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Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Dias, Patricia Moura; Kinouti, Lilian; Constantino, Vera Regina Leopoldo; Ferreira, Ana Maria da Costa; Gonçalves, Marcos Brown; Nascimento, Rafael Rodrigues do; Petrilli, Helena Maria; Caldas, Marilia Junqueira; Frem, Regina C. G.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.58418%
Herein, the immobilization of some Schiff base-copper(II) complexes in smectite clays is described as a strategy for the heterogenization of homogeneous catalysts. The obtained materials were characterized by spectroscopic techniques, mostly UV/Vis, EPR, XANES and luminescence spectroscopy. SWy-2 and synthetic Laponite clays were used for the immobilization of two different complexes that have previously shown catalytic activity in the dismutation of superoxide radicals, and disproportionation of hydrogen peroxide. The obtained results indicated the occurrence of an intriguing intramolecular redox process involving copper and the imine ligand at the surface of the clays. These studies are supported by computational calculations.

Double-strand DNA cleavage induced by oxindole-Schiff base copper(II) complexes with potential antitumor activity

SILVEIRA, Vivian Chagas da; LUZ, Juliana Silva; OLIVEIRA, Carla Columbano; GRAZIANI, Ilaria; CIRIOLO, Maria Rosa; FERREIRA, Ana Maria da Costa
Fonte: ELSEVIER SCIENCE INC Publicador: ELSEVIER SCIENCE INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
57.478613%
Some oxindole-Schiff base copper(II) complexes have already shown potential antitumor activity towards different cells, inducing apoptosis in a process modulated by the ligand, and having nuclei and mitochondria as main targets. Here, three novel copper(II) complexes with analogous ligands were isolated and characterized by spectroscopic techniques, having their reactivity compared to the so far most active complex in this class. Cytotoxicity experiments carried out toward human neuroblastoma SH-SY5Y cells confirmed its proapoptosis property. DNA cleavage studies were then performed in the presence of these complexes, in order to verify the influence of ligand structural features in its nuclease activity. All of them were able to cause double-strand DNA scissions, giving rise to nicked circular Form II and linear Form III species, in the presence of hydrogen peroxide. Additionally, DNA Form II was also detected in the absence of peroxide when the most active complex, [Cu(isaepy)(2)](2+) 1, was used. In an effort to better elucidate their interactions with DNA, solutions of the different complexes titrated with DNA had their absorption spectra monitored. An absorbance hyperchromism observed at 260 nm pointed to the intercalation of these complexes into the DNA structure. Further...

Isatin-Schiff base copper(II) complexes-A DFT study of the metal-ligand bonding situation

Caramori, Giovanni F.; Parreira, Renato L. T.; Da Costa Ferreira, Ana Maria
Fonte: WILEY-BLACKWELL; MALDEN Publicador: WILEY-BLACKWELL; MALDEN
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Herein, we report results of calculations based on density functional theory (BP86/TZVP) of a set of isatin-Schiff base copper(II) and related complexes, 1-12, that have shown significant pro-apoptotic activity toward diverse tumor cells. The interaction of the copper(II) cation with different ligands has been investigated at the same level of theory. The strength and character of the Cu(II)-L bonding was characterized by metal-ligand bond lengths, vibrational frequencies, binding energies, ligand deformation energies, and natural population analysis. The metal-ligand bonding situation was also characterized by using two complementary topological approaches, the quantum theory of atoms-in-molecules (QTAIM) and the electron localization function (ELF). The calculated electronic g-tensor and hyperfine coupling constants present significant agreement with the EPR experimental data. The calculated parameters pointed to complex 10 as the most stable among the isatin-Schiff base copper(II) species, in good agreement with experimental data that indicate this complex as the most reactive in the series. (C) 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012; FAPESP (Processo Tematico); FAPESP (Processo Tematico) [05/60596-8]; FAPESP [2007/04379-3...

