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1.
J Ethnopharmacol ; 331: 118292, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38705428

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Tabebuia impetiginosa (Bignoniaceae) was traditionally used for memory enhancement and central nervous system (CNS) stimulation. AIM OF THE STUDY: This study aims to create a metabolic profile of the ethyl acetate fraction of T. impetiginosa (TEF) and investigate for the first time its neuroprotective potential on cyclophosphamide (CP)-induced chemobrain, validating its traditional use. MATERIALS AND METHODS: Metabolite profiling of TEF was performed using Liquid Chromatography coupled with Quadrupole Time of Flight-Mass/Mass Spectrometry (LC-qTOF-MS/MS). For the in vivo study, CP (200 mg/kg, i.p.) was administered to induce cognitive impairment in rats; TEF (30 mg/kg, p.o.) was administered throughout the 14 days of the experiment to assess its role in mitigating CP-induced neuronal deficits. Behavioral tests including locomotor, Y-maze, and passive avoidance tests were conducted. Additionally, biochemical markers such as reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and caspase-3 immunoexpression were assessed in the hippocampus area. RESULTS: Forty-four phytoconstituents were tentatively identified in TEF, mainly iridoids and organic acids. TEF showed significant memory enhancement as evidenced by the increase in step-through latency in the passive avoidance test by 1.5 folds and the increase in sequence alternation percentage (SAP) in the Y-maze test by 67.3%, as compared to CP-group. Moreover, it showed pronounced antioxidant and anti-inflammatory potentials evidenced by the significant elevation in reduced glutathione (GSH) levels by 80% and a pronounced decline in MDA and TNF-α levels by 24% and 45%, respectively relative to the CP group. TEF treatment restored normal hippocampal histological features and attenuated apoptotic caspase-3 expression by 70% compared to the CP group. CONCLUSIONS: TEF can act as a promising natural scaffold in managing the chemobrain induced by CP in cancer patients.


Assuntos
Fármacos Neuroprotetores , Extratos Vegetais , Folhas de Planta , Espectrometria de Massas em Tandem , Animais , Fármacos Neuroprotetores/farmacologia , Espectrometria de Massas em Tandem/métodos , Masculino , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Folhas de Planta/química , Ratos , Cromatografia Líquida/métodos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Compostos Fitoquímicos/farmacologia , Compostos Fitoquímicos/análise , Ratos Wistar , Ciclofosfamida/toxicidade , Aprendizagem em Labirinto/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Glutationa/metabolismo , Estresse Oxidativo/efeitos dos fármacos
2.
Life Sci ; 335: 122245, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37926296

RESUMO

AIMS: Carfilzomib, an irreversible proteasome inhibitor, has been increasingly used to treat multiple myeloma worldwide. However, case studies showed its treatment has been associated with cardiac, renal, and pulmonary deleterious effects. Lactoferrin is an iron-binding glycoprotein present in milk. It is a multifunctional protein with antimicrobial activity, antitumor, antioxidant, and anti-inflammatory effects. Thus, this study aimed to assess the protective effects of lactoferrin against carfilzomib-induced nephrotoxicity and pulmonary toxicity, in addition to identifying the possible underlying molecular mechanisms. MAIN METHODS: Mice were treated with lactoferrin (300 mg/kg/day) concomitantly with carfilzomib (4 mg/kg, i.p.) twice weekly for three weeks. Kidney and lung indices, serum creatinine, blood urea nitrogen (BUN), uric acid, kidney injury molecule-1 (KIM-1), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and histological examination were assessed. In addition, biochemical analyses of the inflammasome NLRP3/NF-κB and PI3K/Akt/GSK-3ß/MAPK axes were conducted. KEY FINDINGS: Treatment with lactoferrin decreased serum levels of creatinine, BUN, uric acid, KIM-1, ALP, AST, and LDH and reversed carfilzomib-induced histological changes in both kidney and lung. The inflammatory markers NLRP3, p65 NF-kB, caspases1, interleukin-1ß, and interleukin-18, as well as the MAPK signaling pathway, were significantly reduced in renal and pulmonary tissues of mice following lactoferrin administration. Moreover, lactoferrin significantly counteracted carfilzomib-induced reduced expression of pAkt and pGSK-3ß in both renal and pulmonary tissues. SIGNIFICANCE: The current study suggests lactoferrin might be a promising candidate for ameliorating carfilzomib-induced nephrotoxicity and pulmonary toxicity.


