Synthesis, spectral and antifungal studies of some coordination compounds of cobalt(II) and copper(II) of a novel 18-membered octaaza [N8] tetradentate macrocyclic ligand

The stereochemistry and coordination behavior of Co(II) and Cu(II) complexes of a novel 18-membered quadridentate macrocyclic ligand (3,4,12,13-tetraphenyl-1,2,5,6,10,11,14,15-octaazacyclooctadecane-7,9,16,18-tetraone-2,4,11,13-tetraene) have been investigated after their template synthesis. The synthesized macrocycles have been characterized by means of various physicochemical techniques viz. elemental analyses, magnetic, conductivity measurements,and spectral (IR, electronic, mass and EPR) techniques. The structure of complexes has been determined with the help of spectroscopic as well as conductivity values and found to be six coordinated octahedral and tetragonal for Co(II) and Cu(II), respectively. The ligand was coordinated to the metal ion via the malonylhydrazide moiety’s imine nitrogen in a tetradentate fashion. Molar conductance measurements revealed that reported macrocyclic complexes were non-ionic in nature. All the complexes have been screened for their in vitro antifungal activity against a number of fungi isolated from plants. The compounds exhibit significant antifungal activity.