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ABSTRACT: The Co(II), Ni(II), and Cu(II) complexes with Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and
fluvastatin have been synthesized. Schiff bases exhibited thiol–thione tautomerism and coordinated to metal ion through azomethine
nitrogen and thiolate sulphur atoms. Square planar geometry for all the metal complexes of the type ML2 has been proposed in the light of analytical, spectral (IR, UV–Vis., ESR, and FAB-mass), magnetic, and thermal studies. The
antimicrobial studies of Schiff bases and their metal complexes against various antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis) and antifungal (Aspergillus niger, and Pencillium Chrysogenum) species by Minimum Inhibitory Concentration method revealed that, the metal complexes possess more healing antibacterial
activity than the Schiff bases. Co(II), Ni(II), and Cu(II) complexes cleave the DNA isolated from A. niger.
KeywordsAntibacterial–Antifungal–DNA cleavage–Spectroscopic studies–Schiff base complexes–Transition metal complexes
Medicinal Chemistry Research 04/2012; 20(3):346-354. · 1.27 Impact Factor
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ABSTRACT: A novel series of 17-membered complexes [MLCl2] (M=Co2+, Ni2+ and Cu2+) have been synthesized with newly derived biologically active ligands (LI–LIV). These ligands were synthesized by the condensation of 3-subtituted-4-amino-5-hydrazino-1,2,4-triazole with bis(phthalaldehyde)ethylenediamine precursor. The structure of the complexes has been proposed by elemental analyses, IR, EPR,
electronic spectral studies, conductivity, magnetic, thermal and electrochemical studies. All the complexes are soluble in
DMF and DMSO and are non-electrolytes. All these Schiff bases and their complexes have been screened for their antibacterial
(Escherichia coli, Staphylococus aureus, Salmonella typhi, Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by the Agar and Potato dextrose agar diffusion method. The DNA cleavage study was done by Agarose gel electrophoresis technique.
KeywordsPhthalaldehyde-Triazole-Ethylenediamine-Macrocycle-Biologically active
Journal of Inclusion Phenomena 04/2012; 68(3):347-358. · 1.89 Impact Factor
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ABSTRACT: A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial (Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities (Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 05/2011; 79(5):1128-36. · 2.10 Impact Factor
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ABSTRACT: A series of metal complexes ML2 · 2H2O [M = Co(II), Ni(II), and Cu(II)] have been synthesized with Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and 4-chloro-3-coumarinaldehyde. The structures of these metal complexes have been proposed from elemental analyses, spectral (IR, UV-Vis, FAB-mass, ESR, and fluorescence), magnetic, and thermal studies. Low molar conductance values in DMF indicate that the metal complexes are non-electrolytes. Cyclic voltammetric studies suggested that the Ni(II) and Cu(II) complexes are single-electron transfer quasi-reversible. The Schiff bases and their metal complexes have been screened for in vitro antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhi) and antifungal activities (Candida albicans, Cladosporium, and Aspergillus niger) by the minimum inhibitory concentration method. The Schiff base I and its Co(II) and Ni(II) complexes exhibit DNA cleavage activity on isolated DNA of S. aureus and A. niger.
Journal of Coordination Chemistry 01/2011; 64(2):323-336. · 1.55 Impact Factor
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ABSTRACT: A novel series of 22-membered macrocyclic complexes of the type [MLCl(2)] (M=Co(2+), Ni(2+) and Cu(2+)) have been synthesized with newly derived biologically active ligands (L(1)-L(IV)). These ligands were synthesized by the condensation of ortho-phthalaldehyde and bis-(4-amino-5-mercapto-1, 2, 4-triazole-3-yl)alkanes. The mode of bonding and overall geometry of the complexes have been inferred through IR, EPR, electronic spectral studies, conductivity, magnetic, thermal, and electrochemical studies. All these complexes have been screened for their antibacterial (Escherichia coli, Staphylococus aureus, Salmonella typhi, Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the minimal inhibitory concentration (MIC) method. The DNA cleavage study was done by agarose gel electrophoresis technique.
Nucleosides Nucleotides & Nucleic Acids 09/2010; 29(9):658-75. · 0.90 Impact Factor
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ABSTRACT: A novel series of N2O2 diazadioxa macrocyclic complexes [MLCl2] (M=Co2+, Ni2+ and Cu2+) have been synthesized with newly derived biologically active ligands (LI-LIV). These ligands were synthesized by the condensation of 1, 6-bis(2-formylphenyl)hexane and 3-subtituted-4-amino-5-hydrazino-1, 2, 4-triazole. The mode of bonding and overall geometry of the complexes have been inferred through IR, EPR, electronic spectral studies, conductivity, magnetic, thermal and electrochemical studies. All the complexes are soluble in DMF and DMSO and are non-electrolytes. All these complexes have been screened for their antibacterial (Escherichia coli, Staphylococus aureus, Salmonella typhi, Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by the MIC method. The DNA cleavage study was done by Agarose gel electrophoresis.
