对光线敏感的蓝瓶子实验

当亚甲蓝水溶液中溶解氧气时,它是蓝色的,溶液中加入强还原剂连二亚硫酸钠Na2S2O4（俗称保险粉）,将溶解的氧还原,使亚甲蓝变为无色的还原态。     

染料与高聚物间的相互作用——Ⅱ.亚甲蓝的聚集态和它产生单线态氧的能力间的关系

本工作研究了染料亚甲蓝和聚电解质——聚苯乙烯磺酸间的相互作用,发现在聚苯乙烯磺酸和亚甲蓝当量比(P/D)不同的体系中,亚甲蓝处于不同的聚集状态.聚集状态对亚甲蓝敏化产生单线态氧的能力有很大的影响.     

硅藻精土负载纳米铁处理有机染料废水的研究

将二价铁离子负载在硅藻精土上并用硼氢化钠还原形成纳米零价铁,制备出一种新型复合材料,用FESEM观察了其微观表面形态,以亚甲蓝水溶液模拟有机染料废水并用COD清除率与脱色率两个指标对处理效果进行了评价分析。评价实验主要研究了复合材料不同负载量、不同投放量以及亚甲蓝水溶液不同初始pH值对于处理效果的影响。结果表明,当复合材料负载量为20%、投放量为12g·L~(-1)、亚甲蓝水溶液不调pH时,COD清除率达到83.84%,脱色率达到99.72%,且处理效果在pH=3～11的范围内都比较稳定,说明制备的复合材料能有效处理亚甲蓝水溶液并且反应条件易控制。     

硫化态Ru-Co-Mo/Al2O3加氢脱硫催化剂的表征

应用程序升温还原和化学吸附考察了硫化态Mo/Al_2O_3, Co-Mo/Al_2O_3, Ru-Mo/Al_2O_3, Ru-Co-Mo/Al_2O_3系列催化剂中的钴与钌的助剂作用. 实验结果发现, TPR谱图中Co-Mo/Al_2O_3上的Co 中心的还原峰强度比Co/Al_2O_3上的大大降低, 并且氧在Co-Mo/Al_2O_3上化学吸附量少于分别在Co/Al_2O_3和Mo/Al_2O_3上的吸附量之和, 说明钴和钼发生了相互作用, 可能生成了所滑的CoMoS相, 减少了独立的钴或钼中心. 与Co不同, 在Ru-Mo/Al_2O_3催化剂上助剂钌使得部分高温还原的Mo中心位移到中温区还原, 并且还增加了H_2和O_2在Mo中心上的吸附量, 这表明在硫化和还原过程中Ru促进了Mo中心的还原, 生成了更多的配位不饱和铝中心, 在Ru-Co-Mo/Al_2O_3催化剂上也发现了类似的钌助还原现象, 钉的这种助还原功能可以用氢溢流机理来解释.     

氧化钼在CH4/H2气氛中还原碳化机理研究

采用TG-DTA技术研究了MoO3在CH4/H2气氛中的还原碳化行为,考察了程序升温速率和还原碳化终点温度对氧化钼还原碳化行为的影响,并探索适宜的还原碳化条件。结果表明,在1℃/min的程序升温条件下,MoO3在CH4/H2气氛中经三段失重过程被还原碳化为Mo2C,相应的反应历程为MoO3→MoO2→MoOxCy→Mo2C,适宜的还原碳化终点温度为675℃;程序升温速率升至2℃/min以上时,MoO3在CH4/H2气氛中的反应历程为MoO3→MoO2→Mo＋MoOxCy→Mo2C,且随程序升温速率的增大,第二段失重过程中金属Mo的生成量增大,还原碳化反应的始、终点温度升高。提高还原碳化终点温度,MoO3在CH4/H2气氛中的还原碳化反应规律相同,但过高的还原碳化温度会引起有机烃类分解生炭反应的发生,沉积在催化剂的表面,导致制备的碳化钼催化剂表面积炭增多,比表面积降低,从而引起催化活性的下降。     

