Synthesis,Crystal Structure and Biological Activity of N′-tert-butyl-N-(3-methoxylbenzoyl)-N-(4-methyl-1,2,3-thiadiazole-5-formylhydrazine

Abstract  

The title compound, N′-tert-butyl-N-(3-methoxylbenzoyl)-N-(4-methyl-1,2,3-thiadiazole-5-formylhydrazine (C₁₆H₂₀N₄O₃S) was prepared from the reaction of 4-methyl-1,2,3-thiadiazole-5-carbonyl chloride with N′-tert-Butyl-3-methoxylbenzohydrazine, and its structure was characterized by ¹Hydrogen Nuclear Magnetic Resonance, High-Resolution Mass Spectrometry, IR spectra, and single crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic system, space group P 21/c with cell parameters a = 17.986(2) ?, b = 8.0180(10) ?, c = 12.0190(14) ?, α = 90°, β = 91.160(5)°, γ = 90°, V = 1732.9(4) ?³, Z = 4, D _c  = 1.335 g/cm³, μ (Mo Ka) = 0.209 mm⁻¹, F (000) = 736, R = 0.0367 and wR = 0.0932. X-ray diffraction analysis indicates that all rings in the title compound are non-planar. The bioassay results indicated that, the title compound had good fungicide activity against Sclerotinia sclerotiorum, certain extent of insecticidal activity against Plutella xylostella L.     

Peculiarities of adsorption of organic compounds and water on silicas with bonded polyfluoroalkyl groups

The adsorption isotherms of benzene revealed the low adsorption potential of polyfluoroalkyl silicas compared with both initial silica and hexadecyl silica. Hydrophobicity of all modified silicas, measured by water adsorption, was rather close at p/p(s)=1 and was significantly different in the initial p/p(s) region: polyfluoroalkyl silicas did not nearly adsorb water but alkyl silica did it gradually. Thermodynamic parameters of adsorption of organic compounds of different nature were studied at a zero surface coverage by gas chromatography (GC). The high enough contributions of specific interactions as well as polar molecular group increments to the Gibbs adsorption energy were found to be characteristic of polyfluoroalkyl silica. The selectivity of polyfluoroalkyl silicas and the commonly used fluorinecontaining liquid stationary phase for GC (OV-210) toward homologous ethers, esters, and alcohols was comparable in most cases. GC data, IR spectra, and adsorption measurements were in good agreement with each other. It was shown that residual SiOH-groups of silica do not nearly take part in the adsorption process because they are effectively screened by the attached organic groups.     

Aqueous electrochemistry of binuclear copper complex with Robson-type ligand: dissolved versus surface-immobilized reactant

The electrochemical behaviour of binuclear copper complex with Robson-type ligand [Cu₂L]Cl₂ in aqueous medium is studied by cyclic voltammetry at highly oriented pyrolytic graphite, glassy carbon and gold electrodes. The overall reduction from solution of this reactant is found to be irreversible resulting in metallic copper formation. It is also complicated by chemical transformations of Cu(I) containing species. When attached to carbon support, [Cu₂L]Cl₂ is redox active in aqueous medium in the same potential range. The reduction is more reversible if reactant is immobilized at HOPG surface, and is in general agreement with reversible copper demetallation scheme. For dissolved reactant, the contribution of surface-attached species is screened by predominating voltammetric response of irreversible reduction. These conclusions are supported by data on the reduction of free protonated ligand and its hydrolysis products. Ex situ STM is applied to characterize electrode surfaces modified by [Cu₂L]Cl₂. Adsorbate monolayer of periodic structure is observed at highly oriented pyrolytic graphite (HOPG). Adsorption is more disordered at GC and less strong at polycrystalline gold support.     

Characteristic features of polytypism in compounds with the La18W10O57‐type structure

Crystals with the La₁₈W₁₀O₅₇‐type structure (6H and 5H polytypes) were obtained by a self‐flux method from high‐temperature solutions. Some of the crystal samples were studied by single‐crystal X‐ray structure analysis. The diffraction patterns indicated that two phases co‐exist in each sample. The hexagonal lattices have a common period of a ≈ 9.0 Å and are non‐equal in length but have equally oriented superstructure periods 6c (phase I) and 5c (phase II), c ≈ 5.4 Å. The structures of phases I and II were solved in the symmetry groups P2c and P321, respectively, based on the X‐ray data for crystals I and II, with predominant content of the first and second phase. The motif of isolated WO₆ prisms with W atoms on the cell edges is common to both phases. WO₆ octahedra, both isolated and joined by faces, are distributed along the c axis within the unit cells. Phase I contains extra layers of isolated WO₆ octahedra compared to phase II. Tungsten sites in joined octahedra are disordered and partially occupied. Disordering is more expressed in phase II, which in return contains rather more W and O per atom of La. The refined chemical compositions are La₁₈W₁₀O₅₇ for I and La₁₅W_8.5O₄₈ for II.     

Profile of the ν1 Raman Band of Pure CD4 and Its Mixtures with Ar and Kr in the Gas Phase

The ν₁ band profile of isotropic Raman spectrum of pure CD₄ and its mixtures with Ar and Kr is recorded in the temperature range 140–360 K at pressure of pure CD₄ ranging from 4 to 20 atm and at total pressure of gas mixtures in the interval 4–160 atm. The dependences of the band shape on temperature and density are analyzed. The coefficients of the CD₄ band broadening by Ar and Kr are determined, and the decisive role of vibrational contributions, in particular of the intramolecular energy transfer, is pointed out.     

Asymmetric Hubbard model in the generating functional method: Spectral functions in the Falicov-Kimball limit

In the framework of the dynamical mean field theory, we investigate the densities of states of the fermionic and bosonic branches of the spectrum of the asymmetric Hubbard model, which is used to describe a strongly correlated two-sort (A, B) system of fermions (electrons). To solve the effective one-site problem, we develop an approximate analytic approach based on the Kadanoff-Baym generating functional method. This technique allows constructing the irreducible part (the mass operator) of the particle Green’s function in the form of a formal expansion in powers of the coherent potential. In the first order, the scheme reproduces the so-called generalized approximation Hubbard-III. To improve it, we develop a self-consistent method for calculating both the fermionic and bosonic Green’s functions. As U → ∞ in the Falicov-Kimball limit for the asymmetric Hubbard model, when the particles of sort B become localized, we find the spectral densities ρ_B and ρ_AB of states of both branches and consider the changes of their forms depending on temperature and particle concentrations. Comparing with the exact thermodynamic dependences μ_B(n_B), we establish the applicability limits of the self-consistent generalized approximation Hubbard-III. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 154, No. 1, pp. 164–182, January, 2008.