Investigation of the Optical Properties of the Solutions of the Tetraaquabis(saccharinato)metal(II)dihydrate [Metal: Co(II) and NMI)] Complexes at Different Molarity and Volume of Stock Solutions

We investigated the optical properties and the transmittance characterizations of the stock solutions of the Co (II) and Ni(II) complexes of Saccharin and determined the molar extinction coefficients at different molarity. The molar extinction coefficients (epsilon) values of the Co(II) and Ni(II) complexes in the first region decrease with increasing molarity, and the e values of the Co(II) and Ni(II) complexes at lower wavelength are higher than that of the values at higher wavelength. The absorption band edge values of the Co(II) complex shift from 3.584 to 3.139 eV with the increasing molarity, while the absorption band edge values of the Ni(II) complex shift from 3.574 to 3.493 eV with the increasing molarity. The plots of refractive index of the Co(II) and Ni(II) complexes consist of two anomalous (abnormal) dispersion regions and one normal dispersion region. The direct energy-gap of the Co(II) complex can be more decreased with molarity. The absorbance, molar extinction coefficients, refractive index values of the Co(II) and Ni(II) complexes decrease, while the average transmittance in the visible region, direct optical band-gap values of the Co(II) and Ni(II) complexes increase with increasing volume of DMF solvent or decreasing volume of the solutions of the Coal) and Ni(II) complexes.