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。     

方波伏安法研究[Ru（bpy）2dppz]2+与DNA的相互作用

合成了含有嵌入配体二吡啶并[3,2-a:2′,3′-c]-吩嗪(dppz)的钌配合物二联吡啶二吡啶并[3,2-a;2′,3′-c]吩嗪钌([Ru(bpy)2dppz]2+),并对其结构和物理化学性质进行了表征。采用方波伏安法研究了[Ru(bpy)2dppz]2+与天然双链小牛胸腺DNA的相互作用,实验结果表明,[Ru(bpy)2dppz]2+配合物的嵌入配体会嵌入DNA的碱基对中,与DNA结合形成体积较大的"金属配合物-DNA"联合体,该联合体在电解质溶液中扩散速度较慢,导致溶液中游离的钌配合物分子减少,峰电流信号降低。计算得到[Ru(bpy)2dppz]2+与DNA的结合常数Ka=1.7×105 L/mol,结合位点n=0.84。     

多吡啶钴(Ⅲ)配合物与Zn2+形成的新型“关-开”荧光探针

近十几年来,对小分子过渡金属配合物与大分子DNA键合与识别机理的研究一直是国际上生物无机化学领域十分活跃的研究课题[1￣3],已发展了一系列具有特定功能的配合物,如DNA结构探针和DNA荧光探针等。与其他类型的金属配合物相比,八面体过渡金属多吡啶配合物具有丰富的光化学和光物理信息,当这些配合物与DNA相互作用时,由于结构匹配或微环境的差异,配合物的光谱特征会出现不同程度的改变,从而达到对DNA的检测。传统的DNA荧光探针有[Ru(bpy)2dppz]2 和[Ru(phen)2dppz]2 (bpy=2,2′-联吡啶,phen=1,10-菲咯啉,dppz=二吡啶[3,2-a∶2′,3′…     

噻吩基钌配合物与酵母RNA的相互作用研究

通过紫外-可见吸收光谱和荧光光谱滴定、稳态荧光猝灭以及盐效应实验研究了噻吩基钌配合物[Ru(bpy)2(Htip)]Cl2(1)、[Ru(Htip)2(dppz)]Cl2(2)、[Ru(Htip)3]Cl2(3)和[Ru2(bpy)4(H2bipt)]Cl4(4){bpy=2,2'-联吡啶;Htip=2-噻吩咪唑[4,5-f][1,10]邻菲咯啉;H2bipt=2,5-二(2-咪唑[4,5-f][1,10]邻菲咯啉)噻吩;dppz=二吡啶并[3,2-a:2',3'-c]吩嗪}与酵母RNA(yeast-RNA)的相互作用,并比较了该类配合物与yeast-RNA和小牛胸腺DNA(ct-DNA)的键合性质。结果表明,该类噻吩基钌配合物是较强的RNA嵌入试剂,其中配合物2和3的RNA键合强度大于其DNA键合强度;此系列配合物在低盐和高盐浓度时均能与RNA较强地结合,即使在100 mmol/L Na Cl条件下仍具有较大的RNA键合常数;配合物1与RNA键合时荧光强度下降,配合物2在水溶液中以及与RNA键合时几乎无荧光,而它们与DNA作用时荧光强度明显增大,显示出良好的区分RNA和DNA的荧光特性。     

乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)2(dppz)]2+光致发光的调控

应用荧光光谱、荧光显微镜和伏安法研究了乙醇/水体系中Cu(Ⅱ)对十二烷基硫酸钠(SDS)和鱼精DNA增强[Ru(bpy)2(dppz)]2+(bpy=2,2′-联吡啶,dppz=邻联二吡啶[3,2-a:2′,3′-c]吩嗪)光致发光的调控。结果表明,在乙醇/三羟甲基氨基甲烷(Tris)-水(V乙醇∶VTris=1∶5)体系中,DNA和阴离子表面活性剂SDS均能增强[Ru(bpy)2(dppz)]2+的光致发光,其与[Ru(bpy)2(dppz)]2+间的键合常数分别为5.5×105和4.2×102L.mol-1;Cu(Ⅱ)离子能通过DNA和SDS介导的光诱导电子转移淬灭乙醇/水溶液中[Ru(bpy)2(dppz)]2+的光致发光,DNA介导的Stern-Volmer淬灭常数为2.0×105L.mol-1,远远大于SDS介导的淬灭常数(9.0×103L.mol-1)。此外,结合SDS、DNA和Cu(Ⅱ)对[Ru(bpy)2(dppz)]2+在铟锡氧化物(ITO)电极上发生的氧化还原反应的影响,进一步探讨了乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)2(dppz)]2+光致发光的调控机理。该研究有助于更好地理解DNA嵌入剂的发光和淬灭机制,为生物分子光开关的构建提供新思路。     

