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Articles by Nahid Nishat
Total Records ( 7 ) for Nahid Nishat
  Tansir Ahamad , Nahid Nishat and Shadma Parveen
  A new polymeric Schiff base containing formaldehyde and piperazine moieties has been synthesized by condensation of salicylaldimine, formaldehyde and piperazine in alkaline medium; its metal polychelates have also been synthesized with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) acetate. The synthesized Schiff base and its metal polychelates were characterized by elemental, spectral (IR, 1H NMR, UV-visible) and thermogravimetric analysis (TGA). Electronic spectra and magnetic moments indicate that Mn(II), Co(II) and Ni(II) polychelates show octahedral geometry, while Cu(II) and Zn(II) polychelates show square planar and tetrahedral geometry, respectively. All compounds show excellent anti-bacterial as well as anti-fungal activity against three bacteria and two fungi. The anti-microbial activities were determined by using agar well diffusion method, with 50 µg mL-1 and 100 µg mL-1 concentration of each compound tested against the microbes.
  Nahid Nishat , Rahis-Ud-Din and Swati Dhyani
  The semicarbazone (L1) has been prepared by reaction of semicarbazide and glutaraldehyde (2 : 1) in distilled water and methanol (1 : 1). The reaction of semicarbazide, glutaraldehyde and diethyl oxalate in distilled water and methanol gave Schiff-base L2, 1,2,4,7,9,10-hexaazacyclo-pentadeca-10,15-dien-3,5,6,8-tetraone. Complexes of first row transition metal ions Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have also been synthesized. The ligand and its complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, 1H NMR, UV-Visible spectra and thermogravimetric analysis (TGA). Molar conductance values show that the complexes of Ni(II), Cu(II), Zn(II), Mn(II) and Co(II) are 1 : 2 electrolytes. On the basis of electronic spectral studies and molar conductance measurements an octahedral structure has been proposed for Mn(II) and Co(II) complexes, tetrahedral for Zn(II) complex and square planar for Ni(II) and Cu(II). The thermal behavior of the compounds, studied by TGA in a nitrogen atmosphere up to 800°C, reveal that the complexes have higher thermal stability than the macrocycle. All the synthesized compounds and standard drugs kanamycin (antibacterial) and miconazole (antifungal) have been screened against bacterial strains Staphylococcus areus, Escherichia coli and fungal strains Candida albicans, Aspergillus niger. The metal complexes inhibit growth of bacteria to a greater extent than the ligand.
  Nahid Nishat , Asma and Swati Dhyani
  This article reports synthesis of Co(II), Ni(II), Mn(II), Cu(II), and Zn(II) complexes with a new macrocyclic ligand 1,4,11,14-tetraazacyclonanodeca-5,10-dioxo-1,14-diene (H2L). The ligand (L1) was prepared by reaction of adipic acid and ethylenediamine in 1 : 2 ratio while the macrocycle was derived from 1,4-bis-(2'-amino-ethanamide)butane and glutaraldehyde. The synthesized complexes were characterized by elemental analysis, molar conductance, spectral analyses (1H NMR spectra, FT-IR spectra, electronic spectra, and mass spectra), magnetic susceptibility measurements, and thermogravimetric studies. On the basis of electronic spectral studies and molar conductance measurements, octahedral geometry was confirmed for Ni(II), Mn(II), and Co(II) while tetrahedral for Zn(II) and square planar for Cu(II) complexes. The TGA results revealed that the complexes exhibited higher thermal stability than the macrocycle. All the complexes were screened against bacterial and fungal strains and preliminary antimicrobial results showed that these complexes inhibited bacterial/fungal growth to a greater extent than the ligand.
