Antifungal active tetraaza macrocyclic transition metal complexes: Designing, template synthesis, and spectral characterization

Abstract

Eight novel macrocyclic complexes as candidates of antifungal agent were designed and synthesized by incorporating an N₄ donor site via the template condensation of 4,4′-diaminodiphenylmethane, formaldehyde. p-anisidine, and metal salts. The structural features were determined on the basis of their elemental analyses, magnetic susceptibility, molar conductance, FAB Mass, UV-Vis, and IR spectral data. Electronic absorption spectral data of the complexes suggest a square-planar geometry around the central metal ion except the VO(IV) complex, which shows square-pyramidal geometry. The stoichiometry of the complexes had been found to be 1: 1 (metal: ligand). Electrolytic nature of the complexes is assessed from their high conductance data. Monomeric nature of the complexes is confirmed from magnetic susceptibility values. The X-band ESR spectra of the Cu(II) and VO(IV) complexes in DMSO at 300 and 77 K were recorded, and their salient features are reported. The antifungal activity of the macrocyclic metal complexes were screened in vitro against Aspergillus niger, Aspergillus fluvus, Trichoderma harizanum, Trichoderma viridae, and Rhizoctonia solani. The data showed that they possessed antifungal activity.