Catalisadores de rutênio coordenados à base de Schiff para polimerização via metátese; Catalysis ruthenium Schiff base ligand for methatesis polymerization

Marques, Fernando Mattiucci
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/09/2013 PT
Relevância na Pesquisa
68.01488%
Essa pesquisa tem como meta estudar a atividade catalítica de complexos do tipo [RuCl2(PPh3)x(BS)] a partir de reações entre [RuCl2(PPh3)3] e os compostos do tipo Base de Schiff (BS) do tipo R1N=CHR2 onde os grupos R1 = cicloexil, fenil ou sec-butil, para aplicações em reações de polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE). As reações foram realizadas na presença de etildiazoacetato (EDA) e os resultados dos complexos foram comparados em relação às características dos polímeros isolados em função da temperatura e do tempo de reação. Os complexos foram caracterizados por análise elementar CNH, espectroscopia na região do infravermelho e UV-Vis, RMN (31P; 1H) e voltametria cíclica. Os poliNBE apresentaram um σc = 0,41 determinado por RMN 13C. Experimentos realizados por 60 minutos a 25 °C na razão [NBE]/[Ru] = 5000 mostraram que o complexo [RuCl(PPh3)2(Ph)(IminCy)] formou 95% de poliNBE, enquanto que o complexo [RuCl(PPh3)2(Ph)(IminPh)] sintetiza 81,4% de NBE. Para o complexo [RuCl(PPh3)2(Ph)(IminBu)] sua atividade em ROMP para o NBE foi de 70,3%. Assim foi comparado a reatividade entre os ligantes Cy, Ph e Bu. Nas mesmas condições, apenas o complexo [RuCl(PPh3)2(Ph)(IminCy)] obteve melhora significativa no rendimento a 50 °C. Foram investigados também os efeitos de agentes promotores como ácido...

Preparação e caracterização de bases de Schiff e complexos metálicos a partir de quitosana e derivados de salicilaldeído; Preparation and characterization of Schiff base and metal complexes from chitosan and derivatives of salicylaldehyde

Araújo, Eliene Leandro de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/03/2015 PT
Relevância na Pesquisa
58.05847%
Bases de Schiff biopoliméricas à base de quitosana foram preparadas a partir do salicilaldeído e de seus derivados substituídos na posição 5 do anel aromático do salicilaldeído (5-bromo, 5-cloro, 5-metil, 5-metóxi e 5-nitrosalicilaldeído), utilizando condições de síntese otimizadas para aumentar o grau de substituição (GS). Durante a caracterização das bases foram observados GS (%) = 78,7; 51,3; 43,7; 28,1; 22,1 e 17,5, respectivamente para os derivados 5-metóxi, salicilaldeído, 5-nitro, 5-cloro, 5-metil e 5-bromo, tendo sido as diferenças atribuídas ao caráter indutivo e de ressonância de cada um dos grupos substituintes. A partir desses ligantes foram sintetizados os complexos de cobre (II) e níquel (II) com quitosana e todas as bases de Schiff biopoliméricas. A quitosana, os ligantes e os complexos foram caracterizados por espectroscopia vibracional na região do infravermelho com transformada de Fourier (FTIR) e técnicas termoanalíticas (termogravimetria, TG; termogravimetria derivada, DTG e análise térmica diferencial, DTA). A quitosana utilizada apresentou grau de desacetilação, GD = 75,6%, determinado por 1H RMN, e apresentou as bandas características para estes biopolímeros nos espectros FTIR e decomposição térmica em dois eventos exotérmicos...

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Dias, Patrícia M.; Kinouti, Lilian; Constantino, Vera R. L.; Ferreira, Ana M. D. C.; Gonçalves, Marcos B.; Nascimento, Rafael R. do; Petrilli, Helena M.; Caldas, Marília; Frem, Regina C. G.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: 2135-2142
ENG
Relevância na Pesquisa
67.58418%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Herein, the immobilization of some Schiff base-copper(II) complexes in smectite clays is described as a strategy for the heterogenization of homogeneous catalysts. The obtained materials were characterized by spectroscopic techniques, mostly UV/Vis, EPR, XANES and luminescence spectroscopy. SWy-2 and synthetic Laponite clays were used for the immobilization of two different complexes that have previously shown catalytic activity in the dismutation of superoxide radicals, and disproportionation of hydrogen peroxide. The obtained results indicated the occurrence of an intriguing intramolecular redox process involving copper and the imine ligand at the surface of the clays. These studies are supported by computational calculations.