流动注射分析测定稀土物料中铕

本文研究了铕的流动注射分析方法。铕(Ⅲ)经微型锌还原柱还原为铕(Ⅱ),后者具强还原性,可使亚甲蓝还原褪色,其褪色程度与铕(Ⅱ)的浓度成正比,据此建立了测定稀土物料中铕的分光光度方法。     

Ba、K促进的活性炭负载钌基氨合成催化剂的活化过程

采用TPR-MS技术研究了Ba(NO3)2/AC(AC:活性炭)、KNO3/AC和Ba-Ru-KNO3/AC在H2中的还原情况。实验结果表明,KNO3/AC和Ba(NO3)2/AC分别在400℃和350℃发生还原,生成N2O和N2两种较高价态的还原产物,且助剂的还原不完全。与Ba(NO3)2/AC和KNO3/AC相比,Ba-Ru-KNO3/AC催化剂在加入活性物质钌的情况下,不仅使助剂的还原温度显著降低,而且反应的主要产物也发生了变化,大部分的硝酸根离子被彻底还原成NH3。这可能是由于Ru的存在使氢发生溢流现象,氢活化能力增强,使催化剂表面富含还原所需活化氢物种,导致助剂在较低的温度下被彻底还原。由于Ru的催化作用,载体的甲烷化温度明显降低。提高还原温度虽然对催化剂中氯离子的脱除有利,但同时也会使钌晶粒长大烧结,抑制氨合成的活性。实验结果表明,在制备钌催化剂时,还原除氯的适宜温度为200℃左右。     

测定抗坏血酸的亚甲蓝褪色光度法

确定了亚甲蓝与抗坏血酸褪色反应的最佳条件,在 pH=2的缓冲溶液和对氨基苯磺酸存在的条件下,抗坏血酸能够很快还原亚甲蓝并使之褪色,褪色反应的体系具有很好的稳定性。该反应的摩尔吸光系数为 2.0× 103 L· mol－ 1· cm－ 1,线性范围 0.4～ 40.0 mg/L。该法具有优良的选择性,常见的能够与抗坏血酸共存的阴、阳离子和还原剂、表面活性剂不干扰测定,应用于药品、饮料、蔬菜中抗坏血酸的测定,获得满意结果。     

基于医用纱布负载的二氧化锰纳米颗粒用于亚甲蓝染料的去除

以医用纱布(medical gauze,MG)同时作为模板和还原剂,通过原位氧化还原反应,简便地制备了MG负载的MnO₂纳米颗粒(MnO₂ NPs/MG),并对其形貌、成分进行表征。结果表明,MnO₂ NPs均匀地分散于MG纤维表面。结合MnO₂纳米材料的吸附性能和MG复合材料的操作便捷性,将MnO₂ NPs/MG进一步应用于亚甲蓝染料的去除。结果表明,在中性条件下,通过简单的浸泡搅拌,MnO₂ NPs/MG对亚甲蓝的去除率可达85.09%,并且可以通过增大吸附材料用量与染料初始浓度的比例提高去除率。等温吸附和动力学研究证明,MnO₂ NPs/MG对亚甲蓝的吸附符合Langmuir吸附等温模型和拟二级动力学模型。     

基于医用纱布负载的二氧化锰纳米颗粒用于亚甲蓝染料的去除

以医用纱布（medical gauze,MG）同时作为模板和还原剂,通过原位氧化还原反应,简便地制备了MG负载的MnO₂纳米颗粒（MnO₂ NPs/MG）,并对其形貌、成分进行表征。结果表明,MnO₂ NPs均匀地分散于MG纤维表面。结合MnO₂纳米材料的吸附性能和MG复合材料的操作便捷性,将MnO₂ NPs/MG进一步应用于亚甲蓝染料的去除。结果表明,在中性条件下,通过简单的浸泡搅拌,MnO₂ NPs/MG对亚甲蓝的去除率可达85.09%,并且可以通过增大吸附材料用量与染料初始浓度的比例提高去除率。等温吸附和动力学研究证明,MnO₂ NPs/MG对亚甲蓝的吸附符合Langmuir吸附等温模型和拟二级动力学模型。     

Analytical applications of gold electrodes modified with monolayers of thiolated cyclodextrins

The sequential method for the preparation of cyclodextrin monolayers is used to prepare modified electrodes responsive towards selected guest molecules: ferrocene, ibuprofen, methylene blue, dopamine and menadione. The inclusion into cyclodextrin cavities is monitored using cyclic voltammetry and the mediating role of the immobilized molecules towards solution species is shown on the example of dopamine oxidation.     

