Bimodal association of a bis-1,2,3-dithiazolyl radical

The N-ethyl pyrazine-bridged bis-1,2,3-dithiazolyl radical (R(1) = Et) associates at room temperature as a C-C bonded sigma-dimer which, on heating, converts to a laterally S-S sigma-bonded structure.     

A pi-stacked 1,2,3-dithiazolyl radical. Preparation and solid state characterization of (Cl2C3NS)(ClC2NS2)

Crystals of (Cl2C3NS)(ClC2NS2), an isothiazolyl-substituted 1,2,3-dithiazolyl radical, consist of evenly spaced, slipped pi-stacks; magnetic and conductivity measurements indicate the material is a Mott insulator with sigma RT = 2 x 10(-7) S cm-1.     

Sulfur- and selenium-containing merocyanine dyes

The corresponding merocyanine dyes were obtained by reaction of aminomethylene derivatives of 5-pyrazolone and 5-thio- and 5-selenopyrazolones with tetramethylindoleninium and phenanthridinium salts. Their UV spectra and the possibility of the formation of spiropyrans from them were studied.     

Photoelectron spectra of 1,2,3-triazine and its methyl derivatives

The He(1α) photoeletron (PE) spectra of 1,2,3-triazabenzene and its five mono-, di-, and tri-methyl derivatives are repored. The PE bands are assigned by comparison with the results of molecular orbital (MO) calculations and empirical correlation procedures.     

Selenoimidoylation of alcohols with selenium and isocyanides and its application to the synthesis of selenium-containing heterocycles

The reaction of alcohols with selenium and isocyanides in the presence of DBU gave oxyimidoylselenoates 6. Trapping of 6 with BuI resulted in high-yield formation of selenocarbonimidates 4. When alk-2-yn-1-ols 9 were allowed to react with selenium and isocyanides under similar conditions, new selenium-containing heterocycles 10, 2-imino-4-alkylidene-1,3-oxaselenolanes, were obtained via cycloaddition of oxyimidoylselenoates 13 generated in situ by intramolecular addition of selenolates to carbon-carbon triple bonds.     

New 1,2,3-selenadiazole and 1,2,3-thiadiazole derivatives

New 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives, 14-23, were prepared from the ketones 1-5 via the corresponding semicarbazones or hydrazones 6-12. The Hurd-Mori and Lalezari methods were used, respectively, for the preparation of these 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives. The intermediate 13 was also trapped, separated and fully characterized. These derivatives are important for photocrosslinking processes and due to their potential biological activity.     

1,4-二氰基萘一维亚微米结构材料的制备及光学性能

用再沉淀法制备了1,4-二氰基萘（DCN）一维亚微米结构。通过改变制备条件分别得到了DCN的线状及管状一维结构。所制备的有机亚微米材料具有良好的结晶性,不同结构的生长取向存在一定的差别。由于DCN分子的有序堆积,亚微米结构的的发光比溶液的发光有一定的红移。通过对单根材料的表征发现,DCN亚微米结构具有良好的光波导性能。空心结构的光波导性能要明显优于实心结构,主要原因在于空气介质减小了光学损耗。     

Preparations and reactions of 1,2,3-trialkyl-1,2-dihydroquinolines and its related compounds

Several 1,2,3-trialkyl-1,2-dihydroquinolines (4 and 5) were prepared from the reactions of N-alkylanilinomagnesium bromide (1 and 2) with aliphatic aldehydes (3). Solutions of these dihydroquinolines in carbon tetrachloride or chloroform gave the corresponding 1,2,3- trialkylquinolinium chlorides (10 and 11) in high yields. Alkali treatment of 1,3-dimethyl-2- ethylquinolinium chloride (10b) led to 1,3 - dimethyl - 2 - acetyl - 1,2 - dihydroquinoline (13), which was unstable and readily converted to 1,3-dimethyl-2-quinolone (6) in the air.     

Separation and detection of selenium-containing proteins in human serum

Selenium-containing proteins or their subunits in human serum were separated and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the amount of selenium in each protein band was determined by HPLC with a fluorescence detector after derivatization with 2,4-diaminonaphthalene (DAN). This procedure provides a detection limit of 0.06 ng in a linear range of 0–1.5 ng. A protein is defined as a selenium-containing protein if its mean Se content exceeds twice the detection limit (0.12 ng) and twice the standard deviation of three replicates in sample determination. At least 4 selenium-containing bands with apparent molecular masses of 57–74, 46–56, 40–42 and 21–22 kDa could be detected from human serum collected from 4 volunteers.     

Biological activity of some sulfur- and selenium-containing spiro compounds

Russian Chemical Bulletin - Cytotoxicity to K-562 leukemia cell line of two spiro compounds containing selenium or sulfur atom in their structure were compared....     

Tetrazoles with oxygen-, sulfur-, and selenium-containing substituents

The data on the synthesis, properties, reactions, and practical application of tetrazoles with oxygen-, sulfur-, and selenium-containing substituents are systematized. Comparative analysis of structure and reactivity was carried out for the compounds under consideration.     

Separation and detection of selenium-containing proteins in human serum

Selenium-containing proteins or their subunits in human serum were separated and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the amount of selenium in each protein band was determined by HPLC with a fluorescence detector after derivatization with 2,4-diaminonaphthalene (DAN). This procedure provides a detection limit of 0.06 ng in a linear range of 0-1.5 ng. A protein is defined as a selenium-containing protein if its mean Se content exceeds twice the detection limit (0.12 ng) and twice the standard deviation of three replicates in sample determination. At least 4 selenium-containing bands with apparent molecular masses of 57-74, 46-56, 40-42 and 21-22 kDa could be detected from human serum collected from 4 volunteers.     