Assuntos
NF-kappa B , Proteínas Proto-Oncogênicas c-akt , Camundongos , Animais , NF-kappa B/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Inflamassomos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Lactoferrina/farmacologia , Ácido Úrico/metabolismo , Rim/metabolismo , Pulmão/metabolismo
3.
Sci Rep ; 13(1): 7703, 2023 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-37169856

RESUMO

Breast cancer is the second leading cause of cancer death among women. The present study is an effort to reveal the antiproliferative and antioxidant actions of mango seed kernel extract (KE), peel extract (PE), and their combination (KEPE) on mammary tumors induced by 7,12 dimethylbenz[a]anthracene (DMBA). Seven groups of adult female Sprague-Dawley rats were prepared, including C: (control), DMBA: (rats were administered with DMBA), (DMBA-KE), (DMBA-PE), and (DMBA-KEPE): rats were administered with DMBA and then treated with KE, PE, and (both KE and PE), respectively, (KE) and (PE): rats were administered with KE and PE, separately. The study focused on the assessment of markers of endocrine derangement [serum 17-ß estradiol (E2)], apoptosis [caspase-3 and deoxyribonucleic acid fragmentation (DNAF)], and oxidative stress [lipid peroxidation and antioxidants (glutathione, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, and superoxide dismutase)]. Histopathological examination and immunohistochemical expression of caspase-3 and estrogen receptor-α (ER-α) in mammary gland tissues (MGTs) were determined, as well as the characterization of mango extracts. The results showed that DMBA administration induced mammary tumors by increasing cell proliferation and evading apoptosis. In addition, DMBA administration caused oxidative stress by the production of reactive oxygen species, which increased lipid peroxidation and decreased cellular antioxidants, allowing cancer to progress. In contrast, treatment with DMBA-KE, DMBA-PE, or DMBA-KEPE diminished mammary tumors induced by DMBA, where they reduced oxidative stress via increased antioxidant parameters including reduced glutathione, superoxide dismutase, total glutathione peroxidase, glutathione reductase, and glutathione S-transferase. Also, different treatments decreased proliferation through the reduction of E2, and ER-α expression levels. However, these treatments increased the apoptosis of unwanted cells as they increased caspase-3 activity and DNAF. All these changes led to the prevention of breast injuries and the reduction of mammary tumors. This demonstrates that the contents of mango extracts, especially phenolics and flavonoids, have an important role in mammary tumor treatment through their potential antioxidant, antiproliferative, proapoptotic, and anti-estrogenic effects. KE and PE administration for 4 weeks had no adverse effects. Conclusion: Each of KE, PE, and KEPE has a therapeutic effect against DMBA-induced mammary tumors via induction of apoptosis and reduction of each of the OS, proliferation, and estrogenic effects. So, they can play an important role in the pharmacological tole.


Assuntos
Neoplasias Mamárias Experimentais , Mangifera , Ratos , Feminino , Animais , Antioxidantes/metabolismo , Ratos Sprague-Dawley , Mangifera/metabolismo , Caspase 3 , 9,10-Dimetil-1,2-benzantraceno/toxicidade , Neoplasias Mamárias Experimentais/induzido quimicamente , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/prevenção & controle , Glutationa , Superóxido Dismutase , Carcinogênese , Oxirredutases
4.
Heliyon ; 6(5): e04005, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32478191

RESUMO

The present study was carried out to evaluate the relationship between physiochemical parameters, microorganisms, wastewater and climate in Stabilization Pond Performance. This study performed as a post-treatment after the secondary wastewater treatment using extended aeration in Rashid city, Egypt. The model of the extended aeration as secondary wastewater treatment was developed based on the combination with lagoon after the secondary sedimentation basin. The Climatic functions have an important impact on the mechanism of ponds as it actuates vertical mixing of the pond contents. The interaction between bacteria, algae and other organisms are the main idea of oxidation pond treatment beside the relationship between the climatic functions, physiochemical parameters and microorganisms biomass. The removal of biodegradable organic loads specially nitrogen and phosphorous are perfectly happens in oxidation maturation ponds which reflects a higher treatment efficiency of the sewage by 98%-99% of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and heavy metals. The study included some recommendations aiming at improving both water quality and its recycling in plants irrigation.

