钌(Ⅱ)配合物与DNA相互作用的瞬态发光特性

以三种新合成的钌配合物[Ru(bpy)₂(7-CH₃-dppz)]²⁺、[Ru(bpy)₂(7-F-dppz)]²⁺、[Ru(phen)₂(7-F-dppz)]²⁺为研究对象,采用时间分辨的荧光光谱技术分别测量了这三种钌配合物与小牛胸腺DNA相互作用时的瞬态荧光动力学过程。结果表明:[Ru(bpy)₂(7-CH₃-dppz)]²⁺的发光寿命最长(约382 ns),而[Ru(bpy)₂(7-F-dppz)]²⁺的发光寿命最短(约65 ns)。分析表明:钌配合物的发光来源于配合物分子中的电荷转移态到基态的辐射跃迁。通过钌配合物与DNA的相互作用,使得配合物激发态分子的无辐射弛豫几率减小,从而导致发光寿命的增加。配合物的分子与DNA相互作用越强,激发态分子的无辐射弛豫几率越小,发光寿命也越长,最终导致高的发光效率。配合物的分子结构对配合物的分子与DNA的相互作用具有重要的影响。     

甲基对钌配合物与DNA相互作用的瞬态发光特性的影响

采用时间分辩的发光光谱技术,测量了新合成的钌配合物［Ru(phen)2(7 CH3 dppz)］2+与小牛胸腺DNA相互作用的瞬态发光动力学过程,并与以往研究的配合物［Ru(phen)2(dppz)］2+和［Ru(phen)2(dppx)］2+的瞬态发光特性进行对比,更全面地研究了甲基对钌配合物与DNA相互作用的瞬态发光特性的影响.［Ru(phen)2(7 CH3 dppz)］2+的结构介于［Ru(phen)2(dppz)］2+和［Ru(phen)2(dppx)］2+之间,但发光寿命却比这两种配合物短,表明了甲基的疏水性、空间位阻及推电子能力对配合物的发光寿命均有影响.该结论为进一步研究配合物分子与DNA的相互作用的机理提供了一定的依据.     

Synthesis, DNA-binding, Cytotoxicity, Photo Cleavage, Antimicrobial and Docking Studies of Ru(II) Polypyridyl Complexes

Three Ruthenium(II) polypyridine complexes, [Ru(phen)₂(mipc)]²⁺(1), [Ru(bpy)₂(mipc)]²⁺ (2) and [Ru(dmb)₂(mipc)]²⁺(3) [mipc?=?2-(6-methyl-3-(1H-imidazo[4, 5-f][1,10]-phenanthroline-2-yl)-4H-chromene-4-one, phen?=?1,10-phenanthroline,bpy?=?2, 2′bipyridine,dmb?=?4, 4′-dimethyl-2, 2′-bipyridine] have been synthesized and characterized by elemental analysis, IR, UV–Vis, ¹H& ¹³C NMR and mass spectra. The DNA-binding properties of the Ruthenium(II) complexes were investigated by spectrophotometric methods, viscosity measurements and light switch studies. These three complexes have been focused on photo activated cleavage studies with pBR-322 and antimicrobial studies. Experimental results indicate that the three complexes intercalate into DNA base pairs and follows the order of 1?>?2?>?3 respectively. Molecular docking studies also support the DNA interactions with complexes through hydrogen bonding and vander Waal’s interactions. Cytotoxicity studies with Hela cell lines has been revealing about anti tumor activity of these complexes.     

Synthesis,Characterization, DNA Binding Properties,Fluorescence Studies and Toxic Activity of Cobalt(III) and Ruthenium(II) Polypyridyl Complexes

The new ligand 4-(isopropylbenzaldehyde)imidazo[4,5-f ][1,10]phenanthroline (ippip) and its complexes [Ru(phen)₂(ippip)]²⁺(1),[Co(phen)₂(ippip)]³⁺(2),[Ru(bpy)₂(ippip)]²⁺(3),[Co(bpy)₂(ippip)]³⁺(4)(bpy=2,2-bipyridine) and (phen=1,10-phenanthroline) were synthesized and characterized by ES⁺-MS, ¹H and ¹³C NMR. The DNA binding properties of the four complexes were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that complexes bind to calf thymus DNA (CT-DNA) through intercalation. When irradiated at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than 2, 3, 4 complexes under comparable experimental conditions. Furthermore, photocleavage studies reveal that singlet oxygen (¹O₂) plays a significant role in the photocleavage.     

