甲醇-联吡啶钌(II)体系的电致化学发光研究

研究了碱性溶液中甲醇-联吡啶钌(II)[Ru(bpy)3^2^+]的电致化学发光行为。在玻碳电极上甲醇于+1.28V(vs.Ag/AgCl)处被氧化为甲氧基离子(CH3O.), 该自由基离子发生歧化反应, 生成激发态的甲醛(HCHO), 发出波长为545nm的光。另一方面当体系含有少量的Ru(bpy)3^2^+时会得到较强的发光信号, 发光波长为608nm, 该发光起因于在甲醇的氧化电位下, Ru(bpy)3^2^+被氧化成Ru(bpy)3^3^+, CH3O.与Ru(bpy)3^3^+反应, 生成激发态的Ru(bpy)3^2^+而发光。     

流动体系中维生素B~1的电致化学发光研究

在0.1mol/LNaOH水溶液中(pH12.6),维生素B~1的水解产物在玻碳电极上于+0.88V(vs.Ag/AgCl,下同)处被氧化,其氧化产物在+1.20V处与被氧化的Ru(bpy)~3^2^+反应,生成激发态的Ru(bpy)~3^2^+^*而发光,发光波长为609nm,研究结果表明水溶液的pH值影响了维生素B~1的水解速率,从而引起发光强度的明显差异。     

槐定碱-联吡啶钌电致化学发光的研究

研究了槐定碱在碱性联吡啶钌(Ru(bpy)32 )水溶液(pH 9.0)中电致化学发光行为。在玻碳电极上,槐定碱中的氨基氮于 1.30 V(vs.Ag/AgCl)左右被氧化为氮正自由基离子,该自由基离子与Ru(bpy)32 反应生成激发态的Ru(bpy)32 *而发光。利用原位在线电致化学发光方法,槐定碱的检出限为1.0×10-10g/mL。     

金属离子对联吡啶钌电致化学发光影响的研究

在玻碳电极上, 联吡啶钌[Ru(bpy)₃^2＋]于＋1.50 V (vs. Ag/AgCl)左右被氧化为Ru(bpy)₃^3＋, 该氧化态离子与碱性水溶液中(pH 8.2)的OH•反应生成激发态的[Ru(bpy)₃^2＋*]而发光. 研究比较了15种金属离子对Ru(bpy)₃^2＋碱性水溶液电致化学发光的影响, 并对这些影响进行了初步的解释.     

取代基对胺化合物联吡啶钌电致化学光影响的研究

研究了苦豆子中主要生物碱槐定碱、苦参碱,以及神经兴奋药物甲基安非他命 、安非他命等化合物,在碱性联吡啶钌[Ru(bpy)_3~(2+)]水溶液（pH 9.0）中的电 致化学发光（ECL）行为。在玻碳电极上,生物碱中的氨基氮于+1.30 V（vs. Ag/AgCl）左右被氧化为氮正自由基离子,该自由基离子与Ru(bpy)_3~(2+)反应生 成激发态的Ru(bpy)_3~(2+*)而发光。研究比较了取代基性质、氨基氮周围的三维 空间结构对各生物碱ECL的影响,并结合生物碱氨基氮的电离势和键角的计算,对 这些影响进行了解释。     

取代基对胺化合物联吡啶钌电致化学光影响的研究

研究了苦豆子中主要生物碱槐定碱、苦参碱，以及神经兴奋药物甲基安非他命 、安非他命等化合物，在碱性联吡啶钌[Ru(bpy)_3~(2+)]水溶液（pH 9.0）中的电 致化学发光（ECL）行为。在玻碳电极上，生物碱中的氨基氮于+1.30 V（vs. Ag/AgCl）左右被氧化为氮正自由基离子，该自由基离子与Ru(bpy)_3~(2+)反应生 成激发态的Ru(bpy)_3~(2+*)而发光。研究比较了取代基性质、氨基氮周围的三维 空间结构对各生物碱ECL的影响，并结合生物碱氨基氮的电离势和键角的计算，对 这些影响进行了解释。     

多吡啶钌(Ⅱ)配合物化学发光性质研究

详细研究了Ru(bpy)3^2+,Ru(bpy)2(dppx)^2+,Ru(bpy)2(dppz)^2+,Ru(phen)3^2+,Ru(phen)2(dppx)^2+和Ru(phen)2(dppz)^2+六个多吡啶钌(Ⅱ)配合物的化学发光性质,筛选出Ru(bpy)3^2+和Ru(phen)3^2+两种性能优良的化学发光试剂;并探讨了它们发光的可能机理和影响因素,为钌(Ⅱ)配合物在化学发光分析中的应用提供了可供参考的理论依据。     

