Synthesis and redox properties of trinuclear ruthenium-acetylide complexes with tri(ethynylphenyl)amine bridge

Novel trinuclear ruthenium complexes have been prepared by using tri(4-ethynylphenyl)amine as a bridging ligand. Cyclic voltammetry of the trinuclear ruthenium complexes revealed stepwise quasi-reversible redox behavior of three ruthenium-acetylide species and the central triphenylamine unit, whereas the mononuclear analog showed two sequential quasi-reversible redox waves. The spectroelectrochemical UV-VIS spectral studies suggested that the 1e- oxidized triruthenium species was stable and showed a characteristic absorption at lambda(max) = 505 nm. Chemical oxidation of the triruthenium complex with ferrocenium hexafluorophosphate led to the isolation of the 1e- oxidized complex, the near-IR spectrum of which revealed an intervalence charge transfer band due to the electronic coupling among three ruthenium species. The 1e(-) oxidized triruthenium complexes can be classified as class II mixed-valence compounds.     

Synthesis, structure, redox properties and azide binding for a series of biphenyl-based Cu(II) complexes

A series of biphenyl-based N(3)O ligands, 2, 4, 6, and 8 were synthesized and their Cu(II) complexes prepared. These complexes were characterized by a combination of elemental analysis, FAB-MS, UV-vis spectroscopy and electrochemistry. The structure of [Cu(N(3)O-mpy-NO2)Cl2], 12 [N(3)O-mpy = 2-(3-pyridylmethylimino)-2'-(2-methylaminophenol)biphenyl], was solved and showed that the ligand coordinates through the three nitrogens with the phenol oxygen uncoordinated. Titration of azide anion into solutions of the complexes in methanol resulted in the appearance of a new band between 485-495 nm at the expense of the starting peak at 380 nm. Cyclic voltammetry studies indicated that the complexes undergo quasi-reversible one-electron reductions in acetonitrile at potentials between 0.13-0.58 V vs. Ag/AgCl. The complexes were found to be weakly active for the oxidation of di-tert-butyl catechol (DTBC).     

酸性大红3R的电化学研究及应用

采用循环伏安法和方波伏安法考察了酸性大红3R在碳糊电极上的伏安行为和反应机理。当扫描速率为0.1 V/s时,在pH 1的0.05 mol/L H2SO4支持电解液中,酸性大红3R有一对峰电位分别是0.74 V和0.72 V（vs.饱和甘汞电极）的氧化峰和还原峰,并且显示吸附控制的2电子单质子的准可逆氧化还原过程。在最佳实验条件下,酸性大红3R的方波氧化峰峰电流与其浓度在2.12×10^-5-3.39×10^-4mol/L范围内呈线性关系,检出限为8.35×10^-6mol/L,由此建立测定酸性大红3R含量的方波伏安法。该方法可用于计算酸性大红3R常规染羊毛与蚕丝的上染率,测定结果与分光光度法一致。     

A fluorinated ruthenium porphyrin as a potential photodynamic therapy agent: synthesis, characterization, DNA binding, and melanoma cell studies

When the new porphyrin 5,10-(4-pyridyl)-15,20-(pentafluorophenyl)porphyrin is reacted with 2 equiv of Ru(bipy)(2)Cl(2) (where bipy = 2,2'-bipyridine) formation of the target ruthenated porphyrin is achieved with 40% yield. Strong electronic transitions are observed in the visible region of the spectrum associated with the porphyrin Soret and four Q-bands. A shoulder at slightly higher energy than the Soret band is attributed to the Ru(dpi) to bipy(pi*) metal to ligand charge transfer (MLCT) band. The bipyridyl pi to pi* transition occurs at 295 nm. Cyclic voltammetry experiments reveal two single-electron redox couples in the cathodic region at E(1/2) = -0.80 and -1.18 V vs Ag/AgCl associated with the porphyrin. Two overlapping redox couples at E(1/2) = 0.83 V vs Ag/AgCl due to the Ru(III/II) centers is also observed. DNA titrations using calf thymus (CT) DNA and the ruthenium porphyrin give a K(b) = 7.6 x 10(5) M(-1) indicating a strong interaction between complex and DNA. When aqueous solutions of supercoiled DNA and ruthenium porphyrin are irradiated with visible light (energy lower than 400 nm), complete nicking of the DNA is observed. Cell studies show that the ruthenated porphyrin is more toxic to melanoma skin cells than to normal fibroblast cells. When irradiated with a 60 W tungsten lamp, the ruthenium porphyrin preferentially leads to apoptosis of the melanoma cells over the normal skin cells.     

