Search

Novel arylhydrazones of methylene active compounds – 3-(2-(1-ethoxy-1,3-dioxobutan-2-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonic acid (1), 2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-2 H-indene-1,3-dione (2), 5-chloro-2-hydroxy-3-(2-(4,4,4-trifluoro-1,3-dioxo-1-(thiophen-2-yl)butan-2-ylidene)hydrazinyl) benzenesulfonic acid (3), 5-chloro-2-hydroxy-3-(2-(2,4,6-trioxo-tetrahydropyrimidin-5(6 H)-ylidene)-hydrazinyl)benzenesulfonic acid (4), 5-(2-(2-hydroxyphenyl)hydrazono)pyrimidine-2,4,6(1 H,3 H,5 H)-trione (5), 4-hydroxy-5-(2-(2,4,6-trioxo-tetrahydro-pyrimidin-5(6 H)-ylidene)hydrazinyl)benzene-1,3-disulfonic acid (6), 5-(2-(2-hydroxy-4-nitrophenyl)hydrazono)pyrimidine-2,4,6(1 H,3 H,5 H)-trione (7) and 5-chloro-3-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-2-hydroxybenzenesulfonic acid (8) have been synthesized by a reaction between the corresponding methylene active compounds and aryldiazonium salts, and characterized by IR, 1 H and 13 C NMR spectroscopies and element analysis. The collected information confirms that 2, and 4 – 8 exist in DMSO solution in hydrazone form, being stabilized by an intramolecular hydrogen bond, while 1 and 3 exist in mixed enol-azo and hydrazo tautomeric forms. The antimicrobial activity of 1 – 8, as well as that of known analogs 5-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-4-hydroxybenzene-1,3-disulfonic acid (9), 2-(2-sulfophenylhydrazo)malononitrile (10), 2-(2-carboxyphenylhydrazo) malononitrile (11), 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)phenylarsonic acid (12) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2,3-dihydrophthalazine-1,4-dione (13), have been studied. It was found that arylhydrazones of barbituric acid are more active than other methylene active compounds. A whole-cell bacterial luminescence biosensor method was used to detect the antimicrobial activity of the synthesized compounds. The results show that compounds 5 and 9 effectively inhibit the luminescence of Staphylococcus aureus at a minimum inhibitory concentration (MIC50) of 10 and 9 μg/ml, respectively. For Staphylococcus epidermidis, compound 11 showed the most potent activity with MIC50 of 17 μg/mL; for Pseudomonas aeruginosa, compounds 11 showed the most potent activity at MIC50 of 10 μg/mL. Observed results have been verified to be statistically significant using the two-tailed test.

The thermodynamics of dissociation of 3-(2-hydroxyphenylhydrazo)pentane-2,4-dione (H 2 L 1 ), 5,5-dimethyl-2-(2-hydroxyphenylhydrazo)cyclohexane-1,3-dione (H 2 L 2 ), 5,5-dimethyl-2-(2-hydroxy-4-nitrophenylhydrazo)cyclohexane-1,3-dione (H 2 L 3 ), 1-ethoxy-2-(2-hydroxyphenylhydrazo)butane-1,3-dione (H 2 L 4 ) and 1-ethoxy-2-(2-hydroxy-4-nitrophenylhydrazo)butane-1,3-dione (H 2 L 5 ) and of their complexation with copper(II) was studied in aqueous–ethanol solutions by potentiometry and UV–vis spectrophotometry. It was found that the thermodynamic parameters of the proton dissociation in H2L1–5 and of their complexation with copper(II) depend on the substituents in the aromatic and β-diketone fragments of the molecules. Thus, the acidic properties of H2L increase from H2L1 to H2L5, reflecting the electron-acceptor character of the substituents, whereas all of the thermodynamic functions tend to decrease with increasing electron-withdrawing capacity of the substituents. The complexation of Cu(II) with H2L1–5 is exothermic, which is connected with the formation of two stable chelating cycles.

A range of coprecipitated Fe(III)-Me(II) (Me(II) = Ni, Cu) hydroxides and of the products of their thermolysis have been investigated by the IR spectroscopy method. The basic absorption bands has been assigned, and the chemistry of the process of formation of coprecipitated hydroxides has been discussed from the standpoint of generation of heteronuclear hydrococomplexes.

Coprecipitated copper(II)-nickel(II) hydroxides and mechanical mixtures of these were obtained at varied metal ion ratio and time of mother liquor aging and studied by potentiometric titration, chemical and differential thermal analyses, IR spectroscopy, and X-ray phase analysis.