钌铁双核配合物的合成及猝灭[Ru(bpy)~3]^2^+发光过程研究

合成了含二氮芴和联吡啶等配体的一系列新型钌铁双核配合物:[(C~1~0H~6N~2)C=N-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,[(C~1~0H~6N~2)C=N--C~6H~4-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,[(C~1~0H~6N~2)C=N-C~6H~4-C~6H~4-N=CR-Fc)Ru(bpy)~2]·(PF~6)~2,并对其进行了光谱表征,通过对该类配合物的循环伏安和发光光谱研究,讨论其激发态的氧化还原性和对[Ru(bpy)~3]^2^+发光过程的猝灭作用.研究表明猝灭过程为扩散控制的双分子交换能量传递     

四(三羟甲基氨基甲烷)合铜(Ⅱ)电催化联吡啶钌/二氧化硅复合纳米粒子电化学发光分析特性研究

水分子与联吡啶钌(Ru(bpy)32+)之间的电化学发光(ECL)反应早已被人们发现,但其增敏Ru(bpy)32+电化学发光信号的能力不强,很难实现分析应用.我们发现四(三羟甲基氨基甲烷)合铜(Ⅱ)(Cu(Tris)42+)可电催化水的氧化反应生成活性中间产物羟基自由基(·OH),·OH能够快速进入二氧化硅基质,有效地增敏联吡啶钌/二氧化硅复合纳米粒子(RuSNPs)的电化学发光,并利用紫外-可见吸收光谱、电化学方法、电化学发光方法等研究了可能的电化学反应机理.基于以上研究,发展了一种以水分子作为共反应试剂,测定铜离子的电化学发光分析新方法.该方法在铜离子浓度为2.0×10-7~1.0×10-4mol/L的范围内,电化学发光强度与铜离子浓度呈现良好的线性,同时该方法具有很好的灵敏度和选择性,检出限(S/N=3)达到1.0×10-7mol/L,且Ca2+、Mg2+、Na+、Fe3+、Pb2+、Cd2+、Co2+、Ni2+、Mn2+等常见离子不干扰测定.使用该法对自来水和黑河水样中铜离子含量进行测定,分别往两个水样中加入2~3倍的铜离子标准溶液,其加标回收率在97.0%~102.5%之间;与原子吸收分光光度法对比,相对误差分别为4.1%和4.7%,说明该方法测定结果具有一定的可靠性.     

一种混合价态钌配合物的合成、晶体结构和电化学性质

[Ru6(μ-O2CCH3)12(CH3OH)2(HCOO)2][Ru2(μ-O2CCH3)4(H2O)2](PF6)2.2H2O(Ru2(Ⅱ,Ⅲ)混合价)是通过二步反应合成的。首先Ru2(O2CCH3)4Cl在加热条件下与甲醇反应得到红棕色中间物,然后将该中间物在甲醇水(体积比7∶1)溶液中用Ag2SO4和NH4PF6进行脱氯配位反应得到此化合物。用元素分析、红外光谱、热重分析、循环伏安、X-衍射单晶结构分析等对其进行了表征。晶体结构表明,标题化合物的晶体属单斜晶系,空间群为P21/n,晶胞参数:a=0.85362(14)nm,b=1.19589(19)nm,c=3.6642(6)nm,β=92.316(3)°,Z=2,每个结构基元包含2个不同的配离子,其中[Ru2(μ-O2CCH3)4(H2O)2]+是1个双核钌配离子,[Ru6(μ-O2CCH3)12(CH3OH)2(HCOO)2]+是由另1个由甲醇配位、甲酸根桥连的六核钌配离子。2个独立的结构单元通过氢键形成三维超分子网络结构。采用循环伏安法对其电化学性质进行了表征,结果为一对准可逆的氧化还原峰,表明该配合物的中心金属二价钌原子Ru(Ⅱ)与三价钌原子Ru(Ⅲ)之间存在电子转移。     

Electrogenerated Chemiluminescence Based on Tris(2,2′-bipyridyl) Ruthenium(II) with Hydroxyl Carboxylic Acid

