Crystal Engineering of Schiff Base Zn(II) and Cd(II) Homo- and Zn(II)M(II) (M = Mn or Cd) Heterometallic Coordination Polymers and Their Ability to Accommodate Solvent Guest Molecules.

Based on solvothermal synthesis, self-assembly of the heptadentate 2,6-diacetylpyridine bis(nicotinoylhydrazone) Schiff base ligand (H2L) and Zn(II) and/or Cd(II) salts has led to the formation of three homometallic [CdL]n (1), {[CdL]∙0.5dmf∙H2O}n (2) and {[ZnL]∙0.5dmf∙1.5H2O}n (3), as well as two heterometallic {[Zn0.75Cd1.25L2]∙dmf∙0.5H2O}n (4) and {[MnZnL2]∙dmf∙3H2O}n coordination polymers. Compound 1 represents a 1D chain, whereas 2-5 are isostructural and isomorphous two-dimensional structures. The entire series was characterized by IR spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction and emission measurements. 2D coordination polymers accommodate water and dmf molecules in their cage-shaped interlayer spaces, which are released when the samples are heated. Thus, three solvated crystals were degassed at two temperatures and their photoluminescent and adsorption-desorption properties were recorded in order to validate this assumption. Solvent-free samples reveal an increase in volume pore, adsorption specific surface area and photoluminescence with regard to synthesized crystals.

Novel vic-dioximes: synthesis, structure characterization, and antimicrobial activity evaluation.

The vic-dioximes are compounds with various industrial uses and scientific applications. Many coordination compounds have been synthesized based on vic-dioximes. This study presents the synthesis and full characterization of two vic-dioximes based on dichloroglyoxime, p-aminobenzoic acid, and p-aminotoluene. Their structures were proved by IR, 1H, 13C and 15N NMR spectral analysis, and single crystal X-ray diffraction. One of the reported vic-dioximes, bis(di-p-aminotoluene)glyoxime mono-p-aminotoluene trihydrate showed good to moderate antimicrobial activity against both nonpathogenic gram-positive and gram-negative bacteria (Bacillus subtilis and Pseudomonas fluorescens), phytopathogenic (Xanthomonas campestris, Erwinia amylovora, E. carotovora) and the fungi (Candida utilis and Saccharomyces cerevisiae) at MIC - 70-150 µg/mL.

p-Aminobenzoate Organic Salts as Potential Plant Growth Regulators for Tomatoes.

The discovery of environmentally friendly and inexpensive plant growth regulators (PGRs) for agronomically important crops is a necessity and must be considered a priority worldwide. This study provides the synthesis, structure determination and the biological evaluation of two binary organic salts as potential PGRs. New compounds have dual biological activity and are based on natural metabolite p-aminobenzoic acid (pABAH) and different alkanolamines. Studied compounds exhibit hydrogen-bonded 3D supramolecular architectures with different crystal packing due to the formation of one homosynthon and various heterosynthons. The biological profile of new compounds was investigated in laboratory and greenhouse on Solanum lycopersicum L., revealing the efficiency in promoting plant rooting and plant productivity. The results may have a positive impact on agricultural economics, developing new sustainable PGRs for tomatoes.

Synthesis, structure and toxicity evaluation of ethanolamine nitro/chloronitrobenzoates: a combined experimental and theoretical study.

BACKGROUND: Nitroaromatic and chloronitroaromatic compounds have been a subject of great interest in industry and recently in medical-pharmaceutic field. 2-Chloro-4-nitro/2-chloro-5-nitrobenzoic acids and 4-nitrobenzoic acid are promising new agents for the treatment of main infectious killing diseases in the world: immunodeficiency diseases and tuberculosis. RESULTS: New ethanolamine nitro/chloronitrobenzoates were synthesized and characterized by X-ray crystallography, UV-vis, FT-IR and elementary analysis techniques. The toxicity of the compounds prepared and correspondent components was evaluated using Hydractinia echinata as test system. A significant lower toxicity was observed for nitro-derivative compared with chloronitro-derivatives and individual components. Crystallographic studies, together with the chemical reactivity and stability profiles resulted from density functional theory and ab initio molecular orbital calculations, explain the particular behavior of ethanolamine 4-nitrobenzoate in biological test. CONCLUSIONS: The experimental and theoretical data reveal the potential of these compounds to contribute to the design of new active pharmaceutical ingredients with lower toxicity.

Synthesis, crystal structure and biological activity of 2-hydroxyethylammonium salt of p-aminobenzoic acid.

p-Aminobenzoic acid (pABA) plays important roles in a wide variety of metabolic processes. Herein we report the synthesis, theoretical calculations, crystallographic investigation, and in vitro determination of the biological activity and phytotoxicity of the pABA salt, 2-hydroxyethylammonium p-aminobenzoate (HEA-pABA). The ability of neutral and anionic forms of pABA to interact with TIR1 pocket was investigated by calculation of molecular electrostatic potential maps on the accessible surface area, docking experiments, Molecular Dynamics and Quantum Mechanics/Molecular Mechanics calculations. The docking study of the folate precursor pABA, its anionic form and natural auxin (indole-3-acetic acid, IAA) with the auxin receptor TIR1 revealed a similar binding mode in the active site. The phytotoxic evaluation of HEA-pABA, pABA and 2-hydroxyethylamine (HEA) was performed on the model plant Arabidopsis thaliana ecotype Col 0 at five different concentrations. HEA-pABA and pABA acted as potential auxin-like regulators of root development in Arabidopsis thaliana (0.1 and 0.2 mM) and displayed an agravitropic root response at high concentration (2 mM). This study suggests that HEA-pABA and pABA might be considered as potential new regulators of plant growth.