四苯基卟啉镁的合成、表征及光化学性质

提出一种以乙酸镁和乙酸钠为原料合成四苯基卟啉镁(MgTPP)的新方法, 合成样品以柱层析法进行分离纯化. 分离产物经UV-Vis、1H-NMR、MALDI-TOF-MS(基质辅助激光解吸电离飞行时间质谱)等技术表征, 确定为MgTPP. UV-Vis光谱分析结果表明, 四苯基卟啉镁的Soret 吸收带为424 nm, Q 吸收带为563 nm 和602 nm. 此外, 光照对MgTPP的二氯甲烷溶液光谱性质的影响结果表明, 经光照射后MgTPP的UV-Vis光谱的Soret吸收带吸收强度明显降低, 同时, 经550 nm的光激发产生的荧光有明显的猝灭. 对光照后的MgTPP样品进行MALDI-TOF-MS分析, 发现有新的质核比(m/z)出现, 其为668, 这一结果表明, 在光照条件下, MgTPP分子可能与氧分子发生光化学作用, 形成MgTPP与氧的复合物MgTPP-O2.     

Layer-by-layer assembled composite films of side-functionalized poly(3-hexylthiophene) and CdSe nanocrystals: electrochemical, spectroelectrochemical and photovoltaic properties

Regioregular poly(3-hexylthiophene) containing one diaminopyrimidine side group per ten repeat units (P3HT-co-P3(ODAP)HT) can form molecular composites with 1-(6-mercaptohexyl)thymine capped CdSe nanocrystals (CdSe(MHT)) via hydrogen bonds directed molecular recognition. Here we report complementary spectroscopic, electrochemical and spectroelectrochemical investigations of both the functionalized poly(thiophene) and its composite with the nanocrystals, the latter being fabricated using the layer-by-layer (LbL) deposition technique. UV-Vis-NIR and Raman spectroelectrochemical investigations unequivocally show that the onset of the first anodic peak in the cyclic voltammogram of the copolymer can be attributed to the oxidation of the pi-conjugated backbone in the polymer chains. For this reason, it is possible to determine the width and the position of its band gap (corresponding to the pi-pi* transition) by UV-Vis spectroscopy combined with cyclic voltammetry. These studies show that the polymer exhibits a slightly larger band gap with the HOMO level insignificantly lower in energy (by 0.03 eV) as compared to the case of regioregular poly(3-hexylthiophene) of comparable degree of polymerization. Hydrogen bond interactions of the polymer with CdSe(MHT) in the molecular composite result in a hypsochromic shift of the band corresponding to the pi-pi* transition from 504 nm to 488 nm. This can be taken as a spectroscopic manifestation of the conformational changes induced by shortening of the conjugation length. The observed spectral modifications are consistent with electrochemically determined lowering of the polymer HOMO level (from -4.91 eV in the pure polymer to -4.99 eV in the composite). Cyclic voltammetry studies supported by spectroelectrochemistry also show that the redox stability of CdSe(MHT) in the molecular composite with P3HT-co-P3(ODAP)HT is lower than that determined for stearate-capped nanocrystals. Their irreversible oxidation starts at E = +0.7 V vs. Ag/0.1 M Ag(+)i.e. at potentials by ca. 0.3 V lower than the oxidation of stearate stabilized CdSe nanocrystals of the same size. We show that-despite these modifications-the alignment of the HOMO and LUMO levels of the composite components remains appropriate for its use in hybrid solar cells, which is demonstrated by the photovoltaic effect observed for the LbL-processed composite sandwiched between two electrodes.     

