含二茂铁基偶氮染料的光稳定性研究

利用UV-Vis吸收光谱仪和光化学反应器研究了含二茂铁基偶氮染料及相应的偶氮染料溶液的光降解动力学.在溶液中,它们的光降解反应遵循零级动力学模型.与相应的偶氮染料相比,含二茂铁基的偶氮染料溶液具有较好的光稳定性.这表明,在其分子内存在着有效的从偶氮染料母体到二茂铁基团的分子内三重态-三重态能量传递,上述过程降低了偶氮染料激发三重态的生成,避免了染料的过早降解,提高了其稳定性.     

Optical Recording Performance of Azo Nickel Chelate Thin Film

The absorption,transmission and reflection spectra of spin-coated films of Ni(azo)2 (azo nickel chelate) were measured. Because of the intermolecular aggregation,the absorption peak of Ni(azo)2 thin film has a red-shift of about 40 nm with respect to that of it in methanol solution. The fabricated optical disk showed a reflectivity of 48% and its carrier-noise ratio (CNR) was greater than 45 dB when recording with 7.5 mW laser power at the wavelength of 780 nm.     

The synthesis of azo compounds from nitro compounds using lead and triethylammonium formate

Aromatic nitro compounds were reduced to the corresponding symmetrically substituted azo compounds using lead as catalyst and triethylammonium formate as hydrogen donor. Various azo compounds containing additional reducible substituents including halogens, nitrile, acid, phenol, ester, methoxy functions, etc, have been synthesized in a single step by the use of this reagent. The conversion is reasonably fast, clean, high yielding and occurs at room temperature in methanol.     

高效液相色谱-串联质谱法测定纺织品中的致癌芳香胺

建立了高效液相色谱-串联质谱法(LC/MS/MS)测定纺织品中致癌芳香胺的检测方法.纺织品中的偶氮染料在柠檬酸缓冲液中用连二亚硫酸钠还原为芳香胺,用硅藻土提取还原液中的芳香胺,用乙醚洗脱,浓缩至近干后用甲醇定容.使用液相色谱-串联质谱进行测定,色谱柱为XTerra MS C18柱,流动相为甲醇和0.025 mol/L乙...     

Novel Wormlike Nanostructures Self‐Assembled in a Well Defined Liquid Crystalline Diblock Copolymer with Azobenzene Moieties

Novel wormlike nanostructures were self‐assembled in bulk films of a well defined diblock copolymer with azobenzene moieties, which was prepared by atom transfer radical polymerization (ATRP). For comparison, a homopolymer with almost the same repeat units of azobenzene as those in the copolymer was also prepared. They both had well defined structures and exhibited a smectic liquid crystalline phase. Upon annealing the copolymer films, poly(methyl methacrylate) formed a matrix with excellent optical properties, and the azobenzene segment in the minority phase self‐assembled into a wormlike mesogenic domain in the bulk films. Such block copolymer films exhibited stability and transparency by eliminating the scattering of visible light, indicating their potential application as photoresponsive functional materials. Although wormlike morphologies have been obtained in micelles from block copolymer solutions, to the best of our knowledge, such wormlike nanostructures have never been explored in bulk films.

     

Preparation,characterization, biological activity,density functional theory calculations and molecular docking of chelates of diazo ligand derived from m‐phenylenediamine and p‐chlorophenol

A novel azo dye ligand, 2,2′‐(1,3‐phenylenebis(diazene‐2,1‐diyl))bis(4‐chlorophenol), was synthesized from the diazotization of m ‐phenelyenediamine and coupling with p ‐chlorophenol in alkaline medium. Mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of the azo ligand (H₂L) were prepared and characterized using elemental analyses, infrared spectroscopy, electron spin resonance, magnetic susceptibility, conductance measurements and thermal analyses. The UV–visible, ¹H NMR and mass spectra of the ligand and its chelates were also recorded. The analytical data showed that the metal‐to‐ligand ratio in the mononuclear azo complexes was 1:1. Diffuse reflectance and magnetic moment measurements revealed the complexes to have octahedral geometry. The infrared spectral data showed that the chelation behaviour of the ligand towards transition metal ions was through phenolic oxygen and azo nitrogen atoms. The electronic spectral results indicated the existence of π → π* (phenyl rings) and n → π* (─N═N) and confirmed the mentioned structure. Molar conductivity revealed the non‐electrolytic nature of all chelates. The presence of water molecules in all complexes was supported by thermal studies. Molecular docking was used to predict the binding between H₂L and the receptors of breast cancer mutant 3hb5‐oxidoreductase, crystal structure of Escherichia coli (3 t88) and crystal structure of Staphylococcus aureus (3q8u). The molecular and electronic structure of H₂L was optimized theoretically and the quantum chemical parameters were calculated. In addition, the effects of the H₂L azo ligand and its complexes on the inhibition of bacterial or fungal growth were evaluated. The prepared complexes had enhanced activity against bacterial or fungal growth compared to the H₂L azo ligand.     

NIR light and enzyme dual stimuli‐responsive amphiphilic diblock copolymer assemblies

Using atom transfer radical polymerization (ATRP) and macromolecular azo coupling reaction, both o‐nitrobenzyl (ONB) group and azobenzene group were efficiently incorporated into the center of the amphiphilic diblock copolymer chain. The prepared diblock copolymer was well characterized by UV–vis, ¹H NMR, and GPC methods. Self‐assembly of the amphiphilic copolymer in selected solvents can result in uniform self‐assembly aggregates. In the presence of external stimuli [upconversion nanoparticles (UCNPs)/NIR light or enzyme], the amphiphilic diblock copolymer chain could be broken by the cleavage of ONB or azobenzene group, which would lead to the disruption of the self‐assembly aggregates. This photo‐ and enzyme‐triggered disruption process was proved by using transmission electron microscopy (TEM) and GPC method. Fluorescence emission spectra measurements indicated that the release of Nile red, a hydrophobic dye, encapsulated by the self‐assembly aggregates, could be successfully realized under the NIR light and enzyme stimuli. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2450–2457     

New azo derivatives of gossypol

New azo derivatives of gossypol are described. Their physicochemical properties are reported. The presence of hydroxyazo- and quinonhydrazo-tautomers is proposed.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (99871) 162 70 71. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 145–148, March–April, 2000.