Zheng Ze-Bao, Kang Si-Yuan, Yi Xun, Zhang Na, Wang Ke-Zhi
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, PR China.
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, PR China.
J Inorg Biochem. 2014 Dec;141:70-78. doi: 10.1016/j.jinorgbio.2014.08.010. Epub 2014 Sep 3.
A ruthenium(II) complex Ru(bpy)2(HL(1))2·3H2O {bpy=2,2'-bipyridine and HL(1)=2-(2,6-di(pyridin-2-yl)pyridin-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline}, denoted as RuHL(1), was synthesized and characterized by elemental analysis, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The pH effects on the UV-visible (UV-vis) absorption and emission spectra and the luminescence lifetimes of RuHL(1) have been studied, and their ground- and excited-state acid ionization constants were derived. The complex was found to exhibit pH-induced "off-on-off" luminescence switching properties via protonation/deprotonation of the grafted imidazole and terpyridyl groups. A pH-induced emission on-off intensity ratio of 166 was observed as pH was increased from 2.00 to 5.44, which is one of the largest values observed among imidazole-containing Ru(II) complex-based acidic-pH-induced pH luminescence switches. RuHL(1) also strongly binds to calf thymus DNA in mixed binding modes involving classic intercalation and partial intercalation, as determined by UV-vis absorption and emission spectrophotometric DNA titration, ethidium bromide displacement, DNA denaturation and DNA viscosity measurements.
合成了一种钌（II）配合物Ru(bpy)2(HL(1))2·3H2O {bpy = 2,2'-联吡啶，HL(1)= 2-(2,6-二(吡啶-2-基)吡啶-4-基)-1H-咪唑并[4,5-f][1,10]菲咯啉}，记为RuHL(1)，并通过元素分析、质子核磁共振光谱和质谱对其进行了表征。研究了pH值对RuHL(1)的紫外可见（UV-vis）吸收光谱、发射光谱和发光寿命的影响，并推导了其基态和激发态酸离解常数。发现该配合物通过接枝的咪唑和三联吡啶基团的质子化/去质子化表现出pH诱导的“关-开-关”发光切换特性。当pH值从2.00增加到5.44时，观察到pH诱导的发射开关强度比为166，这是在含咪唑的Ru(II)配合物基酸性pH诱导的pH发光开关中观察到的最大值之一。通过UV-vis吸收和发射分光光度法DNA滴定、溴化乙锭置换、DNA变性和DNA粘度测量确定，RuHL(1)还以涉及经典插入和部分插入的混合结合模式与小牛胸腺DNA强烈结合。
