Ab initio study of magnetic property of BEST2 [Fe(CN)5NO] charge-transfer salt

By means of ab initio method of the full potential linearized augmented-plane-wave, electronic band structure and its magnetic property for a charge transfer compound of bis (ethylenediselena)-tetrathiafulvalene(BEST) with [Fe(CN)₅NO] anions are investigated for the first time, where the exchange-correlation effects of electrons are accounted in the generalized gradient approximation. The spin density of states and the magnetic moment are analyzed in detail. It is found that there exists a new antiferromagnetic coupling in the organic donors because of alternating spin population in the organic donors. Besides the localized 3d electrons of Fe in [Fe(CN)₅NO] anion, the ligand nitric oxide and the cyanogen radical play important roles in the magnetic properties of the system. Our results are in good agreement with the experimental observations.     

Base-promoted regioselective synthesis of 1,2,3,4-terahydroquinolines and quinolines from N-boc-3-piperidone

An efficient synthesis of 1,2,3,4-tetrahydroquinolines with donor and acceptor group has been delineated by base mediated ring transformation of 6-aryl-4-substituted-2H-pyran-2-one-3-carbonitriles by N-boc-3-piperidone followed by consecutive deprotection of Boc group under acidic conditions. This reaction involves 2 new bond formations namely C4a-C5 and C8a-C8 in order to create the nucleus. Various donor and acceptor functional groups like aryl, heteroaryl, nitrile, methylsulfanyl and secondary amine were installed in 1,2,3,4-tetrahydroquinolines. We extended our approach to synthesize the fused 1,2,3,4-tetrahydroquinolines by using 2-oxobenzo[h]chromenes as precursor. Further, we synthesized fused and isolated quinolines through aromatization of 1,2,3,4-tetrahydroquinolines by DDQ in excellent yields. Single-crystal X-ray analysis of the Boc protected tetrahydroisoquinoline 6t showed the steric hindrance between N-Boc and aryl group.     

Synthesis and structural characterization of oxovanadium(IV) complexes of dimedone derivatives

We have successfully synthesized new oxovanadium (IV) complexes with dimedone derivatives and their structure were confirmed by elemental analyses, spectroscopic techniques (FT-IR, UV–visible, EPR) and thermal analysis. The reaction of [VO (acac)₂] with the azo dimedone ligands ( HL _n ) produced mononuclear oxovanadium (IV) complexes with formula [VO (L_n)₂]H₂O. Results of the molar conductance proved that VO²⁺ complexes are non-electrolytes and fall in the range 14–16 Ω-¹cm²mol⁻¹. The coordination geometry of VO (IV) complexes is square-pyramidal, where vanadium (IV) ion is coordinated by oxygen atom of the carbonyl (C=O) group, and nitrogen atom of the deprotonating hydrazone moiety (–NH–), while the fifth position is occupied by an oxo group. Moreover, the optimized structure, bond angles, bond lengths, as well as the calculated quantum chemical parameters of the complexes have been estimated. DNA binding activities of the complexes were investigated using electronic absorption titration and viscosity measurements. The obtained results showed groove binding of the complexes to CT-DNA accompanied with a partial insertion of the ligand between the base stacks of the DNA with a binding constant of 2.07–5.51 x 10⁵ M⁻¹ range. Evaluation results of the synthesized complexes against the human cancer cell lines HepG-2 and MCF-7, as compared to the positive controls in the viability assay of vinblastine and colchicine have been reported. The in vitro anti-oxidant activity of all the complexes is determined by DPPH free radical-scavenging assay. Finally, the anti-microbial activities of the complexes have been investigated against fungal (Candida albicans), gram negative bacteria (Escherichia coli), and gram positive bacteria (Staphylococcus aureus) using the disc-diffusion method.     

Green synthesis approach for Fe (III), Cu (II), Zn (II) and Ni (II)-Schiff base complexes,spectral, conformational,MOE-docking and biological studies

Green synthesis of Fe (III), Cu (II), Zn (II) and Ni (II)-Schiff's-base complexes from 2-oxo-N-(pyridine-2-yl)-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)acetamide(H₂L)ligand. All new complexes were characterized via several spectroscopic and analytical techniques, to establish their molecular and structural formulae. All complexes appeared have 1:1 molar ratio (M:L). The ligand contributed as a neutral poly-dentate towards the metal ions. Moreover, material-studio program was used to predict the most fitted atomic-skeletons for investigated compounds by applying DFT method. MOE docking module (vs. 2015) was used to examine the degree of inhibition for new compounds versus three infected-cell proteins (1bqb, 2gt1 and 4esw). Also, antimicrobial and colorimetric assess for compounds that bind DNA were performed     

Simulative aurintricarboxylic acid molecular docking with antitumor activity for its VO(II), Cr(III), Mn(II) and Fe(III) complexes,HF/DFT modeling and elaborated EPR studies

Journal of Thermal Analysis and Calorimetry - A synthesized aurintricarboxylic acid (ATA) complex was deliberately investigated. Spectral, thermal, theoretical and antitumor studies are...     

