Divalent metal complexes of 4-amino-N-pyrimidin-2-ylbenzene sulphonamide and their antimalarial activities against Plasmodium berghei

Coordination compounds of 4-amino-N-pyrimidin-2-ylbenzene sulphonamide (APS) were synthesized. The complexes were formulated as [Co(APS)2(H2O)2], [Cu(APS)2(H2O)2], [Ni(APS)2(H2O)2], [Cd(APS)2](H2O)2, [Fe(APS)3](H­2O)­3 and [Mn(APS)2(H2O)2] characterized by elemental analysis, conductivity, IR, UV-Vis, magnet moment and 1H-NMR and mass spectroscopies. In all the complexes the metal ions coordinate through pyrimidinic nitrogen and sulphonamidic nitrogen of the two molecules of APS. The suggested structure for Cd(II) complex of APS is tetrahedral, while that of Cu(II), Mn(II) and Ni(II) APS complexes is octahedral. The inner coordination spheres were occupied by two water molecules in Co(II), Mn(II), Cu(II), Ni(II) APS complexes except Cd(II) with 2 molecules of  water outside the coordination  sphere. Fe(III) coordinates with 3 molecules of APS with 3 molecules of water outside the coordination sphere. The antiparasitic studies using Plasmodium berghei as test organism showed that the Fe(III) complex exhibits higher activity than chloroquine and  ligand. All other complexes have lower antiparasitic activity.KEY WORDS: Sulphonamide, Antimalarial activity, Plasmodium berghei Bull. Chem. Soc. Ethiop. 2011, 25(3), 371-380

Synthesis and spectroscopic analysis of Schiff Bases of Imesatin and Isatin derivatives

A series of new Schiff bases of Imesatin and Isatin derivatives which have been previously prepared from the reaction of Hydrazine monohydrate, p-phenylenediamine and 4,4- diaminodiphenylmethane with Isatin were reported. The compounds were characterized by elemental analyses, UV-visible, Infrared and Nuclear Magnetic Resonance (1H NMR and 13C NMR) spectroscopic analyses. The synthesized Schiff bases were obtained in moderate to excellent yields between 55.3 – 89.3%. Infrared spectra of all synthesized compounds contain the characteristic azomethine linkage (-CH=N) between 1580 – 1630 cm-1 and the N–H of the Isatin ring signals between δ 8.32 – 10.68 ppm in their 1H NMR spectra. The present work affords reaction pathway that is efficient and operational simplicity for the synthesis of Schiff bases derivatives.Keywords: Schiff bases, isatin, imesatin, spectroscopic analysis, biological activit

Synthesis and characterization of a tetranuclear Cu(II) coordination polymer containing pyridine-2,6-dicarboxylic acid and 4-amidinopyridine co-ligand

This research demonstrates the preparation of a new coordination polymer, {[Cu4(H2pydc)2(H1apy)(H2O)2DMF].DMF}n, (H2pydc = pyridine-2,6-dicarboxylic acid, H1apy = 4-amidinopyridine) under solvothermal condition by the self-assembly of pyridine-2,6-dicarboxylic acid, 4-midinopyridene and copper(II) acetate. The compound was characterized by elemental analysis and infrared spectroscopic technique. The analysis indicated that the 4-amidinopyridine coordinated to the copper ions through the terminal nitrogen in a monodentate fashion while the pyridine-2,6-dicarboxylic acids coordinated through the carboxylate oxygens in monodentate mode. Both the elemental analysis and the infrared spectroscopic data agreed with the proposed stoichiometry. This result represent the first report of a tetranuclear Cu(II) coordination polymer having coordinated 4-amidinopyridine as the nitrogen donor moiety in its structure

Synthesis and crystal structures of zinc(II) coordination polymers of trimethylenedipyridine (tmdp), 4-nitrobenzoic (Hnba) and 4-biphenylcarboxylic acid (Hbiphen) for adsorptive removal of methyl orange from aqueous solution

