Double template effect in [4 + 4] Schiff base macrocycle formation; an ESI-MS study

The mechanism of self-assembly of a polynuclear complex of a [4 + 4] Schiff base iminomethylenediphenolate macrocycle [BaCu(4)(4 + 4)](2+) via a non-macrocyclic dialdehyde intermediate has been followed using ESI-MS of the reaction solutions. Both assembly of the intermediate and Schiff-base condensation with diamine give rise to single products; formation of the intermediate metallacycle is fast but Schiff-base condensation is much slower. Both intermediate complex and macrocyclic product have been structurally characterised.     

Revision of structural properties of GdBO3 nanopowders doped with Eu3+ ions through spectroscopic studies

Monoclinic Gd(1-x)Eu(x)BO(3) nanopowders were successfully synthesized using a modified Pechini method. The crystal structure of the prepared materials was revised and confirmed using several techniques such as: IR, XRD, TEM, Raman spectroscopy and EDX analysis. The obtained material was comprised of particles, consisting of parts with the average size 350 nm. The luminescence properties of the prepared phosphors with different concentrations of Eu(3+) ions were characterized by excitation and emission spectra and its kinetic decay. The Judd-Ofelt parameters (Ω(2), Ω(4)), quantum efficiency, η, and chromaticity coordinates were also calculated.     

Novel Pd(ii)-salen complexes showing high in vitro anti-proliferative effects against human hepatoma cancer by modulating specific regulatory genes

We have reported the synthesis of a novel salen ligand and its mononuclear Pd-salen complexes derived from 2-{[2-hydroxy-3-{[(E)-(2-hydroxyphenyl)methylidene]amino}propyl)imino]methyl}phenol. The newly synthesized and isolated Pd(ii) complexes have been identified and fully characterized by various physico-chemical studies viz., elemental analyses, IR, UV-Vis, (1)H, (13)C NMR spectroscopy, electron spray ionization mass spectrometry (ESI-MS) and TGA/DTA studies. The molecular structure of the salen ligand has been ascertained by single-crystal XRD and it is coordinated to Pd(ii) ion through two nitrogen and two oxygen atoms. The UV-Vis data clearly suggest a square-planar environment around both the Pd(ii) ions. The DNA binding studies of the synthesized compounds has been investigated by electron spectroscopy and fluorescence measurements. The results suggest that Pd(ii) complexes bind to DNA strongly as compared to the free ligand. The free salen ligand and its Pd(ii) complexes have also been tested against human hepatoma cancer cell line (Huh7) and results manifested exceptional anti-proliferative effects of the Pd(ii) complexes. The anti-proliferative activity of Pd(ii) complexes has been modulated by specific regulatory genes.     

The Synthesis of Zinc(II) and Cadmium(II) 2,4-Dichlorophenoxyacetates in Water–Methanol Environment. Structure and Properties of Polymeric [Zn(2,4-D)2(MeOH)2]n and [Cd(2,4-D)2(H2O)2]n

Abstract  

The zinc(II) and cadmium(II) 2,4-dichlorophenoxyacetate salts were synthesized in mixed water–methanol environment and characterized by elemental analysis, IR spectrometry and thermal analysis coupled with mass spectrometry. The crystal structures were determined by X-ray crystallography (compound 1, [C₁₈H₁₈Cl₄O₈Zn] _n : monoclinic, P2₁/c, a = 19.094, b = 7.378, c = 8.008, α = 90.00, β = 101.134, γ = 90.00, V = 1106.95; compound 2, [C₁₆H₁₄Cl₄O₈Cd] _n : monoclinic, P2₁/c, a = 17.730, b = 7.293, c = 8.060, α = 90.00, β = 95.18, γ = 90.00, V = 1037.9). The structural and some thermal data about the presented cadmium salt were previously reported (Song et al. Acta Crystallogr E 62:m2397, 2006; Kobylecka et al. Thermochim Acta 482:49, 2009).     

The optimal value and optimal solutions of the proximal average of convex functions

The proximal average of a finite collection of convex functions is a parameterized convex function that provides a continuous transformation between the convex functions in the collection. This paper analyzes the dependence of the optimal value and the minimizers of the proximal average on the weighting parameter. Concavity of the optimal value is established and implies further regularity properties of the optimal value. Boundedness, outer semicontinuity, single-valuedness, continuity, and Lipschitz continuity of the minimizer mapping are concluded under various assumptions. Sharp minimizers are given further attention. Several examples are given to illustrate our results.     

The heat risk during hardening of dental glass-ionomer cements using a light-curing

Journal of Thermal Analysis and Calorimetry - An use of a polymerization lamp to irradiate chemically hardened glass-ionomer materials may improve their properties and accelerate the setting time....     

Interdiffusion and thermotransport in Ni–Al liquid alloys

In this paper, we present extensive self-consistent results of molecular dynamics (MD) simulations of diffusion and thermotransport properties of Ni–Al liquid alloys. We develop a new formalism that allows easy connection between results of the MD simulations and the real experiments. In addition, this formalism can be extended to the case of ternary and higher component liquid alloys. We focus on the temperature and composition dependence of the self-diffusion coefficients, interdiffusion coefficients, thermodynamic factor, Manning factor and the reduced heat of transport. The two latter quantities both represent measures of the off-diagonal Onsager phenomenological coefficients. The Manning factor and the reduced heat of transport can be related to experimentally obtainable quantities provided the thermodynamic factor is available. The simulation results for the reduced heat of transport show that for all compositions, in the presence of a temperature gradient, Ni tends to migrate to the cold end. This is in agreement with an available experimental study for a Ni_21.5Al_78.5 melt (only qualitative result is available so far).     

Characterization of 2-methylglyceric acid oligomers in secondary organic aerosol formed from the photooxidation of isoprene using trimethylsilylation and gas chromatography/ion trap mass spectrometry

In the present work, we have characterized in detail the chemical structures of secondary organic aerosol (SOA) components that were generated in a smog chamber and result from the photooxidation of isoprene under high-NO(x) conditions typical for a polluted atmosphere. Isoprene high-NO(x) SOA contains 2-methylglyceric acid (2-MG) and oligoester derivatives thereof. Trimethylsilylation, in combination with capillary gas chromatography (GC)/ion trap mass spectrometry (MS) and detailed interpretation of the MS data, allowed structural characterization the polar oxygenated compounds present in isoprene SOA up to 2-MG trimers. GC separation was achieved between 2-MG linear and branched dimers or trimers, as well as between the 2-MG linear dimer and isomeric mono-acetate derivatives thereof. The electron ionization (EI) spectra of the trimethylsilyl derivatives contain a wealth of structural information, including information about the molecular weight (MW), oligoester linkages, terminal carboxylic and hydroxymethyl groups, and esterification sites. Only part of this information can be achieved with a soft ionization technique such as electrospray (ESI) in combination with collision-induced dissociation (CID). The methane chemical ionization (CI) data were used to obtain supporting MW information. Interesting EI spectral differences were observed between the trimethylsilyl derivatives of 2-MG linear and branched dimers or trimers and between 2-MG linear dimer mono-acetate isomers.     

A SIMPLE ONE-STEP SYNTHESIS OF MONOESTERS OF AMINOPHOSPHONIC

Abstract

Alkyl monoesters of N-substituted aminophosphonic acids have been prepared by heating of the corresponding dialkyl aminophosphonates oxalate salts in water. The formed monoesters were separated as crystalline solids from the aqueous reaction mixture.