咪唑修饰的卟啉及其锌、铜配合物的合成和非线性光学性质

合成了一种新型咪唑修饰的卟啉(1)及其锌、铜配合物(2、3). 通过核磁共振氢谱(1H NMR)、紫外-可见(UV-Vis)光谱、傅里叶变换红外(FT-IR)光谱、电喷雾质谱(ESI-MS)及元素分析等多种谱学方法对其结构进行表征. 卟啉环流效应对侧链咪唑芳环的影响导致咪唑环上三个氢原子的化学位移向高场移动, 且卟啉的紫外-可见光谱的Soret带发生裂分. 采用分子模拟方法得到的自由卟啉最低能量构象与光谱分析结果一致, 即侧链咪唑环位于卟啉环上方. 同时, 利用Z-扫描技术对卟啉及其锌、铜配合物的三阶非线性光学性质进行了研究, 结果表明: 卟啉及其锌、铜配合物均具有很强的反饱和吸收性质, 且铜卟啉的非线性光学性质强于锌卟啉的.     

聚间亚苯亚乙烯的性能研究

自1990年Burroughes等首次报道聚对亚苯亚乙烯的电致发光以来,由于电致发光高分子材料在平面显示(特别是大面积显示)方面具有其他显示材料难以比拟的优势,因而近年来受到人们的广泛关注,在合成方法、加工性能、发光颜色的调控以及器件性能等多方面取得显著进展,不     

经过吸附处理的Ti-Si沸石的IR和UV-Vis光谱研究

用IR和UV-Vis光谱对Ti-Si沸石吸附H₂O、H₂O₂、烯丙基氯后的变化情况进行了研究。观察到H₂O₂的吸附将引起Ti-Si沸石IR光谱中960cm^-1谱带的减弱,同时一个弱带在880cm^-1处形成;而在UV-Vis光谱中,吸附H₂O₂将导致一个新的电子跃迁带在425nm处形成。这时若吸附烯丙基氯,则可发现880cm^-1的弱带及UV-Vis425nm的宽带会进一步减弱,同时一个新的IR带重又出现在980cm^-1处。吸附H₂O₂后导致的IR880cm^-1弱带的出现及UV-Vis425nm宽带的出现均证实此时在沸石表面形成了过氧钛物种。推测骨架晶格钛可能在H₂O₂参加的氧化反应中起活性中心作用。     

用氧化偶联聚合法合成新型电活性聚酰胺及其结构表征

使用氧化偶联聚合的方法, 合成了一种新的电活性聚酰胺, 使其同时具有聚酰胺和聚苯胺性质. 该反应操作简便易行, 室温下即可进行. 通过红外光谱和核磁共振谱对其结构进行了表征, 用紫外-可见光谱和循环伏安法研究了氧化还原性质和电活性, 并测试了导电率.     

Evaluation of ferryl formation by electrocatalytic oxidation of alkene using luminol chemiluminescence

Electrochemical formation of ferryl porphyrin was examined by electrocatalytic oxidation of alkene by measuring luminol chemiluminescence using a flow-injection method. Emission was observed both below the reduction potential of Fe(III)TMPyP (-0.08 V at pH 11, -0.02 V at pH 7 and 0.15 V at pH 3) and above the oxidation potential (0.6 V at pH 11, 0.75 V at pH 7 and 1.1 V at pH 3). However, both anodic and cathodic emissions were inhibited significantly by the addition of alkene (cyclopent-2-ene-1-acetic acid) solutions downstream of the working electrode. Further, the spectra at both anodic and cathodic sides shifted to the longer wavelength (>424 nm) compared to the original spectrum of Fe(III)TMPyP (422 nm), which was not observed with the addition of alkene solution. Therefore, the results suggest that the electrochemically generated oxo-ferryl species have been engaged in catalytic oxidation of alkene before the flow reaches the observation cell.     