5.
Heliyon ; 5(11): e02912, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31844764

RESUMO

Synthesis and spectrothermal characterization of new fabricated pyrazinamide complexes with metal [Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)] salts are reported. The structural chemistry of these complexes is achieved via elemental analysis, spectral (UV, visible, and IR), thermal (DTA and TGA) as well as magnetic susceptibility. In these new octahedral complexes (Zn complex is tetrahedral), pyrazinamide acts as a bidentate ligand. Pyrazinamide complexes show higher activity than pyrazinamide for some strains. The geometry of the complexes is converted from Oh to Td during their thermal decomposition. The decomposition mechanisms are suggested and the thermodynamic parameters for the thermal decomposition steps are evaluated.

6.
Biochem Pharmacol ; 156: 431-443, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30195730

RESUMO

Epilepsy is one of the serious neurological sequelae of bacterial meningitis. Rifampicin, the well-known broad spectrum antibiotic, is clinically used for chemoprophylaxis of meningitis. Besides its antibiotic effects, rifampicin has been proven to be an effective neuroprotective candidate in various experimental models of neurological diseases. In addition, rifampicin was found to have promising antioxidant, anti-inflammatory and anti-apoptotic effects. Herein, we investigated the anticonvulsant effect of rifampicin at experimental meningitis dose (20 mg/kg, i.p.) using lithium-pilocarpine model of status epilepticus (SE) in rats. Additionally, we studied the effect of rifampicin on seizure induced histopathological, neurochemical and behavioral abnormalities. Our study showed that rifampicin pretreatment attenuated seizure activity and the resulting hippocampal insults marked by hematoxylin and eosin. Markers of oxidative stress, neuroinflammation and apoptosis were evaluated, in the hippocampus, 24 h after SE induction. We found that rifampicin pretreatment suppressed oxidative stress as indicated by normalized malondialdehyde and glutathione levels. Rifampicin pretreatment attenuated SE-induced neuroinflammation and decreased the hippocampal expression of interleukin-1ß, tumor necrosis factor-α, nuclear factor kappa-B, and cyclooxygenase-2. Moreover, rifampicin mitigated SE-induced neuronal apoptosis as indicated by fewer positive cytochrome c immunostained cells and lower caspase-3 activity in the hippocampus. Furthermore, Morris water maze testing at 7 days after SE induction showed that rifampicin pretreatment can improve cognitive dysfunction. Therefore, rifampicin, currently used in the management of meningitis, has a potential additional advantage of ameliorating its epileptic sequelae.


Assuntos
Hipocampo/patologia , Cloreto de Lítio/toxicidade , Transtornos da Memória/induzido quimicamente , Pilocarpina/toxicidade , Rifampina/farmacologia , Convulsões/induzido quimicamente , Animais , Apoptose/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Cloreto de Lítio/administração & dosagem , Masculino , Transtornos da Memória/prevenção & controle , Estresse Oxidativo , Pilocarpina/administração & dosagem , Ratos , Ratos Wistar , Convulsões/tratamento farmacológico
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 193: 458-466, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29289744

RESUMO

Synthesis, physicochemical characterization and thermal analysis of ceftazidime complexes with transition metals (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were discussed. It's obtained that ceftazidime act as bidentate ligand. From magnetic measurement and spectral data, octahedral structures were proposed for all complexes except for cobalt, nickel and mercury had tetrahedral structural. Hyper chemistry program confirmed binding sites of ceftazidime. Ceftazidime complexes show higher activity than ceftazidime for some strains. From TG and DTA curves the thermal decomposition mechanisms of ceftazidime and their metal complexes were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides as a final product except in case of Hg complex.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Ceftazidima/química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Metais/química , Antibacterianos/química , Ligantes , Estrutura Molecular , Termodinâmica
8.
Artigo em Inglês | MEDLINE | ID: mdl-25974669

