Two polypyridyl ligands namely 5-(2-ferrocenylethynyl)-2,2-bipyridine (L1) and 3-(2-ferrocenylethynyl)-1,10-phenanthroline (L2) and corresponding Ru(II) complexes [(bpy)2Ru(L1-2)](PF6)2 (Ru-L1, Ru-L2) (bpy = 2,2-bipyridine) have been synthesized and characterized. Both ligands were synthesized by cross-coupling reactions of ethynyl ferrocene with 5-bromo-2,2-bipyridine and 3-bromo-1,10-phenanthroline, respectively, in the presence of (PPh3)2PdCl2, CuI and Et3N under nitrogen atmosphere. The Ru(II) complexes, [(bpy)2Ru(L1)](PF6)2 and [(bpy)2Ru(L2)](PF6)2, have been obtained by refluxing Ru(bpy)2Cl2·2H2O with each ligand in ethanol under nitrogen atmosphere. The spectroscopic behaviour of both heterobinuclear complexes was investigated with UV/visible absorption and emission spectroscopy. Both complexes exhibit metal-to-ligand charge transfer (MLCT) absorption at around 450 nm. Complex Ru-L1 is non-emissive and Ru-L2 exhibits weak fluorescence in CH3CN solution at room temperature. In 4:1 EtOH:MeOH glassy matrix at 77 K, both complexes display weak fluorescence. Electrochemical studies of the two complexes display two metal-centered and three ligand-centered redox couples.
本研究合成并表征了两种多
吡啶配体,即 5-(2-
二茂铁乙炔基)-2,2-联
吡啶(L1)和 3-(2-
二茂铁乙炔基)-
1,10-菲罗啉(
L2)以及相应的 Ru(II) 复合物 [(bpy)2Ru(L1-2)](PF6)2 (Ru-L1, Ru-
L2)(bpy = 2,2-联
吡啶)。这两种
配体都是在氮气氛下,在 (PPh3)2PdC
L2、CuI 和 Et3N 的存在下,通过
二茂铁乙炔与 5-
溴-2,2-联
吡啶和
3-溴-1,10-菲罗啉的交叉耦合反应合成的。Ru(II) 复合物 [(bpy)2Ru(L1)](PF6)2 和 [(bpy)2Ru(
L2)](PF6)2 是在氮气环境下将 Ru(bpy)2C
L2-2H2O 与每种
配体在
乙醇中回流得到的。通过紫外/可见吸收和发射光谱研究了这两种异核配合物的光谱特性。两种配合物在 450 纳米波长处都表现出
金属-
配体电荷转移(MLCT)吸收。络合物 Ru-L1 在室温下的 CH3CN 溶液中无发射光谱,而 Ru-
L2 则显示出微弱的荧光。在 77 K 的 4:1 EtOH:MeOH
玻璃基质中,两种复合物都显示出微弱的荧光。对这两种配合物的电
化学研究显示出两种
金属中心氧化还原偶联和三种
配体中心氧化还原偶联。