School of Technology and Sciences, São Paulo State University (Unesp), R. Roberto Simonsen, 305, Presidente Prudente, SP, 19060-900, Brazil.
Institute of Chemistry, São Paulo State University (Unesp), Araraquara, Brazil.
Photochem Photobiol Sci. 2022 Jun;21(6):1077-1090. doi: 10.1007/s43630-022-00200-8. Epub 2022 Mar 18.
Two red-emitting heteroleptic iridium(III) complexes (Ir-p and Ir-q) were synthesized and their photophysical and biological properties were analyzed. After their structures have been confirmed by several techniques, such as H NMR, C NMR, FT-IR, UV-Vis, and MALDI TOF analyses, their luminescence behavior was investigated in ethanol and PBS (physiological medium, pH ~ 7.4) solutions. Emission spectra of both complexes are dominated by MLCT states at room temperature in ethanolic solution, but at 77 K the Ir-q exhibits the LC as the dominant emission state. The Ir-q complex shows one of the highest emission quantum yields, 11.5%, for a red emitter based on iridium(III) complexes in aerated PBS solution, with color coordinates (x;y) of (0.712;0.286). Moreover, both complexes display high potential to be used as a biological marker with excitation wavelengths above 400 nm, high water solubility (Ir-p 1838 μmol L, Ir-q 7601 μmol L), and distinct emission wavelengths from the biological autofluorescence. Their cytotoxicity was analyzed in CHO-k1 cells by MTT assays, and the IC was estimated as being higher than 131 μmol L for Ir-p, and higher than 116 μmol L for Ir-q. Concentrations above 70% of viability were used to perform cell imaging by confocal and fluorescence microscopies and the results suggest that the complexes were internalized by the cell membrane and they are staining the cytoplasm region.
合成了两个发射红光的杂化铱（III）配合物（Ir-p 和 Ir-q），并分析了它们的光物理和生物性质。通过核磁共振氢谱（1H NMR）、核磁共振碳谱（13C NMR）、傅里叶变换红外光谱（FT-IR）、紫外-可见光谱（UV-Vis）和基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）等多种技术确认其结构后，研究了它们在乙醇和 PBS（生理介质，pH~7.4）溶液中的发光行为。在乙醇溶液中，室温下两种配合物的发射光谱均由 MLCT 态主导，但在 77 K 时 Ir-q 以 LC 为主发射态。Ir-q 配合物在有氧 PBS 溶液中显示出基于铱（III）配合物的红光发射器中最高的发射量子产率之一，为 11.5%，色坐标（x; y）为（0.712; 0.286）。此外，两种配合物都具有高的作为生物标记物的潜力，激发波长大于 400nm，具有高的水溶性（Ir-p 为 1838 μmol L，Ir-q 为 7601 μmol L），并且与生物自发荧光的发射波长明显不同。通过 MTT 测定法在 CHO-k1 细胞中分析了它们的细胞毒性，IC50 估计为 Ir-p 高于 131 μmol L，Ir-q 高于 116 μmol L。使用高于 70%的存活率进行共聚焦和荧光显微镜细胞成像，结果表明配合物被细胞膜内化，并且它们在细胞质区域染色。