Upon the electrochemical oxidation of tris(2,2′-bipyridyl) ruthenium(II) [Ru(bpy)²⁺₃] and hydroxyl carboxylic acids, for instance, citric acid, tartaric acid, malic acid, and -gluconic acid, bright electrochemiluminescences (ECLs) were observed. Different luminescent reactions were presented depending on the applied potential. The light emission was mainly caused by the reaction between alkoxide radical ion and Ru(bpy)³⁺₃below the potential +1.80 V (vs Ag/AgCl). The luminescence intensity obviously increased because of the more complex reaction process. The luminescence wavelength of 608 nm, which could be found either at higher potential than +1.80 V or in the potential range from +1.30 to +1.80 V, confirmed that ECL was caused by Ru(bpy)²⁺₃*. The factors which affect the determination and HPLC separation of the four acids were also investigated.     

Photoreduction of Ru(bpy)(3)2+ by amines in aqueous solution. Kinetics characterization of a long-lived nonemitting excited state

The photochemistry of Ru(bpy)(3)+2 in the presence of amines was investigated in water by laser flash photolysis. N,N'-Dimethylaniline and p-phenylenediamine quench the luminescent metal to ligand charge transfer (MLCT) excited state of the complex by an electron transfer reaction that produces the semireduced form Ru(bpy)3+ in relatively high yields. On the other hand, triethylamine (TEA) and aniline do not quench the MLCT. Nevertheless, when laser flash irradiation at 532 nm is carried out in the presence of these amines, the formation of Ru(bpy)3+ is clearly detected by its transient absorption at 510 nm. These results are interpreted by an electron transfer reaction with the participation of a nonemitting excited state of the complex, formed independently of the MLCT from the Franck-Condon or the relaxed singlet excited state. The rate constants for the quenching of this state by TEA and aniline and the quantum yields for Ru(bpy)(3)+ were determined. The new state is formed in a very fast process and has a lifetime of ca 4 micros in water.     

Photoinduced electron-transfer processes based on novel bipyridine-Ru(II) complex: properties of cis-[Ru(2,2'-bipyridine)2(5,6-bis(3-amidopyridine)-7-oxanorbornene)](PF6)2 and cis-[Ru(2,2'-bipyridine)2(3-aminopyridine)2](PF6)2 complexes

This paper presents the synthesis, MO calculations, and photochemical and photophysical properties of cis-[Ru(bpy)2(3Amdpy2oxaNBE)](PF6)2 (2), where bpy is 2,2'-bipyridine and 3Amdpy2oxaNBE is the novel 5,6-bis(3-amidopyridine)-7-oxanorbornene chelate-ligand (1). Complex 2 is considered in relation to the cis-[Ru(bpy)2(3Amnpy)2](PF6)2 (3) analogous complex, where 3Amnpy is 3-aminopyridine. Complexes 2 and 3 exhibit absorptions near 350 nm and in the 420-500 nm region attributable to a contribution from MLCT transitions (dpi-->bpy and dpi-->L; L=3Amdpy2oxaNBE or 3Amnpy). Whereas complex 3 is photochemically reactive, complex 2 shows luminescence either at 77 K or at room temperature in fluid solution. The emission of 2 assignable as an MLCT (Ru-->bpy) emission is characterized by a long lifetime at room temperature (650 ns in CH3CN and 509 ns in H2O). It is independent of lambdairr, but it is temperature dependent; i.e., it increases as the temperature is lowered. Considering the chelate ring of 1 contributes to the stability of the complex 2 under continuous light irradiation, the difference in the primary photoprocesses of 3 (loss of 3Amnpy) and 2 (luminescence) may be caused by a lowering of the lowest excited state from 3 to 2. The surface crossing to the lowest MC state value of 987 cm-1 (similar to that of [Ru(bpy)3]2+) will be prevented in the case of complex 2, and as a result, efficient 3Amdpy moiety loss cannot occur. The electronic depopulation of the {Ru(bpy)2} unit and population of a bpy* orbital upon excitation are evident by comparing the photophysical properties with those of a [Ru(bpy)3]2+ related complex. Moreover, a reduction of a bpy ligand in the MLCT excited state is indicated by time-resolved spectra that show features typical of bpy*-. The photocatalytic property of 2 is spectroscopically demonstrated by oxidative quenching using either methylviologen2+ or [RuCl(NH3)5]+2 electron-acceptor ions.     