Parallel Detection of Different DNA Sequences on One Gold Electrode

Motivated by the potential of electrochemical techniques to analyze hybridization events fast and in a simple and cost‐effective way we present here a detection system allowing a parallel electrochemical DNA analysis. For this purpose different probe DNA strands have been immobilized on one electrode. By the use of two different target DNA sequences, both marked with the redox active methylene blue, we can show that hybridization with the complementary probe sh“NA strands can occur without steric hindrance. Each target has been recognized down to 3nM with a very high specificity of the sensor. In addition, we can detect two different ssDNA targets labeled with different redox active molecules, methylene blue and ferrocene, on one sensor surface simultaneously.     

Organometallic dyes: Part 1. Synthesis of orange to cyan dyes based on donor–conjugated–acceptor chromogenes using ferrocene as the donor group

A novel series of organometallic donor–conjugated–acceptor dyes derived from ferrocene as the donor group have been synthesized via the Knoevenagel reaction of ferrocene carboxaldehyde and various active methylene compounds to give a range of dyes ranging from orange to blue–green in color. The most bathochromic dye is that derived from dialkyl thiobarbituric acid and the least is that derived from the tetralone. The dyes showed an unusual negative solvatochromism as the solvent polarity increased. All dyes synthesized are expected to have some non‐linear optical properties, as evidenced from the pronounced solvatochromism. Copyright © 2001 John Wiley & Sons, Ltd.     

Investigation on the iodination reaction of methylene blue by liquid chromatography-mass spectrometry with ionspray ionisation.

Radioactive iodine (131I and 123I) labelled methylene blue is used for the early diagnosis of melanoma metastases. We studied the iodination reaction of methylene blue (using "cold" iodine) in order to characterise the iodination product(s) as far as number and position of iodine atoms introduced on the aromatic ring(s) is concerned. The reaction was carried out under the same experimental conditions used for the radioactive one, that is in a large excess of methylene blue. The ionspray HPLC-MS analysis of the reaction mixture showed that the iodinated methylene blue was present only in a very small amount and the main iodinated product was a demethylated one, coming out from the iodination of an impurity azure B. We also studied the iodination reaction of azure B in order to better explain the reaction pathway. Commercial azure B contains impurities of methylene blue and all the possible demethylated derivatives. HPLC-MS analysis of the reaction mixture allowed a complete characterisation of the iodinated and bis-iodinated products.     

Ferrocene‐Linkage‐Facilitated Charge Separation in Conjugated Microporous Polymers

Conjugated microporous polymers (CMPs) have full access to the organic synthesis toolbox and feature‐rich functionality, structural diversity, and high surface area. We incorporated ferrocene (Fc) into the backbones of CMPs and systematically engineered their optical energy gaps. Compared with the CMPs without Fc units yet adopting a similar molecular orbital level, Fc‐based CMPs can sufficiently generate reactive oxygen species (ROS) under visible light. The resultant ROS are able to effectively decompose the absorbed pollutants, including organic dyes and chemical warfare agents. Specifically, Fc‐based CMPs significantly outperform commercial TiO₂ (P25) in the degradation of methylene blue and are capable of converting 2‐chloroethyl ethyl sulfide (a mustard gas simulant) into a completely nontoxic product.     

