Omoruyi G. Idemudia

Synthesis, Characterization, and Antibacterial Studies of Pd(II) and Pt(II) Complexes of Some Diaminopyrimidine Derivatives

Pd(II) and Pt(II) complexes of trimethoprim and pyrimethamine were synthesized and characterized by elemental analysis, UV-Vis, FTIR, and NMR spectroscopy. The complexes are formulated as four coordinate square planar species containing two molecules of the drugs and two chloride or thiocyanate ions. The coordination of the metal ions to the pyrimidine nitrogen atom of the drugs was confirmed by spectroscopic analyses. The complexes were screened for their antibacterial activities against eight bacterial isolates. They showed varied activities with the active metal complexes showing more enhanced inhibition than either trimethoprim or pyrimethamine. The Pd(II) complexes of pyrimethamine showed unique inhibitory activities against P. aeruginosa and B. pumilus, and none of the other complexes or the drugs showed any activity against these bacteria isolates. The MIC and MBC determinations revealed that these Pd(II) complexes are the most active. Structure activity relationship showed that Pt(II) complexes containing chloride ions are more active, while for Pd(II) complexes containing thiocyanate ions showed more enhanced activity than those containing chloride ions.

Synthesis and Characterization of Bioactive Acylpyrazolone Sulfanilamides and Their Transition Metal Complexes: Single Crystal Structure of 4-Benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one Sulfanilamide

Two Schiff base ligands Ampp-Sn 1 and Bmpp-Sn 2, afforded by a condensation reaction between sulfanilamide and the respective acylpyrazolone carbonyl precursors, their Mn(II), Co(II), Ni(II), and Cu(II) complexes prepared by the reaction of ligands and corresponding metal salts in aqueous solutions, were synthesized and then characterized by both analytical and spectroscopic methods, in a view to developing new improved bioactive materials with novel properties. On the basis of elemental analysis, spectroscopic and TGA results, transition metal complexes, with octahedral geometry having two molecules of the bidentate keto-imine ligand each, have been proposed. The single crystal structure of Bmpp-Sn according to X-ray crystallography showed a keto-imine tautomer type of Schiff base, having three intramolecular bonds, one short N2⋯H2⋯O3 hydrogen bond of 1.90 Å and two long C13⋯H13⋯O2 and C32⋯H32⋯O3 hydrogen bonds of 2.48 Å. A moderate to low biological activities have been exhibited by synthesized compounds when compared with standard antimicrobial agents on screening the synthesized compounds against Staphylococcus aureus, Bacillus pumilus, Proteus vulgaris, and Aeromonas hydrophila for antibacterial activity and against free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) for antioxidant activity.

3-Methyl-1-phenyl-4-[(phen-yl)(2-phenyl-hydrazin-1-yl)meth-ylidene]-1H-pyrazol-5(4H)-one.

The title compound, C23H20N4O, is a heterocyclic phenylhydrazone Schiff base with a pyrazole moiety. In the crystal, a variety of interactions occur, including N—H⋯π and π–π stacking between the phenyl ring of the phenylhydrazinyl group and its symmetry-generated equivalent [centroid–centroid distance = 3.6512 (7) Å].

Metal Complexes of New Bioactive Pyrazolone Phenylhydrazones; Crystal Structure of 4-Acetyl-3-methyl-1-phenyl-2-pyrazoline-5-one phenylhydrazone Ampp-Ph

The condensation reaction of phenylhydrazine and dinitrophenylhydrazine with 4-acetyl and 4-benzoyl pyrazolone precipitated air-stable acetyldinitrophenylhydrazone Ampp-Dh, benzoylphenylhydrazone Bmpp-Ph and benzoyldinitrophenylhydrazone Bmpp-Dh in their keto imine form; a study inspired by the burning interest for the development of new bioactive materials with novel properties that may become alternative therapeutic agents. Elemental analysis, FTIR, 1H, and 13C NMR, and mass spectroscopy have been used to justify their proposed chemical structures, which were in agreement with the single crystal structure of Bmpp-Dh earlier reported according to X-ray crystallography. The single crystal structure of 4-acetyl-3-methyl-1-phenyl--pyrazoline-5-one phenylhydrazone Ampp-Ph, which crystallizes in a triclinic crystal system with a P-1 (No. 2) space group is presented. Octahedral Mn(II), Ni(II), Co(II), and Cu(II) complexes of these respective ligands with two molecules each of the bidentate Schiff base, coordinating to the metal ion through the azomethine nitrogen C=N and the keto oxygen C=O, which were afforded by the reaction of aqueous solutions of the corresponding metal salts with the ligands are also reported. Their identity and proposed structures were according to elemental analysis, FTIR spectroscopy, UV-VIS spectrophotometry (electronic spectra) and Bohr magnetic moments, as well as thermogravimetric analysis (TGA) results. A look at the antibacterial and antioxidant activities of synthesized compounds using the methods of the disc diffusion against some selected bacterial isolates and 1,1-diphenyl-2-picryl-hydrazil (DPPH) respectively, showed biological activities in relation to employed standard medicinal drugs.

