College of Chemistry, Beijing Normal University, Beijing Key Laboratory of Energy Conversion and Storage Materials, Beijing 100875, P.R. China.
Dalton Trans. 2014 Feb 28;43(8):3273-84. doi: 10.1039/c3dt52568f.
A new heterobimetallic ruthenium(II)-rhenium(I) complex of Ru(bpy)2(HL)Re(CO)3Cl2·6H2O (RuHLRe) {bpy = 2,2'-bipyridine and HL = 2-(4-(2,6-di(pyridin-2-yl)pyridin-4-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} was synthesised and characterised by elemental analysis, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The ground- and excited-state acid-base properties of RuHLRe were studied using UV-Vis absorption spectrophotometric and spectrofluorimetric titrations in a 100 : 1 (v/v) Britton-Robinson buffer-CH3CN solution combined with luminescence lifetime measurements. The complex exhibited two-step separate protonation-deprotonation processes in both the ground and excited states. The complex acted as pH-induced "off-on-off" luminescence switches (I(on)/I(off) = 31.0 and 14.6), with one of the switching actions being driven by pH variations over the physiological pH range (5.3-8.0). Importantly, cellular imaging and cytotoxicity experiments demonstrated that RuHLRe rapidly and selectively illuminated the membrane of HeLa cells over fixed cells and exhibited reduced cytotoxicity at the imaging concentration compared to the Re(I)-free parent Ru(II) complex. In addition, RuHLRe acted as an efficient "turn on" emission sensor for H2PO4(-) and "turn off" emission sensor for F(-) and OAc(-).
一种新的偕二金属钌（II）-铼（I）配合物Ru(bpy)2(HL)Re(CO)3Cl2·6H2O（RuHLRe）{bpy = 2,2'-联吡啶，HL = 2-(4-(2,6-二(吡啶-2-基)吡啶-4-基)苯基)-1H-咪唑并[4,5-f][1,10]菲咯啉}，通过元素分析、质子核磁共振波谱和质谱进行了合成和表征。通过在 100：1（v/v）Britton-Robinson 缓冲液-CH3CN 溶液中进行 UV-Vis 吸收分光光度法和荧光分光光度法滴定以及荧光寿命测量，研究了 RuHLRe 的基态和激发态酸碱性质。该配合物在基态和激发态均表现出两步独立的质子化-去质子化过程。该配合物作为 pH 诱导的“关-开-关”发光开关（I(on)/I(off) = 31.0 和 14.6），其中一个开关作用是由生理 pH 范围（5.3-8.0）内的 pH 变化驱动。重要的是，细胞成像和细胞毒性实验表明，RuHLRe 能够快速且选择性地照亮 HeLa 细胞的膜，相对于无 Re(I)的 Ru(II)母体配合物，在成像浓度下表现出降低的细胞毒性。此外，RuHLRe 作为 H2PO4(-)的有效“开启”发射传感器和 F(-)和 OAc(-)的“关闭”发射传感器。
