Synthesis and characterization of cobalt (II) complexes of chromen-2-one-3-carboxy hydrazide and 2-(chromen-2'-onyl)-5-(aryl) 1,3,4-oxadiazole derivatives

Abstract

Cobalt(II) complexes or chromen-2-one-3-carboxy hydrazide and 2-(chromen-2'-onyl)-5-(aryl) 1,3,4-oxadiazole derivatives have been synthesized and characterized by elemental analysis, magnetic suscecptibility, molar conductance, spectral studies [IR, UV-vis,and ¹H NMR]. All the Co(II) complexes exhibit the composition M(Ln )₂X₂: where M = Co(II). Ll is chromcn-2-one-3-carboxy hydrazide, L2 is 2-(chromen-2ʹ-onyl)-5-(2"hydroxylphenyl) 1,3,4-oxadiazole, L3 2-(chromen-2'-onyl)-5-(4 "nitrophenyl) 1,3,4-oxadiazole and L4 is 2-(chromen-2 '-onyl)-5-(4"-chlorophenyl) 1,3,4 -oxadiazole. X = Cl^-, Br^-, NO₃^-, CH₃COO^-,ClO₄^- , CNS^-, SO₄^--. The N,O donor ligands act as a bidentate ligand in all the complexes. Di storted octahedral geometry for all the Co(II) complexes is proposed. X-ray structure determination have been made for the exact definition of the coordination sphere. The newly synthesized Co(II) complexes have been screened for their antimicrobial activity against some bacterial species like <i>E</i>. <i>coli,S. aureus, Pseudomonas aeruginosa</i> and few fungal strains, <i>C. albicans</i> &nbsp;and <i>Cryptococcus neoformans.</i>