Dynamics of tRNAtyr Probed with Long-Lifetime Metal-Ligand Complexes

The metal-ligand complexes, [Ru(bpy)₂(dppz)]²⁺ (bpy = 2,2??-bipyridine, dppz = dipyrido[3,2-a:2??,3??-c]phenazine) (RuBD) and [Ru(phen)₂(dppz)]²⁺ (phen = 1,10-phenanthroline) (RuPD), display favorable photophysical properties including long lifetime, polarized emission, and very little background fluorescence. To check if RuBD and RuPD reflect the overall rotational mobility of small nucleic acid, we measured the intensity and anisotropy decays of RuBD and RuPD when intercalated into tRNA^tyr using pBC SK(+) phagemid as a control. We used frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. We observed shorter lifetimes for tRNA^tyr than those for the pBC SK(+) phagemid for both probes, however, RuPD showed much larger decrease in the mean lifetime values (64%). The slow rotational correlation time of RuBD (31.3 ns) and the fast rotational correlation time of RuPD (26.0 ns) reflected the overall rotational mobility of tRNA^tyr. In addition, the steady-state anisotropy and time-resolved anisotropy decay data showed a clear difference between tRNA^tyr and pBC SK(+) phagemid. This suggests the possibility of a homogeneous assay for identifying target nucleic acids and/or nucleic acid binding proteins.     

Optical oxygen sensing materials based on trinuclear starburst ruthenium(II) complexes assembled in mesoporous silica

The preparation and oxygen sensing properties of optical materials based on two trinuclear starburst ruthenium(II) complexes: [Ru₃(bpy)₆(TMMB)]⁶⁺ (1) and [Ru₃(phen)₆(TMMB)]⁶⁺ (2) (bpy=2,2′-bpyridine, phen=1,10-phenathroline, TMMB=1,3,5-tris[2-(2′-pyridyl)benzimidazoyl]methylbenzene) assembled in two mesoporous silicate (MS) are described in this paper. The luminescence of Ru complexes/silicate assemble materials can be quenched by molecular oxygen with good sensitivity (I₀/I₁>5 for 2/MS and I₀/I₁>3 for 1/MS), indicating that trinuclear starburst Ru(II) complexes/MS systems are sensitive to oxygen molecules.     

Spectroscopy and photophysics of chloro-bis-bipyridyl complexes of ruthenium(II) with pyridine ligands

The absorption, luminescence, and luminescence excitation spectra of ruthenium(II) complexes cis-[Ru(bpy)₂(L)Cl]⁺[bpy=2,2′-bipyridyl; L=NH₃, pyrazine, pyridine, 4-aminopyridine, 4-picoline, isonicotinamide, 4-cyanopyridine, 4,4′-bipyridyl, or trans-1,2-bis(4-pyridyl)ethylene] in alcoholic (4: 1 EtOH-MeOH) solutions are studied. At 77 K, the quantum yields and decay times of the luminescence of the complexes are measured and the deactivation rate constants of the lowest electronically excited metal-to-ligand charge transfer state (³MLCT) are determined. The linear correlation between the energy of the lowest state ³MLCT d _π(Ru)>π*(bpy) of the cis-[Ru(bpy)₂(L)Cl]⁺ complexes and the parameter pK_a of the free 4-substituted pyridines and pyrazine used as ligands is established.     

