Copper complexes of carboxamidrazone derivatives as anticancer agents. 3. Synthesis, characterization and crystal structure of [Cu(appc)Cl2], (appc=N1-(2-acetylpyridine)pyridine-2-carboxamidrazone)

Copper(II) complexes of the derivatives of pyridyl-2-carboxamidrazone [Cu(appc)Cl2] (1) (appc=N1-(2-acetylpyridine)pyridine-2-carboxamidrazone) and [Cu(atpc)Cl2] (2) (ATPC=N1-(2-acetylthiophene)pyridine-2-carboxamidrazone) have been prepared and characterized by various physicochemical techniques including electrochemistry, IR and UV–Vis spectroscopy. The crystal structure of 1 is reported (space group P21/n, a=8.2535(6) Å, b=16.7479(15) Å, c=10.5320(8) Å). The geometry around copper in 1 is best described as trigonal bipyramidal (τ=0.58) where the chloride ions occupy equatorial positions on the trigonal plane in a cis-configuration and are involved in the hydrogen bonding interactions with the protons of the amino group of the neighboring molecules. The in vitro antiproliferative activity against mouse melanoma cell line B16F10 indicates compound 1 to be highly potent, clearly establishing the importance of copper conjugation in the drug design for melanomal cancers.