Chemiluminescence parameters of peroxynitrous acid in the presence of short-chain alcohols and Ru(bpy)<Stack><Subscript>3</Subscript><Superscript>2+</Superscript></Stack>

The chemiluminescence behaviour and mechanism of peroxynitrous acid and Ru(bpy)₃²⁺ were studied in the presence of short-chain alcohols (methanol, ethanol, propan-1-ol, propan-2-ol, butanol, 2-methylpropan-1-ol, pentanol). It was found that the chemiluminescence intensity of peroxynitrous acid and Ru(bpy)₃²⁺ system could be significantly enhanced by these seven short-chain alcohols. The maximum chemiluminescence wavelength of 608 nm of [Ru(bpy)₃²⁺]* in the excited state was attributed to the reaction between Ru(bpy)₃²⁺ and dihydroxyalkyl radicals which were generated during the redox course of peroxynitrous acid and alcohols. In addition, the chemiluminescence signals of the system presented depended largely on the solubility and branched-chain structure as well as the length of carbon chain. The analytical characteristics and parameters of the peroxynitrous acid/Ru(bpy)₃²⁺/alcohols chemiluminescence system were investigated under optimum conditions.     

[Ru(bpy)_2tpphz]~(2+)与Zn~(2+)形成的双核配合物的荧光性质研究

近年来,钌多吡啶配合物与DNA的作用得到了比较广泛的研究,并且发展了一系列具有特定功能的钌配合物犤1犦。如传统的DNA分子光开关犤Ru(bpy)2dppz犦2+和犤Ru(phen)2dppz犦2+犤2,3犦(bpy=2,2'-联吡啶,phen=1,10-菲咯啉,dppz=二吡啶犤3,2-a:2',3'-c犦吩嗪)。这些配合物与DNA具有较强的结合力,在水溶液中几乎不发光,但在DNA存在下则有强烈荧光发出。这是由于配合物插入DNA的碱基对之后,保护了dppz的吡嗪环上的N原子,使其免受水分子的进攻从而导致配合物荧光的恢复。但是对于大多数的多吡啶钌配合物来讲,由于其自身较强的背景荧光或与DN…     

Tris(Bipyridine) Ruthenium(II): An Efficient Detector of Excited Species Generated by Chemiluminescent Processes*

In systems that are known to generate electronically excited species, the tris(bipyridine) ruthenium(II) cation, Ru(bpy)₃²⁺, ion is found to be an efficient, chemically stable, emissive energy acceptor for probing excited state formation. The chemiexcitation system employed was the thermolysis of tetramethyldioxetane. The system employed for enzymatic generation of excited species was the horseradish peroxidase-catalyzed oxidation of appropriate substrates such as isobutyraldehyde, phenylacetal-dehyde and indoleacetic acid. The versatility of the Ru(bpy)₃²⁺ ion is exemplified by its capacity to detect excited state formation in both chemical and enzymatic systems and in homogeneous and microheterogeneous media. The long wavelength emission and chemical stability of Ru(bpy)₃²⁺ facilitate quantitative studies of the sensi-tization process. Possible routes leading to excitation of the Ru(bpy)₃²⁺ ion by the chemi- or enzyme-generated excited species include electronic energy transfer and electron transfer-induced luminescence.     

Influence of the protonic state of an imidazole-containing ligand on the electrochemical and photophysical properties of a ruthenium(II)-polypyridine-type complex

The synthesis and characterisation of [Ru(bpy)2(PhenImHPh)]2+ where PhenImHPh represents the 2-(3,5-di-tert-butylphenyl)imidazo[4,5-f][1,10]phenanthroline ligand are described. The compounds issued from the three different protonic states of the imidazole ring [Ru(bpy)2(PhenImPh)]+ (I), [Ru(bpy)2(PhenImHPh)]2+ (II) and [Ru(bpy)2(PhenImH2Ph)]3+ (III) were isolated and spectroscopically characterised. The X-ray structures of [Ru(bpy)2(PhenImPh)](PF6)H2O.6 MeOH, [Ru(bpy)2(PhenImHPh)](NO3)2H2O.3 MeOH and [Ru(bpy)2(PhenImH2Ph)](PF6)3 5 H2O are reported. Electrochemical data obtained on these complexes indicate almost no potential shift for the Ru(III/II) redox couple. Therefore a Coulombic effect between the imidazole ring and the metal centre can be ruled out. The monooxidised forms of I and II have been characterised by EPR spectroscopy and are reminiscent of the presence of a radical species. The emission properties of the parent compound [Ru(bpy)2(PhenImHPh)]2+ were studied as a function of pH and both the lifetimes and intensities decreased upon deprotonation. Photophysical properties, investigated in the absence and presence of an electron acceptor (methylviologen), were distinctly different for the three compounds. Transient absorption features indicate that unique excited states are involved. Theoretical data obtained from DFT calculations in water on the three protonic forms are presented and discussed in the light of the experimental results.     