Synthesis, characterization and spectroscopic studies of two new schiff-base bithienyl pendant-armed 15-crown-5 molecular probes

Pedras, Bruno; Fernandes, Luz; Oliveira, Elisabete; Rodríguez, Laura; Raposo, M. Manuela M.; Capelo, José Luis; Lodeiro, Carlos
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2009 ENG
Relevância na Pesquisa
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Nickel(II); Palladium(II); Mercury(II); Sodium(I); ; Crown ether, Schiff base, Luminescence; Two new ligands provided with a 15-crown-5 as receptor unit and bithiophen unit as emissive probe have been synthesized and characterized in order to evaluate the coordination capabilities and their sensor effect. Ligand L1 presents an aromatic crown ether moiety directed linked to the imine-2,2´-bithiophene π–conjugated system and ligand L2 is constituted by an aliphatic crown ether moiety linked to the same imine-2,2´-bithiophene system through a methylene unit. Solid metal complexes of Ni(II), Pd(II), Hg(II) and Na(I) have been synthesized using both macrocyclic compounds, and have been studied in solution in the presence of the same metal ions. All solid compounds have been characterized by common analytical and spectroscopic techniques. The sensorial effect has been studied using absorption, emission and MALDI-TOF-MS spectroscopies.; Fundação para a Ciência e a Tecnologia (FCT)

Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

Dias,Patrícia M.; Kinouti,Lilian; Constantino,Vera R. L.; Ferreira,Ana M. D. C.; Gonçalves,Marcos B.; Nascimento,Rafael R. do; Petrilli,Helena M.; Caldas,Marília; Frem,Regina C. G.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
67.58418%
Herein, the immobilization of some Schiff base-copper(II) complexes in smectite clays is described as a strategy for the heterogenization of homogeneous catalysts. The obtained materials were characterized by spectroscopic techniques, mostly UV/Vis, EPR, XANES and luminescence spectroscopy. SWy-2 and synthetic Laponite clays were used for the immobilization of two different complexes that have previously shown catalytic activity in the dismutation of superoxide radicals, and disproportionation of hydrogen peroxide. The obtained results indicated the occurrence of an intriguing intramolecular redox process involving copper and the imine ligand at the surface of the clays. These studies are supported by computational calculations.

Heterogeneously catalyzed phosphine-free heck cross-coupling reaction of aryl halides with reusable palladium(II) schiff base complex

Islam,Manirul; Mondal,Paramita; Tuhina,Kazi; Roy,Anupam S
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2011 EN
Relevância na Pesquisa
67.58418%
The coupling between aryl halides with terminal alkenes (Heck reaction) has been investigated in the presence of a polystyrene-supported Schiff base palladium(II) catalyst. The present catalyst is air and moisture-stable and has significant catalytic activity in Heck cross-coupling reactions under operating conditions. Various aryl halides and terminal alkenes were coupled smoothly under air, to afford the corresponding cross-coupled products in excellent yields. Furthermore, the catalyst can be easily recovered quantitatively by simple filtration and reused up to seven cycles without losing its activity.

Selected topics in fast atom bombardment (FAB) mass spectrometry a)specially designed probe tips and ion generation, b)structures of vitamin B6 schiff base complexes

Fulcher, Adrian N.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
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This thesis can be broken down into two sections. Section one is a study . of the ionization mechanisms and the ion source optimization for Fast Atom Bombardment (FAB) ionization. For this study, several specially designed probe tips were created and tested under various experimental conditions. The aIm of this section is to understand the operating characteristics of a FAB IOn source better. The second section involves the study of several Vitamin B6 Schiff Base complexes using both positive and negative ion FAB MS. This section is an exploration of the usefulness of FAB MS as a structure probe for the metalcoordination complexes of Vitamin B6.