In vitro photodynamic activity of a series of methylene blue analogues

We have synthesized a series of symmetrical phenothiazines in which the methyl groups of methylene blue have been substituted by longer alkyl chains. Intrinsic photosensitizing ability was not altered by increasing the chain length. However, in vitro phototoxicity after 2 h incubation of RIF-1 murine fibrosarcoma cells followed the order n-propyl > n-pentyl > n-butyl > n-hexyl > ethyl > methyl, with ethyl and n-propyl analogues being 14- and 130-fold more phototoxic than methylene blue, respectively. All analogues also had an improved ratio of phototoxicity: dark toxicity (4:1 to 27:1) compared with methylene blue (3:1). Phototoxicity did not correlate with cellular phenothiazine levels, suggesting that the site of subcellular localization may be more important. After 2 h incubation of RIF-1 cells with the phototoxicity LD50 concentration, methylene blue and all analogues were observed to be localized in the lysosomes by fluorescence microscopy. On exposure to light, methylene blue relocalized to the nucleus, the ethyl analogue did not relocalize, whereas the more phototoxic n-propyl - n-hexyl analogues relocalized to the mitochondria. Relocalization to the mitochondria was associated with an octanol: buffer partition coefficient > or = 1. Therefore, the longer-chain analogues of methylene blue show significantly improved phototoxicity in vitro and, in addition, are expected to avoid the problems of mutagenicity associated with the nuclear localization of methylene blue.     

Charge Transport within a Three-Dimensional DNA Nanostructure Framework

Three-dimensional (3D) DNA nanostructures have shown great promise for various applications including molecular sensing and therapeutics. Here we report kinetic studies of DNA-mediated charge transport (CT) within a 3D DNA nanostructure framework. A tetrahedral DNA nanostructure was used to investigate the through-duplex and through-space CT of small redox molecules (methylene blue (MB) and ferrocene (Fc)) that were bound to specific positions above the surface of the gold electrode. CT rate measurements provide unambiguous evidence that the intercalative MB probe undergoes efficient mediated CT over longer distances along the duplex, whereas the nonintercalative Fc probe tunnels electrons through the space. This study sheds new light on DNA-based molecular electronics and on designing high-performance biosensor devices.     

Thermotropic main chain liquid crystalline polyesters containing ferrocene and phosphate units: synthesis and characterization

A new series of liquid crystalline main chain copolyesters were prepared, having ferrocene in the mesogenic segment and a methyl phosphate group along with a methylene spacer. The even numbered methylene groups were varied from two to ten. Liquid crystalline behaviour was investigated on a hot stage optical polarized microscope. Thermal properties of the polymers were analysed by TGA and DSC, revealing that the polymers yield high char products, probably caused by the formation of phosphorus and iron oxides. The glass transition (T_g) temperatures of the polymers were found to be fairly low, the result of the incorporation of bulky phosphorus and ferrocene moieties in the chain. The phase behaviour was analysed and correlated with the structure of the polymers. The liquid crystalline textures of the polymers became more transparent with increasing spacer length. Energy minimized structures for the polymer repeating units reveal that both the ferrocene and phosphorus moieties produce more molecular entanglement, thus reducing the T_g and T_m of the polymers.     

Photo-induced destruction of giant vesicles in methylene blue solutions

We study the photodecomposition of phospholipid bilayers in aqueous solutions of methylene blue. Observation of giant unilamellar vesicles under an optical microscope reveals a consistent pattern of membrane disruption as a function of methylene blue concentration and photon density for different substrates supporting the vesicles.     

Photoinduced Electron Transfer in Dry Gelatin Containing Bound Methylene Blue

Excited states of methylene blue bound to dry gelatin undergo electron-transfer quenching reactions with neighboring amino acid residues to give reduced, methylene blue-free radicals. At the low loadings of methylene blue bound to gelatin used in this work, the absorption spectra indicated that the methylene blue existed principally in its monomeric form. The rates of methylene blue fluorescence quenching depended on the temperature at which the gelatin was dried. There was no detectable fluorescence characteristic of the localized excited singlet state of methylene blue when the dye is bound to gelatin dried at 15°C, where a significant proportion of the protein exists in its a -helical form. Instead, weak emission with a maximum at 645 nm is observed. It is inferred from this that the rate of quenching of any localized excited singlet states of the dye bound to a -helical gelatin is very fast thereby competing efficiently with radiative relaxation. The weak emission at 645 nm is ascribed to a fluorescent exciplex formed between bound methylene blue and a neighboring electron/proton donor residue of the gelatin. While fluorescence characteristic of the localized methylene blue singlet state was observed from dyed gelatin dried at 50°C, i.e. in its random coil form, the triplet state is subject to rapid quenching by electron/proton transfer with protein moieties.