The reaction of cis-trans-cis-RuCl2(RaaiRâ²)2 [RaaiRâ²Â = 1-alkyl-2-(arylazo)imidazole, p-RâC6H4âNNâC3H2âNN-1-Râ², where R = H (a), Me (b), Cl (c) and Râ²Â = Me (1), Et (2) and CH2Ph (3)] either with 2,2â²-bipyridine (bpy) and AgNO3 followed by NaClO4 or [Ag(bpy)2](ClO4) in boiling acetone led to red-brown [Ru(bpy)(RaaiRâ²)2](ClO4)2. The complex may exist in three isomeric structures. The structure of [Ru(bpy)(MeaaiMe)2](ClO4)2
was confirmed by X-ray diffraction study and suggests that only one isomer is crystallised. Electronic spectra exhibit a strong MLCT band at 520 ± 5 nm along with two weak transitions at longer wavelength. The complexes emit at 77 K and quantum yields vary from 0.011â0.025. The 1H NMR spectral measurements of the complexes suggest the existence of two isomers in 1 â¶Â 0.3 concentration ratio. The methylene, âCH2â, in RaaiEt of [Ru(bpy)(RaaiEt)2]2+ gives a complex AB type multiplet while the RaaiCH2Ph moiety of [Ru(bpy)(RaaiCH2Ph)2]2+ shows AB type quartets. Cyclic voltammograms show a Ru(III)/Ru(II) redox couple along with three successive ligand reductions. The plot of difference in potential of first oxidation and reduction versus energy of main MLCT band (CT) is linear. Electrochemical
parametrization of the Ru(III)/Ru(II) redox couple determines ligand potential EL(L). Using EL(L) the potential of the present complexes has been predicted and is linearly related to the observed potential.
cis-trans-cis-RuCl2(RaaiR²)2 [RaaiR² = 1-烷基-2-(芳基偶氮)
咪唑,p-R–
C6H4–NN–
C3H2–NN-1-R²,其中 R = H (a), Me (b), Cl (c) 和 R² = Me (1), Et (2) 和 Ph (3)]与2,2′-联
吡啶 (bpy) 及
硝酸银 (AgNO3),然后加
氯酸钠 (Na ) 或在沸腾的
丙酮中使用 [Ag(bpy)2](
ClO4) 反应,得到了红棕色的 [Ru(bpy)(RaaiR²)2]( )2。该配合物可能存在三种异构体结构。通过 X 射线衍射研究确认了 [Ru(bpy)(MeaaiMe)2]( )2 的结构,表明只有一种异构体结晶。电子光谱在 520 ± 5 nm 处显示出强 MLCT 带,以及两个在更长波长处的弱跃迁。该配合物在 77 K 下发光,量子产率在 0.011–0.025 之间。配合物的 1H NMR 光谱测量表明存在两个异构体,其浓度比为 1 : 0.3。 [Ru(bpy)(RaaiEt)2]2+ 中 RaaiEt 的亚甲基 (–
CH2–) 给出了复杂的 AB 型多重峰,而 [Ru(bpy)(Raai Ph)2]2+ 中的 Raai Ph 部分则显示 AB 型四重峰。循环伏安图显示出 Ru(III)/Ru(II) 的氧化还原对以及三个连续的
配体还原。首次氧化与还原的电位差与主要 MLCT 带 (CT) 能量的关系图呈线性关系。Ru(III)/Ru(II) 的电
化学参数化确定了
配体电位 EL(L)。利用 EL(L),预测了当前配合物的电位,并与观察到的电位呈线性关系。