  Nahid Nishat , M. Zulfequar , Asma and Sumaiya Hasnain
  A new polymeric ligand was synthesized by the reaction of bisphenol-A and formaldehyde in the basic medium, followed by condensation polymerization with barbituric acid in the acidic medium. Polymer metal complexes were prepared by reaction of this resin with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The polymeric resin and its metal polychelates were characterized by elemental analysis, FT-IR, 13C-NMR, and 1H-NMR spectra. The geometry of the polymer metal complexes was evaluated by electronic spectra (UV-Vis) and magnetic moment measurement. Thermal stabilities show an increased thermal stability of the metal polychelates compared to the ligand. The antibacterial activities of all the synthesized polymers were investigated against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, showing good antibacterial activities against these bacteria. Cu(II) polychelate showed highest biocidal activity.
  Nahid Nishat , Sumaiya Hasnain , Swati Dhyani and Asma
  Glycine metal complexes were prepared by the reaction of glycine with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) in 1 : 2 molar ratio. Thereafter their condensation polymerization was done with glutaraldehyde to obtain polymer metal complexes. All the synthesized polymer metal complexes were characterized by elemental analysis, FT-IR, 1H-NMR, and UV-Vis spectrometry, magnetic susceptibility, and thermogravimetric studies. The analytical data of all the polymers agreed with 1 : 1 molar ratio of metal complex to glutaraldehyde and magnetic moment data suggest that PGG-Mn(II), PGG-Co(II), PGG-Ni(II), and PGG-Cu(II) have an octahedral geometry around the metal atom, whereas the tetrahedral geometry was proposed for PGG-Zn(II) polymer. The PGG-Mn(II) and PGG-Cu(II) showed octahedral geometry. Thermal behavior of the polymer metal complexes was obtained at a heating rate of 10°C min-1 under nitrogen atmosphere from 0°C to 800°C. The antimicrobial activities of synthesized polymers were investigated against Streptococcus aureus, Escherichia coli, Bacillus sphaericus, Salmonella sp. (Bacteria), Fusarium oryzae, Candida albicans, and Aspergillus niger (Yeast).
  Nahid Nishat , Tansir Ahamad , Sharif Ahmad and Shadma Parveen
  The polymeric ligand (BFP) was synthesized by condensation of bisphenol-A, formaldehyde, and piperazine in alkaline medium at 70–80°C. The polymer–metal complexes were synthesized by the reaction of BFP with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetates in 1 : 0.5 (ligand : metal) molar ratio. All the synthesized polymers were characterized by elemental, spectral (infrared, 1H-NMR, and UV-Vis), magnetic moment measurements, and thermal (TGA) analysis. The ligand-field and nephelauxetic parameters have been determined from UV-Vis spectra using ligand-field theory. Elemental analyses indicate the association of water with metal for Mn(II), Co(II), and Ni(II), which is also supported by TGA. The antimicrobial activities of the synthesized polymers were studied by agar well diffusion methods against Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Shigella boydii. The antimicrobial activity and thermal stability of Cu(II)–polymer were higher than the other polymer–metal complexes due to the higher stability constant of Cu(II).
  Nahid Nishat , Raza Rasool , Shamim Ahmad Khan and Shadma Parveen
  Advances in metal incorporated resins are now an active field of research. To develop resin having better antimicrobial and thermal activity, a series of metal-chelated resins have been synthesized by the condensation of (4-aminobenzene-1,3-diyl)dimethanol with 2,6-diaminohexanoic acid in alkaline medium and then this polymeric ligand further reacts with transition metal ions forming various coordination polymers. (4-Aminobenzene-1,3-diyl)dimethanol was initially prepared by the reaction of aniline and formaldehyde in 1 : 2 molar ratio in alkaline medium. The analytical data reveal that the polymer metal complexes of Mn(II), Co(II), and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. Comparative analyses of the polymer metal complexes in thermal curves show better thermal stability than the polymeric ligand. Since these resins are relatively stable at high temperatures, they can be used for medical and biomaterial applications requiring thermal sterilization, solvent-resist coating materials because of their insoluble nature, and antifouling coating materials owing to antimicrobial activity in fields such as life-saving medical devices and the bottoms of ships.
 
 
 
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