NO Release from trans-[Ru(NH3)4L(NO)]3+ Complexes Upon Reduction (L = 1-Methylimidazole or Benzoimidazole)

The synthesis, characterization and reactivity of trans-[Ru(NH₃)₄(L)NO](PF₆)₃(L = benzoimidazole or 1-methylimidazole in trans position to NO) are presented. ¹H-n.m.r. spectroscopy data indicate that the benzoimidazole and 1-methylimidazole ligands are coordinated to Ru^II through carbon and nitrogen, respectively. The nitrosyl stretching frequencies [(NO) > 1900 cm^–1] suggest that the coordinated nitrosyl has substantial NO⁺ character. The complexes undergo a single-electron reduction (E ⁰–0.245 versus NHE), which involves the coordinated nitrosyl. Dissociation of NO in the reduced species is facilitated by the 1-methylimidazole ligand, which is not observed for the benzoimidazole species. The complex with 1-methylimidazole does not suffer hydroxide attack on the NO⁺, at least at pH values lower than 11.     

Elucidating interactions of ionic liquids with polymer films using confocal Raman spectroscopy

We report on the molecular interactions between room-temperature ionic liquids (RTILs) and Nafion and PDMS membranes, proving that in contact with these polymers RTILs behave like electrolytes rather than solvents.     

Surmounting tumor resistance to metallodrugs by co-loading a metal complex and siRNA in nanoparticles

Copper complexes are promising anticancer agents widely studied to overcome tumor resistance to metal-based anticancer drugs. Nevertheless, copper complexes per se encounter drug resistance from time to time. Adenosine-5′-triphosphate (ATP)-responsive nanoparticles containing a copper complex CTND and B-cell lymphoma 2 (Bcl-2) small interfering RNA (siRNA) were constructed to cope with the resistance of cancer cells to the complex. CTND and siRNA can be released from the nanoparticles in cancer cells upon reacting with intracellular ATP. The resistance of B16F10 melanoma cells to CTND was terminated by silencing the cellular Bcl-2 gene via RNA interference, and the therapeutic efficacy was significantly enhanced. The nanoparticles triggered a cellular autophagy that amplified the apoptotic signals, thus revealing a novel mechanism for antagonizing the resistance of copper complexes. In view of the extensive association of Bcl-2 protein with cancer resistance to chemotherapeutics, this strategy may be universally applicable for overcoming the ubiquitous drug resistance to metallodrugs.

Bcl-2-related tumor resistance to anticancer drugs can be overcome by silencing the cellular Bcl-2 gene via RNA interference. The realization of the goal is exemplified by delivering Bcl-2 siRNA and a tumor-resistant Cu complex to cancer cells with an ATP-responsive nanocarrier.     

A sensitive spectrophotometric method for lead determination by flow injection analysis with on-line preconcentration

A new flow injection (FI) system for the determination of Pb(II) at trace level with a preconcentration step and spectrophotometric detection is proposed. It is based on preconcentration of lead ions on chitosan and dithizone-lead complex formation in aqueous medium (pH 9). The chemicals and FIA variables influencing the performance of the system were optimized and applied to the determination of lead in natural, well, and drinking water samples. It is a simple, highly sensitive, and low cost alternative methodology. The method provided a linear rage between 25 and 250 μg l⁻¹, a detection limit of 5.0 ng ml⁻¹ and a sample throughput of 15 h⁻¹. The obtained results of spiked samples are in good agreement between the proposed method and ICP-AES.     

蒙脱土表面键合配位体固相萃取填料的制备及其对重金属离子的吸附性能

通过酸洗、硅烷偶联剂表面活化、键合苯甲酰异硫氰酸酯对蒙脱土进行改性,制得新型固相萃取(SPE)材料。 采用红外光谱、扫描电子显微镜、X射线光电子能谱表征了改性蒙脱土的结构和形貌。 考察了制备的SPE填料对水中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺的吸附性能,确定了最佳固相萃取条件,对6种金属离子吸附容量分别为10.83、11.92、12.67、10.43、10.01及10.54 mg/g。 通过SPE与电感耦合等离子体质谱联用测定了样品中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺ 6种重金属离子的含量,检出限分别为0.024、0.013、0.075、0.037、0.011和0.064 μg/L。     

Nature of plant stimulators in the production ofAcetobacter xylinum (“tea fungus”) biofilm used in skin therapy

Caffeine and related xanthines were identified as potent stimulators for the bacterial cellulose production in A. xylinum. These compounds are present in several plants whose infusions are useful as culture-medium supplements for this acetobacterium.

The proposed target for these native purine-like inhibitory substances is the novel diguanyl nucleotide phosphodiesterase(s) that participate(s) in the bacterial cellulogenic complex.

A better understanding of this feature of A. xylinum physiology may facilitate the preparation of bacterial cellulose pellicles, which are applied as a biotechnological tool in the treatment of skin burns and other dermal injuries.

     

Speciation of sulfur-containing compounds in diesel by comprehensive two-dimensional gas chromatography

Sulfur-containing compounds in diesel have been speciated by comprehensive two-dimensional gas chromatography (GCxGC) with a sulfur chemiluminescence detector (SCD). The advantages of GCxGC technique are higher resolution and greater sensitivity. GCxGC-SCD can achieve the class separation of sulfur-containing compounds with an appropriate separation column combination. The major classes of sulfur-containing compounds in diesel are benzothiophenes and dibenzothiophenes. Relative concentration of each class as well as each carbon number family can be quantitated by the summation of the integrated areas corresponding to the individual group(s) in the GCxGC space. In practical applications, GCxGC-SCD can be used to characterize different diesels and to reflect desulfurization process efficiency. In this study, GCxGC-SCD has demonstrated its value in speciation of sulfur-containing compounds classes, which is difficult to accomplish by any other single technique.     

3—Mercaptopropionic Acid Capped Gold Nanoclusters：Quantized Capacitance in Aquesous Media

3-Mercaptopropionic acid monolayer protected gold nanoclusters (MPA-MPCs) were synthesized and characterized by transmission electorn microscopy,UV-Vis spectroscopy,X-ray photoelectron spectroscopy and Fourler transform infrared spectroscopy.The exact value of quantized double-layer capacitance of MPCs in aqueous media was obtained by differential pulse voltammograms.     

Preparation and Characterization of Three-dimensionally Ordered Crystalline Macroporous CeO2

Three-dimensional ordered macroporous (3DOM) materials are of great potential importance in catalysis, selective separation, sensor arrays and communications with optical band gaps1. Many results in the synthesis of 3DOM materials have been reported, such as closed-packed silica spheres or polystyrenes (PS) templating routes for silica2, metal oxides1-6 and metals7. Recently, poly(methyl methacrylate) (PMMA) colloidal crystal templates have been used to prepare 3DOM materials of metals8,…