Two novel Zn(II) coordination polymers (CPs), [Zn(nba)2(tmdp)]n (1) and [Zn(biphen)2(tmdp)]n (2), were synthesised by reacting Zn(NO3)2·6H2O and 4,4′-trimethylenedipyridine (tmdp) with corresponding carboxylates: 4-nitrobenzoic (Hnba) and 4-biphenylcarboxylic acid (Hbiphen). Their structures were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compounds 1 and 2 are one-dimensional CPs with the zinc(II) carboxylate units bridged through the N-donor spacer ligand. The zinc (II) atom adopts a tetrahedral arrangement in 1 and 2 coordinated by two nitrogen atoms from two tmdp ligand molecules and two deprotonated oxygen atoms from two carboxylate ligand molecules. The adsorption capacities of MO in this study was found to be 546.31 mg/g and 22.67 mg/g for 1 and 2, respectively. DFT studies confirmed that adsorption is primarily due to π-π stacking and electrostatic interactions between MO and 1. It is noteworthy that binding energy (BE) values for 1 (-74.14 KJ/mol) and 2 (-61.11 KJ/mol) correlate reasonably well with the observed adsorption capacities of MO. The study demonstrated that 1 has higher adsorption efficiency in comparison to 2 and could be an effective and easily reusable adsorbent for the removal of MO from wastewater

Removal of hexavalent chromium from aqueous solutions by adsorption on modified groundnut hull

AbstractThere is an emerging serious threat to the environment from indiscriminate release of heavy metals into the wastewaters and soil from human industrial practices. In this study therefore, the uptake of hexavalent chromium, being among the major pollutants from our industries, by modified and unmodified groundnut hull was investigated. The effects of different conditions of contact time, adsorbate concentration, solution pH, and temperature on sorption process were studied. The adsorbent materials were characterized by Fourier Transform Infrared Spectroscopy (FT-IR). Analysis of the surface morphology by Scanning Electron Microscopy (SEM) revealed a change in morphology upon chromium adsorption. The adsorption process of Cr(VI) ions onto both the unmodified groundnut hull (UGS) and the modified groundnut hull (MGS) is in good agreement with the Langmuir adsorption isotherm and follows the pseudo-second-order kinetic model. According to the equilibrium studies, chromium(VI) ions are better adsorbed by modified groundnut hull

Solvent-free mechanochemical synthesis and X-ray studies of Cu(II) and Ni(II) complexes of 5-(3,4,5-Trimethoxybenzyl)pyrimidine-2,4-diamine (Trimethoprim) in a ball-mill

Solvent-free synthesis of [Cu(CH3COO)2(TMP)2](1) and [Ni(CH3COO)2(TMP)2](2) by ball milling of Cu(CH3COO)2.H2O and Ni(CH3COO)2.4H2O with Trimethoprim in the absence of solvent is described. Conventional synthesis of 1. CH3OH and 2. CH3OH was carried out by the reaction of metal acetate salt and Trimethoprim using the solution-based method (reflux in CH3OH for 2 h) for comparison purposes. The mechanochemical products were characterized by comparison of melting points, conductivity values, spectral data, XRPD patterns with those of free ligand and solution based conventional synthesis products. X-ray diffraction patterns of the complex were similar to the simulated pattern of the complex obtained from single crystal structure suggesting the formation of identical compounds as obtained in solvent medium. The process presented here is operationally simple, environmentally benign and affords excellent yields without the need for solvents or external heating. Clearly, it can present a higher efficiency in terms of materials, energy and time compared to classical solution phase synthesis

Synthesis and crystal structure of Cd-based metal-organic framework for removal of methyl-orange from aqueous solution

A novel [Cd(INA)2(H2O)]. ISB (1) (INA = isonicotinate; ISB = isobutanol) was synthesized through the reaction between the isonicotinic acid ligand and cadmium (II) salt and characterized by elemental analysis, FTIR and UV–Visible spectroscopies, SEM and Single crystal X-ray diffraction. The crystal is orthorhombic, space group Pbca, a = 12.24(10) Å, b = 15.4646(13) Å, c = 18.8445(17) Å, V = 3569(3) Å3, Z = 8. The pentagonal bipyramid (seven coordinate) around the cadmium (II) ion is of the form CdN2O5 coordinating to four oxygen atoms from carboxylates, one oxygen atom from water molecule and two nitrogen atoms of pyridine. The structure of compound is stabilized by two hydrogen bonds namely intermolecular (O-H--O) and intramolecular type C-H--O accounting for polymeric nature of the metal-organic frameworks. 1 was studied for adsorptive removal of methyl orange (MO) from aqueous solution. Equilibrium isotherm study reveals that Langmuir model gave a better fitting result than the Freundlich model. The pseudo-second order model could be used to interpret adsorption kinetics. The maximum adsorption capacity calculated by Langmuir was 166 mg/g at 300 K. These results indicate the adsorption of MO on 1 is partly due to electrostatic interaction between methyl orange and the adsorbent. 1 could be used as adsorbent to remove methyl orange from aqueous solution