Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong, Meghalaya 793022, India.
Department of Biotechnology and Bioinformatics, North-Eastern Hill University, Shillong, Meghalaya 793022, India.
Dalton Trans. 2022 Aug 2;51(30):11372-11380. doi: 10.1039/d2dt01634f.
A new cyclometalated Ir(III) complex of a methylene-bridged benzimidazole-substituted 1,2,3-triazole methanol ligand has been synthesized for the photoluminescent detection of pyrophosphate (HPO) anions. The solution structure of 1[PF6] was fully characterized by 1D (H, C) and 2D (H-H COSY, H-C HSQC, and H-C HMBC) NMR spectroscopy, and ESI-HRMS. The 1[PF6] acted as a highly selective luminescent sensor for HPO in CHCN over other competitive ions, including HPO, ATP, ADP and AMP. The PL titration of 1[PF6] with HPO in CHCN furnished the association constant = 8.6 × 10 M and a low detection limit of ∼127 nM. The structure of the analyte interacting ligand renders the Ir(III) complex-based probe highly selective for HPO ions. The PL enhancement with HPO is due to the hydrogen bonding interaction of HPO with the triazole C-H, imidazole N-H, methylene hydrogen and hydroxyl groups of the ligand that has been supported by H NMR titration. Further, the PL enhancement of 1·HPO adducts was supported by triplet-state TDDFT calculations. In 1·HPO, the MLCT-MC energy gap is increased, and the 1·HPO emits efficiently from the MLCT and ILCT excited states. Finally, a cytotoxicity study and live-cell imaging were performed. The probe showed low cytotoxicity against HeLa cells and was suitable for intracellular pyrophosphate imaging.
一种新的桥连亚甲基的苯并咪唑取代的 1,2,3-三唑甲醇配体的偕二甲基铱(III)配合物被合成用于焦磷酸盐（HPO）阴离子的光致发光检测。1[PF6]的溶液结构通过 1D（H、C）和 2D（H-H COSY、H-C HSQC 和 H-C HMBC）NMR 光谱和 ESI-HRMS 得到了充分的表征。1[PF6]在 CHCN 中对 HPO 表现出比其他竞争离子（包括 HPO、ATP、ADP 和 AMP）更高的选择性发光传感。1[PF6]与 HPO 在 CHCN 中的 PL 滴定提供了结合常数 = 8.6 × 10 M 和低检测限约 127 nM。分析物相互作用配体的结构使得基于 Ir(III)配合物的探针对 HPO 离子具有高度选择性。与 HPO 的 PL 增强归因于 HPO 与三唑 C-H、咪唑 N-H、配体的亚甲基氢和羟基之间的氢键相互作用，这得到了 H NMR 滴定的支持。此外，三重态 TDDFT 计算支持了 1·HPO 加合物的 PL 增强。在 1·HPO 中，MLCT-MC 能隙增大，并且 1·HPO 从 MLCT 和 ILCT 激发态有效地发射。最后，进行了细胞毒性研究和活细胞成像。探针对 HeLa 细胞表现出低细胞毒性，适合用于细胞内焦磷酸盐成像。