Spectroscopic and quantum-chemical investigations of chloro-bis-bipyridyl complexes of ruthenium(II) with 4-substituted pyridine ligands

The luminescence spectra of cis-[Ru(bpy)₂(L)Cl]⁺ (bpy is 2,2′-bipyridyl; L is pyrazine, pyridine, 4-amino-pyridine, 4-picolin, isonicotinamide, 4-cyanopyridine, or 4,4′bipyridyl) complexes are studied in alcoholic (4: 1 EtOH-MeOH) solutions at 77 K. A linear correlation is found between the energy of the lowest electronically excited metal-to-ligand charge transfer (³MLCT) state d _π(Ru) → π* (bpy) and the parameter pK _a of the free 4-substituted pyridines and pyrazine used as ligands L. The [B3LYP/6-31G + LanL2DZ(Ru)] hybrid method of the density functional theory is used to optimize the geometry of complexes and calculate their electronic structure and the charge distribution on the atoms of the nearest environment of the ruthenium ion. It is shown that there exists a linear unambiguous correlation between the negative charge on the nitrogen atom (qN ^L) of ligands L coordinated in the complex and the parameters pK _a of free ligands. The calculated energies of ³MLCT excited states almost linearly (correlation coefficient 0.958) depend on the charge qN ^L, which completely agrees with experimental data.     

Ru L2,3 XANES theoretical simulation with DFT: A test of the core-hole treatment

Density functional theory (DFT)-based relativistic calculations were performed to model the Ru L-edge X-ray absorption near edge structure (XANES) spectra of the hexaammineruthenium complex [Ru(NH₃)₆]³⁺ and “blue dimer” water oxidation catalyst, cis,cis- [(bpy)₂(H₂O)Ru^IIIORu^III(OH₂)(bpy)₂]⁴⁺ (bpy is 2,2-bipyridine). Two computational approaches were compared: simulations without the core-hole and by modeling of the core-hole within the Z+1 approximation. Good agreement between calculated and experimental XANES spectra is achieved without including the core-hole. Simulations with algorithms beyond the Z+1 approximation were only possible in a framework of the scalar relativistic treatment. Time-dependent DFT (TD-DFT) was used to compute the Ru L-edge spectrum for [Ru(NH₃)₆]³⁺ model compound. Three different core-hole treatments were compared in a real-space full multiple scattering XANES modeling within the Green function formalism (implemented in the FEFF9.5 package) for the [Ru(Mebimpy)(bpm)(H₂O)]²⁺ complex. The latter approaches worked well in cases where spin–orbit treatment of relativistic effects is not required.     

The key Cl− ligand for metal‐to‐ligand charge transfer in mononuclear terpyridine ruthenium(II) and binuclear ruthenium(II) tetrapyridylpyrazine complexes

Electronic structures of binuclear ruthenium complexes [Ru₂(terpy)₂(tppz)]⁴⁺ ( 1A ) and [Ru₂Cl₂(L)₂(tppz)]²⁺ {L = bpy ( 2A ), phen ( 3A ), and dpphen ( 4A )} were studied by density functional theory calculations. Abbreviations of the ligands (Ls) are bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, dpphen = 4,7‐diphenyl‐1,10‐phenanthroline, terpy = 2,2′:6′,2″‐terpyridine, and tppz = tetrakis(2‐pyridyl)pyrazine. Their mononuclear reference complexes [Ru(terpy)₂]²⁺ ( 1B ) and [RuClL(terpy)]⁺ {L = bpy ( 2B ), phen ( 3B ), and dpphen ( 4B )} were also examined. Geometries of these mononuclear and binuclear Ru(II) complexes were fully optimized. Their geometric parameters are in good agreement with the experimental data. The binuclear complexes were characterized by electrospray ionization mass spectrometry, UV–Vis spectroscopy, and cyclic voltammograms. Hexafluorophosphate salts of binuclear ruthenium complexes of 3A and 4A were newly prepared. The crystal structure of binuclear complex 1A (PF₆)₄ was also determined. Orbital interactions were analyzed to characterize the metal‐to‐ligand charge‐transfer (MLCT) states in these complexes. The Cl^? ligand works to raise the orbital energy of the metal lone pair, which leads to the low MLCT state. Copyright © 2011 John Wiley & Sons, Ltd.     

