Anagostic Interactions under Pressure: Attractive or Repulsive?

Square‐planar d⁸‐ML₄ complexes might display subtle but noticeable local Lewis acidic sites in axial direction in the valence shell of the metal atom. These sites of local charge depletion provide the electronic prerequisites to establish weakly attractive 3c–2e M⋅⋅⋅H C agostic interactions, in contrast to earlier assumptions. Furthermore, we show that the use of the sign of the ¹H NMR shifts as major criterion to classify M⋅⋅⋅H C interactions as attractive (agostic) or repulsive (anagostic) can be dubious. We therefore suggest a new characterization method to probe the response of these M⋅⋅⋅H C interactions under pressure by combined high pressure IR and diffraction studies.     

Ion-Solvent Interaction of Biunivalent Electrolytes in Dioxane-Water Mixtures from Conductivity Data at Different Temperatures

This paper presents the conductivity measurements for some alkaline earth metal salts MgCl₂, MgBr₂, Mg(NO₃)₂, CaCl₂, CaBr₂ and Ca(NO₃)₂ by which the ion-solvent interactions are reported in the concentration range in dioxane-water mixtures at mass fraction of 0, 3, 10, 20 and 30% at 30°, 35°, 40° and 45°C ± 0.01. The conductance data were analyzed for the limiting molar conductivity, A_o, by the Fuoss-Edelson conductivity equation for the 2:1 unsymmetrical electrolytes. The results were discussed in terms of the solute-solvent interaction from the temperature coefficient of Walden product, Λ_oη of the electrolyte solutions. Moreover, Λ_oη was found to exhibit a linear relationship with the dielectric constant, ?, of the dioxane-water mixtures. The study gives information regarding the ion-solvent interactions from the mobilities and Walden product of the ions in the solvent. The ions appear to interact appreciably and the ion-solvent interaction tends to increase in the order Ca > Mg for the same anion while for the anions, the trend decreases in the order Cl^? < Br^? < No^?₃.     

Structural studies of 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone complexes

Summary Complexes of Cu^II, Ni^II, Co^II, Zn^II, Cd^II and Hg^II with 4-benzamido-1-o-aminoacetophenone-3-thiosemicarbazone (H₂BATS) are reported and have been characterized by elemental analyses, molar conductivities, magnetic moments, spectral (visible, i.r.) and thermal (d.t.a., t.g., d.t.g.) measurements. I.r. spectra show that H₂BATS behaves as a dianionic, monoanionic or neutral tetradentate ligand or as a monoanionic tridentate ligand. [Cu₂(H₂BATS)Cl₂]·2H₂O and [Cu₂(H₂BATS)Ac₂]·2H₂O complexes are diamagnetic while [Co(HBATS)OH]·2H₂O and [Ni(HBATS)OH]·2H₂O are octahedral. All the complexes are non-electrolytes. Generally, the solid metal acetate complexes have a unique decomposition exotherm profile which can be used as a rapid and sensitive tool for the detection of acetate-containing complexes.     

Mechanical characterisation of a viscoplastic material sensitive to hydrostatic pressure

The present paper deals with the characterisation of the static mechanical behaviour of an energetic material all along its lifespan. The material behaviour is viscoplastic, damageable and sensitive to hydrostatic pressure. For such materials, existing models have generally been developed in the framework of transient dynamic behaviour. These models are not suitable for a static study. Therefore a specific experimental protocol and an associated model are developed. Characterisation is derived from both uniaxial compressive, tensile tests and triaxial tests. Plastic behaviour is described by means of a parabolic yield criterion and a new hardening law. Non-associated plastic flow rule and isotropic damage complete the model. The performance of the model is illustrated through the simulation of various loading paths.     

X-ray peak profiling,optical parameters and catalytic properties of pure and CdS doped ZnO–NiO nanocomposites

Russian Journal of Applied Chemistry - In the current study, XRD peak profile analysis, optical and catalytic properties of pure ZnO–NiO and CdS doped ZnO-NiO nanocomposites were...     

Synthesis,Structural Stability Calculation,and Antibacterial Evaluation of Novel 3,5-Diphenylcyclohex-2-en-1-one Derivatives

Starting with 3,5-diphenylcyclohex-2-en-1-one, 3,5-diphenylcyclohex-2-en-1-semicarbazone, 1-chloro-3,5-diphenylcyclohex-2-en-2-carbaldehyde, and 3,5-diphenylcyclohex-2-en-1-hydrazone were synthesized via the reactions with semicarbazide hydrochloride, POCl₃/ dimethylformamide, and hydrazine hydrate, respectively. These products were used as key intermediates for the preparation of novel series of tetrahydrobenzothiadiazol-1-oxide, indazole, benzo-thiazepines, pentahydroxyhexylidene and N-thiazines. Some of these derivatives exhibit high antibacterial activity against Gram-positive bacteria.     

Synthesis of New Polyfused Thienopyrimidine,Thienopyridine, Thienothiazine,Thienoxazine, and Thienodiazepine Derivatives

3,4-Diamino-2-carbethoxy-5-cyanothieno(2,3-b)thiophene (1) was treated with ethylenediamine to afford 3,4-diamino-2,5-bi[2-(4,5-dihydro-1H-imidazole-2-yl]-thieno(2,3-b)thiophene 2 , which in turn was treated with chloroacety chloride to give bis[imidazolothieno diazepine] derivative 3 and with each of p-chlorobenzaldehyde, triethyl orthoformate, and Lawesson's reagent (LR) to yield bis[imidazolothienopyrimidine] derivatives 4-6 . Compound 1 was subjected to Mannich reaction to afford Mannich bases 7 and 8a , b . The later products ( 8a , b ) were treated with malononitrile yielding 9a and 9b . Treatment of compound 1 with CS 2 , NaOH and CH 3 I produced compounds 10 and 11 . The reaction of compound 10 with each of o-aminothiphenal, o-phenylenediamen, hydrazine hydrate, and phenylhydrazine afforded compounds 12a , b , 13a , b . Compound 1 was allowed to react with CS 2 , phenyl (benzoyl)isothiocyanate and phenylisocyanate to get the described products 14-19 , respectively. On reacting compound 1 with ethylcyanoacetate thieno(2,3-b)pyridine derivative 21 was obtained through the intermediate 20 . Finally, compound 1 was treated with malononitrile to yield compound 22 .     

Structure-based design,synthesis and biological evaluation of β-glucuronidase inhibitors

Using structure-based virtual screening approach, a coumarin derivative (1) was identified as β-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of β-glucuronidase with IC₅₀ values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against β-glucuronidase, however, their potency varied substantially from IC₅₀ = 9.9–352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC₅₀ values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent.     

Cyclization of diketones to pyridazine and furan derivatives

Condensation of (±)-2,3-bis(3,4-dimethoxybenzoyl)butane-1,4-dione 1 with different hydrazine bases afforded the corresponding pyridazines 2 and 3 . Refluxing the diketone 1 with methanolic hydrogen chloride yielded the corresponding 3,4-dimethylfuran derivative 5 . Reaction of acetonylacetone 6 with p-sulfamylphenylhydrazine afforded the corresponding 3,6-dimethyl-1H-pyridazine derivative 7 . Reaction of 7 with the appropriate isocyanate and isothiocyanate yielded the corresponding benzenesulfonylurea 8 and thiourea 9 derivatives respectively. The structures of the compounds synthesized were affirmed by microanalyses and spectral studies.