含磺基苯甲酸及联吡啶钌配合物的合成、结构和催化苯甲硫醚氧化研究

利用水热方法合成了一个三联吡啶钌磺基苯甲酸配合物, [Ru(2, 2′-bipy)₃](3-Hsb)(3-sb)·5H₂O (1)(2, 2′-bipy为2, 2′-联吡啶;3-sb^2-为3-磺基苯甲酸根离子), 对配合物进行了元素分析、红外、紫外、荧光和差热热重表征, 解析了配合物的晶体结构。晶体结构解析表明:配合物1是阴离子-阳离子型化合物, 阴离子与水分子形成三维有孔洞的氢键网络, 阳离子占据这些孔洞。电化学性质测试表明:氧化还原是一个单电子可逆的过程, 对应的可逆对为Ru(Ⅳ)/Ru(Ⅲ), E_1/2=1.350 V。室温苯甲硫醚氧化催化实验表明:钌配合物与酸结合具有较高的催化活性与亚砜选择性。     

基于酰胺-吡唑双功能配体的钯配位“夹子”的自组装及其催化性能

利用配位驱动吡唑基配体在溶液中自发去质子自组装的方法,用金属转子[（bpy）₂Pd₂（NO₃）₂]（NO₃）₂、[（dmbpy）₂Pd₂（NO₃）₂]（NO₃）2（bpy=2,2''-联吡啶,dmbpy=4,4''-二甲基-2,2''-联吡啶）和酰胺-吡唑双功能配体（HL¹、HL²）合成了含有Pd（Ⅱ）…Pd（Ⅱ）相互作用的[Pd₂L₂]²⁺类型的吡唑基双钯（Ⅱ,Ⅱ）“夹子” C1~C4。利用¹H和¹³C NMR、ESI-MS、红外光谱和X射线单晶衍射等测试手段对配合物C1~C4的结构进行了表征。同时,合成的夹子状双金属配合物对Suzuki-coupling反应均表现出较好的催化活性。     

含有席夫碱配体的钌配合物的合成、表征及抗肿瘤活性

设计并合成了3个含有席夫碱基团的配体（BLⁿ,n=1~3）及相应的双核联吡啶钌配合物[Ru （BLⁿ）（bpy）₂]₂（ClO₄）₄,其中bpy=2,2''-联吡啶,BLⁿ=（（PyCHN）-Ph-O-C₆H₄）₂R （PyCHN=N-2-吡啶亚甲基,R=none （Ru1）,—C （CH₃）₂（Ru2）,—SO₂（Ru3））。通过元素分析、核磁氢谱、红外光谱、质谱等方法对配体和配合物进行了表征。通过体外细胞毒性实验研究了Ru1~Ru3对宫颈癌细胞（Hela）、胃癌细胞（BGC823）、胃癌细胞（SGC-7901）三种肿瘤细胞和人正常胚肺成纤维细胞MRC-5的细胞毒性,实验结果表明Ru3的抗肿瘤活性最好,而Ru1~Ru3均对BGC823具有选择性。     

两个紫精-多酸杂化材料的合成、结构及其光致变色和光催化性质

分别利用1,1''-二甲基-4,4''-联吡啶(甲基紫精,MV)二氯化物和1,1''-二乙基-4,4''-联吡啶(乙基紫精,EV)二溴化物的阳离子作为电子受体,富电子的杂多酸阴离子作为电子给体,合成了 2 个新的紫精-多酸杂化晶态材料：(MV)₂[HPW^Ⅴ₂W^Ⅵ₁₀O₄₀]₂·2H₂O (1)和(EV)₂[Mo₈O₂₆] (2),并解析了其单晶结构,在化合物 1和 2中,阴、阳离子间均存在氢键相互作用。2具有光致变色性能,光响应时间为1 min以内。通过固体漫反射、电子顺磁共振和理论计算等手段,探究了2的光致变色机理。1和2对光降解有机染料(亚甲蓝、盐酸对甲苯胺和罗丹明6G)均具有一定的催化性能。     