Two‐Photon Chemistry in Ruthenium 2,2′‐Bipyridyl‐Functionalized Single‐Wall Carbon Nanotubes

Ruthenium polypyridyl complexes are widely used as light harvesters in dye‐sensitized solar cells. Since one of the potential applications of single‐wall carbon nanotubes (SWCNTs) and their derived materials is their use as active components in organic and hybrid solar cells, the study of the photochemistry of SWCNTs with tethered ruthenium polypyridyl complexes is important. A water‐soluble ruthenium tris(bipyridyl) complex linked through peptidic bonds to SWCNTs (Ru‐SWCNTs) was prepared by radical addition of thiol‐terminated SWCNT to a terminal C?C double bond of a bipyridyl ligand of the ruthenium tris(bipyridyl) complex. The resulting macromolecular Ru‐SWCNT (≈500 nm, 15.6 % ruthenium complex content) was water‐soluble and was characterized by using TEM, thermogravimetric analysis, chemical analysis, and optical spectroscopy. The emission of Ru‐SWCNT is 1.6 times weaker than that of a mixture of [Ru(bpy)₃]²⁺ and SWCNT of similar concentration. Time‐resolved absorption optical spectroscopy allows the detection of the [Ru(bpy)₃]²⁺‐excited triplet and [Ru(bpy)₃]⁺. The laser flash studies reveal that Ru‐SWCNT exhibits an unprecedented two‐photon process that is enabled by the semiconducting properties of the SWCNT. Thus, the effect of the excitation wavelength and laser power on the transient spectra indicate that upon excitation of two [Ru(bpy)₃]²⁺ complexes of Ru‐SWCNT, a disproportionation process occurs leading to delayed formation of [Ru(bpy)₃]⁺ and the performance of the SWCNT as a semiconductor. This two‐photon delayed [Ru(bpy)₃]⁺ generation is not observed in the photolysis of [Ru(bpy)₃]³⁺; SWCNT acts as an electron wire or electron relay in the disproportionation of two [Ru(bpy)₃]²⁺ triplets in a process that illustrates that the SWCNT plays a key role in the process. We propose a mechanism for this two‐photon disproportionation compatible with i) the need for high laser flux, ii) the long lifetime of the [Ru(bpy)₃]²⁺ triplets, iii) the semiconducting properties of the SWNT, and iv) the energy of the HOMO/LUMO levels involved.     

Visible-light-driven photoreactions of [(bpy)2Ru(II)L]Cl2 in aqueous solutions (bpy = bipyridine, l = 1,2-bis(4-(4'-methyl)-2,2'-bipyridyl) ethene)

Visible-light-induced photoreactions of [(bpy)2Ru(II)L]Cl2 (bpy = bipyridine, L = trans-1,2-bis(4-(4'-methyl)-2,2'-bipyridyl) ethene) in aqueous solution are examined. From pH titrations, it is found that the Ru complex is a stronger base (pKa* = 6) in the excited state than in the ground state (pKa = 4). Photolysis of the [(bpy)2Ru(II)L] complex in solutions at pH 7 and 12 led to formation of species with increased emission quantum yields, approximately 55 nm blue-shift of the emission maximum to 625 nm, and disappearance of the absorption band at 330 nm, the latter arising from the olefinic bond of the L ligand. No spectral changes are observed in solutions at pH < or = 4. With the help of chromatography, mass spectroscopy, Raman spectroscopy, and NMR, photoproducts formed at neutral pH have been analyzed. It is found that the major product is a dimer of [(bpy)2Ru(II)L], dimerizing around the double bond. Photoreactions do not occur in the dark or in the aprotic solvent acetonitrile. We propose that a Ru(III) radical intermediate is formed by photoinduced excited-state electron and proton transfer, which initiates the dimerization. The radical intermediate can also undergo photochemical degradative reductions. Below pH 4, the emission quenching is proposed to arise via protonation of the monoprotonated [(bpy)2Ru(II)LH] followed by electron transfer to the viologen-type moiety created by protonation. The products of photodegradation at pH > 12 are different from those of pH 7, but the mechanism of the degradation at pH > 12 was not elucidated.