RESUMO
The chelating behavior of ligands based on carbohydrazone core modified with pyridine end towards Co(II), Ni(II) and Cu(II) ions have been examined. The ligands derived from the condensation of carbohydrazide with 2-acetylpyridine (H(2)APC) and 4-acetylpyridine (H(2)APEC). The (1)H NMR, IR data and the binding energy calculations of H(2)APC revealed the presence of two stereoisomers syn and anti in the solid state and in the solution. The (1)H NMR, IR data and the binding energy calculations confirmed the presence of H(2)APEC in one keto form only in the solid state and in the solution. The spectroscopic data confirmed that H(2)APC behaves as a monobasic pentadentate in Co(II) and Cu(II) complexes and as mononegative tetradentate in Ni(II) complex. On the other hand, H(2)APEC acts as a mononegative tridentate in Co(II) complex, neutral tridentate in Ni(II) complex and neutral bidentate in Cu(II) complex. The electronic spectra and the magnetic measurements of complexes as well as the ESR of the copper complexes suggested the octahedral geometry. The bond length and bond angles were evaluated by DFT method using material studio program. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and in vitro Ehrlich ascites of the compounds have been screened.
Assuntos
Cobalto/farmacologia , Cobre/farmacologia , Hidrazonas/farmacologia , Níquel/farmacologia , Piridinas/química , Animais , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Benzotiazóis/farmacologia , Compostos de Bifenilo/química , Carcinoma de Ehrlich/patologia , Espectroscopia de Ressonância de Spin Eletrônica , Elétrons , Eritrócitos/efeitos dos fármacos , Sequestradores de Radicais Livres/química , Hemólise/efeitos dos fármacos , Concentração Inibidora 50 , Cinética , Ligantes , Espectroscopia de Ressonância Magnética , Camundongos , Modelos Moleculares , Picratos/química , Ratos , Espectrofotometria Infravermelho , Ácidos Sulfônicos/farmacologia , TermogravimetriaRESUMO
The molecular modeling and parameters have been calculated to confirm the geometry of oxalyl bis(3,4-dihydroxybenzylidene) hydrazone, H(6)L. The metal complexes of Cr(3+), VO(2+), ZrO(2+), HfO(2+), UO(2)(2+) and MoO(2)(2+) with H(6)L have been prepared and characterized by partial elemental analysis, spectral studies (electronic; IR), thermal analysis and magnetic measurements. The data suggest the formation of polymer complexes with a unit [Cr(H(4)L)(H(2)O)(3)Cl].H(2)O, [VO(H(4)L)(H(2)O)(2)], [Hf(H(4)L)(H(2)O)].H(2)O [UO(2)(H(4)L)(H(2)O)(2)].2H(2)O [MoO(2)(H(4)L)] and [(ZrO)(2)(H(2)L)-(C(2)H(5)OH)(2)]. The ligand behaves as a dibasic bidentate in all complexes except ZrO(2+) which acts as a tetrabasic tetradentate with the two ZrO(2+) ions. An octahedral geometry was proposed for the Cr(3+), HfO(2+), MoO(2)(2+)and UO(2)(2+) complexes and square pyramid for VO(2+). The Cr(3+) is necessary to degrade the DNA of eukaryotic subject completely; the other complexes have little effect. H(6)L was found suitable as a new reagent for the separation and preconcentration of ZrO(2+) ions from different water samples using flotation technique with satisfactory results.
Assuntos
Compostos de Benzil/química , Compostos de Benzil/farmacologia , Hidrazonas/química , Hidrazonas/farmacologia , Animais , Bovinos , Cor , DNA/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Elétrons , Íons , Magnetismo , Modelos Moleculares , Espectrofotometria Infravermelho , Temperatura , Termogravimetria , Zircônio/químicaRESUMO
Flotation is a separation technology for removing toxic heavy metal ions from aqueous solutions. Here a simple and rapid flotation procedure is presented for the removal of copper(II) from aqueous solutions. It is based on the use of polyaluminum chloride silicate (PAX-XL60 S) as coagulant and flocculent, carbonate ion as activator and oleic acid (HOL) as surfactant. Both ion and precipitate flotation are included depending on the solution pH. Ion and precipitate flotation in the aqueous HOL-PAX-XL60 S-Cu2+-CO3(2-) system gave powerful preferential removal of Cu2+ (F -100%) over the HOL-PAX-XL60 S-Cu2+ system containing no CO3(2+) ion (F approximately 86%). The role of CO3(2-) ion is also evident from decreasing the dose of PAX-XL60 S from 700 mg l(-1) to 200 mg l(-1). The other parameters, influencing the flotation process, namely: metal ion, surfactant and PAX-XL60 S concentrations, ionic strength, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cu2+ ions from different volumes up to 11 and from natural water samples.
