SYNTHESIS AND STRUCTURE OF Zn(II) AND Hg(II) COMPLEXES WITH 4-ACETYL-3-AMINO-5-METHYL PYRAZOLE

Abstract

Thanking to their essential theoretical and practical importance, pyrazole derivatives and their metal complexes have been since long a subject of interest of resarchers of different profiles. The present work is concerned with the synthesis and structure of zinc(II) and mercury(II) complexes with 4-acetyl-3-amino-5-methylpyazole (aamp). Monocrystals of the neutral tetrahedral bis(aamp)-diisothiocyanato-zinc(II) complex were obtained by the reaction of warm diluted ethanolic solutions of aamp and a mixture of zinc(II) nitrate and ammonium thiocyanate. Besides, another tetrahedral complex, tetracyanatomercurate(II), containing two monoanion derivatives of pyrazole as the counter ions, Haamp+, was obtained from an ethanolic solution of the ligand and a mildly acidic aqueous solution of mercury(II) thiocyanate and ammonium thiocynate. In the zinc complex, aamp is coordinated in the usual way, i.e. through the pyridine nitrogen atom, whereas the mercury complex involves strong hydrogen bonds. The complexes were characterized by elemental and x-ray structural analyses, IR spectrometry, conductometric measurements and thermal analysis methods.