钌(II)多吡啶配合物的合成、荧光性质及与脱氧核糖核酸DNA的 作用机制研究

设计合成含多个配位中心的多吡啶配体ODCIP (3,4-二氯基苯并咪唑并[4,5-f][1,10]邻菲咯啉)及其钌(II)多吡啶配合物[Ru(bpy)2ODCIP]2＋. 运用元素分析、红外光谱、核磁谱和质谱对配体及配合物进行结构表征. 利用紫外吸收光谱、荧光光谱和粘度法研究了[Ru(bpy)2ODCIP]2＋与DNA(脱氧核糖核酸)的作用机制、与Co2＋配位后与DNA的作用机制及其荧光变化情况. 结果表明[Ru(bpy)2ODCIP]2＋与DNA通过部分插入模式作用, [Ru(bpy)2ODCIP]2＋与Co2＋配位形成的双核配合物[Ru(bpy)2(ODCIP)Co]4＋也能与DNA插入结合. 进一步利用稳态荧光发射光谱、荧光淬灭实验等方法研究了单核配合物[Ru(bpy)2ODCIP]2＋和双核配合物[Ru(bpy)2(ODCIP)Co]4＋的荧光性质.     

钌（Ⅱ）多吡啶配合物的合成、荧光性质及与脱氧核糖核酸DNA的作用机制研究

设计合成含多个配位中心的多吡啶配体ODCIP(3,4-二氯基苯并咪唑并[4,5-f][1,10]邻菲咯啉)及其钌(Ⅱ)多吡啶配合物[Ru(bpy)2ODCIP]2 .运用元素分析、红外光谱、核磁谱和质谱对配体及配合物进行结构表征.利用紫外吸收光谱、荧光光谱和粘度法研究了[Ru(bpy)2ODCIP]2 与DNA(脱氧核糖核酸)的作用机制、与Co2 配位后与DNA的作用机制及其荧光变化情况.结果表明[Ru(bpy)2ODCIP]2 与DNA通过部分插入模式作用,[Ru(bpy)2ODCIP]2 与Co2 配位形成的双核配合物[Ru(bpy)2(ODCIP)Co]4 也能与DNA插入结合.进一步利用稳态荧光发射光谱、荧光淬灭实验等方法研究了单核配合物[Ru(bpy)2ODCIP]2 和双核配合物[Ru(bpy)2(ODCIP)Co]4 的荧光性质.     

新型双核配合物的形成及荧光性质研究

利用光谱学方法研究了[Ru(bpy)2TPPHZ]2+(TPPHZ=四吡啶[3,2-a: 2',3'-c: 3",2"-h: 2'",3'"-j]吩嗪)和[Ru(bpy)2ODHIP]2+(ODHIP=3,4-二羟基-咪唑并[4,5-f][1,10]邻菲咯啉)与Ni2+的配位情况及配位后的荧光性质变化, 探讨了配合物与Ni2+配位形成双核配合物后与DNA的作用机制变化. 结果表明, [Ru(bpy)2TPPHZ]2+和[Ru(bpy)2ODHIP]2+均可与Ni2+配位, 形成双核配合物[Ru(bpy)2(TPPHZ)Ni]4+和[Ru(bpy)2(ODHIP)Ni]4+, 配合物的荧光强度随着Ni2+浓度的增加而减弱. 与DNA作用后, 配合物仍可与Ni2+配位形成双核配合物, [Ru(bpy)2(TPPHZ)Ni]4+的荧光几乎完全消失, 同时配合物与DNA保持插入模式作用, 而配合物[Ru(bpy)2(ODHIP)Ni]4+与DNA的作用则由沟面结合改为插入结合, 同时配合物的荧光减弱.     