Metallkomplex-modifizierte-Kieselgelpartikel - Synthese und Charakterisierung von Stöber-SiO2-Materialien und Co-Schiff-Basen-Komplexen für deren Modifizierung; Metal complexe modified silica particles - Synthesis and characterization of Stöber-SiO2-Materials and Co-Schiff-base complexes for their modification

Ruff, Adrian
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Masterarbeit
DE_DE
Relevância na Pesquisa
57.76855%
Monodisperse, sphärische, unporöse Kieselgelpartikel mit Durchmessern von 140 - 600 nm wurden nach dem Stöber-Prozess dargestellt und mittels DLS, REM, DRIFT und BET Messungen charakterisiert. Dabei wurde der Partikeldurchmesser durch die Temperatur kontrolliert. Für die Modifizierung der Partikel wurden verschiedene Co(II)-Komplexe mit vierzähnigen N2O2-Schiff-Basen-Liganden dargestellt und mit spektroskopischen (NMR, IR, MS) und elektroanalytischen Methoden (CV) untersucht. Mittels DRIFT-Spektroskopie und Elementaranalyse konnte die erfolgreiche Immobilisierung eines Co(II)-Komplexes mit Alkoxysilylsubstituenten auf einem mit Hydroxygruppen modifiziertem Kieselgelmaterial nachgewiesen werden.; Monodisperse, spherical, nonporous silica particles with diameters from 140 - 600 nm have been prepared by the Stöber process and were characterized by DLS, SEM, DRIFT and BET messurements. The particle diameter was controlled by temperature. Several Co(II) complexes with tetradentate N2O2-Schiff-base ligands have been synthesized as possible modifiers. These were studied by spectroscopic (NMR, IR, MS) and electrochemical (CV) methods. The successful immobilization of an alkoxysilyl substituted Co(II) complexe on hydroxy modified silica particles was studied by DRIFT spectroscopy and elemental analysis.

Synthesis and characterisation of nickel Schiff base complexes containing the meso-1,2-diphenylethylenediamine moiety: selective interactions with a tetramolecular DNA quadruplex

Davis, Kimberley J; Richardson, Christopher; Beck, Jennifer L; Knowles, Brett M; Guédin, Aurore; Mergny, Jean-Louis; Willis, Anthony C; Ralph, Stephen F
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Artigo de Revista Científica Formato: 15 pages
Relevância na Pesquisa
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As part of a program of preparing metal complexes which exhibit unique affinities towards different DNA structures, we have synthesised the novel Schiff base complex N,N'-bis-4-(hydroxysalicylidine)meso-diphenylethylenediaminenickel(ii) (), via the reaction of meso-1,2-diphenylethylenediamine and 2,4-dihydroxybenzaldehyde. This compound was subsequently reacted with 1-(2-chloroethyl)piperidine or 1-(2-chloropropyl)piperidine, to afford the alkylated complexes N,N'-bis-(4-((1-(2-ethyl)piperidine)oxy)salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) () and N,N'-bis-(4-((1-(3-propyl)piperidine)oxy)-salicylidine)meso-1,2-diphenylethylenediaminenickel(ii) (), respectively. These complexes were characterised by microanalysis and X-ray crystallography in the solid state, and in solution by (1)H and (13)C NMR spectroscopy. Electrospray ionisation mass spectrometry (ESI-MS) was used to confirm the identity of () and (). The affinities of () and () towards a discrete 16 mer duplex DNA molecule, and examples of both tetramolecular and unimolecular DNA quadruplexes, was explored using a variety of techniques. In addition, the affinity of two other complexes () and (), towards the same DNA molecules was examined. Complexes () and () were prepared by methods analogous to those which afforded () and ()...

Synthesis, Characterization and Biological Activities of a Bidentate Schiff Base Ligand: N,N '-Bis(1-phenylethylidene)ethane-1,2-diamine and its Transition Metals (II) Complexes

Parvez, Shoukat; Anis, Itrat; Afza, Nighat; Aslam, Muhammad; Hussain, Muhammad Tahir; Hussain, Ajaz; Sherazi, Tauqir Ali; Shah, Muhammad Raza; Khalid, Muhammad; Bokhari, Tanveer Hussain
Fonte: CHEM SOC PAKISTAN; KARACHI Publicador: CHEM SOC PAKISTAN; KARACHI
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
67.782964%
Schiff base ligand: N,N'-bis(1-phenylethylidene)ethane-1,2-diamine (L), was derived from acetophenone and ethylenediamine by condensation and its complexes (1-5) were prepared with Pb2+, Ni2+, Co2+, Cu2+ and Cd2+ metal ions. Their structures were characterized by FAB-MS, IR spectra, elemental analyses and molar conductance. The octahedral geometry of the complexes was proposed by electronic spectra and magnetic moment data. The conductivity data showed that the complexes have non-electrolytic nature. The complexes (1-5) have higher in vitro antimicrobial activity than the Schiff base ligand (L). In the nuclease activity, the complexes cleave DNA as compared to control DNA in the presence of H2O2.

