Crystal structures and anticancer activities of five novel pyrazolone-enamine transition metal complexes with 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one

Abstract

Three pyrazolone-enamine ligands HL1, HL2 and H2L3 were synthesized by the reaction of 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HPMBP) with methyl 4-aminophenylacetate, 4-aminobenzamide and 2-amino-5-methylphenol, respectively, followed by tautomeric reactions. Their complexes [Zn(L1)2] (1), [Co(L2)2(H2O)2] (2), [CuL3(H2O)2] (3a), [ZnL3(H2O)2] (3b) and [CdL3(H2O)2] (3c) were synthesized and characterized by single-crystal X-ray, IR, elemental analysis, 1H NMR, TG analysis. Single-crystal X-ray analysis reveals that HL1, complex 1 and complex 2 are all connected by hydrogen bonds, CH···π interactions and van der Waals forces to form the 3-D network. The Zn(II) ion in complex 1 is four coordinated to two L1 ligands. The Co(II) ion in complex 2 is six coordinated to two L2 ligands and two water molecules. The metal ions in complexes 3a, 3b and 3c are five coordinated to one L3 ligand and two water molecules. After coordination, the structures of the ligands reversed to the Schiff base structures. Moreover, the anticancer activities were investigated, the results show that complexes 3a and 3b can effectively inhibit the proliferation of human breast cancer MDA-MB-231 cells. Besides, complexes 1, 2, 3b and 3c exhibit excellent luminescence properties.