在Cu ²⁺和Fe ³⁺的存在下，配体SA和JA的荧光被完全淬灭。但是，使用半胱氨酸可以可逆地恢复JA -Fe ³⁺复合物的猝灭荧光。