由于DNA与［Ru(bpy)3］2+(bpy=2,2′-联吡啶)及Cu2+间的静电作用, 用自铸膜法在铟锡氧化物(ITO)上制备了橙红色［Ru(bpy)3］2+-DNA-Cu2+复合膜, 并应用稳态和暂态荧光光谱、 紫外可见光谱、 荧光显微镜和扫描电镜对复合膜进行了表征和DNA介导的光诱导电子转移(PET)研究。 结果表明, ［Ru(bpy)3］2+-DNA-Cu2+复合膜(摩尔比为10∶20∶1)呈现了明显的吸收特征峰(450 nm)和发射峰(λem=595 nm), 发光呈单指数衰减, 发光寿命为188.6 ns, Cu2+通过DNA介导PET机制猝灭［Ru(bpy)3］2+发光, 猝灭常数为6.94×103 L·mol-1, 猝灭速率常数为3.80×1010 L·mol-1·s-1; 复合膜中Cu2+摩尔比(10倍)的增大使发射峰蓝移了11 nm, 吸收和发射强度衰减至消失, Cu2+通过静态猝灭机制削弱［Ru(bpy)3］2+发光。 此外, 对比于溶液和复合膜中Cu2+对［Ru(bpy)2(tatp)］2+-DNA(tatp=1,4,8,9-四氮三苯)的发光调控, Cu2+仅能因静电作用猝灭复合膜中［Ru(bpy)3］2+的发光。

An orange-red ［Ru(bpy)3］2+-DNA-Cu2+ composite film (bpy = 2,2′-bipyridine) was fabricated on an indium-tin (ITO) surface based on electrostatic interactions among ［Ru(bpy)3］2+, DNA and Cu2+ by using self-standing cast methods. The photoinduced electron transfer (PET) properties of the resultant composite film mediated by DNA were studied by means of steady-state and time-resolved fluorescence spectroscopy, UV-visible absorption spectroscopy, fluorescence microscopic imaging and scan electron microscopy. The ［Ru(bpy)3］2+-DNA-Cu2+ composite film with molar ratio of 10∶20∶1 shows an obvious absorption band (450 nm) and an intense emission peak (λem=595 nm), whose emission exhibits a single-exponential decay with τ=188.6 ns and is quenched by Cu2+ via DNA-mediated PET mechanism, indicating that the quenching constant is 6.94×103 L·mol-1 and quenching rate constant is 3.80×1010 L·mol-1·s-1. The increasing molar ratio of Cu2+ in composite films (10-fold) leads to an 11 nm blue-shift of the emission peak, which is dramatically weakened by Cu2+ via a static quenching mechanism. In addition, compared with the emission quenching of DNA-［Ru(bpy)2(tatp)］2+ (tatp=1,4,8,9-tetra-aza-triphenylene) tuned by Cu2+, which is present either in solutions or in composite films, Cu2+ only quenches the emission of ［Ru(bpy)3］2+ bound to DNA via an electrostatic interaction mode in composite films.