Journal of Macromolecular Science Part A 06/2010; Part A: Pure and Applied Chemistry(Vol. 47):510-520. · 0.89 Impact Factor
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ABSTRACT: A series of Co(II), Ni(II) and Cu(II) complexes of the type ML2 of Schiff bases derived from methylthiosemicarbazide and isatin/chloroisatin have been synthesized. Schiff bases exhibit thiol–thione tautomerism wherein sulfur plays an important role in the coordination. In view of analytical, spectral (IR, NMR, UV-vis, ESR, FAB-Mass) and magnetic studies, it has been concluded that all the metal complexes possess octahedral geometry. The measured molar conductance values in DMF indicate that the complexes are non-electrolytes in nature. The redox behaviors of the metal complexes are investigated by using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by the minimum inhibitory concentration method. The DNA cleavage studies showed the cleavage of DNA by the agarose gel electrophoresis method.
Journal of Sulfur Chemistry 04/2010; 31(2):109-121. · 1.01 Impact Factor
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ABSTRACT: A series of metal complexes of cobalt(II), nickel(II), and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 2-amino-4-phenyl-1,3-thiazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of analytical and spectroscopic data (IR, UV-Vis, ESR, FAB-mass, and thermoanalytical). Electrochemical study of the complexes is also reported. Elemental analysis of the complexes confined them to stoichiometry of the type ML(2).2H(2)O [M = Co(II), Ni(II), and Cu(II)]. The Schiff base and its metal(II) complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes, and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the MIC method. The brine shrimp bioassay was carried out to study their in vitro cytotoxic properties, and also the Schiff base and its metal(II) complexes have been studied for DNA cleavage.
Journal of Enzyme Inhibition and Medicinal Chemistry 04/2010; 25(3):430-9. · 1.62 Impact Factor
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ABSTRACT: A series of Co(II), Ni(II), and Cu(II) complexes of the type ML.2H2O have been synthesized with Schiff bases derived from 8-formyl-7-hydroxy-4-methylcoumarin and o-phenylenediamine/ethylenediamine. The structure of the complexes has been proposed in the light of analytical, spectral (IR, UV-Vis, ESR, and FAB-mass), magnetic, thermal, and fluorescence studies. The complexes are soluble in DMF and DMSO. The measured molar conductance values indicate that the complexes are non-electrolytes in nature. In view of IR, UV-Vis, and magnetic studies, it has been concluded that all the complexes possess octahedral geometry, in which ligand is coordinated to metal ion through the azomethine nitrogen and phenolic oxygen via deprotonation. Thermal studies provide useful information about the coordination of water molecules to the metal ion and the stability of the complexes. The redox behavior of the complexes has been investigated by an electrochemical method using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the minimum inhibitory concentration method. DNA binding with Co(II) and Cu(II) complexes has been studied by the agarose gel electrophoresis method.
Journal of Enzyme Inhibition and Medicinal Chemistry 02/2010; 25(1):87-96. · 1.62 Impact Factor
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ABSTRACT: Co(II), Ni(II), and Cu(II) complexes, ML2 · 2H2O have been synthesized with Schiff bases derived from m-substituted thiosemicarbazides and 2-methoxy benzaldehyde. The complexes are soluble in DMF/DMSO and non-electrolytes. From analytical, spectral (IR, UV-Vis, ESR, and FAB-mass), magnetic and thermal studies octahedral geometry is proposed for the complexes. The redox behavior of the complexes was investigated using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by Minimum Inhibitory Concentration method. DNA cleavage is studied by agarose gel electrophoresis method.
Journal of Coordination Chemistry 02/2010; 63(4):688-699. · 1.55 Impact Factor
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ABSTRACT: A series of Co(II), Ni(II), and Cu(II) complexes have been synthesized with Schiff bases (H2LI and H2LII) derived from 8-formyl-7-hydroxy-4-methylcoumarin or 5-formyl-6-hydroxycoumarin and o-aminophenol. Structures have been proposed from elemental analyses, spectral (IR, UV-Vis, FAB-mass, and Fluorescence), magnetic, and thermal studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Elemental analyses indicate ML · 3H2O [M = Co(II), Ni(II), and Cu(II)] stoichiometry. Spectroscopic studies suggest coordination through azomethine nitrogen, phenolic oxygen of o-aminophenol, and the coumarin via deprotonation. The Schiff bases and their complexes have been screened for antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, and Cladosporium) activities by minimum inhibitory concentration (MIC) method. The redox behavior of the complexes was investigated using cyclic voltammetry (CV).
