4-Hydroxy-2-methyl-N-(2-thiazole)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (EX15) and its Cu(II) Complex as New Oxicam Selective Cyclooxygenase-2 Inhibitors

4-Hydroxy-2-methyl-N-(2-thiazole)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (EX15) as nonsteroidal antiinflammatory drug (NSAIDs) of oxicam family has been synthesized bearing high se-lectivity for cyclooxygenase-2 (COX-2) inhibition and high ability to chelate with Cu(II) ions. The EX15-Cu(II) complex, and [Cu(EX15)(OAc)(H2O)2], were synthesized and characterized by using elemental analysis, spectral (UV-Vis, IR), conductance, thermal and magnetic studies. Two equations were predicted using quantitative structure activity relationship (QSAR) and regression analysis for the COX-2 and COX-1 selectivity (microsomal assay) with a regression correlation (R) close to unity. Two techniques were used to investigate the validity of these equations; macrophage cell line (in vitro) selectivity and collagen-adjuvant arthritis model in rats (in vivo) which showed a significant antioxidant, analgesic and antirheumatic effect for 4-hydroxy-2-methyl-N-(2-thiazole)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide and its Cu(II) complex, [Cu(EX15)(OAc)(H2O)2]. (doi: 10.5562/cca1802

Chelation activity of N'1,N'6-bis((E)-3,4-dihydroxybenzylidene)adipohydrazide towards some transition metal ions

New chelating agent, N'1,N'6-bis((E)-3,4-dihydroxybenzylidene)adipohydrazide (DBAH) was synthesized and its crystal structure was analyzed by X-ray single crystal diffractometer. Homometallic complexes of Zr(IV), Co(II), Ni(II), Cu(II), Cd(II) and heterometallic complex of Co(II)/Zn(II) or Co(II)/Zn(II)/Cd(II) have been synthesized and characterized by spectroscopic and physicochemical methods. The data confirms the formation of bi- and tetra-metallic complexes. The ligand behaves as a neutral tetradentate in the Co(II) and Ni(II) complexes; tetranegative tetradentate in Zr(IV) and Cd(II) complexes and binegative octadentate in [Co2Zn2(DBAH)Cl6] and [Co2ZnCd(DBAH-4H)(H2O)4Cl4].H2O. A tetrahedral structure was proposed for the Ni(II), Zr(IV) and Co(II)/Zn(II) complexes; square-planar for the Cu(II) complex and octahedral geometry for the Co(II) complex. The ESR spectrum confirms the proposed structure of the Cu(II) complex. The thermal analyses confirm the stability of these complexes in the range 275-418 °C. The molecular modeling of [Co2Zn2(DBAH)Cl8] was drawn and its parameters were calculated

Flotation, speciation and determination of iron(III) using aluminon in water, real samples and wastes of power stations

Aluminon has been investigated for the separation of iron(III) by flotation technique. This reagent formed a 1:1 stable complex in aqueous solution. An intense violet layer is formed after flotation using oleic acid (HOL). A highly selective and sensitive spectrophotometric procedure is proposed for the determination of Fe(III) after overcoming all interferences. Preliminary studies show the possibility of forming a complex with Fe(II) to an extremely low extent. Trials have been carried out to separate Fe(II) and Fe(III) using NH4SCN or NaF. To prevent the oxidation of Fe(II), NaBH4 is used.  The separation of Fe(III) and Fe(II) can be achieved using 0.6 mg L-1 NaBH4.  The flotation- determination method was carried out at pH 2-3. The formation constant is 1.3×107 L mol-1 with molar absorptivity of 0.2×105 L mol-1 cm-1 and detection limit of 5×10-6 mol L-1. The effect of foreign ions is avoided using excess aluminon and 0.5 mg L-1 NaBH4. The proposed procedure was applied to synthetic mixtures [Fe(III) + Fe(II)], Fe(III) and some cations, wastes of power stations, simulated samples and real ores

Spectral, thermal, optical and biological studies on (E)-4-[(2-hydroxyphenyl)imino]pentan-2-one and its complexes

Metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates and (E)-4-(2-hydroxyphenylimino)pentan-2-one (H2L) have been synthesized and characterized by elemental analyses, MS, IR, UV-Vis., 1H NMR, thermal analyses (TGA and DTG) and magnetic measurements. In all complexes except for Zn(II) complex, the Schiff base ligand acts as a mono-negative tridentate (NOO) donor, through the azomethine nitrogen, the hydroxyl oxygen and the enolic carbonyl oxygen. The structure of the Cu(II) complex is square-planar, the Co(II) is octahedral while, the Ni(II) and Zn(II) are tetrahedral. The optical band gap measurements indicated a semi-conducting nature of these complexes. The biological activities have been screened against two bacteria and two fungi. Some of the studied complexes showed activity against bacteria and fungi