Cr(III)-取代磷钨杂多配合物对4-甲基吡啶的电催化氧化作用

利用Cr(III)-取代磷钨杂多配合物PW₁₁O₃₉Cr^III(H₂O)^4－的内球电子转移特性, 通过与反应活性中心Cr^III(H₂O)第六配位水分子的交换反应, 将4-甲基吡啶分子络合修饰到该活性中心上进行阳极催化氧化. 可见吸收光谱证实4-甲基吡啶和Cr^III(H₂O)中心进行配体交换反应生成PW₁₁O₃₉Cr^III(NC₆H₇)^4－; 而循环伏安和恒电位电解实验结果表明, 修饰在Cr(III)活性中心上的4-甲基吡啶分子每一步都经历2电子氧化, 依次生成吡啶-4-甲醇, 吡啶-4-甲醛和吡啶-4-甲酸. 由此提出了一个关于这类反应的分子内电催化模板机制, 为过渡金属取代杂多配合物作为间接氧化电催化剂的应用开辟了一条新途径.     

Cr(III)-取代磷钨杂多配合物对4-甲基吡啶的电催化氧化作用

利用Cr(III)-取代磷钨杂多配合物PW₁₁O₃₉Cr^III(H₂O)^4－的内球电子转移特性, 通过与反应活性中心Cr^III(H₂O)第六配位水分子的交换反应, 将4-甲基吡啶分子络合修饰到该活性中心上进行阳极催化氧化. 可见吸收光谱证实4-甲基吡啶和Cr^III(H₂O)中心进行配体交换反应生成PW₁₁O₃₉Cr^III(NC₆H₇)^4－; 而循环伏安和恒电位电解实验结果表明, 修饰在Cr(III)活性中心上的4-甲基吡啶分子每一步都经历2电子氧化, 依次生成吡啶-4-甲醇, 吡啶-4-甲醛和吡啶-4-甲酸. 由此提出了一个关于这类反应的分子内电催化模板机制, 为过渡金属取代杂多配合物作为间接氧化电催化剂的应用开辟了一条新途径.     

蒽醌基金属-有机笼光氧化性能

将光活性蒽醌配体L¹和L²（L¹=N²,N⁷-双（（2,2''-联吡啶）-5-基）-9,10-蒽醌-2,7-双酰胺,L²=N²,N⁷-双（4-（（2,2''-联吡啶）-5-基）苯基）-9,10-蒽醌-2,7-双酰胺）与锌离子和亚铁离子通过配位自组装构筑得到一系列配合物1-Zn、2-Zn和2-Fe,单晶X射线衍射和电喷雾质谱等表征表明这一系列配合物为“2+3”的M₂L₃型金属-有机超分子结构。将蒽醌基金属-有机笼1-Zn与2-Zn应用于甲苯光催化氧化反应中,结果表明笼状催化剂和底物分子间形成超分子主客体化合物是其能有效氧化甲苯的关键。通过对芳香醇的光氧化反应进一步探究1-Zn与2-Zn的光氧化性能,实验结果表明催化产率受到取代基的电子效应和底物分子的尺寸的影响。     

高浓度氮掺杂多孔石墨烯的可控制备及类酶催化性质

通过改进的Hummer法合成氧化石墨烯（GO）,然后以氨水为氮源,经过一步水热法温和地制备了具有丰富纳米孔的氮掺杂还原氧化石墨烯（N-RGO）筛网状片层。N-RGO显示出高效的类酶催化活性,可以催化氧化多种有机化合物发生显色反应,如3,3'',5,5''-四甲基联苯胺（TMB）、邻苯二胺（OPD）、2,2''-叠氮基-二（3-乙基苯并噻唑啉磺酸）（ABTS）等。利用透射电子显微镜（TEM）、Raman光谱和X射线光电子能谱（XPS）对其进行系统表征。通过平行试验证明N-RGO催化氧化TMB是氧气参与的高效4电子转移反应过程。催化性能测试表明N-RGO相对辣根过氧化物酶（HPR）表现出了更强的耐受性,在较宽范围内（温度25~85℃,pH值4~7,NaCl浓度0~100 mmol·L^-1）均具有类酶催化活性。通过Michaelis-Menten模型的拟合可知,当GO浓度为5 mg·mL^-1时合成的N-RGO表现出较低的米氏常数（K_m≈0.2 mmol·L^-1）和较高的反应速率（v_max≈0.07 μmol·L^-1）。     

