Synthesis and crystal structures of three Schiff bases derived from 3-formylacetylacetone and o-, m- and p-aminobenzoic acid

Treatment of 3-formylacetylacetone with the isomeric o-, m- and p-aminobenzoic acids led to the formation of the corresponding Schiff bases, namely, 3-[(2-carboxyphenylamino)methylidene]pentane-2,4-dione, 1, 3-[(3-carboxyphenylamino)methylidene]pentane-2,4-dione, 2, and 3-[(4-carboxyphenylamino)methylidene]pentane-2,4-dione, 3, all C13H13NO4, that contain a planar amino-methylene-pentane-2,4-dione core with a strong intramolecular N—H...O hydrogen bridge. The carboxyphenyl groups attached to the nitrogen atom are almost coplanar to the central molecular fragment. Depending on the position of the carboxyl unit, different supramolecular structures with hydrogen-bonding networks are formed in the three title structures.

para-Aminobenzoic acid-capped Hematite as an Efficient Nanocatalyst for Solvent-free CO2 Fixation under Atmospheric Pressure

Utilization of carbon dioxide by converting it into value-added chemicals is a sustainable remedy approach which stipulates abundant, cheap, non-toxic and efficient catalytic materials. In this study, we have demonstrated...

Impact of the isomerism of peptide mimetics on the assembly and properties: quick and onsite gas phase detection of acid and alcohols

The effect of isomerism on the structure, self-assembly and properties of two peptide mimetics has been investigated. The peptide mimetics contain m-aminobenzoic acid, p-aminobenzoic acid and N,N'-dicyclohexylurea. From X-ray crystallography,...

A Rational Analysis on Key Parameters Ruling Zerovalent Iron-Based Treatment Trains: Towards the Separation of Reductive from Oxidative Phases

The development of treatment trains for pollutant degradation employing zerovalent iron has been attracting a lot of interest in the last few years. This approach consists of pre-treatment only with zerovalent iron, followed by a Fenton oxidation taking advantage of the iron ions released in the first step. In this work, the advantages/disadvantages of this strategy were studied employing commercial zerovalent iron microparticles (mZVI). The effect of the initial amount of mZVI, H2O2, pH, conductivity, anions and dissolved oxygen were analysed using p-nitrobenzoic acid (PNBA) as model pollutant. 83% reduction of PNBA 6 µM into p-aminobenzoic acid (PABA) was achieved in natural water at an initial pH 3.0 and 1.4 g/L of mZVI, under aerobic conditions, in 2 h. An evaluation of the convenience of removing mZVI after the reductive phase before the Fenton oxidation was investigated together with mZVI reusability. The Fenton step against the more reactive PABA required 50 mg/L of H2O2 to achieve more than 96% removal in 15 min at pH 7.5 (final pH from the reductive step). At least one complete reuse cycle (reduction/oxidation) was achieved with the separated mZVI. This approach might be interesting to treat wastewater containing pollutants initially resistant to hydroxyl radicals.

Synthesis, characterization and biological studies of some new organometallic compounds containing mercury, selenium and tellurium based on p-aminobenzoic acid

Ten chalcogen and mercury bearing compounds based on 4-aminobenzoic acid (i.e., (2-amino-5-(ethoxycarbonyl)phenyl)mercury(II) chloride (1), (2-amino-5-(ethoxycarbonyl)phenyl) phenyl selenide (2), (2-amino-5-(ethoxycarbonyl)phenyl) phenyl telluride (3), (4-carboxyphenyl)mercury(II) chloride (4), 4-selenocyanatobenzoic acid (5), 4-tellurocyanatobenzoic acid (6), bis(4-carboxyphenyl) diselenide (7) bis(4-carboxyphenyl) ditelluride (8), bis(4-carboxyphenyl) selenide (9) bis(4-carboxyphenyl) telluride (10) were prepared and characterized by various spectroscopic techniques. All compounds were screened for antibacterial activity against Gram-positive bacterial strains of Staphylococcus aureus and the Gram-negative bacteria Escherichia coli by using the disk diffusion technique. The antibacterial activity of these compounds was dependent on the molecular structure of the compounds, and the bacterial strain under consideration.