Polymeric graphitic carbon nitride doped with CuO dispersed on dealuminated clinoptilolite (CuO/HCP): synthesis and characterisation

CuO dispersed on dealuminated clinoptilolite (CuO/HCP) and further doped with polymeric graphitic carbon nitride (CuO/HCPg-C 3N4) was synthesized through 2 facile routes: precipitation method for CuO/HCP and impregnation through ultrasonication method for the hybrid composite material. The hybrid composite material crystalline phase, surface morphology, and structural and thermal properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and thermal analysis. The formation of the hybrid composite material was confirmed by XRD showing crystalline phase of CuO and g-C3N4 present on the surface of dealuminated clinoptilolite (HCP). SEM images analysis depicts no aggregation of the mixed metal oxide semiconductor nanoparticles at the center of HCP. The hybrid composite material, CuO/HCP-g-C3N4, with a good homogeneously dispersed metal oxide conductor having excellent catalytic activities has been synthesized.

4-[(4-Meth­oxy­benzyl­idene)amino]­benzene­sulfonamide

The title Schiff base compound, C14H14N2O3S, is non-planar, with a dihedral angle of 24.16 (7)° between the benzene rings. In the crystal, N—H⋯O and N—H⋯N hydrogen bonds link the molecules into a layer parallel to (011). Intra- and interlayer C—H⋯O interactions and π–π interactions [centroid–centroid distances = 3.8900 (9) and 3.9355 (8) Å] are also present.

4-{[2-(2,4-Dinitro-phen-yl)hydrazinyl-idene](phen-yl)meth-yl}-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one ethanol monosolvate.

In the title compound, C23H18N6O5·C2H6O, all three benzene rings lie in an approximate plane [maximum deviation = 0.2688 (16) Å] that makes an angle of 53.56 (3)° with the plane of the pyrazolone ring. Intramolecular N—H⋯O hydrogen bonds occur. In the crystal, the ethanol solvent molecule links adjacent molecules through N—H⋯O—H⋯O hydrogen bonds, leading to an infinite chain along the c-axis direction. The ethyl group of the ethanol solvent molecule is disordered over two set of sites in a 0.762 (5):0.238 (5) ratio.

Synthesis and characterization of rhodium doped on TiO 2 /HCP for enhanced photocatalytic performance on pentachlorophenol

Visible-light-responsive material based on Rhodium doped on titanium dispersed on dealuminated clinoptilolite (TiO2/HCP) was synthesized via a combination of the sol-gel method and photoreductive deposition technique. The photocatalyst surface characterization, structural and optical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and UV-visible spectra (UV-VIS). Doping TiO2/HCP with Rh imparts a red shifting of the absorption band into the visible light region according to UV-VIS. The prepared composite materials were evaluated for their photocatalytic activities on pentachlorophenol (PCP) degradation under sunlight irradiation. The Rhodium doped TiO2/HCP exhibited enhanced photocatalytic activity and can be considered as a potential photocatalyst in wastewater treatment.

Bis(4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olato-κ2O,O′)bis­(ethanol-κO)cobalt(II)

The title compound, [Co(C17H13N2O2)2(C2H5OH)2], is a CoII complex with two 4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olate (BMPP) ligands and two coordinating ethanol molecules. In the asymmetric unit, there are two half molecules, with the CoII atoms located on inversion centres. The two cobalt complexes have slightly different geometries and in one, the ethyl group of the ethanol is disordered over two sets of sites [occupancy ratio 0.757 (7):0.243 (7)]. Each BMPP ligand is deprotonated with the negative charge delocalized. The hydroxy group of each ethanol molecule forms hydrogen bonds with a pyrazole N atom in an adjacent BMPP ligand. Weaker C—H⋯O and C—H⋯N interactions link the molecules into a three-dimensional structure.

Substituted 4-Acyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazones with Antioxidant Properties: X-Ray Crystal and Spectroscopic Studies

Phenylhydrazine was reacted with synthesized acylpyrazolone derivatives 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one and 4-propyl-5-methyl-2-phenyl-pyrazol-3-one, to obtain two new azomethine phenylhydrazones, a study in continuation of our probe into the effects of acyl group substitutions on the physicochemical and free radical scavenging properties of acylpyrazolone Schiff bases. The keto imine tautomers of 4-ethyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Empp-Ph) and 4-propyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Prmpp-Ph) according to single X-ray crystallography data which precipitated in good yield are reported. Furthermore they have been characterized by elemental analysis, FTIR, 13C and 1H NMR, and mass-spectroscopy techniques. Both phenylhydrazone Schiff bases crystallize in a triclinic crystal system, each with a space group of P-1 (number 2) having short intramolecular N3—H3…O1 hydrogen interaction between the first hydrazine hydrogen H3 and the pyrazolone oxygen O1. The antioxidant free radical scavenging activities of titled compounds against 2,2-diphenyl-1-picrylhydrazyl (DPPH) showed a positive response almost as good as that of vitamin c under the same conditions, with the propyl substituted 4-propyl-5-methyl-2-phenyl-pyrazol-3-one-phenylhydrazone (Prmpp-Ph) having a stronger activity (calculated IC50 value of 175.66 μg/ml).