过氧铌杂多配合物位置异构体的合成、表征及催化性能

合成了6种钨硅杂多配合物异构体α、β_i-M₃H₂[SiW₁₁(NbO₂)O₃₉]·H₂O(M=Me₄N⁺(TMA),Bu₄N⁺(TBA),Et₄N⁺(TEA);β_i=β₁,β₂,β₃)。IR光谱、UV光谱、极谱、I^--S₂O₃^2-滴定证明合成的杂多配合物中有NbO₂基存在, ¹⁸³W NMR光谱证明其阴离子具有Keggin结构,催化实验结果表明,合成的化合物对烯烃环氧化反应具有催化活性,且过氧杂多配合物的催化活性高于非过氧杂多配合物,β异构体的催化活性高于α。     

基于二甲基苯并联咪唑的钌(Ⅱ)多吡啶配合物的合成、光谱和电化学性质

合成了一组钌多吡啶化合物[Ru（bpy）₂（DMBbimH_x）]^y+（bpy=2,2''-联吡啶,DMBbimH₂=7,7''-二甲基-2,2''-苯并联咪唑,1-A：x=2;y=2;1-B：x=1,y=1;1-C：x=0,y=0）并测试了它们的核磁氢谱、紫外吸收和电化学性质。随着DMBbimH_x配体逐个脱去质子,配合物的光谱和电化学性质发生明显的变化。有趣的是,脱去一个质子的配合物1-B在不同极性的二氯甲烷和乙腈中的电化学性质呈现明显的差异：在二氯甲烷中,单核的1-B却能发生两步氧化,这是因为在弱极性的溶剂中,[Ru（bpy）₂（DMBbimH）]⁺阳离子通过氢键结合形成二聚体,[Ru（bpy）₂（DMBbimH）]⁺阳离子间存在质子耦合电子传递现象。在1-B的二氯甲烷溶液中得到了化合物[Ru（bpy）₂（DMBbimH）]PF₆·2CH₂Cl₂（2）的单晶。晶体结构分析表明[Ru（bpy）₂（DMBbimH）]⁺阳离子确实通过氢键结合形成二聚体,这与电化学测试的结果一致。而在极性较大的乙腈中,氢键二聚体不能稳定存在,在循环伏安曲线上只有一个峰存在。     

A Calix[4]arene-Based Cyclic Dinuclear Ruthenium Complex for Light-Driven Catalytic Water Oxidation

A cyclic dinuclear ruthenium(bda) (bda: 2,2’-bipyridine-6,6’-dicarboxylate) complex equipped with oligo(ethylene glycol)-functionalized axial calix[4]arene ligands has been synthesized for homogenous catalytic water oxidation. This novel Ru(bda) macrocycle showed significantly increased catalytic activity in chemical and photocatalytic water oxidation compared to the archetype mononuclear reference [Ru(bda)(pic)₂]. Kinetic investigations, including kinetic isotope effect studies, disclosed a unimolecular water nucleophilic attack mechanism of this novel dinuclear water oxidation catalyst (WOC) under the involvement of the second coordination sphere. Photocatalytic water oxidation with this cyclic dinuclear Ru complex using [Ru(bpy)₃]Cl₂ as a standard photosensitizer revealed a turnover frequency of 15.5 s⁻¹ and a turnover number of 460. This so far highest photocatalytic performance reported for a Ru(bda) complex underlines the potential of this water-soluble WOC for artificial photosynthesis.     

Self‐Assembled Amphiphilic Water Oxidation Catalysts: Control of O−O Bond Formation Pathways by Different Aggregation Patterns