一种钌配合物与DNA相互作用发光增强的超快过程研究

采用时间分辩激光光谱技术,研究了一种钌配合物[Ru(dmb)2(mitatp)]2 发光增强的超快过程。采用比较方法测量了[Ru(dmb)2(mitatp)]2 和[Ru(dmb)2(mitatp)]2 /DNA复合物的瞬态发光弛豫过程。[Ru(dmb)2(mitatp)]2 和[Ru(dmb)2(mitatp)]2 /DNA复合物的发光均来源于[Ru(dmb)2(mitatp)]2 中的电荷转移单态和三重态到基态的辐射跃迁。通过钌配合物与DNA的相互作用,[Ru(dmb)2(mitatp)]2 的荧光寿命由339 ns延长至589 ns;磷光寿命由16μs延长至21μs,总的发光强度增强了约1个数量级。分析表明,[Ru(dmb)2(mitatp)]2 发光寿命和发光强度的增加可能来源于[Ru(dmb)2(mitatp)]2 与DNA之间的电荷转移态的形成,它导致[Ru(dmb)2(mitatp)]2 的最低激发单态和三重态到基态的无辐射概率的减小,增强了[Ru(dmb)2(mitatp)]2 发光效率。     

Spectroscopy and quantum-chemical calculations of nitro-bis-bipyridyl complexes of ruthenium(II) with 4-substituted pyridine ligands

The luminescence, absorption, and luminescence excitation spectra of complexes cis-[Ru(bpy)₂(L)(NO₂)]⁺ [bpy = 2,2′-bipyridyl, L = pyridine, 4-aminopyridine, 4-dimethylaminopyridine, 4-picoline, isonicotinamide, or 4,4′-bipyridyl] in alcoholic (4 : 1 EtOH–MeOH) solutions are studied at 77 K. A linear correlation is established between the energy of the lowest electronically excited metal-toligand charge transfer state d_π(Ru) → π*(bpy) of the complexes and the pK_a parameter of the free 4-substituted pyridines used as ligands L. The B3LYP/[6-31G(d)+LanL2DZ(Ru)] hybrid density functional method is used to optimize the geometry of complexes and calculate their electronic structure and the charge distribution on the atoms of the nearest environment of ruthenium(II) ions. It is shown that there exists a mutually unambiguous correspondence between the charge on the nitrogen atom of ligands L coordinated in the complex and the pK_a parameter of ligands. The calculated energies of the electronically excited metal-to-ligand charge transfer states of complexes linearly (correlation coefficient 0.99) depend on the charge on the nitrogen atom of ligands L, which completely agrees with the experimental data.     

Photoinduced electron‐transfer reactions of tris(2,2′‐bipyridine)ruthenium(II)‐based carbonic anhydrase inhibitors tethering plural binding sites

Tris(2,2′‐bipyridine)ruthenium(II) complex‐based carbonic anhydrase (CA) inhibitors, [Ru(bpy)₂(bpydbs)]²⁺ {bpy = 2,2′‐bipyridine and bpydbs = 2,2′‐bipyridinyl‐4,4′‐dicarboxilic acid bis[(2‐{2‐[2‐(4‐sulfamoylbenzoylamino)ethoxy]ethoxy}ethyl)amide]} and [Ru(bpydbs)₃]²⁺, tethering plural benzenesulfonamide groups have been prepared. The CA catalytic activity was effectively suppressed by these synthetic [Ru(bpy)₂(bpydbs)]²⁺ and [Ru(bpydbs)₃]²⁺ inhibitors, and their dissociation constants at pH = 7.2 and at 25°C were determined to be K_I = 0.93 ± 0.02 μM and K_I = 0.24 ± 0.03 μM, respectively. Next, 2 photoinduced electron‐transfer (ET) systems comprising a Ru²⁺‐CA complex and an electron acceptor, such as chloropentaamminecobalt(III) ([CoCl(NH₃)₅]²⁺) or methylviologen (MV²⁺) were studied. In the presence of CA and a sacrificial electron acceptor, such as pentaamminechlorocobalt(III) complex, the photoexcited triplet state of ³([Ru(II)]²⁺)* was quenched through an intermolecular photoinduced ET mechanism. In case of the [Ru(bpydbs)₃]²⁺‐CA‐MV²⁺ system, the photoexcited triplet state of ³([Ru(bpydbs)₃]²⁺)* was quenched by sacrificial quencher through an intermolecular photoinduced ET mechanism, giving the oxidized [Ru(bpydbs)₃]³⁺. Then the following intramolecular ET from the amino acid residue, Tyr6, near the active site of CA proceeded. We observed a transient absorption around at 410 nm, arising from the formation of a Tyr^?+ in the [Ru(bpydbs)₃]²⁺‐CA‐MV²⁺ system. These artificial Ru(II)‐CA systems may clearly demonstrate both intermolecular and intramolecular photoinduced ET reactions of protein and could be one of the interesting models of the ET proteins. Their photophysical properties and the detailed ET mechanisms are discussed in order to clarify the multistep ET reactions.     

