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Synthesis and Spectroscopic Studies of 14-Membered Dithiadiaza Macrocyclic Complexes of Transition Metal Ions

100%

Khan T. A. , Naseem S.

Polish Journal of Chemistry

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2009

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tom Vol. 83, nr 11

1885-1892

EN

A new series of 14-membered macrocyclic complexes containing nitrogen and sulfur donor atoms have been synthesized by metal template condensation reactions of 1,2-ethane -dithiol, omikron-bromoaniline and succinic or phthalic acid in 1:2:1 molar ratio in metha nol. The proposed stoichiometry and the bonding of the macrocyclic moiety to metal ions along with the over all stereochemistry have been derived from the results of elemental analyses, magnetic susceptibility, conductivity data and the spectral data revealed from FT-IR, 1H NMR, UV-visible and EPR spectral studies. The molar conductance measurements of the complexes in DMSO correspond to be none-electrolyte nature for Co(II) and Zn(II) while 1:2 electrolyte for Ni(II) and Cu(II) complexes. Thus, these complexes may be formulated as [ML1X2] and [ML2X2] (M = Co(II), or Zn(II); X = Cl or NO3), and [ML1]X2 and [ML2]X2 (M = Ni(II) or Cu(II); X = Cl or NO3). On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been as signed for Co(II) and Zn(II) complexes while square-planarfor Ni(II) and Cu(II) complexes.

2

Chromium accumulation and toxicity in corn (Zea mays L.) seedlings

80%

Naseem S. , Yasin M. , Ahmed A. , Faisal M.

Polish Journal of Environmental Studies

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2015

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tom 24

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nr 2

EN

Extensive use of chromate compounds in the last few decades has resulted in contamination of our environment. In the present study we have investigated the effects of two different concentrations (10, 20 µg ml⁻¹) of chromium salts (CrCl₃, K₂CrO₄ K₂Cr₂O₇) on the growth of Zea mays L. As concentrations of chromium salts (CrCl₃, K₂CrO₄, K₂Cr₂O₇) increased, there was a significant decrease in seed germination ( 10-24%), shoot length (6-29%), root length ( 11 -33%), seedling length ( 16-24%), fresh weight of seedlings (17-67%) and increase in dry weight per seedling (3-15%), chromium content, acid phosphatases content (215-707%), and peroxidases activity (129-200%) of Zea mays plants compared to control treatment. In all treatments, the effect of hexavalent salts (K₂CrO₄ andK₂Cr₂O₇) was more severe on plant growth compared to trivalent Cr salts (CrCl₃). Zea mays plants have the ability to accumulate various chromium salts in their tissues and thus help to remediate the polluted soil.

3

Synthesis of NiO nanoparticles by sol-gel technique

80%

Kayani Z. N. , Butt M. Z. , Riaz S. , Naseem S.

Materials Science Poland

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2018

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tom Vol. 36, No. 4

547--552

EN

NiO nanoparticles were fabricated by sol-gel route using ammonium hydroxide and nickel nitrate as precursors. The NiO nanoparticles were calcinated at 400 °C and 1000 °C. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermogravimetry analysis/differential thermal analysis (TGA/DTA). The structural properties were evaluated by X-ray diffraction (XRD). XRD confirmed the formation of well-crystallized and high purity NiO phase. The XRD showed that the peaks were sharpened and the crystallite size increased as the calcination temperature increased. The average crystallite size ranged from 12 nm to 20 nm, when calcined at temperatures 400 °C and 1000 °C, respectively. Fourier transform infrared spectroscopy (FT-IR) revealed the chemical composition and confirmed the formation of NiO nanoparticles. The nanoparticles showed paramagnetic behavior.

4

Fabrication and properties of zinc oxide thin film prepared by sol-gel dip coating method

70%

Kayani Z. N. , Iqbal M. , Riaz S. , Zia R. , Naseem S.

Materials Science Poland

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2015

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tom Vol. 33, No. 3

515--520

EN

ZnO thin films were deposited on a glass substrate by dip coating technique using a solution of zinc acetate, ethanol and distilled water. Optical constants, such as refractive index n and extinction coefficient k, were determined from transmittance spectrum in the ultraviolet-visible-near infrared (UV-Vis-NIR) regions using envelope methods. The films were found to exhibit high transmittance, low absorbance and low reflectance in the visible regions. Absorption coefficient µ, and the thickness of the film t were calculated from interference of transmittance spectra. The direct optical band gap of the films was in the range of 3.98 to 3.54 eV and the thickness of the films was evaluated in the range of 173 to 323 nm, while the refractive index slightly varied in the range of 1.515 to 1.622 with an increase in withdrawal speed from 100 to 250 mm/s. The crystallographic structure of the films was analyzed with X-ray diffractometer. The films were amorphous in nature.