The oxidation of water to molecular oxygen is the key step to realize water splitting from both biological and chemical perspective. In an effort to understand how water oxidation occurs on a molecular level, a large number of molecular catalysts have been synthesized to find an easy access to higher oxidation states as well as their capacity to make O?O bond. However, most of them function in a mixture of organic solvent and water and the O?O bond formation pathway is still a subject of intense debate. Herein, we design the first amphiphilic Ru‐bda (H₂bda=2,2′‐bipyridine‐6,6′‐dicarboxylic acid) water oxidation catalysts (WOCs) of formula [Ru^II(bda)(4‐OTEG‐pyridine)₂] ( 1 , OTEG=OCH₂CH₂OCH₂CH₂OCH₃) and [Ru^II(bda)(PySO₃Na)₂] ( 2 , PySO₃^?=pyridine‐3‐sulfonate), which possess good solubility in water. Dynamic light scattering (DLS), scanning electron microscope (SEM), critical aggregation concentration (CAC) experiments and product analysis demonstrate that they enable to self‐assemble in water and form the O?O bond through different routes even though they have the same bda^2? backbone. This work illustrates for the first time that the O?O bond formation pathway can be regulated by the interaction of ancillary ligands at supramolecular level.     

Light‐Driven Water Splitting Mediated by Photogenerated Bromine

Light‐driven water splitting was achieved using a dye‐sensitized mesoporous oxide film and the oxidation of bromide (Br^?) to bromine (Br₂) or tribromide (Br₃^?). The chemical oxidant (Br₂ or Br₃^?) is formed during illumination at the photoanode and used as a sacrificial oxidant to drive a water oxidation catalyst (WOC), here demonstrated using [Ru(bda)(pic)₂], ( 1 ; pic=picoline, bda=2,2′‐bipyridine‐6,6′‐dicarboxylate). The photochemical oxidation of bromide produces a chemical oxidant with a potential of 1.09 V vs. NHE for the Br₂/Br^? couple or 1.05 V vs. NHE for the Br₃^?/Br^? couple, which is sufficient to drive water oxidation at 1 (Ru^V/IV≈1.0 V vs. NHE at pH 5.6). At pH 5.6, using a 0.2 m acetate buffer containing 40 mm LiBr and the [Ru(4,4′‐PO₃H₂‐bpy)(bpy)₂]²⁺ ( RuP ²⁺, bpy=2,2′‐bipyridine) chromophore dye on a SnO₂/TiO₂ core–shell electrode resulted in a photocurrent density of around 1.2 mA cm^?2 under approximately 1 Sun illumination and a Faradaic efficiency upon addition of 1 of 77 % for oxygen evolution.     

Regulation of electron donating ability to metal center: isolation and characterization of ruthenium carbonyl complexes with N,N- and/or N,O-donor polypyridyl ligands

Polypyridyl ruthenium(II) dicarbonyl complexes with an N,O- and/or N,N-donor ligand, [Ru(pic)(CO)₂Cl₂]⁻ (1), [Ru(bpy)(pic)(CO)₂]⁺ (2), [Ru(pic)₂(CO)₂] (3), and [Ru(bpy)₂(CO)₂]²⁺ (4) (pic=2-pyridylcarboxylato, bpy=2,2′-bipyridine) were prepared for comparison of the electron donor ability of these ligands to the ruthenium center. A carbonyl group of [Ru(L1)(L2)(CO)₂]ⁿ (L1, L2=bpy, pic) successively reacted with one and two equivalents of OH⁻ to form [Ru(L1)(L2)(CO)(C(O)OH)]ⁿ⁻¹ and [Ru(L1)(L2)(CO)(CO₂)]ⁿ⁻². These three complexes exist as equilbrium mixtures in aqueous solutions and the equilibrium constants were determined potentiometrically. Electrochemical reduction of 2 in CO₂-saturated CH₃CN–H₂O at −1.5 V selectively produced CO.     

Protonation effect on catalytic water oxidation activity of a mononuclear Ru catalyst containing a free pyridine unit

Two efficient single-site Ru water oxidation catalysts [Ru(bda)(pic)(Ln)](bda = 2,2'-bipyridine-6,6'-dicarboxylic acid, pic = picoline, L1 = 4,5-bipyridine-2,7-di-tert-butyl-9,9-dimethylxanthene, L2 = 4-pyridine-5-phenyl-2,7-di-tert-butyl-9,9-dimethylxanthene) were only synthesized containing different xanthene ligands at the axial site. These complexes have been thoroughly characterized by spectroscopic(UV-vis, NMR) and electrochemical(CV and DPV) techniques. Kinetic analysis proved that the mechanism of water oxidation comprises the water nucleophilic attack process on high-valence ruthenium species.It is found that the catalyst 1 displayed higher activity than catalyst 2 on water oxidation, caused by the protonation of the axial ligand L1 with a free pyridine.     