钌(Ⅱ)多吡啶配合物与DNA相互作用的光切割与荧光性质研究

利用琼脂糖凝胶电泳法研究了钌(Ⅱ)多吡啶配位物[Ru(bpy)2(ODCIP)]2+(bpy:2,2'-联吡啶,ODCIP:含多个配位中心的多吡啶配体,3,4-二氯基-咪唑并[4,5-f][1,10]邻菲咯啉)对pBR322质粒DNA的光切割作用及其可能机理,并运用紫外可见吸收光谱、荧光光谱和琼脂糖凝胶电泳法研究了[Ru(bpy)2(ODCIP)]2+与Zn2+配位后与DNA的光谱性质和光切割作用.结果表明[Ru(bpy)2(ODCIP)]2+对DNA有较好的光切割作用,其机理可能是产生了超氧阴离子自由基和单线态氧.[Ru(bpy)2(ODCIP)]2+与Zn2+配位可能形成的双核配位物[Ru(bpy)2(ODCIP)Zn]4+与DNA也能进行插入结合,对DNA的光切割效果并没有明显增强。     

Ru(bipy)_2(dppz)~(2+)与DNA相互作用的光谱研究

利用荧光和紫外可见吸收光谱研究了 Ru( bipy) 2 ( dppz) 2 +与 DNA之间的插入键合作用。结果表明 ,Ru( bipy) 2 ( dppz) 2 +是通过 dppz配体插入到 DNA的双螺旋结构中。而且 ,一定浓度的 Fe( CN) 4 - 6 和 Na Cl对 Ru( bipy) 2 ( dppz) 2 +- DNA复合物的荧光无猝灭作用 ,这一结果也证实了 Ru( bipy) 2 ( dppz) 2 +和 DNA之间的插入键合作用     

Chemical control of the DNA light switch: cycling the switch ON and OFF

The emission of the DNA light-switch complex [Ru(bpy)2(tpphz)]2+ (bpy = 2,2'-bipyridine, tpphz = tetrapyrido[3,2-a:2',3'-c:3' ',2' '-h:2' ',3' '-j]phenazine) can be reversibly turned ON and OFF over several cycles. The tpphz and taptp (taptp = 4,5,9,18-tetraazaphenanthreno[9,10-b] triphenylene) ligands in [Ru(bpy)2(tpphz)]2+ and [Ru(bpy)2(taptp)]2+, respectively, intercalate between the DNA bases, and a 50-fold increase in emission intensity of [Ru(bpy)2(tpphz)]2+ is observed upon DNA intercalation. The [Ru(bpy)2(tpphz)]2+ DNA light switch can be turned OFF statically in the presence of Co2+, Ni2+, and Zn2+, and the emission can be fully restored by the addition of EDTA. Cycling of the DNA light switch OFF and ON can be accomplished through the successive introduction of Co2+ and EDTA, respectively, to solutions of DNA-bound [Ru(bpy)2(tpphz)]2+. Owing to the absence of additional coordination sites, the emission of DNA-intercalated [Ru(bpy)2(taptp)]2+ is not quenched by transition metal ions in solution. To our knowledge, this work presents the first example of a reversible DNA light switch.     

Intercalation is not required for DNA light-switch behavior

The DNA light-switch complex [Ru(bpy)2(tpphz)]2+ (1, bpy = 2,2'-bipyridine, tpphz = tetrapyrido[3,2-a:2',3'-c:3',2'-h:2',3'-j]phenazine) is luminescent when bound to DNA and in organic solvents and weakly emissive in water. To date, light-switch behavior by transition metal complexes has generally been regarded as confirmation of DNA intercalation. In contrast, the present work demonstrates that the nonintercalating bimetallic complex [(bpy)2Ru(tpphz)Ru(bpy)2]4+ (2) behaves as a DNA light-switch. Weak emission from the 3MLCT excited state of 2 is observed in water with lambda(em) = 623 nm (phi(em) = 1.4 x 10(-4)), and a red shift (lambda(em) = 702 nm) and 40-fold increase in intensity are observed upon addition of 100 microM calf thymus DNA (ct-DNA). Addition of increasing concentrations of 2 to 1 mM herring sperm DNA does not result in an increase in the viscosity of the solution, indicating that the complex is not an intercalator. Additionally, experiments were conducted to ensure that the emission enhancement did not arise from threading intercalation of the complex. The in situ generation of 2 intercalated between the base pairs of ct-DNA in a threading fashion, however, exhibits emission maximum at 685 nm, which is blue-shifted from that of surface-bound 2. DFT calculations show low-lying orbitals in 2 that are expected to exhibit nonemissive character when contributing to the MLCT state, in accord with the lower emission intensity observed for 2 relative to that for 1. To our knowledge, the present work is the first example of a nonintercalating light-switch metal complex, thus showing that light-switch behavior cannot be used exclusively as confirmation of intercalation.     