Using of a graphite-polyurethane composite electrode modified with a Schiff base as a bio-inspired sensor in the dopamine determination

Santos,Sidney X. dos; Cavalheiro,Éder T. G.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
57.36673%
A solid composite electrode based on graphite and polyurethane resin modified with a copper(II) complex of the symmetrical tetradentate Schiff's base type, N, N'-ethylenebis(salicylideneiminato) copper(II) ([Cu(II)Salen]), was evaluated as a bio-inspired sensor using dopamine (DA) as a model analyte. The voltammetric behavior of the modifier [Cu(II)Salen] was investigated at a modified carbon paste electrode and a redox mechanism was proposed. The analytical potentialities of the composite electrode based on graphite and polyurethane resin (GPU) modified with [Cu(II)Salen] (MGPU) were evaluated using DA as probe. MGPU presents best results when compared with GPU without modification, with electrocatalytic effect, indicating that the electrode can be characterized as a bio-inspired sensor. The MGPU electrode was applied in the determination of DA in pharmaceutical formulation using DPV and the results were compared to those obtained with the official method (high performance liquid chromatography, HPLC) as described in US Pharmacopoeia, agreeing within 95% confidence level according to student's t-test.

1-D arrays of Cu(I)-Schiff base maintained by fourfold phenyl embraces isolating diiodocuprate(I) anions

Amirnasr, Mehdi; Dehno Khalaji, Aliakbar; Falvello, Larry R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
67.58418%
5 pages, 6 figures, 2 tables, 1 appendix.-- Available online 15 Dec. 2005.; The reaction of CuI with the bidentate Schiff base ligand (Phca2-dab) in acetonitrile yields a new mononuclear Cu(I) complex [Cu(Phca2-dab)2][CuI2]. The structure contains cationic moieties of CuI ion coordinated to four N atoms of two Phca2-dab ligands in a distorted tetrahedral fashion and isolated linear diiodocuprate(I) anions. The Phca2-dab ligand adopts a Z,Z configuration. A supramolecular motif that is a one-dimensional array of Phca2-dab embraces formed by the complex has been identified from the crystal packing analysis. The Phca2-dab embrace involves two complexes attracted by two edge-to-face (ef) interactions by the outer phenyl rings of the ligands.; Ministry of Education and Science (Spain) for support under grant BQU2002-00554. M.A. and A.D.K. would like to acknowledge the Isfahan University of Technology Research Council for partial support of this work.; Peer reviewed

Synthesis, structure, and reactivity of bis(N,N'-bis(2-hydroxybenzylidene)-2-hydroxyphenylmethanediaminato)zirconium(IV), a Schiff base complex with 6,4,6-membered chelate rings

Illingsworth, Marvin; Schwartz, Leslie; Jensen, Andrew; Zhu, Tong; Knappenberger, Eric; Sweet, Julie; Wilkinson, Patricia; Waltermire, Beth; Rheingold, Arnold
Fonte: Eight-coordinate Publicador: Eight-coordinate
Tipo: Pré-impressão Formato: 657869 bytes; application/pdf
EN
Relevância na Pesquisa
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The title complex Zr(dshpm)2 has been successfully prepared by heating a 1:2 mole ratio of Zr(OBu")4 and the free ligand in absolute ethanol. It is mononuclear and eight-coordinate in the solid state with a dodecahedral coordination sphere. The two O,N,N,O donor atom quadridentate Schiff base ligands each form 6,4,6-membered chelate rings. As expected, the change in a chelate ring sizes from 6,5,6- to 6,4,6- resulted in significantly more labile complex, as indicatd by TLC and NMR of heated solutions and its subsequent chemical reactions. The 0.010 A shorter average Zr-N bond distance was not anticipated, and appears to result from the zirconium atom's preference that the oxygen atoms occupy certain locations. Preparations of two heteroleptic complexes from the title complex were undertaken to evaluate potential of the title compound as a synthon. A new fluorine-substituted homoleptic Schiff base Zr complex was also prepared, for comparison purposes. Despite the reasonable stability of Zr(dshpm)2 in air, the decomposition of labilized Hdshpm(2-) ligand on silica gel and in heated solution interfered with the purifications of the desired heteroleptic products.; RIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/