Synthesis, spectroscopic characterization, molecular modeling and eukaryotic DNA degradation of new hydrazone complexes

2,5-Hexanedione bis(salicyloylhydrazone) [H4L] formed novel complexes with some transition metal ions. H4L and its complexes were characterized by elemental analyses, spectral (IR, 1H NMR, ESR and MS), thermal and magnetic measurements. The complexes have the formulae [VO(H2L)]·2H2O, [Ni(H2L)]·3H2O, [Zn(H2L)], [Ni(H4L)Cl2]·2H2O and [Cr2(H2L)(OAc)2(OH)2]–·2H2O, [Cu(H4L) (H2L)(EtOH)2]·2H2O, [Co2(H2L)(OAc)2]·H2O, [Mn2(H2L)–(OH)2]·H2O [Cu2(H2L)(OAc)2(H2O)6], and [Co2(H2L)(H2O)4Cl2]·2H2O. H4L released its OH or NH protons during the complex formation. Acetate and hydroxo groups bridged the two chromium in [Cr2(H2L)(OAc)2(OH)2]·2H2O. The magnetic moments and electronic spectra of all complexes provide: tetrahedral for [Co2(H2L)(OAc)2]·H2O, [Ni(H2L)]·3H2O and [Zn(H2L)]; square-pyramidal for [VO(H2L)]·2H2O and octahedral for the rest. In DMF solution, the bands are shifted to higher energy suggesting a weak interaction with the solvent. The ESR spectra support the mononuclear geometry for [VO(H2L)]·2H2O and [Cu(H3L)2(EtOH)2]·2H2O. The thermal decomposition of the complexes revealed the outer and inner solvents as well as the end product which in most cases is metal oxide

Synthesis and characterization of tri- and tetra-metallic complexes of N'1,N'4-bis((E)-3,4-dihydroxybenzylidene)-succinohydrazide

Single crystal of N'1,N'4-bis((E)-3,4-dihydroxybenzylidene)succinohydrazide (SHBH) was grown by slow evaporation method. Its, Co(II), Ni(II), Cu(II), Zn(II), Co(II)/Zn(II), Ni(II)/Zn(II) and Cu(II)/Zn(II) complexes have been prepared and characterized by elemental analysis, UV-Vis, IR, NMR, MS spectra, thermal and magnetic measurements. The data confirm the formation of tri- and tetra-metallic complexes (homo- and hetero-nuclear). The ligand behaves as a tetranegative hexadentate in the Co(II)/Zn(II) complex; hexanegative hexadentate in the Co(II) complex and hexanegative octadentate in the tetrametallic complexes. A square-planar for [Co3(SHBH-6H)(H2O)6], [Cu4(SHBH-H)(H2O)4(OAc)2]⋅3H2O, [Ni3Zn(SHBH-6H)(H2O)6Cl2]⋅H2O and [Cu3Zn(SHBH-6H)(H2O)6Cl2] and tetrahedral for [Ni4(SHBH-H)(H2O)4(OAc)2]⋅6H2O, [Zn3(SHBH-4H)-(H2O)4Cl2]⋅2H2O and [Co2Zn(SHBH-6H) (H2O)6Cl2]⋅2H2O were suggested based on the magnetic and spectral data. The TGA data confirm hydrated and coordinated water as well as the final product. The mass spectra depict their molecular ion peaks and the isotopic species of each complex. It is found that the homometallic complexes are highly stable than the heterometallic complexes. The calculated energies for [Co2Zn(SHBH-4H)(H2O)4Cl2].2H2O are higher than [Co3(SHBH-6H)-(H2O)6] indicating that the three Co stabilized the complex

Investigation of the oxygen affinity of manganese(II), cobalt(II) and nickel(II) complexes with some tetradentate Schiff bases

Oxygen absorption–desorption processes for square planar Mn(II), Co(II) and Mn(II) complexes of tetradentate Schiff base ligands in DMF and chloroform solvents were investigated. The tetradentate Schiff base ligands were obtained by condensation reaction of ethylenediamine with salcyldehyde, o-hydroxyacetophenone or acetylacetone in the molar ratio 1:2. The square planar complexes were prepared by the reaction of the Schiff base ligands with Mn(II) acetate, Co(II) nitrate and Ni(II) nitrate in dry ethanol under nitrogen atmosphere. The sorption processes were undertaken in the presence and absence of (pyridine) axial-base in 1:1 M ratio of (pyridine:metal(II) complexes). Complexes in DMF indicate significant oxygen affinity than in chloroform solvent. Cobalt(II) complexes showed significant sorption processes compared to Mn(II) and Ni(II) complexes. The presence of pyridine axial base clearly increases oxygen affinity