RESUMO

Cefotaxime metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and two mixed metals complexes of (Fe,Cu) and (Fe,Ni) were synthesized and characterized by elemental analysis, IR, electronic spectra, magnetic susceptibility and ESR spectra. The studies proved that cefotaxime may act as mono, bi, tri and tetra-dentate ligand through oxygen atoms of lactam carbonyl, carboxylic or amide carbonyl groups and nitrogen atom of thiazole ring. From the magnetic measurements and electronic spectral data, octahedral structures were proposed for all complexes. Quantum chemical methods have been performed for cefotaxime to calculate charges, bond lengths, bond angles, dihedral angles, electronegativity (χ), chemical potential (µ), global hardness (η), softness (σ) and the electrophilicity index (ω). The thermal decomposition of the prepared metals complexes was studied by TGA, DTA and DSC techniques. Thermogravimetric studies revealed the presence of lattice or coordinated water molecules in all the prepared complexes. The decomposition mechanisms were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides and carbon residue as a final product except in case of Hg complex, sublimation occur at the temperature range 376.5-575.0 °C so, only carbon residue was produced during thermal decomposition. The orders of chemical reactions (n) were calculated via the peak symmetry method and the activation parameters were computed from the thermal decomposition data. The geometries of complexes may be converted from Oh to Td during the thermal decomposition steps.


Assuntos
Antibacterianos/química , Cefotaxima/química , Complexos de Coordenação/química , Antibacterianos/síntese química , Varredura Diferencial de Calorimetria , Cefotaxima/síntese química , Complexos de Coordenação/síntese química , Espectroscopia de Ressonância de Spin Eletrônica , Modelos Moleculares , Espectrofotometria Infravermelho , Termogravimetria
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 137: 1417-25, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25310263

RESUMO

The stability studies of biologically active phenylazo-dinitroso resorsinol and o-hydroxy phenyl azo-dinitroso resorsinol compounds were studied. The dissociation constants and the thermodynamic parameters of dissociation were evaluated and determined potentiometrically. Regression analysis is applied for correlating the different parameters by using the SPSS program. The results help to assign the solute-solvent interactions and the solvatochromic potential of the investigated compounds.


Assuntos
Compostos Azo/química , Corantes/química , Compostos Nitrosos/química , Potenciometria , Solventes/química , Espectrofotometria , Termodinâmica
10.
Artigo em Inglês | MEDLINE | ID: mdl-24211811

RESUMO

Azo gallic derivatives and their iron(III) complexes were synthesized and characterized. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, UV-Vis and IR. The thermal behaviors of the complexes were studied. The effect of pH on the electronic absorption spectra of gallic acid and its azo derivatives are discussed. Different spectroscopic methods (molar ratio, straight line method, continuous variation, slope ratio and successive method) are applied for determination of stoichiometry and pK values for the complex formation of gallic acid with iron(III) in aqueous media. Iron(III) complexes of gallic acid is formed with different ratio: 1:1, 1:2, 1:3 and 1:4 (M:L).


Assuntos
Compostos Azo/química , Complexos de Coordenação/química , Ácido Gálico/química , Ferro/química , Concentração de Íons de Hidrogênio , Espectrofotometria , Espectrofotometria Infravermelho
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 107: 179-87, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23416922

RESUMO

Synthesis of 5-arylidine thiobarbituric acids containing different functional groups with variable electronic characters were described and their Co(2+), Ni(2+) and Cu(2+) complexes. The stereochemistry and mode of bonding of 5-(substituted benzylidine)-2-TBA complexes were achieved based on elemental analysis, spectral (UV-VIS, IR, (1)H NMR, MS), magnetic susceptibility and conductivity measurements. The ligands were of bidentate and tridentate bonding through S, N and O of pyrimidine nucleolus. All complexes were of octahedral configuration. The thermal data of the complexes pointed to their stability. The mechanism of the thermal decomposition is discussed. The thermodynamic parameters of the dissociation steps were evaluated and discussed.


Assuntos
Cobalto/química , Complexos de Coordenação/química , Cobre/química , Níquel/química , Tiobarbitúricos/química , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Termogravimetria
12.
Artigo em Inglês | MEDLINE | ID: mdl-22516126

RESUMO

The electronic absorption spectra of gallic acid and its azo derivatives have been studied in various solvents of different polarities. Multiple regression techniques were applied to calculate the regression and correlation coefficients based on an equation that relates the wavenumbers of the absorption band maxima (υ(max)(-)) to the solvent parameters; refractive index (n), dielectric constant (D), empirical Kamlet-Taft solvent parameters, π*(dipolarity/polarizability), α (solvent hydrogen-bond donor acidity) and ß (solvent hydrogen-bond acceptor basicity). The fitting coefficient obtained from this analysis allows estimating the contribution of each type of interactions relative to total spectral shifts in solution. The dependence of υ(max)(-) on the solvent parameters indicates that the obtained bands are affected by specific and non-specific solute-solvent interactions.