Synthesis, Spectroscopic Characterization, Thermal Analysis and Antibacterial Activity of Ni(II), Cu(II) and Zn(II) Complexes with Schiff bases Derived from β-Diketones

Ahmadzadeh,Razieh; Azarkish,Mohammad; Sedaghat,Tahereh
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
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Five transition metal complexes, [CuLª] (1), [NiLª] (2), [ZnLª] (3), [CuLb] (4) and [NiLb].EtOH (5) have been synthesized from reaction of Ni(II), Cu(II) and Zn(II) acetate salts with two Schiff bases, 3-(2-hydroxy-5-methylphenylamino)-1,3-diphenylprop-2-en-1-one (H2Lª) and 3-(2-hydroxy-5-methylphenylimino)-1-phenylbuten-1-one (H2Lb). On the basis of analytical and spectral data, Schiff base is coordinated to metal as tridentate dianionic ligand via phenolic and enolic oxygens and imine nitrogen. Thermal decomposition of the complexes has been studied by thermogravimetry. The in vitro antibacterial activity of Schiff bases and their complexes has been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and compared with the standard drugs.

Electrochemical Characterization of the Influence of Scanning Number on the Self-assembled Monolayer Formed by Schiff Base

Ding,K.; Wang,Q.; Jia,Z.; Tong,R.; Wang,X.
Fonte: Sociedade Portuguesa de Electroquímica Publicador: Sociedade Portuguesa de Electroquímica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2003 EN
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The influence of potential-scan number on the Schiff base self-assembled monolayer was probed by the Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) techniques for the first time. The results showed that the charge transferring resistance (Rct) could be reduced with the potential-scan, suggesting that the structure of the self-assembled monolayer was altered. Also, the relationship between the content of C=N group, represented approximately by the reduction electric charge (Qr), and the monolayer’s packing degree which was represented by the value of Rct, was described. Providing a new way to change the interface characterization is the main contribution of this paper.

Isolation, characterization and x-ray structure determination of the schiff base ligand: 5-methyl-2-phenyl-4-[phenyl-(4-phenyl-thiazol-2-ylamino)-methylene]-2,4-dihydro-pyrazol-3-one

Thakar,Amit S.; Friedrich,Holger B.; Joshi,Krishnalal T.; Maguire,Glenn E.M.
Fonte: South African Journal of Chemistry Publicador: South African Journal of Chemistry
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
Relevância na Pesquisa
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The structure of the amine tautomer of the new Schiff base derived from 4-benzoyl-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one (2) and 4-phenyl-thiazol-2-ylamine (3) was confirmed by means of single crystal X-ray diffraction. The title compound (4) was synthesized and crystals were grown from a mixture of dichloromethane and n-hexane (1:3). Single crystal X-ray diffraction analysis show that the structure is primarily stabilized by strong intramolecular N3-H3A-O1 hydrogen bonds [N3-H3A = 0.883(19) Ẳ, H3A-O1 = 1.925(18) Ẳ, N3-O1 = 2.6901(13) A, with an angle for N3-H3A-O1 = 144.1(17) °] and this leads to the formation of a pseudo nine-membered hydrogen bonded pattern. Elemental analysis, FTIR and NMR analyses have been employed to characterize the crystal.

A novel coumarin Schiff-base fluorescent probe for Mg2+

Zhou,Xian-Gui; Peng,Ming-Sheng; Feng,Tang-Zhen
Fonte: South African Journal of Chemistry Publicador: South African Journal of Chemistry
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2013 EN
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A novel fluorescent probe for Mg²+ based on coumarin Schiff-base was synthesized and characterized. The sensor displayed high selectivity toward Mg²+ in acetonitrile, and shows 1:1 complex formation with Mg²+ in acetonitrile.