Isomeric diadamantylphosphinic acid chlorides

The syntheses of isomeric diadamantylphosphinic acid chlorides are reported. By high-field two-dimensional NMR spectroscopy all proton and carbon-13 signals were identified and assigned unequivocally. Diastereotopism effects and the conformational behaviour of these compounds are discussed.     

Some electrical properties of wood pulp treated with sodium hydroxide

The effect of the degree of crystallinity and degree of polymerization on the electrical properties of soda-treated wood pulp has been investigated. The dielectric constant (E′) and the dielectric loss (E″) were measured for the treated samples over a frequency band 0.2–10 MHz at 20°C. Also, the electrical conductivity (σ) was calculated from the measured data of the dielectric constant. From the results obtained we found that the degree of crystallinity and the degree of polymerization decrease with time of oxidation while the number of carboxylic groups increased. E″,E′, and σ were found to increase with the decrease in the degree of crystallinity.     

Stability Of 2-Carboxyphenylhydrazoacetoacetanilide,and 2-Carboxyphenylhydrazobenzoylacetone Complexes of Rare-Earth Elements in Mixed Solvents

The overall stability constants of the 1:1 and 2:1 2-Carboxyphenylhydrazoacetoacetanilide (2-CPHAAA) and 2-Carboxyphenylhydrazobenzoylacetone (2-CPHBA) rare-earth chelates, were determined by a potentiometric method. The variation of the overall stability constants, “log β” with atomic number, of the lanthanide was ascribed to different degrees of dehydration of the cations. The 2-CPHBA ligand exhibited less affinity for rare earth cations than 2-CPHAAA. The correlation of “log β” versus the basicity of the ligands showed that 2-CPHAAA and 2-CPHBA form the same type of chelate in polar solvents but differ in non polar solvents.     

Structure-antibacterial activity relationship of secondary metabolites from Ajuga pseudoiva Rob. leaves

A selection of steroids, glycerides, clerodane diterpenoids, and a beta-hydroxy fatty acid methyl ester, all previously isolated from Ajuga pseudoiva leaves, were tested for their antibacterial activity toward three Gram- rods and one Gram+ coccus using the dilution method; MIC values were determined. The results suggested some importance for a free beta-hydroxy group in the fatty acid ester and also in the glycerides and clerodane derivatives; the absolute configurations of the latter, notably at C2, had little influence on activity.     

Theoretical characterization of axial deformation effects on hydrogen storage of Ti decorated armchair (5,5) SWCNT

Theoretical calculations have been performed in the framework of density functional theory to characterize the effect of axial deformation on hydrogen storage of Ti decorated armchair (5,5) SWCNT. The theoretical characterization has been carried out in terms of H₂ adsorption energies that are lying in the desirable energy window (?0.2 to ?0.6?eV) recommended by DOE, as well as a variety of physicochemical properties. A remarkable and significant change in H₂ adsorption energy is observed under the effect of only (1%) axial strain. Axial relaxation leads to H₂ adsorption energies within the recommended energy range for hydrogen storage, in contrast to axial compression. Simultaneous weakening of π and σ interactions, due to the effect of axial relaxation and loss of spatial orbital overlap, is in favor of hydrogen adsorption in the recommended energy range, and dominates the effect of charge transfer from Ti 3d to C 2p of the SWCNT. The calculated pairwise and non pairwise additive components confirm that the role of the SWCNT is not restricted to supporting the metal. Polarizability and hperpolarizabilty calculations as well as spectral analysis characterize the relaxed structure (Z?=?1.02), for which H₂ adsorption energy (?0.34?eV) is in the recommended energy range for hydrogen storage, to be energetically more preferable than the compressed structure (Z?=?0.99). The results offer a way to control and characterize the hydrogenation process of metal functionalized SWCNTs by strain loading.     

Structural,vibrational and thermal properties of a new inorganic compound: Tl0.92(NH4)0.08(SO4)0.65(SeO4)0.35Te(OH)6

Research on Chemical Intermediates - A new compound thallium ammonium sulfate selenate tellurate: Tl0.92(NH4)0.08(SO4)0.65(SeO4)0.35Te(OH)6 (TlNSSeTe) has been synthesized by slow evaporation at...     

Utility of 2-furan-2-yl-4-mercapto-6-methylpyrimidine-5-carbonitrile as a precursor for the synthesis of some novel pyrimidines: antibacterial activity

The starting material 2-furan-2-yl-4-mercapto-6-methylpyrimidine-5-carbonitrile 3 was reacted with various reagents resulting in the formation of a group of new pyrimidines and condensed pyrimidines including quinazoline 6 tetrazolopyrimidine 12, pyrazolopyrimidines 14, 18, and 19, triazolopyrimidine 16, and pyrimidopyridazine 20. The antibacterial activity was evaluated for a group of the synthesized compounds against examples of Gram-positive and Gram-negative bacteria.     

Rovibrational laser jet-cooled spectroscopy of the NH3–Ar complex in the ν2 umbrella region of NH3: comparison between new infrared data and an ab initio calculated spectrum*

ABSTRACT

Five ortho and para bands of the ν₂ umbrella mode of the NH₃–Ar van der Waals complex have been recorded at high resolution using jet-cooled infrared laser spectroscopy. A rovibrational analysis provides accurate band centres and upper state rotational constants for the Π_s(j?=?1,k?=?0)?←?Σ_a(j,k?=?0) and Σ_s(j?=?1,k?=?0)?←?Σ_a(j,k?=?0) ortho bands. The puzzling para bands observed in the region of the lower and upper components of the inversion splitting doublet have been assigned by comparison with rovibrational and tunnelling levels and transitions calculated ab initio. The latter calculations are based on the four-dimensional potential energy surface reported by Loreau et al. [J. Chem. Phys. 141, 224303 (2014)], which takes explicitly into account the umbrella motion of the ammonia molecule. The very good agreement found between Π_s/a,lower(j?=?1,k?=?1)?←?Σ_a(j?=?1,k?=?1) and Π_s/a,upper(j?=?1,k?=?1)?←?Σ_s(j?=?1,k?=?1) experimental and calculated transitions has been exploited to determine precisely two different inversion splittings in the ν₂ state (32.003(1) and 36.008(1)?cm^?1) from extrapolated Q(0) line frequencies and to obtain a qualitative picture of Coriolis couplings present in both the ν₂?=?0 and ν₂?=?1 states.