Assuntos
Hidróxido de Alumínio/química , Carbonatos/química , Coagulantes/química , Cobre/isolamento & purificação , Silicatos/química , Purificação da Água/métodos , Precipitação Química , Concentração de Íons de Hidrogênio , Íons , Concentração Osmolar , Tensoativos/química , TemperaturaRESUMO
Several complexes of thiosemicarbazone derivatives with Ni(II) have been prepared. Structural investigation of the ligands and their complexes has been made based on elemental analysis, magnetic moment, spectral (UV-Vis, i.r., (1)H NMR, ms), and thermal studies. The i.r. spectra suggest the bidentate mononegative and tridentate (neutral, mono-, and binegative) behavior of the ligands. Different stereochemistries were suggested for the isolated complexes. The thermogravimetry (TG) and derivative thermogravimetry (DTG) have been used to study the thermal decomposition and kinetic parameters of some ligands and complexes using the Coats-Redfern and Horowitz-Metzger equations. The redox properties and stability of the complexes toward oxidation waves explored by cyclic voltammetry are related to the electron withdrawing or releasing ability of the substituent of thiosemicarbazone moiety. The samples displayed Ni(II)/Ni(I) couples irreversible waves associated with Ni(III)/Ni(II) process.
Assuntos
Compostos Organometálicos/química , Tiossemicarbazonas/química , Eletroquímica , Elétrons , Cinética , Ligantes , Magnetismo , Espectrometria de Massas , Estrutura Molecular , Espectrofotometria Infravermelho , TemperaturaRESUMO
A simple and economic experimental sorptive -flotation procedure is presented for the removal of copper(II) species from aqueous solutions. It is based on using powdered marble wastes (PMW), which are widespread and inexpensive and may represent an environmental problem, as the effective inorganic sorbent and oleic (HOL) as the surfactant. The main parameters (i.e. initial solution pH, sorbent, surfactant and copper concentrations, stirring times, ionic strength, temperature and the presence of foreign ions) influencing the flotation of PMW and /or Cu(II) were examined. Nearly, 100% of PMW and Cu(II) were removed from aqueous solutions at pH7 after stirring for 10 min and at room temperature, (approximately 25 degrees C). The procedure was successfully applied to recover Cu(II) spiked to some natural water samples. A mechanism for sorption and flotation is suggested.
Assuntos
Carbonato de Cálcio/química , Cobre/análise , Cobre/isolamento & purificação , Poluentes da Água/análise , Poluentes da Água/isolamento & purificação , Materiais de Construção , Monitoramento Ambiental/métodos , Pós , TensoativosRESUMO
A simple, selective and sensitive procedure is described for the preconcentration by flotation followed by spectrophotometric determination of trace amounts of Cd(II). Cadmium forms an intense red 1:2 complex with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH > or = 6. The colored Cd-PPT complex was floated quantitatively with oleic acid (HOL) surfactant at pH 6.5, exhibiting maximum absorbance at 520 nm and having a molar absorptivity of 2.4 x 10(5) L mol(-1) cm(-1). The stability constant of the formed complex is 1.5 x 10(12); log K = 12.2. Beer's law was obeyed over the concentration range 0.01-0.34 mg/L. The Sandell sensitivity and relative standard deviation are 0.4 ng/cm2 and 2.6%, respectively. The results obtained spectrophotometrically were compared to those obtained by AAS analysis. The analytical parameters affecting flotation and hence determination have been thoroughly investigated. The proposed procedure was successfully applied to the determination of Cd(II) traces in certified and real human hair samples as well as in natural waters. The structure of the complex formed and the mechanism of flotation were proposed.
