Facile and rapid synthesis of tetrakis-2-amino-5-methylpyridinecopper(II) chloride pentahydrate

Abstract

Pyridine and its derivatives are important compounds with tremendous applications. Pyridine derivatives, such as aminopyridine, have been widely investigated concerning their biological activity. It is reported that generally biological activities of the compound increased after complexation. Tetrakis-2-amino-5-methylpyridinecopper(II) chloride pentahydrate has been synthesized facilely in less than five minutes. It was formed by mixing CuCl2-2H2O and 2-amino-5-methylpyridine in 1:4 mole ratio in ethanol at room temperature. The complex was characterized to determine its proposed empirical formula and the structure. The forming of the complex was indicated by shifting of maximum wavelength (Amax) of UV-Vis spectra towards smaller than CuCl2-2H2O from 850 nm to 675 nm. Atomic Absorption Spectroscopy (AAS) measurement showed the content of copper to be 9.63 % corresponding to the theoretical value of copper content in Cu(2-amino-5-methylpyridine)4Cl2(H2O)x (x= 4, 5, or 6). Thermogravimetric Analysis and Differential Scanning Calorimetry (TGA-DSC) showed a mass reduction of 13.02 % which was equivalent to the evaporation of five molecules of lattice water. The cation and anion charge ratio of the complex was 2:1. This four coordinated-complex was paramagnetic with an effective magnetic moment of 1.83 BM. The proposed empirical formula of the complex was [Cu(2-amino-5-methylpyridine)4]Cl2-5H2O.