钌多吡啶配合物与DNA相互作用的发光动力学分析

采用三能级模型,对六种钌多吡啶配合物[Ru(L)₂(R)]2+(L=bpy,phen,bpy=2,2’-联吡啶, phen=1,10-邻菲咯啉,R=7-CH₃-dppz,7-F-dppz,dpbpd(NH₂)₂)水溶液与小牛胸腺DNA相互作用的时间分辩发光光谱进行对比分析,讨论了取代基对配合物与DNA作用时方式的影响。结果表明:(1) 六种配合物与DNA作用存在侧面插入方式和垂直插入方式,其中垂直插入方式的权重较大;(2) 取代基的性质对两种作用方式的权重有重要影响。上述结论为进一步研究配合物分子与DNA的相互作用的机理提供了动力学依据。     

带-NH2的嘧啶环对钌配合物与DNA相互作用的瞬态发光特性的影响

采用时间分辨的发光光谱技术,分别测量了两种新合成的钌配合物[Ru(bpy)2 (dpbpd(NH2)2)]2 和[Ru(phen)2(dpbpd(NH2)2)]2 与小牛胸腺脱氧核糖核酸(ctDNA)相互作用时的瞬态发光动力学过程,并与以往对[Ru(phen)2dppz]2 等的研究结果进行对比,从而研究带-NH2的嘧啶环对配合物与DNA作用动力学过程的影响.结果表明:这两种含有带-NH2的嘧啶环的钌配合物与DNA相互作用时的发光按双指数规律衰减,发光寿命为几十纳秒,比dppz类钌配合物与DNA作用时的发光衰变寿命(几百纳秒)小一个数量级.归因于嘧啶环上的N和-NH2可能与水分子、DNA的碱基对或磷酸骨架形成氢键,从而加快激发态的无辐射弛豫,削弱发射光强,缩短发光寿命.该结论为进一步研究配合物分子与DNA的相互作用的机理提供了一定的依据.     

Sonochemiluminescence in an aqueous solution of Ru(bpy)3Cl2

The sonochemiluminescence spectra of electron-excited ions ^*[Ru(bpy)₃]²⁺ was registered for the first time during sonolysis of argon saturated aqueous solutions of Ru(bpy)₃Cl₂ with low concentration. At single-bubble sonolysis, the luminescence band of ruthenium is recorded at a concentration of Ru(bpy)₃Cl₂ from 10⁻⁶ M, and at multibubble from 10⁻⁵ M. Possible mechanisms for the appearance of the band of a tris-bipyridyl ruthenium(II) complex on the background of an structureless continuum of water in the spectra of sonoluminescence are analyzed. Based on the results of the comparison of the sonoluminescence spectra of Ru(bpy)₃Cl₂ aqueous solutions with the sonoluminescence spectra of aqueous solutions of rhodamine B (which has a high quantum yield of photoluminescence) it was established that a possible mechanism of sonophotoluminescence does not play a decisive role in ruthenium sonoluminescence. The effect of radical acceptors (O₂, C₂H₅OH, Cd²⁺, I⁻) on ruthenium sonoluminescence is analyzed. The most significant mechanism for the formation of electron-excited ions ^*[Ru(bpy)₃]²⁺ during sonolysis is the sonochemiluminescence in oxidation-reduction reactions involving [Ru(bpy)₃]²⁺ ions and radical products of sonolysis of water (OH, H, e⁻_aq) in the solution volume.     

