New nitrification inhibitors based on copper(II) complex compounds

Abstract

The work presents the results of research aimed at the synthesis of new nitrification inhibitors based on complex compounds of Cu2+ with 4-amino-1,2,4-triazole (ATC) and dicyandiamide (DCD). The purpose of the conducted work is the synthesis of new nitrification inhibitors based on complex copper compounds followed with subsequent studies of their structure, properties and biological activity. Four compounds of different compositions were obtained. A number of physical and chemical properties of substances were established: thermal behavior, and solubility in the KAS-28 system (a saturated solution of urea and ammonium nitrate with a nitrogen content of 28%)–water. With the help of infrared spectroscopy, the presence of functional groups and bonds inherent in ligands was proven in the synthesized compounds. Possible ways of coordination of 4-amino-1,2,4-triazole (monodentately through the atom N1 or N2) and dicyandiamide (through the group C=NH or CN with equal probability) were proposed. The content of Cu2+ ions in the synthesized compounds was determined by iodometry. The biological activity of the synthesized substances in relation to soil bacteria was investigated by the potentiometric method. The dynamics of changes in NH4+ and NO3– ions in research samples containing the obtained substances and commonly used nitrification inhibitors (ATC and DCD) was established. All results were equated relative to the control. It was established that the substance with the probable empirical formula [Cu(ATC)2(DCD)1(H2O)1]SO4 had the highest biological activity.