Role of electronic structure on DNA light-switch behavior of Ru(II) intercalators

A series of ruthenium(II) complexes possessing ligands with an extended pi system were synthesized and characterized. The complexes are derived from [Ru(bpy)3](2+) (1, bpy = 2,2'-bipyridine) and include [Ru(bpy)2(tpphz)](2+) (2, tpphz = tetrapyrido[3,2-a:2',3'-c:3',2'-h:2',3'-j]phenazine), [Ru(bpy)2(dppx)](2+) (3, dppx = 7,8-dimethyldipyrido[3,2-a:2',3'-c]phenazine), [Ru(bpy)2(dppm2)](2+) (4, dppm2 = 6-methyldipyrido[3,2-a:2',3'-c]phenazine), and [Ru(bpy)2(dppp2)](2+) (5, dppp2 = pyrido[2',3':5,6]pyrazino[2,3-f][1,10]phenanthroline). The excited-state properties of these complexes, including their DNA "light-switch" behavior, were compared to those of [Ru(bpy)2(dppz)](2+) (6, dppz = dipyrido[3,2-a:2',3'-c]phenazine). Whereas 2, 3, and 4 can be classified as DNA light-switch complexes, 5 exhibits negligible luminescence enhancement in the presence of DNA. Because relative viscosity experiments show that 2-6 bind to DNA by intercalation, their electronic absorption and emission spectra, electrochemistry, and temperature dependence of the luminescence were used to explain the observed differences. The small energy gap between the lowest-lying dark excited state and the bright state in 2-4 and 6 is related to the ability of these complexes to exhibit DNA light-switch behavior, whereas the large energy gap in 5 precludes the emission enhancement in the presence of DNA. The effect of the energy gap among low-lying states on the photophysical properties of 1-6 is discussed. In addition, DFT and TD-DFT calculations support the conclusions from the experiments.     

新型双核配合物的形成、与DNA的作用机制及荧光性质研究

利用紫外、荧光和粘度等方法研究了含不同配体的钌(II)配合物[Ru(phen)₂CImP]^2＋(CImP＝3,4-二羟基-咪唑并[4,5-i][1,10]邻菲咯啉)和[Ru(phen)₂TPPZ]^2＋(TPPZ＝四吡啶[3,2-a:2',3'-c:3',2'-h:2'',3''-j]吩嗪)与DNA的作用机制, 并研究了配合物与Zn^2＋配合后荧光性质变化. 结果表明[Ru(phen)₂TPPZ]^2＋与DNA以插入模式作用, 而[Ru(phen)₂CImP]^2＋与DNA则以沟面结合模式作用. 向配合物溶液中滴加Zn^2＋后, 配合物[Ru(phen)₂TPPZ]^2＋和[Ru(phen)₂CImP]^2＋均可以与Zn^2＋形成双核配合物[Ru(phen)₂(TPPZ)Zn]^4＋和[Ru(phen)₂(CImP)Zn]^4＋, 配合物的荧光减弱. 与DNA作用后, 配合物仍可以与Zn^2＋配位形成双核配合物, 但[Ru(phen)₂(TPPZ)Zn]^4＋保持插入模式与DNA作用, 配合物的荧光减弱. 而[Ru(phen)₂(CImP)Zn]^4＋与DNA则由沟面结合改为插入结合, 配合物的荧光增强.     

Adjacent- versus remote-site electron injection in TiO2 surfaces modified with binuclear ruthenium complexes

