Synthesis and characterization of tetrasulfapyridine-copper(II) sulfate trihydrate

Copper(II)-sulfapyridine complex has been successfully synthesized by 1:4 mole ratio of CuSO4·5H2O and sulfapyridine in methanol as solvent. Indication of the complex formation was shown by shifting of maximum wavelength (λmax) of UV-Visible (UV-Vis) spectra towards smaller than CuSO4·5H2O from 816 nm to 793 nm. Atomic Absorption Spectroscopy (AAS) analysis showed the percentage of copper to be 4.93% corresponding to the theoretical value of copper content in Cu(sulfapyridine)4SO4(H2O)x (x= 3, 4, or 5). Thermogravimetric and differential thermal analysis showed a mass reduction of 4.3% which was equivalent to the evaporation of three molecules of lattice water. The cation and anion charge ratio of the complex was 1:1. Infrared analysis indicated the functional groups of NH2 from sulfapyridine were coordinated to center atom Cu2+. The formed complex was paramagnetic with the effective magnetic moment of 1.82 BM. The broadband peak of UV-Vis spectrum showed a at 793 nm (12610 cm-1) due to d–d [ 2B1g→2Eg−(v1)(dx−y22→dyz) ] transition. From the data, the proposed formula of the complex was [Cu(sulfapyridine)4]SO4·3H2O with square planar geometry.