Assuntos
Cádmio/análise , Cádmio/química , Fenantrenos/química , Espectrofotometria/métodos , Tiossemicarbazonas/química , Calibragem , Cabelo/química , Humanos , Concentração de Íons de Hidrogênio , Íons , Estrutura Molecular , Ácido Oleico/química , Sensibilidade e Especificidade , Soluções/química , TemperaturaRESUMO
Copper(II) forms 1:1 and 1:2 intense red complexes with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH 3-3.5 and > or =6.5, respectively. These complexes exhibit maximal absorbance at 545 and 517 nm, the molar absorptivity being 2.3 x 10(4) and 4.8 x 10(4) l mol(-1) cm(-1), respectively. However, the 1:1 complex was quantitatively floated with oleic acid (HOL) surfactant in the pH range 4.5-5.5, providing a highly selective and sensitive procedure for the spectrophotometric determination of CuII. The molar absorptivity of the floated Cu-PPT complex was 1.5 x 10(5) l mol)(-1) cm(-1). Beer's law was obeyed over the range 3-400 ppb at 545 nm. The analytical parameters affecting the flotation process and hence the determination of copper traces were reported. Also, the structure of the isolated solid complex and the mechanism of flotation were suggested. Moreover, the procedure was successfully applied to the analysis of CuII in natural waters, serum blood and some drug samples.
Assuntos
Cobre/análise , Preparações Farmacêuticas/química , Fenantrenos/química , Espectrofotometria/métodos , Tiossemicarbazonas/química , Água/química , Cobre/química , Humanos , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , TemperaturaRESUMO
A simple, rapid and selective procedure for the indirect spectrophotometric determination of Se(IV) and As(V) has been developed. It is based on the reduction of Se(IV) to Se(0) and As(V) to As(III) with hydroiodic acid (KI + HCl). The liberated iodine, equivalent to each analyte, is quantitatively extracted with oleic acid (HOL) surfactant. The iodine-HOL system exhibits its maximum absorbance at 435 nm. The different analytical parameters affecting the extraction and determination processes have been examined. The calibration graphs were found to be linear over the ranges 5-120 and 0.25-20 ppm of Se(IV) and As(V), with lower detection limits of 2.5 and 0.15 ppm and molar absorptivities of 1 x 10(4) and 0.5 x 10(4) dm3 mol(-1) cm(-1), respectively. Sandell's sensitivity was calculated to be 0.0078 and 0.0149 microg/cm2 in the same order. The relative standard deviation for five replicate analyses of 40 ppm Se(IV) and 4 ppm As(V) were 1.0 and 0.9%, respectively. The proposed procedure in the presence of EDTA as a masking agent for foreign ions has been successfully applied to the determination of Se(IV) in a reference sample and As(V) in copper metal, in addition to their determination in spiked and polluted water samples.
Assuntos
Arsênio/análise , Selênio/análise , Ácidos/análise , Calibragem , Cátions/análise , Concentração de Íons de Hidrogênio , Iodo/análise , Compostos de Iodo/análise , Íons/análise , Ácido Oleico/análise , Oxirredução , Iodeto de Potássio/metabolismo , Sensibilidade e Especificidade , Espectrofotometria/métodos , Tensoativos/metabolismo , Fatores de TempoRESUMO
A highly selective and sensitive procedure for flotation separation followed by spectrophotometric determination, confirmed by AAS, of Ni(II) traces is proposed. The maximum flotation separation (100%) is achieved at approximately 25 degrees C in the pH range of 1-3 using sodium diethyldithiocarbamate (as a collector) and oleic acid surfactant. The floated (1 : 2) colored complex is measured spectrophotometrically at 430 nm over a concentration range of 0.5-4.0 microg/g with a molar absorptivity of 0.44 x 10(4) L mol(-1) cm(-1). The procedure was successfully applied for the separation and determination of Ni(II) in fresh and sea waters.