1-(2′-Pyridylazo)-2-naphtholate complexes of ruthenium: Synthesis,characterization, and DNA binding properties

Reaction of 1-(2′-pyridylazo)-2-naphthol (Hpan) with [Ru(dmso)₄Cl₂] (dmso = dimethylsulfoxide), [Ru(trpy)Cl₃] (trpy = 2,2′,2″-terpyridine), [Ru(bpy)Cl₃] (bpy = 2,2′-bipyridine) and [Ru(PPh₃)₃Cl₂] in refluxing ethanol in the presence of a base (NEt₃) affords, respectively, the [Ru(pan)₂], [Ru(trpy)(pan)]⁺ (isolated as perchlorate salt), [Ru(bpy)(pan)Cl] and [Ru(PPh₃)₂(pan)Cl] complexes. Structures of these four complexes have been determined by X-ray crystallography. In each of these complexes, the pan ligand is coordinated to the metal center as a monoanionic tridentate N,N,O-donor. Reaction of the [Ru(bpy)(pan)Cl] complex with pyridine (py) and 4-picoline (pic) in the presence of silver ion has yielded the [Ru(bpy)(pan)(py)]⁺ and [Ru(bpy)(pan)(pic)]⁺ complexes (isolated as perchlorate salts), respectively. All the complexes are diamagnetic (low-spin d⁶, S = 0) and show characteristic ¹H NMR signals and intense MLCT transitions in the visible region. Cyclic voltammetry on all the complexes shows a Ru(II)–Ru(III) oxidation on the positive side of SCE. Except in the [Ru(pan)₂] complex, a second oxidative response has been observed in the other five complexes. Reductions of the coordinated ligands have also been observed on the negative side of SCE. The [Ru(trpy)(pan)]ClO₄, [Ru(bpy)(pan)(py)]ClO₄ and [Ru(bpy)(pan)(pic)]ClO₄ complexes have been observed to bind to DNA, but they have not been able to cleave super-coiled DNA on UV irradiation.     

Chemical and Photochemical Water Oxidation Catalyzed by Mononuclear Ruthenium Complexes with a Negatively Charged Tridentate Ligand

Two mononuclear ruthenium complexes [RuL(pic)₃] ( 1 ) and [RuL(bpy)(pic)] ( 2 ) (H₂L=2,6‐pyridinedicarboxylic acid, pic=4‐picoline, bpy=2,2′‐bipyridine) have been synthesized and fully characterized. Both complexes could promote water oxidation chemically and photochemically. Compared with other known ruthenium‐based water oxidation catalysts using [Ce(NH₄)₂(NO₃)₆] (Ce^IV) as the oxidant in solution at pH 1.0, complex 1 is one of the most active catalysts yet reported with an initial rate of 0.23 turnover s^?1. Under acidic conditions, the equatorial 4‐picoline in complex 1 dissociates first. In addition, ligand exchange in 1 occurs when the Ru^III state is reached. Based on the above observations and MS measurements of the intermediates during water oxidation by 1 using Ce^IV as oxidant, [RuL(pic)₂(H₂O)]⁺ is proposed as the real water oxidation catalyst.     

Half-sandwich η-benzene Ru(II) complexes of pyridylpyrazole and pyridylimidazole ligands: Synthesis, spectra, and structure

New series of half-sandwich ruthenium(II) complexes supported by a group of bidentate pyridylpyrazole and pyridylimidazole ligands [(η⁶-C₆H₆)Ru(L²)Cl][PF₆] (1), [(η⁶-C₆H₆)Ru(HL³)Cl][PF₆] (2), [(η⁶-C₆H₆)Ru(L⁴)Cl][PF₆] (3), and [(η⁶-C₆H₆)Ru(HL⁵)Cl][PF₆] (4) [L², 2-[3-(4-chlorophenyl)pyrazol-1-ylmethyl]pyridine; HL³, 3-(2-pyridyl)pyrazole; L⁴, 1-benzyl-[3-(2′-pyridyl)]pyrazole; HL⁵, 2-(1-imidazol-2-yl)pyridine] are reported. The molecular structures of 1-4 both in the solid state by X-ray crystallography and in solution using ¹H NMR spectroscopy have been elucidated. Further, the crystal packing in the complexes is stabilized by C-H?X (X = Cl and π), N-H?Cl, and π-π interactions.     

