Synthesis, spectroscopic characterization and biological activities of complexes of light lanthanide ions with 3-hydroxyflavone.

New solid compounds of light lanthanide ions with 3-hydroxyflavone were synthesized in good yields (up to 85 %). The resulting complexes have been thoroughly characterized using various analytical and spectral techniques, including elemental analysis, complexometry, thermogravimetry, UV-VIS, FT-IR, H NMR, AgNPET LDI MS and fluorescence spectroscopy. The molecular formulas of the complexes were determined as follows: Ln(3HF), where 3HF-3-hydroxyflavone, Ln = La(III), Pr(III), Nd(III) and Ln(3HF)·nHO, where n = 1 for Ln = Ce(III), Sm(III), Eu(III), and n = 2 for Gd(III).

Synthesis, Spectral Characterization and Potential Fluorescent Properties of Three Lanthanide(III) Ions Complexes with Nalidixic Acid.

Three new solid lanthanide complexes with nalidixic acid (HNal) with the stoichiometry [Ln(Nal)]·5·.5HO (Ln = Tb, Dy and Ho) were synthesized applying the green synthesis method from the aqueous solutions without the organic solvent addition and fully characterized by the elemental analysis, XRF, complexometric titration, gravimetric analysis, molar conductivity and solubility measurements, powder X-Ray diffraction, UV-Vis and infrared (FT-IR) spectroscopies. Moreover, the luminescent properties of the Tb(III), Dy(III), and Ho(III) complexes in the solid state and in the solutions were investigated.

Analysis of adsorption energy distribution in selected hydrophilic-interaction chromatography systems with amide, amine, and zwitterionic stationary phases.

Adsorption mechanisms of caffeine, quercetin, and phenol as test substances in various chromatographic systems have been analyzed. The investigations were conducted using three different chromatographic columns packed with polar bonded stationary phases, that is, amide, amine, and zwitterionic. Methanol-water and acetonitrile-water systems with different organic solvent contents have been used as mobile phases.

Tautomeric and Microscopic Protonation Equilibria of Anthranilic Acid and Its Derivatives.

The acid-base chemistry of three zwitterionic compounds, namely anthranilic (2-aminobenzoic acid), -methylanthranilic and -phenylanthranilic acid has been characterized in terms of the macroconstants , , the isoelectric point p, the tautomerization constant and microconstants , , , . The potentiometric titration method was used to determine the macrodissociation constants. Due to the very poor water solubility of -phenylanthranilic acid the dissociation constants p and p were determined in MDM-water mixtures [MDM is a co-solvent mixture, consisting of equal volumes of methanol (MeOH), dioxane and acetonitrile (MeCN)].

Studies on equilibrium of anthranilic acid in aqueous solutions and in two-phase systems: aromatic solvent-water.

The acid-base equilibria of anthranilic acid have been characterized in terms of macro- and microdissociation constants (dissociation constants K(a1), K(a2) and tautomeric constant K(z)). On the basis of spectrophotometric investigations the values of the distribution ratio D of anthranilic acid in the two-phase systems: aromatic solvent (benzene, ethylbenzene, toluene, chlorobenzene, bromobenzene)-aqueous solution were obtained. Employing the results of potentiometric titration in the two-phase systems: aromatic solvent-aqueous solution the distribution constant K(D) and dimerization constant K(dim) values were calculated.

Studies on the distribution of N-phenylanthranilic acid in two-phase system: Aromatic solvent-water.

The detailed description of equilibria of N-phenylanthranilic acid in the aqueous solutions and in the two-phase systems: aromatic solvent-aqueous solution were obtained. The isoelectric point, pH(I), the dissociation constants of the protonated form, K(a1), and the neutral form, K(a2), in the aqueous solutions were determined from the apparent ionization constant in methanol-water solutions of various proportions by extrapolation to zero co-solvent using Yasuda-Shedlovsky procedure. On the basis of the spectrophotometric investigations, the values of the distribution ratio, D, of N-phenylanthranilic acid in the two-phase systems: aromatic solvent (benzene, ethylbenzene, toluene, chlorobenzene, bromobenzene)-aqueous solution were obtained.