Synthesis, characterization and electrochromic properties of copolymer of 3-{[4-(thien-3-yl-methoxy)phenoxy]methyl}thiophene with thiophene

(3-{[4-(Thien-3-yl-methoxy)phenoxy]methyl}thiophene) (TMPMT) was synthesized via the reaction of 3-bromomethylthiophene with hydroquinone and characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Electrochemical copolymerization of TMPMT with thiophene in acetonitrile/boron trifluoride diethyl etherate (AN/BFEE) solvent mixture was achieved using tetrabutylammonium tetrafluoroborate (TBAFB) as the supporting electrolyte. Resulting copolymer was characterized via cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), four probe technique conductivity measurement and UV-Vis spectroscopy. Spectroelectrochemical analysis of the copolymer [P(TTMT-co-Th)] revealed that π-π^∗ electronic transition occurs at 427 nm with a band gap value of 2.20 eV. Copolymer gives brown color at the fully reduced state whereas; at fully oxidized state the film has a gray-blue color. Kinetic studies were carried out at the maximum contrast wavelength upon measuring the percent transmittance, T% (7.6%) and switching time (2.0 s) to examine the switching ability of the copolymer. Dual type electrochromic device (ECD) of P(TMPMT-co-Th) and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed. Spectroelectrochemistry, switching ability, open circuit memory and stability of the device were examined by UV-Vis spectroscopy and cyclic voltammetry. The device switches between brown and blue at switching voltages of 0.0 V and 2.8 V with a short switching time of 1.4 s.     

One-electron oxidized product of difluoroiron(III) porphyrin: is it iron(IV) porphyrin or iron(III) porphyrin π-cation radical?

The electronic structure of [Fe(TMP)F(2)], which is formally a one-electron oxidation equivalent above [Fe(III)(TMP)F(2)](-), has been examined in solution by (1)H NMR, UV-Vis, and M?ssbauer spectroscopy. In CD(2)Cl(2)-CD(3)OD solution at 193 K, the pyrrole-H and m-H signals appeared at 128.2 and 116.7 ppm, respectively. The UV-Vis spectrum showed broad absorption bands at 560-680 nm. The M?ssbauer spectrum taken in frozen toluene-methanol solution exhibited a very broad single line from which the IS and QS values were determined by computer simulation to be 0.50 and 0.14 mm s(-1), respectively. On the basis of these results, it was concluded that the one-electron oxidized product of [Fe(TMP)F(2)](-) should be formulated as the iron(III) radical cation [Fe(III)(TMP˙)F(2)], not as iron(IV) porphyrin [Fe(IV)(TMP)F(2)] as previously suggested.     

New riches in carbaporphyrin chemistry: silver and gold organometallic complexes of benzocarbaporphyrins

The NH-N-NH-N core of the porphyrin system represents one of the best studied and most versatile platforms for coordination chemistry. However, the replacement of one or more of the interior nitrogens with carbon atoms would be expected to diminish the ability of these systems to form metallo derivatives considerably. Despite this expectation, carbaporphyrinoid systems have been shown to form stable organometallic derivatives. Although azuliporphyrins and benziporphyrins act as dianionic ligands, benzocarbaporphyrins are trianionic ligands. Treatment of five different meso unsubstituted benzocarbaporphyrins and two different meso tetraarylbenzocarbaporphyrins with excess silver(I) acetate afforded 65-97% yields of the corresponding silver(III) organometallic derivatives. The insertion of silver metal was confirmed by mass spectrometry and X-ray crystallography. The UV-vis spectra showed a strong Soret band at wavelengths between 437 and 451 nm, together with a series of Q-type bands at longer wavelengths. The new metallo carbaporphyrins demonstrate the presence of a strong diatropic ring current in their proton NMR spectra, and carbon-13 NMR spectroscopy indicates that the derivatives retain a plane of symmetry. The reaction of meso tetraaryl carbaporphyrins with gold(III) acetate afforded the related gold(III) complexes, and these also showed strongly porphyrin-like aromatic characteristics. The UV-vis spectra for the gold complexes again showed a strong Soret band between 437-439 nm, but a secondary band near 400 nm is somewhat intensified for the gold species compared to the spectra for the related silver(III) meso tetrasubstituted carbaporphyrins. The ring currents observed for the gold(III) complexes by proton NMR spectroscopy were comparable to those of the silver(III) derivatives, implying that both series have similar macrocyclic conformations. Cyclic voltammetry was performed on two different carbaporphyrins, their silver(III) derivatives, and a gold(III) complex. The silver complexes display a reversible cathodic wave that is assigned to the Ag(III/II) couple. However, the gold porphyrinoid gave a value for the reductive wave that could be due to a gold(III/II) couple or a ligand-based process.     

