A new cationic Ir(III) complex with aldehyde and amino groups was synthesized and characterized. The Ir(III) complex has rich photophysical properties. The reaction of the aldehyde group in the Ir(III) complex with homocysteine (Hcy) afforded thiazinane derivatives which resulted in obvious changes in the luminescence spectra. After addition of Hcy to the Ir(III) complex containing 4,4′-diamino-2,2′-bipyridine, the luminescence intensity at ca. 580–610 nm decreased, and a new band at ca.490–520 nm appeared and enhanced strongly with a large blue shift of ca.90 nm, and the luminescent color changed from orange red to green. Based on this ratiometric probe, it can sensitively and selectively recognize Hcy by the ratio of emission intensity at two wavelengths to the concentrations of Hcy. While after addition of cysteine (Cys) or glutathione (GSH), the luminescence band showed a mild decrease in intensity with an unnoticeable shift. These different phenomena make it capable of discriminating homocysteine from cysteine and glutathione. The cytotoxicity and imaging of the complex were also studied in this work. The complex exhibited very low cytotoxicity on HeLa cells and showed sensitivity toward Hcy in living cells. These advantages provide it a good candidate for the application in the analytical and bioanalytical field.

合成并表征了具有醛和氨基的新型阳离子Ir（III）配合物。Ir（III）配合物具有丰富的光物理性质。Ir（III）络合物中的醛基与同型半胱氨酸（Hcy）反应生成噻嗪烷衍生物，从而导致发光光谱发生明显变化。向含有4,4'-二氨基-2,2'-联吡啶的Ir（III）络合物中添加Hcy后，在 580–610 nm减少，并出现并在约490–520 nm处出现一个新的带，并随着约90 nm的大蓝移而强烈增强，并且发光颜色从橙红色变为绿色。基于这种比例探针，它可以通过两个波长的发射强度与Hcy浓度的比率来灵敏地和选择性地识别Hcy。加入半胱氨酸（Cys）或谷胱甘肽（GSH）后，发光带显示出强度的轻微降低，并没有明显的变化。这些不同的现象使其能够区分半胱氨酸和半胱氨酸和谷胱甘肽。在这项工作中还研究了复合物的细胞毒性和成像。该复合物对HeLa细胞表现出非常低的细胞毒性，并且对活细胞中的Hcy具有敏感性。这些优点为它在分析和生物分析领域的应用提供了一个很好的选择。