Study on phase stability and oxide ion conductivity in the BIAGVOX system

A novel oxide ion conductor, BIAGVOX formulated as Bi₄Ag_xV_2?xO_11?(2x)?δ is obtained by substituting a fraction (x) of V⁵⁺ by Ag⁺ in Bi₄V₂O₁₁ samples of the BIAGVOX system in the composition range, 0.05≤x≤0.30 were synthesized using the standard solid-state reaction. XRPD, FT-IR, DTA and AC impedance spectroscopy were used for the investigation of the correlation between the structural phase stability and oxide ion performance of the BIAGVOX materials. It has been found that orthorhombic, β, and incommensurate tetragonal, γ′ were stabilized at room temperature for compositions with x≤0.15 and x≥0.20, respectively. The enthalpy of β→γ and γ→γ transition exhibited a general drop with increasing Ag content and a minimum transition temperature was observed for x=0.20. However, the oxide ion conductivity at lower temperatures remarkably increased in composition stability ranges of β- and γ-phase, while a maximum conductivity was reported for the high temperature γ-phase at x=0.15. However, the low temperature conductivity, σ₃₀₀°c measured for x=0.30 was found to be comparable with the maximum ionic conductivity of the BICUVOX system reported for x=0.20 at the same temperature.     

Fractional Boundary Value Problems with Integral Boundary Conditions via Topological Degree Method

This paper examines the existence and uniqueness of solutions for the fractional boundary value problems with integral boundary conditions. Banach''s contraction mapping principle and Schaefer''s fixed point theorem have been used besides topological technique of approximate solutions. An example is propounded to uphold our results.     

Effect of Ni(II) substitution on phase stabilization electrical properties of BICo(III)VOX.20 oxide-ion conductor

The BICO_0.20–xNI_xVOX solid electrolyte was synthesized by the standard solid-state reaction. The effect of Ni(II) substitution for Co(III) on phase stabilization and oxide-ion performance has been investigated in the compositional range 0?≤?x?≤?0.20 using X-ray powder diffraction, differential thermal analysis and AC impedance spectroscopy. The highly conductive γ′-phase was effectively stabilized at room temperature for compositions with x?≥?0.13 whose thermal stability increases with Ni content. The complex plane plots of impedance were typically represented at temperatures below 380?°C, suggesting a major contribution of polycrystalline grains to the overall electrical conductivity. The dielectric permittivity measurements revealed the fact that suppression of the ferroelectric transition is compositionally dependent. Interestingly, the maximum ionic conductivity at lower temperatures (~2.56?×?10^?4?S^?cm^?1 at 300?°C) was observed for the composition with x?=?0.13. The variation of low-temperature conductivity with Ni content was accompanied with a general drop in the corresponding values of ΔE_LT. However, the local minimum high-temperature conductivity, σ₆₀₀?°C?~?2.26?×?10^?2?S^?cm^?1 for x?=?0.10, coupled with a local maximum value of ΔE_HT?~?0.48?eV was attributed to an increased defect trapping effect correlated with the V(V)?→?V(IV) reduction at elevated temperatures.     

Microscopic study on proton elastic scattering of light exotic nuclei at energies below than 100 MeV/nucleon

The proton elastic scattering data on some light exotic nuclei, namely, ^{6, 8}He, ^{9, 11}Li, and ^{10, 11, 12}Be, at energies below than 100MeV/nucleon are analyzed using the single folding optical model. The real, imaginary, and spin-orbit parts of the optical potential (OP) are constructed only from the folded potentials and their derivatives using M3Y effective nucleon-nucleon interaction. These OP parts, their renormalization factors and their volume integrals are studied. The surface and spin-orbit potentials are important to fit the experimental data. Three model densities for halo nuclei are used and the sensitivity of the cross-sections to these densities is tested. The imaginary OP within high-energy approximation is used and compared with the single folding OP. This OP with few and limited fitting parameters, which have systematic behavior with incident energy, successfully describes the proton elastic scattering data with exotic nuclei.