层状K4Ag2Sn3S9·2H2O的溶剂热合成与表征

用溶剂热法合成了K4Ag2Sn3S9·2H2O,通过单晶X射线衍射、DSC、TG、IR和紫外漫反射光谱等手段对其进行了表征.结果表明,K4Ag2Sn3S9·2H2O属单斜晶系,P21/m空间群,a=0.78071(2)nm,b=2.73508(1)nm,c=1.05008nm,α=90°,β=103.87(6)°,γ=90°,Z=4.其层状结构内具有一维孔道,钾离子分离在层间及层内孔道中.     

银纳米棒光学性质的离散偶极近似计算

The optical properties of metal nanoparticles are quite different from those of the bulk materials mainly due to the collective oscillations of their conduction electrons known as the surface plasmon resonance（SPR）,which is strongly dependent on the particle shape and size,and the dielectric properties of the local environment where the nanoparticles are embedded in. Based on the discrete dipole approximation（DDA）method,we studied the optical properties of silver nanorods with different aspect ratios in some special dielectric environment including air,water,acetone,methylene chloride and pyridine. The DDA simulation of the ultraviolet-visible（UV-Vis）extinction spectra of silver nanorods with varying aspect ratios shows the plasmons absorption splits into two bands corresponding to the oscillation of the free electrons along and perpendicular to the long axis of the rods. The transverse mode shows almost a fixed resonance at about 350 nm while the resonance of the longitudinal mode is red-shifted and strongly depends on the aspect ratio of the nanorods. An empirical formula was given to predict the peak position of the longitudinal palsmon band of the silver nanorods with different aspect ratios in the air. The calculation result also shows the maximum of the longitudinal plasmon band of a silver nanorod with a fixed aspect ratio depends on the medium dielectric constant in a linear way. The TEM image and corresponding UV-Vis extinction spectrum of silver nanosphere and nanorods synthesized by our lab are in good agreement with the DDA simulation results.     

纳米银掺杂二氧化硅复合颗粒的制备及表征

0引言金属纳米颗粒因其粒子尺寸小(1￣100nm),比表面积大,表面原子数多,表面能和表面张力随粒径的下降急剧增大而具有量子尺寸效应[1]、小尺寸效应[2]、表面效应[3]及宏观量子隧道效应[4]等,从而出现了不同于常规固体的新奇特性,如:光学性质、磁性质以及电磁学性质[5],使其在催化、信息存储及非线性光学等领域展示了广阔的应用前景[6]。虽然制备金属纳米颗粒的方法有很多[6],但是由于纳米尺寸的金属颗粒具有较高的表面能,容易发生聚集,所以如何保持其稳定性依旧是比较困难的问题。随着纳米科技的发展,人们正尝试用各种方法来解决这个问题:如…     

Synthesis, structure, and characterisation of a new phenolato-bridged manganese complex [Mn2(mL)2]2+: chemical and electrochemical access to a new mono-mu-oxo dimanganese core unit