Assuntos
Compostos Azo/química , Elétrons , Ácido Gálico/química , Solventes/química , Absorção , Cinética , Análise de Regressão , Soluções
13.
Artigo em Inglês | MEDLINE | ID: mdl-22336041

RESUMO

New sixteen uric acid metal complexes of different stoichiometry, stereo-chemistries and modes of interactions were synthesized using different metals Cr, Mn, Fe, Co, Ni, Cu, Cd, UO(2), Na and K. The synthesized complexes were characterized by elemental analysis, spectral (IR, UV-Vis and ESR) methods, thermal analysis (TG, DTA and DSC) and magnetic susceptibility studies. Molecular modeling calculations were used to characterize the ligation sites of the free ligand. Furthermore, quantum chemical parameters of uric acid such as the energies of highest occupied molecular orbital (E(HOMO)), energies of lowest unoccupied molecular orbital (E(LUMO)), the separation energy (ΔE=E(LUMO)-E(HOMO)), the absolute electronegativity, χ, the chemical potential, P(i), the absolute hardness, η and the softness (σ) were obtained for uric acid. Eight different microbial categories were used to study the antimicrobial activity of the free ligand and ten of its complexes. The results indicate that the ligand and its metal complexes possess antimicrobial properties. The stoichiometry of iron-uric acid complex was studied by using different spectrophotometric methods.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Ferro/química , Metais/química , Ácido Úrico/química , Biologia Computacional , Ligantes , Espectroscopia de Ressonância Magnética , Modelos Químicos , Estrutura Molecular , Espectrofotometria Infravermelho , Termodinâmica
14.
Artigo em Inglês | MEDLINE | ID: mdl-21530376

RESUMO

The solvatochromic responses of uric acid (Ua), 6-amino-2-thiouracil (ATU) and a series of their complexes dissolved in ten solvents of different polarity have been measured. The solvent-dependent UV/Vis spectroscopic absorption maxima, λ(max), are assigned to the corresponding electronic transitions and analyzed using SPSS program, regression analysis and Kamlet and Taft methods. The observed solvatochromism is discussed using various solute-solvent interaction mechanisms. The electronic absorption spectra of ATU were investigated in aqueous buffer solutions of varying pH and utilized for the determination of dissociation constants. The ranges of pH, where individual ionic species are predominant have been determined.


Assuntos
Complexos de Coordenação/química , Purinas/química , Pirimidinas/química , Concentração de Íons de Hidrogênio , Espectrofotometria Ultravioleta , Tiouracila/análogos & derivados
15.
Artigo em Inglês | MEDLINE | ID: mdl-21074487

RESUMO

Iron, cobalt, nickel and copper complexes of ceftriaxone were prepared in 1:3 ligand:metal ratio to examine the ligating properties of the different moieties of the drug. The complexes were found to have high percentages of coordinated water molecules. The modes of bonding were discussed depending on the infrared spectral absorption peaks of the different allowed vibrations. The Nujol mull electronic absorption spectra and the magnetic moment values indicated the Oh geometry of the metal ions in the complexes. The ESR spectra of the iron, cobalt, and copper complexes were determined and discussed. The thermal behaviors of the complexes were studied by TG and DTA techniques. The antimicrobial activities of the complexes were examined and compared to that of the ceftriaxone itself.


