Mixed-valence states of rotaxane metal complexes

(1)制备了两种新型的单核（β-二酮酮）钌（III）配合物，其长共轭链由2,4 -戊二酮酮螯合物中3-碳上的乙基和芳基组成。此外，通过新型单核配合物中乙基的氧化偶联反应，制备了两个新型双核（β-双酮酮）钌（III）配合物。在环糊精存在下的氧化偶联反应得到了与相应的双核配合物具有相似可见光谱的未识别钌。(2)选择性间隔的双核钌配合物在循环伏安图上表现出两个重叠的单电子氧化和还原步骤。这两个氧化还原步骤可以分别归属于钌（III）氧化为钌（IV）和钌（III）还原为钌（II）。这些结果表明，在Ru^<IV>-…多Ru^<III>混合价态下，金属间的电化学相互作用明显小于相应的只有一个芳环的双核配合物。(3)对丁二炔基桥接（β-双酮ato）钌（III）二聚体(1)进行了单晶结构分析。单电子氧化态在1.3 nm的距离上有很强的电子耦合。完全离域（III类混合价）体系1^+在1730 nm处有一个极强（ε = 25000 mol^<-1> dm^3 cm^<-1>）的价间电荷转移（IVCT）带，在2078 cm^<-1>处有一个与累积烯共振结构有关的单强振动带。(4)以铁盐为催化剂，用K[Ru(acac)_2(ox)]自二聚化法制备了新型草酸桥接双核钌（III）配合物[{Ru(acac)_2}_2(μ-ox)] （acac^- =乙酰丙酮，ox^<2-> =草酸盐）。当比值常数K_c = 10^<5.0>时，电化学生成的Ru^<III>-Ru^<II>混合价态在1430 nm处表现出弱的IVCT带。光谱电化学的红外光谱显示了部分定域的混价态。少

(1) Tow novel mononuclear (β-diketonato)ruthenium(III) complexes with long conjugated chain composed of alternative ethynyl and aromatic groups at 3-carbon in 2, 4-pentandionato chelate have been prepared.Furthermore, two novel binuclear (β-diketonato)ruthenium(III) complexes have been prepared by oxidative coupling reactions of the ethynyl groups in the novel mononuclear complexes. Reaction of the oxidative coupling in the presence of cyclodextrin gave unidentified ruthenium species which exhibited visible spectrum similar to the corresponding binuclear complexes.(2) The binuclear ruthenium complexes with the alternative spacers exhibited two overlapping one-electron oxidation and reduction steps on the cyclic voltammograms. The two oxidation and reduction steps can be assigned to the oxidation of ruthenium(III) to ruthenium(IV) and to the reduction of ruthenium(III) to ruthenium(II), respectively. These results indicate that electrochemical interactions between metals in the Ru^<IV>- … More Ru^<III> mixed-valence state of the binuclear complexes with two aromatic rings in the spacer are considerably smaller than that of the corresponding binuclear complexes with only one aromatic ring.(3) Single crystal structure analysis has been carried out on a butadiynyl bridged (β-diketonato)ruthenium(III) dimmer(1). Strong electronic coupling over 1.3 nm distance has been observed for the one-electron oxidized state. The fully delocalized (Class III mixed-valent) system 1^+ is distinguished by an extremely intense (ε = 25000 mol^<-1> dm^3 cm^<-1>) inter-valence charge transfer (IVCT) band at 1730 nm and a single intense vibrational band at 2078 cm^<-1> associated with contributions from cumulene resonance structures.(4) A novel oxalate-bridged binuclear ruthenium(III) complex, [{Ru(acac)_2}_2(μ-ox)] (acac^- = acetylacetonate and ox^<2-> = oxalate), has been prepared via self-dimerization of K[Ru(acac)_2(ox)] in aqueous solutions containing ferric salts as catalyst. The Ru^<III>-Ru^<II> mixed-valence species generated electrochemically with K_c = 10^<5.0> for the comproportionation constant exhibits a weak IVCT band at 1430 nm. IR spectra from spectroelectrochemistry indicated a partially localized mixed-valence state. Less