Generation and stabilization of free selenium-containing radicals by complex formation

The reactions of complex formation of some p-XC₆H₄SeSeC₆H₄p-X-MX₃-benzene (or cyclohexane) systems, where X = H, CH₃, F, Cl, Br and MX₃ = GaCl₃ AlBr₃, have been studied by calorimetry, cryoscopy, dielectric measurements, GLC, and ESR spectroscopy. Diaryldiselenides react with gallium trichloride in solution forming 1:1 complexes. The enthalpies of formation and the dipole moments of the complexes have been determined. Formation of diaryldiselenides complexes with aluminium bromide, which is a stronger acceptor, involves cleavage of the SeSe and CSe bonds in the diselenide molecule and yields stable selenium-centred radical complexes of the type ArSeSe^? · AlBr₃ (g-value 2.073) and ArSe^? · AlBr₃ (g value 2.033). In addition, the ESR spectrum reveals a singlet (g value 2.0025) assigned to a hydrocarbon radical. Corresponding di- and mono-selenides as well as biphenyls have been identified by GLC in the products of interaction of free radicals displaced from the mixture of radical complexes by an electron donor (diethyl ether, water) stronger than the radical.     

Naphthalene- and perylenediimides with hydroquinones, catechols, boronic esters and imines in the core

The green-fluorescent protein of the jellyfish operates with the most powerful phenolate donors in the push-pull fluorophore. To nevertheless achieve red fluorescence with the same architecture, sea anemone and corals apply oxidative imination, a process that accounts for the chemistry of vision as well. The objective of this study was to apply these lessons from nature to one of the most compact family of panchromatic fluorophores, i.e. core-substituted naphthalenediimides (cNDIs). We report straightforward synthetic access to hydroxylated cNDI and cPDI cores by palladium-catalyzed cleavage of allyloxy substituents. With hydroxylated cNDIs but not cPDIs in water-containing media, excited-state intramolecular proton transfer yields a second bathochromic emission. Deprotonation of hydroquinone, catechol and boronic ester cores provides access to an impressive panchromism up to the NIR frontier at 640 nm. With cNDIs, oxidative imination gives red shifts up to 638 nm, whereas the expanded cPDIs already absorb at 754 nm upon deprotonation of hydroquinone cores. The practical usefulness of hydroquinone cNDIs is exemplified by ratiometric sensing of the purity of DMF with the "naked eye" at a sensitivity far beyond the "naked nose". We conclude that the panchromatic hypersensitivity toward the environment of the new cNDIs is ideal for pattern generation in differential sensing arrays.     

Synthesis and in vitro antifungal activity of selenium-containing chitin derivatives

Mild and ‘green’ ultrasound-assisted reaction of chitin with 3-(chloromethyl)[1,2,4]selenadiazolo[4,5-a]pyridin-4-ium bromide in water affords novel selenium-containing cationic chitin derivatives. The thus obtained chitin derivatives are water soluble and are characterized by high in vitro antifungal activity comparable with conventional antifungal drug Amphotericin B.     

Structure, bonding, and aggregation of selenium-containing organolithium species

1,3-Dioxo compounds can be prepared from selenium-mediated carbonylation of lithium enolates in the presence of carbon monoxide. Intermediates in this reaction include several organic species that contain both selenium and lithium. The first step in understanding the detailed reaction mechanism is to understand the structure of these intermediates. Like most organolithium compounds, these species can exist as aggregates in solution. The B3LYP density functional theory (DFT) method was used to examine the gas phase and THF solvated structures of these compounds. The calculations showed that each of the compounds forms dimers or higher aggregates in the gas phase. Aggregates are also formed in THF solution, although solvation favors lower aggregates as compared to the gas phase.     

Synthesis of novel 1,2,3-thiadizoles and 1,2,3-selenadiazoles as new antimicrobial agents

Abstract

A series of novel 1,2,3-thiadiazoles and 1,2,3-selenadiazoles having a long alkyl chain were synthesized by reacting semicarbazones with SOCl₂ and SeO₂, respectively. The structures of the target compounds 5–12 were confirmed by spectroscopy (IR, ¹H NMR, ¹³C NMR, and MS) and elemental analysis. Their antibacterial and antifungal activities were evaluated against six bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus) and three fungi (Candida albicans, Candida parapsilosis, Candida tropicalis). The results of bioassays indicated that the compounds 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]selenadiazole (7), 4-Methyl-5-tetradecyl-[1-3]selenadiazole (8) and 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]thiadiazole (11) displayed moderate antibacterial activity against S. Epidermidis. On the other hand, according to antifungal screening results, compounds 5-Dodecyl-4-phenyl-[1-3]selenadiazole (5), 4-p-Tolyl-5-undecyl-[1-3]selenadiazole (6), and 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]selenadiazole (7) exhibited significant antifungal activities studied yeast strains.     

Self-organization and morphological characteristics of selenium-containing nanostructures based on rigid-chain polymers

Macroinitiators containing β-diketonate fragments were prepared by copolymerization of styrene with cobalt(II) 5-Formation and morphological characteristics of selenium-containing nanostructures formed by reduction of selenious acid with ascorbic acid in the presence of ionic or nonionic polymeric stabilizer in aqueous solutions were studied by methods of nonlinear optics and flow birefringence at widely varied selenium to polymer weight ratio in solution ν. The molecular weights, root-mean-square and hydrodynamic sizes, and mean density of the nanostructures were calculated, and the trends in variation of these quantities were compared.