Assuntos
Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Ceftriaxona/síntese química , Ceftriaxona/farmacologia , Metais/farmacologia , Temperatura , Anti-Infecciosos/química , Bactérias/efeitos dos fármacos , Ceftriaxona/química , Cobalto/farmacologia , Cobre/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica , Fungos/efeitos dos fármacos , Ferro/farmacologia , Testes de Sensibilidade Microbiana , Conformação Molecular , Prótons , Espectrofotometria Infravermelho , Eletricidade Estática , Termogravimetria
16.
Artigo em Inglês | MEDLINE | ID: mdl-16458054

RESUMO

The temperature dependent dielectric spectroscopic properties of two heteronuclear complexes of monoethanolamine (MEA) at a wide temperature range (303-413 K) were investigated by impedance spectroscopy, in the frequency range from 100 Hz to 100 kHz. The frequency dependence of the impedance spectra plotted in the complex plane shows semi-circles. The Cole-Cole diagrams have been used to determine the molecular relaxation time, tau. The temperature dependence of tau is expressed by thermally activated process. Relaxation frequencies corresponding to the rotation of the molecules about their long axes are expected to lie above 10 MHz and exhibit Arrhenius behavior, where a single slope is observed with activation energy values equal to 0.67 and 0.78 eV. The ac conductivity sigma(ac) (omega) is found to vary as omega(s) with the index s

Assuntos
Condutividade Elétrica , Etanolaminas/química , Análise Espectral/métodos , Amino Álcoois/química , Simulação por Computador , Temperatura
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 61(13-14): 3102-7, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16165059

RESUMO

A series of diazoaminobenzene derivatives (seven) in which the substituents have a wide range of electronic characters are set out to understand the involvement of the substituent identity in controlling the changes in their electronic absorption spectra. The interactions between the diazoamino group and the different groups account for some spectral shifts. The UV-vis spectrum of each compound is measured in several solvents with wide variations of solvent polarity parameters to examine the role of the chemistry of the solvent in these spectroscopical changes. The electronic transitions are assigned and the solvent induced spectral shifts are analyzed in relation to the different solute-solvent interaction mechanisms using computational chemistry. The regression analysis is applied for correlating the different parameters. The results help to assign the solute-solvent interactions and the solvatochromic potential of the investigated compounds. It is concluded that the electronic character of the substituent and the chemical nature of the solvent are the major factors for the observed solvatochromism.


Assuntos
Solventes/química , Triazenos/química , Aminação , Estrutura Molecular , Espectrofotometria
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 62(4-5): 1114-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15955729

RESUMO

A bright green CoCu(PMP)(OH)2(H2O)2 complex was synthesized. Its structure was elucidated and characterized by different spectroscopic techniques. Both cobalt and copper atoms attain tetrahedral geometry. The complex was investigated by the dielectric relaxation spectroscopy. The dielectric parameters are discussed in terms of temperature and frequency changes. The conductivity of the complex decreased as the temperature increased in the temperature range 30-100 degrees C, while above this temperature range stepwise increase in the conductivity was observed.


Assuntos
Antipirina/análogos & derivados , Cobalto/química , Cobre/química , Antipirina/química , Edaravone , Eletroquímica , Modelos Químicos , Análise Espectral , Temperatura
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 60(13): 3155-9, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15477158

RESUMO

The electronic absorption spectra of a series of the entitled eight compounds containing groups with variable electronic characters were recorded. The solvents were selected to cover a wide range of parameters (refractive index, dielectric constant and hydrogen bonding capacity). The electronic transitions are assigned and the solvent induced spectral shifts have been analyzed in relation to the different solute-solvent interaction mechanisms using computational chemistry. The regression analysis is applied for correlation parameters. The phenomenon of tautomerism is explained. The electronic character of the substituent as well as the chemistry of the solvent are the major factors for the solvatochromic behavior.


Assuntos
Compostos Azo/química , Piridinas/química , Solventes/química , Absorção , Aminação , Elétrons , Estrutura Molecular , Análise de Regressão , Soluções , Espectrofotometria
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 60(12): 2807-17, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15350916

RESUMO

Synthesis and characterization of [o-carboxy phenylazo] moiety of barbituric acid, thiobarbituric acid, thiouracil, citrazinic acid, and disodium chromotropate and their complexes derived from cobalt (II), nickel (II), and copper (II) salts were done. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, NMR, UV-Vis, IR and ESR. The dissociation constants of the free azo ligands are evaluated by spectrophotometric methods.


Assuntos
Compostos Azo/química , Cobalto/química , Cobre/química , Espectroscopia de Ressonância de Spin Eletrônica , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Níquel/química , Espectrofotometria , Espectrofotometria Infravermelho
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