Nanocrystalline thin films of TiO2 cast on an optically transparent indium tin oxide glass were sensitized with ruthenium homo- and heterobinuclear complexes, [LL'Ru(BL)RuLL']n+ (n = 2, 3), where L and L' are 4,4'-dicarboxy-2,2'-bipyridine (dcb) and/or 2,2'-bipyridine (bpy) and BL is a rigid and linear heteroaromatic entity (tetrapyrido[3,2-a:2',3'-c:3",2"-h:2'",3'"-j]phenazine (tpphz) or 1,4-bis([1,10]phenanthroline[5,6-d]imidazol-2-yl)benzene (bfimbz)). The photophysical behavior of the RuII-RuII diads in solution indicated the occurrence of intercomponent energy transfer from the upper-lying Ru --> bpy charge-transfer (CT) excited state of the Ru(bpy)(2) moiety to the lower-lying Ru --> dcb CT excited state of the Ru(bpy)(dcb) (or Ru(dcb)(2)) subunit in the heterobinuclear complexes. These sensitizer diads adsorbed on nanostructured TiO2 surfaces in a perpendicular or parallel attachment mode. Adsorption was through the dcb ligands on one or both chromophoric subunits. The behavior of the adsorbed species was studied by nanosecond time-resolved transient absorption and emission spectroscopy, as well as by photocurrent measurements. In the TiO2-adsorbed samples where BL was bfimbz, the electron injection kinetics was very fast and could not be resolved because an electron is promoted from the metal center to the dcb ligand directly linked to the semiconductor. In the TiO2-adsorbed samples where BL was tpphz, for which, in the excited state, a BL localization of the lowest-lying metal-to-ligand charge transfer (MLCT) is observed, slower injection rates (9.5 x 10(7) s(-1) in [(bpy)(2)Ru(tpphz)Ru(bpy)(dcb(-))](3+)/TiO2 and 5.5 x 10(7) s(-1) in [(bpy)(dcb)Ru(tpphz)Ru(bpy)(dcb(-))](3+)/TiO2) were obtained. Among the systems, the heterotriad assembly [(bpy)(2)Ru(bfimbz)Ru(bpy)(dcb(2-))](2+)/TiO2 gave the best photovoltaic performance. In the first case, this was attributed to a fast electron injection initiated from a dcb-localized MLCT; in the second case, this is attributed to improved molecular orientation on the surface, which was due to rigidity and, at the same time, linearity of the heterotriad system, resulting in a slower charge recombination between the injected electron and the hole.     

钌配合物[Ru(bpy)2(PNT)]2+的合成、表征及与DNA相互作用研究

以cis-Ru(bpy)2Cl2·2H2O与PNT为原料合成钌(Ⅱ)多吡啶配合物[Ru(bpy)2(PNT)]2+(bpy=2,2’-联吡啶, PNT=2-[4’-(5-四唑基)苯基]咪唑-[4,5-f][1,10]邻菲咯啉), 通过元素分析、质谱和核磁共振波谱对该化合物进行了结构表征. 利用紫外-可见吸收光谱、荧光光谱、热变性和黏度实验研究了配合物与CT-DNA的相互作用, 实验结果表明, 该配合物以部分插入模式与DNA结合.     

Ru(bpy)2(L)]Cl2: luminescent metal complexes that bind DNA base mismatches

Here we report the synthesis of luminescent ruthenium complexes that bind DNA base pair mismatches. [Ru(bpy)2(tpqp)]Cl2 (tpqp = 7,8,13,14-tetrahydro-6-phenylquino[8,7-k][1,8]phenanthroline), [Ru(bpy)2(pqp)]Cl2 (pqp = 6-phenylquino[8,7-k][1,8]phenanthroline), and [Ru(bpy)2(tactp)]Cl2 [tactp = 4,5,9,18-tetraazachryseno[9,10-b]triphenylene] have been synthesized, and their spectroscopic properties in the absence and presence of DNA have been examined. While [Ru(bpy)2(pqp)]2+ shows no detectable luminescence, [Ru(bpy)2(tpqp)]2+ is luminescent in the absence and presence of DNA with an excited-state lifetime of 10 ns and a quantum yield of 0.002. Although no increase in emission intensity is associated with binding to mismatch-containing DNA, luminescence quenching experiments and measurements of steady-state fluorescence polarization provide evidence for preferential binding to oligonucleotides containing a CC mismatch. Furthermore, by marking the site of binding through singlet oxygen sensitized damage, the complex has been shown to target a CC mismatch site directly with a specific binding affinity, Kb = 4 x 10(6) M(-1). [Ru(bpy)2(tactp)]2+, an analogue of [Ru(bpy)2(dppz)]2+ containing a bulky intercalating ligand, is luminescent in aqueous solution at micromolar concentrations and exhibits a 12-fold enhancement in luminescence in the presence of DNA. The complex, however, tends to aggregate in aqueous solution; we find a dimerization constant of 9.8 x 10(5) M(-1). Again, by singlet oxygen sensitization it is apparent that [Ru(bpy)2(tactp)]2+ binds preferentially to a CC mismatch; using a DNase I footprinting assay, a binding constant to a CC mismatch of 8 x 10(5) M(-1) is found. Hence results with these novel luminescent complexes support the concept of using a structurally demanding ligand to obtain selectivity in targeting single base mismatches in DNA. The challenge is coupling the differential binding we can obtain to differential luminescence.