Journal of Coordination Chemistry 09/2009; 62(18):3060-3072. · 1.55 Impact Factor
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ABSTRACT: A series of metal complexes of La(III) and Th(IV) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 3-substituted-4-amino-5-hydrazino-1,2,4-triazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The structure of the complexes has been proposed by elemental analyses, spectroscopic data i.e. i.r., (1)H nmr, Uv-Vis, FAB-mass and thermal studies. The elemental analyses of the complexes conform to the stoichiometry of the type [La(L).3H2O].2H2O and [Th(L)(NO3).2H2O].2H2O where (L = L(I)-L(IV)). All the complexes are soluble in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these ligands and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus and cladosporium) by the MIC method. The brine shrimp bioassay was also carried out to study their invitro cytotoxic properties.
Journal of Enzyme Inhibition and Medicinal Chemistry 07/2009; 24(3):730-41. · 1.62 Impact Factor
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ABSTRACT: A macrocyclic hydrazone Schiff base was synthesized by reacting 1,4-dicarbonyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol and a series of metal complexes with this new Schiff base were synthesized by reaction with Co(II), Ni(II) and Cu(II) metal salts. The Schiff base and its complexes have been characterized by elemental analyses, IR, (1)H NMR, UV-vis, FAB mass, ESR spectra, fluorescence, thermal, magnetic and molar conductance data. The analytical data reveal that the Co(II), Ni(II) and Cu(II) complexes possess 2:1 metal-ligand ratios. All the complexes are non-electrolytes in DMF and DMSO due to their low molar conductance values. Infrared spectral data suggest that the hydrazone Schiff base behaves as a hexadentate ligand with NON NON donor sequence towards the metal ions. The ESR spectral data shows that the metal-ligand bond has considerable covalent character. The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry. The Schiff base and its complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Shigella dysentery, Micrococcus, Bacillus subtilis, Bacillus cereus and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Penicillium and Candida albicans) by MIC method. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties.
European journal of medicinal chemistry 05/2009; 44(9):3552-9. · 3.27 Impact Factor
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ABSTRACT: A series of metal complexes of cobalt(II), nickel(II), copper(II), and zinc(II) have been synthesized with newly-derived biologically active ligands. These ligands were synthesized by condensation of 3-substituted-4-amino-5-hydrazino-1,2,4-triazole and orthophthalaldehyde. The probable structure of the complexes has been proposed on the basis of elemental analyses and spectral (IR, 1H-NMR, UV-vis, magnetic, ESR, FAB-mass and thermal studies) data. Electrochemical study of the complexes is also made. All complexes are nonelectrolytes in N,N-dimethyl formamide and DMSO. The Schiff bases and their Co(II), Ni(II), Cu(II), and Zn(II) complexes have been screened for antibacterial (Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa) and antifungal (Aspergillus niger, Aspergillus flavus, and cladosporium) activities by minimum inhibitory concentration method. DNA cleavage is also carried out.
Journal of Coordination Chemistry 05/2009; 62(10):1690-1700. · 1.55 Impact Factor
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ABSTRACT: A series of Co(II), Ni(II) and Cu(II) complexes have been synthesized with newly synthesized Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and isatin. The elemental analyses of the complexes are confined to the stoichiometry of the type ML2 [M=Co(II), Ni(II) and Cu(II)], respectively, where L acts as a deprotonated ligand in which sulfur plays an important role in coordination. In view of analytical, spectroscopic, magnetic and thermal studies, it has been concluded that the Co(II), Ni(II) and Cu(II) complexes possess octahedral geometry. The redox behavior of the complexes investigated with the aid of cyclic voltammetry indicated the two-electron transfer process. The antimicrobial studies of Schiff bases and their complexes against various antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis) and antifungal (Aspergillus niger and Pencillium chrysogenum) species by the minimum inhibitory concentration method revealed that the Schiff bases and some of their metal complexes possess more healing antibacterial activity.