The dinuclear phenolato-bridged complex [(mL)Mn(II)Mn(II)(mL)](ClO(4))(2) (1(ClO(4))(2)) has been obtained with the new [N(4)O] pentadentate ligand mL(-) (mLH=N,N'-bis-(2-pyridylmethyl)-N-(2-hydroxybenzyl)-N'-methyl-ethane-1,2-diamine) and has been characterised by X-ray crystallography. X- and Q-band EPR spectra were recorded and their variation with temperature was examined. All spectra exhibit features extending over 0-800 mT at the X band and over 100-1450 mT at the Q band, features that are usually observed for dinuclear Mn(II) complexes. Cyclic voltammetry of 1 exhibits two irreversible oxidation waves at E(1)(p)=0.89 V and E(2)(p)=1.02 V, accompanied on the reverse scan by an ill-defined cathodic wave at E(1')(p)=0.56 V (all measured versus the saturated calomel electrode (SCE)). Upon chemical oxidation with tBuOOH (10 equiv) at 20 degrees C, 1 is transformed into the mono-mu-oxo species [(mL)Mn(III)-(mu-O)-Mn(III)(mL)](2+) (2), which eventually partially evolves into the di-mu-oxo species [(mL)Mn(III)-(mu-O)(2)-Mn(IV)(mL)](n+) (3) in which one of the aromatic rings of the ligand is decoordinated. The UV/Vis spectrum of 2 displays a large absorption band at 507 nm, which is attributed to a phenolate-->Mn(III) charge-transfer transition. The cyclovoltammogram of 2 exhibits two reversible oxidation waves, at 0.65 and 1.16 V versus the SCE, corresponding to the Mn(III)Mn(III)/Mn(III)Mn(IV) and Mn(III)Mn(IV)/Mn(IV)Mn(IV) oxidation processes, respectively. The one-electron electrochemical oxidation of 2 leads to the mono-mu-oxo mixed-valent species [(mL)Mn(III)-(mu-O)-Mn(IV)(mL)](3+) (2 ox). The UV/Vis spectrum of 2 ox exhibits one large band at 643 nm, which is attributed to the phenolate-->Mn(IV) charge-transfer transition. 2 ox can also be obtained by the direct electrochemical oxidation of 1 in the presence of an external base. The 2 ox and 3 species exhibit a 16-line EPR signal with first peak to last trough widths of 125 and 111 mT, respectively. Both spectra have been simulated by using colinear rhombic Mn-hyperfine tensors. Mechanisms for the chemical formation of 2 and the electrochemical oxidation of 1 into 2 ox are proposed.     

配位键驱动的多卟啉阵列结构在纳米SiO2表面的组装及光电性能

制备了吡啶功能化的纳米二氧化硅(nanoSiO₂BPy), 并利用配位键驱动的层层自组装技术, 以四吡啶基锌卟啉(ZnTPyP)为链接单元, 在nanoSiO₂BPy表面构筑了含有(Pd/ZnTPyP)_n多卟啉阵列结构的有机-无机杂化材料. 利用热重、 紫外-可见吸收光谱和X射线光电子能谱跟踪分析了nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料的组装过程. 结果表明, nanoSiO₂BPy@(Pd/ZnTPyP)₃杂化材料在150~450 ℃升温区间内质量损失17%, 可归结为组装在纳米SiO₂表面的多卟啉阵列和少量有机物的热分解. 紫外-可见和荧光光谱表明, 在nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料中, 锌卟啉Soret带的吸收峰出现在426 nm处, 其Q带的荧光发射峰出现在605和655 nm处, 荧光寿命约为1.78 ns, 光谱数据均与锌卟啉在稀的二甲亚砜溶液中的结果接近, 表明组装在nanoSiO₂BPy表面的锌卟啉环之间相互作用较弱, 没有形成聚集体. 场发射透射电镜照片显示, 由于Pd/ZnTPyP的组装, nanoSiO₂BPy@(Pd/ZnTPyP)₃杂化材料的平均直径由原料的10~16 nm增加到15~20 nm. 杂化材料修饰电极的循环伏安曲线在-0.6~-2.4 V(vs. Ag/AgCl)范围内出现了2对不可逆的氧化还原峰, 归属于卟啉被氧化的电子转移过程. 探讨了nanoSiO₂BPy@(Pd/ZnTPyP)_n杂化材料作为光敏剂在光电转换、 光催化乙基紫精的还原和显色方面的应用.     

含吡唑配体的VIB金属羰基配合物的合成与电化学性质研究

研究了吡唑类配体与M(CO)6(M=Cr,W)的光化学反应,合成了一系列的含吡唑配体的五羰基铬钨配合物。研究了该类化合物的电化学性质。结果表明：铬系列化合物存在一对准可逆的氧化还原峰,而钨系列化合物只存在一个不可逆的氧化峰,用X射线单晶衍射测定了化合物3,4,5－三甲基吡唑五羰基铬的晶体结构。该晶体为单斜晶系,空间群为P2(1)/m,晶胞参数为a=0.9106(3)nm,b=07627(2)nm,c=0.9637(3)nm,β＝91.855(5)°,V=0.6689(3)nm^3,Z=2,R=0.042,Cr为六配位的变形八面体构型。