1-amino-2-thiobenzimidazoleimines as novel ambidentate ligand systems

Azomethine derivatives of 1-amino-2-thiobenzimidazole (H₂L) were synthesized and studied by IR and ¹H NMR spectroscopy. Thiobenzimidazoline tautomeric form of these compounds was found to predominate in a solid state and DMSO solution. Novel mono-and binuclear metal chelates M(HL)₂ and M₂L₂ (M = Ni(II), Cu(II), Co(II), Zn(II), Cd(II)) were synthesized on the basis of H₂L derivatives and their composition and structures were established from IR, ¹H NMR, EXAFS, and magnetochemical data. The composition of coordination sphere was shown to produce no effect on ferromagnetic exchange in binuclear Cu(II) complexes.     

An improved method for constructing a full-length enriched cDNA library using small amounts of total RNA as a starting material

We have developed an improved method for constructing a full-length cDNA library using small quantity of material by modifying the original oligo-capping method. In our devised method, total RNAs are used in sequential oligo-capping steps directly without preliminary mRNA purification. Using this method, we constructed full- length cDNA libraries from 100 mg of total RNA. These libraries contained 8x10(5) to 8x10(6) independent clones with average insert sizes of 2.0 kb. Moreover, the number of full-length cDNAs containing the translation initiation codon ATG in the constructed libraries was estimated to 60-70%. In addition, 54% of the known cDNAs had a longer 5' end than the corresponding genes in the public database. Our results show that the method can be effectively used to construct full-length enriched cDNA libraries, especially, if starting material is limited.     

Tetrakis(thiadiazolo)porphyrazines. 3. Acid-base Properties and Stability of Tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine in Sulfuric Acid Solutions

AM1 calculations gave the proton affinities of different types of donor sites in tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine, H₂{[SN₂)₄PA}, and protonation of the meso-nitrogen atoms was found to be favored. A spectrometric study showed that the basicity of the meso-nitrogen atoms of the porphyrazine macrocycle is strongly diminished and these atoms in CF₃CO₂H are involved in an incomplete acid-base interaction (ABI) to give acid solvates, while a complete ABI (protonation) is found only in the presence of sulfuric acid. The basicity constants of the meso-nitrogen atoms were determined spectrophotometrically in CF₃CO₂H-H₂SO₄. The kinetics of decomposition of the macrocyclic chromophore in concentrated sulfuric acid was studied and a possible mechanism for this process was proposed.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 278–287, February, 2005.     

Nucleophilic substitution in 4-bromo-5-nitrophthalodinitrile: VIII. Synthesis of 4-(benzotriazol-1-yl)-5-[4-(1-methyl-1-phenylethyl)phenoxy]phthalodinitrile and phthalocyanines on its basis

Nucleophilic aromatic substitution of the bromine atom in 4-bromo-5-nitrophthalodinitrile by a 2-aminophenylamine residue followed by conversion of the resulting compound to 4-(1-benzothiazol-1-yl)-5-nitrophthalodinitrile and nucleophilic substitution of the nitro group by a 4-(1-methyl-1-phenylethyl)-phenoxy group gave 4-(benzotriazol-1-yl)-5-[4-(1-methyl-1-phenylethyl)phenoxy]phthalodinitrile. The latter product was reacted with certain metal acetates and chlorides to obtain the corresponding metal complexes of octasubstituted phthalocyanines. Spectral properties of the complexes were studied.     

New materials for sorption of hydrogen

The influence of temperature, duration of thermal treatment, and oxidation modes of the aluminum base on processes in which intermetallic compounds LiLaAl are formed by the method of electrochemical cathodic intercalation was studied. The optimal modes of formation of LiLaAl_ox compounds exhibiting high sorption capacity for hydrogen were determined.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1516–1519.Original Russian Text Copyright © 2004 by Olshanskaya, Sobgaida, Popova.     

Synthesis and properties of tadpole-shaped gold nanoparticles

In this communication, gold nanoparticles with a tadpole shape were synthesized by a simple aqueous-phase chemical method. The unusual three-dimensional and crystallized structures were demonstrated by TEM, AFM, and HRTEM methods. The SEM and UV-visible absorption measurements and electrophoresis experiments revealed that the tadpoles had novel optical and electrical properties. These attractive structures and properties are expected to find uses in many fields such as electrics, optics, electrochemistry, and biological sensing.     

Unusual reaction of α-diketones of the indole series with hydrazine

Symmetrical and unsymmetrical α-diketones of the indole series were synthesized by the Friedel-Crafts reaction of 3-indolylglyoxyl chlorides with heterocycles. A nonconventional reaction of N-unsubstituted diketones with hydrazine producing 3H-pyrazolo[3,4-c]quinoline derivatives was found. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 862–866, May, 2006.     

相转移催化法合成糖苷化合物

糖苷化合物广泛存在于生物体内，中草药和天然药物中的许多抗病活性化合物也是糖苷化合物。根据糖苷化合物分子结构中的配糖体与糖环碳原子相连的原子类型可把糖苷化合物分为氧苷、氮苷、硫苷和碳苷等。未作特殊说明的糖苷化合物均指氧苷，且配糖体为羧酸的糖苷化合物亦称为糖酯。有关糖苷（酯）化合物和其合成方法的研究很多，其中应用相转移催化法较为常见。我们曾用相转移催化法合成过许多糖酯化合物并对其生理活性进行研究报道。本文在原合成糖酯的基础上通过相转移催化法，选用不同于文献报道催化剂及溶剂体系，     

Effect of substituents (NH2, OH, F) on structures and stability of lithofluorosilylenoids

Isomeric structures and energies of three kinds of lithofluorosilylenoids, R₂SiLiF (R = NH₂, OH, F) were studied using theab initio molecular orbital theory. The calculations show that thermal stability of the three-membered ring structures of these three kinds of silylenoids decreases in the order of substituents NH₂ > OH > F because of the conjugation between NH₂, OH or F and Si atom. The interaction of substituents R with Li atom makes R₂SiLiF have a structure with two Li-A-Si-F (A = N, O, F) four-membered rings, which is the most stable of the isomers of each of three kinds of silylenoids and whose stability decreases in the order of substituents F > OH > NH₂. Inductive effect of substituents influences the thermal stability of the linear structure of silylenoids.