Photochemical,Electrochemical, and Photoelectrochemical Water Oxidation Catalyzed by Water‐Soluble Mononuclear Ruthenium Complexes

Two mononuclear ruthenium complexes [Ru(H₂tcbp)(isoq)₂] ( 1 ) and [Ru(H₂tcbp)(pic)₂] ( 2 ) (H₄tcbp=4,4′,6,6′‐tetracarboxy‐2,2′‐bipyridine, isoq=isoquinoline, pic=4‐picoline) are synthesized and fully characterized. Two spare carboxyl groups on the 4,4′‐positions are introduced to enhance the solubility of 1 and 2 in water and to simultaneously allow them to tether to the electrode surface by an ester linkage. The photochemical, electrochemical, and photoelectrochemical water oxidation performance of 1 in neutral aqueous solution is investigated. Under electrochemical conditions, water oxidation is conducted on the deposited indium‐tin‐oxide anode, and a turnover number higher than 15,000 per water oxidation catalyst (WOC) 1 is obtained during 10 h of electrolysis under 1.42 V vs. NHE, corresponding to a turnover frequency of 0.41 s^?1. The low overpotential (0.17 V) of electrochemical water oxidation for 1 in the homogeneous solution enables water oxidation under visible light by using [Ru(bpy)₃]²⁺ ( P1 ) (bpy=2,2′‐bipyridine) or [Ru(bpy)₂(4,4′‐(COOEt)₂‐bpy)]²⁺ ( P2 ) as a photosensitizer. In a three‐component system containing 1 or 2 as a light‐driven WOC, P1 or P2 as a photosensitizer, and Na₂S₂O₈ or [CoCl(NH₃)₅]Cl₂ as a sacrificial electron acceptor, a high turnover frequency of 0.81 s^?1 and a turnover number of up to 600 for 1 under different catalytic conditions are achieved. In a photoelectrochemical system, the WOC 1 and photosensitizer are immobilized together on the photoanode. The electrons efficiently transfer from the WOC to the photogenerated oxidizing photosensitizer, and a high photocurrent density of 85 μA cm^?2 is obtained by applying 0.3 V bias vs. NHE.     

Synthesis, characterization and electron transfer properties of some picolinate complexes of ruthenium

In aqueous solution ruthenium trichloride reacted with picolinic acid (Hpic) in the presence of a base to afford [Ru(pic)₃]. In solution it shows intense ligand-to-metal charge transfer transitions near 310 and 370 nm, together with a low-intensity absorption near 2000 nm. [Ru(pic)₃] is one-electron paramagnetic and shows a rhombic ESR spectrum in 1:1 dimethylsulphoxide-methanol solution at 77 K. The distortions from octahedral symmetry have been calculated by ESR data analysis. The axial distortion is larger than the rhombic one. In acetonitrile solution it shows a reversible ruthenium(III)-ruthenium(II) reduction at −0.09 V vs. SCE and a reversible ruthenium(III)-ruthenium(IV) oxidation at 1.52 V vs. SCE. Chemical or electrochemical reduction of [Ru^III(pic)₃] gives [Ru^II(pic)₃]⁻, which in solution shows intense MLCT transitions near 360, 410 and 490 nm, and is converted back to [Ru(pic)₃] by exposure to air. Reaction of [Ru(pic)₃] with 8-quinolinol (HQ) in dimethylsulphoxide solution affords [RuQ₃]. [Ru(bpy)(pic)₂] (bpy = 2,2′-bipyridine) has been prepared by the reaction of Hpic with [Ru(bpy)(acac)₂]Cl (acac = acetylacetonate ion) in ethyleneglycol. It is diamagnetic and in solution shows intense MLCT transitions near 370, 410 and 530 nm. In acetonitrile solution it shows a reversible ruthenium(II)-ruthernium(III) oxidation at 0.44 V vs. SCE and a reversible one-electron reduction of bpy at − 1.64V vs. SCE.