Journal of Sulfur Chemistry 04/2009; 30(2):145-159. · 1.01 Impact Factor
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ABSTRACT: A series of La(III), Th(IV) and VO(IV) complexes have been synthesized with Schiff bases derived from 8-formyl-7-hydroxy-4-methylcoumarin and o-phenylenediamine/ethylenediamine. The structure of the complexes has been proposed in the light of analytical, spectral (IR, UV-vis, ESR and FAB-mass), Magnetic and thermal studies. The complexes are soluble in DMF and DMSO. The measured molar conductance values indicate that, the complexes are non-electrolytes in nature. The redox behavior of the complexes was investigated by electrochemical method using cyclic voltammetry. The Schiff bases and their complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and cladosporium) by Minimum Inhibitory Concentration method. The DNA cleavage activity of La(III) and VO(IV) metal complexes is studied by agarose gel electrophoresis method.
European journal of medicinal chemistry 01/2009; 44(7):2904-12. · 3.27 Impact Factor
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ABSTRACT: A series of cobalt(II), nickel(II) and copper(II) complexes have been synthesized with Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and indole-3-aldehyde in ethanol. These complexes have been characterized by elemental analyses, magnetic, spectroscopic (IR, UV-Vis, H-NMR, ESR, FAB-mass), thermal, electrochemical (CV) and solid state d.c. electrical conductivity studies. The elemental analyses confirm 1 : 2 stoichiometry of the type ML2·2H2O (M = Co/Ni) and ML2 (M=Cu). The complexes are colored solids and non-electrolytes in DMF and DMSO. Magnetic and spectral data suggest octahedral geometry for Co(II) and Ni(II) complexes and square-planar geometry for Cu(II) complexes. The presence of coordinated water in Co(II) and Ni(II) complexes was confirmed by thermal and IR data of the complexes. The complexes are insoluble in water and common organic solvents and decompose at higher temperature. All these ligands and their complexes have also been screened for antibacterial (Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger and Aspergillus fumigates) by the cup plate method.
Journal of Coordination Chemistry. 06/2008; 61(12):1884-1896.
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ABSTRACT: A series of Co(II) complexes have been synthesized with Schiff bases derived from 3-substituted-4-amino-5-hydrazino-1,2,4-triazole
and substituted salicylaldehydes. These complexes are insoluble in water but more soluble in DMF and DMSO. The complexes have
been characterized by elemental analyses, spectral (IR, UV–Vis, 1H-NMR, FAB-mass, fluorescence), magnetic, thermal, solid-state DC electrical conductivity and molar conductance data. The
molar conductivity values indicate that they are non-electrolytes. The elemental analyses of the complexes suggest a stoichiometry
of the type Co·L1–L16·2H2O. The complexes have been considered as semiconductors on the basis of the solid-state DC electrical conductivity data.
Fluorescence spectra of one Schiff base and its complex were investigated in various solvents and some of the Schiff bases
and their complexes were evaluated for their antimicrobial activities.
Transition Metal Chemistry 03/2008; 33(3):275-283. · 1.02 Impact Factor
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ABSTRACT: A series of metal complexes of cobalt(II), nickel(II) and copper(II) have been synthesized with newly synthesized biologically active 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole and 8-formyl-7-hydroxy-4-methylcoumarin, which have been characterized by elemental analyses, spectroscopic measurements (IR, UV-vis, fluorescence, ESR), magnetic measurements and thermal studies. Electrochemical study of the complexes is also reported. All the complexes are soluble to limited extent in common organic solvents but soluble to larger extent in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these Schiff bases and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by MIC method. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties.
European journal of medicinal chemistry 03/2008; 43(12):2639-49. · 3.27 Impact Factor
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ABSTRACT: In this study, hollow microspheres of cellulose acetate butyrate (CAB) and poly(ethylene oxide) (PEO) were prepared by emulsion–solvent evaporation method. Repaglinide was successfully encapsulated into floating microspheres. Various formulations were prepared by varying the ratio of CAB and PEO, drug loading and concentration of poly(vinyl alcohol) (PVA) solution. Encapsulation of the drug up to 95% was achieved. The microspheres tend to float over the simulated gastric media for more than 10 h. The micromeritic properties of microspheres reveal the excellent flow and good packing properties. The % buoyancy of microspheres was found to be up to 87. SEM showed that microspheres have many pores on their surfaces. Particle size ranges from 159 to 601 μm. DSC and X-RD revealed the amorphous dispersion in the polymer matrix. In vitro release experiments were performed in simulated gastric fluid. In vitro release studies indicated the dependence of release rate on the extent of drug loading and the amount of PEO in the microspheres; slow release was extended up to 12 h. The release data were fitted to an empirical equation to compute the diffusional exponent (n), which indicated that the release mechanism followed the non-Fickian trend. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Journal of Applied Polymer Science 09/2007; 105(5):2764 - 2771. · 1.29 Impact Factor