Long-lifetime metal-ligand complexes as luminescent probes for DNA

We examined the intensity and anisotropy decays of DNA labeled with two ruthenium metalligand complexes, [Ru(bpy)₂(dppz)]²⁺ and [Ru(phe)₂(dppz)]²⁺. Both complexes display high emission anisotropies in the absence of rotational diffusion, making them suitable probes for rotational motions. When bound to DNA, these complexes display decay times as long as 294 ns, providing long-lived probes of DNA dynamics. The decay times of both complexes were rather insensitive to dissolved oxygen. We examined anisotropy decays of these complexes bound to B-form DNA. The anisotropy decays revealed correlation times near 10, 50, and several hundred nanoseconds, suggesting that these probes are sensitive to a wide range of DNA motions. The use of metalligand complexes should allow resolution of both the torsional and bending motions of DNA, the latter of which has been mostly inaccessible using shorter-lived fluorescent probes bound to DNA. Dedicated to Professor Robert F. Steiner upon his retirement     

Fabrication of Ru(bpy)3-titanate nanotube nanocomposite and its application as sensitive solid-state electrochemiluminescence sensor material

A novel and facile method for effective immobilization of Ru(bpy)₃²⁺ within titanate nanotubes (TiNTs) and its application as a sensitive solid-state electrochemiluminescence (ECL) sensor material was studied. The process involved the formation of Ru(bpy)₃²⁺-titanate nanotube nanocomposite (Ru-TiNTs) via electrostatic interactions by mixing TiNTs and Ru(bpy)₃(ClO₄)₂ in aqueous medium. Then Ru-TiNTs were attached to the surface of a Pt electrode to form an ECL sensor. Characterization of Ru(bpy)₃²⁺-titanate nanotube nanocomposite was accomplished by transmission electron microscopy, X-ray photoelectron spectrum, and field emission scanning electron microscope. The electrochemistry and ECL behavior of Ru(bpy)₃²⁺ immobilized on TiNTs were studied with tripropylamine as a coreactant. As-prepared Ru-TiNTs exhibited very good stability and Ru(bpy)₃²⁺ species contained showed excellent ECL behavior. Therefore, the as-prepared Ru(bpy)₃²⁺-titanate nanotube nanocomposite exhibited great promise as new luminescent materials for solid-state ECL detection.     

Oxygen-sensing materials based on [Ru(bpy)3] covalently grafted MSU-3 mesoporous molecular sieves

Novel oxygen-sensing materials consisting of [Ru(bpy)₂(Bpy-Si)]²⁺ portions covalently grafted onto the backbone of MSU-3 mesostructured silica-based network were prepared in a two-step process with the help of P123 surfactant. The 2,2′-bipyridyl covalently grafted with 3-aminopropyltriethoxysilane was used not only as sol-gel precursor but also as the second ligand of the Ru(bpy)₂Cl₂·2H₂O complex for the preparation of sol-gel-derived silicates for oxygen-sensing materials. The downward oxygen-sensing Stern-Volmer plots can be attributed to the heterogeneous environment of the luminophore within the MSU-3 silica. The MSU-3 sample obtained at 10 °C showed better oxygen-sensing performance due to its special morphology.     

Mononuclear Co(III) and Ni(II) Complexes with Polypyridyl Ligands, [Co(phen)2(taptp)]3+ and [Ni(phen)2(taptp)]2+: Synthesis, Photocleavage and DNA-binding

Two novel, mixed ligand complexes of cobalt(III) and nickel(II), [Co(phen)₂(taptp)]³⁺ (1) and [Ni(phen)₂(taptp)]²⁺ (2) (phen = 1,10-phenanthroline and taptp = 4,5,9,18-tetraazaphenanthreno [9,10-b]triphenylene), were synthesized and characterized by elemental analyses, UV-visible and NMR spectroscopies. The binding interactions of the two complexes with DNA have been investigated using absorption and emission spectroscopy methods and electrophoresis measurement mode. The intrinsic binding constants for these complexes to DNA are in the order of 10⁵. In Tris buffer, the Co(III) complex shows a moderate luminescence which was enhanced after binding to DNA. However for complex Ni(II), no emission was observed in Tris buffer. The [Co(phen)₂(taptp)]³⁺ and [Ni(phen)₂(taptp)]²⁺ can cause the photocleavage of DNA supercoiled pBR322 upon irradiation by 360 nm light. Based on the data, an intercalative mode of DNA binding is suggested for the two complexes.