Coordination complexes constructed from pyrazole-acetamide and pyrazole-quinoxaline: effect of hydrogen bonding on the self-assembly process and antibacterial activity.

Two mononuclear coordination complexes of -(2-aminophenyl)-2-(5-methyl-1-pyrazol-3-yl)acetamide (L), namely [Cd(L)Cl] (C) and [Cu(L)(CHOH)](NO) (C) and one mononuclear complex [Fe(L)(HO)](NO)·2HO (C), obtained after oxidation of L, have been synthesized and characterized spectroscopically. As revealed by single-crystal X-ray diffraction, each coordination sphere made of two heterocycles is completed either by two chloride anions (in C), two ethanol molecules (in C) or two water molecules (in C). The crystal packing analysis of C, C and C, revealed 1D and 2D supramolecular architectures, respectively, various hydrogen bonding interactions, which are discussed in detail. Furthermore, evaluation of the ligands and their metal complexes for their antibacterial activity against (ATCC 4157), (ATCC 27853), (ATCC 25923) and (ATCC 29212) strains of bacteria, revealed outstanding results compared to chloramphenicol, a well-known antibiotic, with a normalized minimum inhibitory concentration as low as 5 μg mL.