Synthesis, Characterization and <i>in vitro</i> Antifungal Screening of Manganese(II) and Copper(II) Complexes of Hexaaza [N₆] Macrocyclic Ligand

Abstract

New manganese(II) and copper(II) complexes of 12-membered macrocyclic Schiff
base ligand containing thiosemicarbazone moiety have been prepared of general
composition [MLX₂] where M = Mn(II) or Cu(II), L = 3,4,9,10–tetra-2-furanyl-1,2,5,6,8,11-
hexaazacyclododeca-7,12-dithione-2,4,8,10–tetraene, X = Cl^-, NO₃^- and NCS^-. The
complexes have been characterized by elemental analysis, molar conductance, magnetic
susceptibility measurements and spectral (IR, electronic, EPR and mass) analyses. The IR
spectra of complexes suggested that ligand is coordinated to the metal ion through imine
nitrogen atoms. On the basis of spectral studies, an octahedral and tetragonal geometry has
been assigned for Mn(II) and Cu(II) complexes, respectively. EPR spectra of polycrystalline
Mn(II) complexes gave an isotropic signal with g value centered around free electron g
value. EPR spectra of Mn(II) complexes in DMSO showed hyperfine splitting containing six
lines, whereas EPR spectra of polycrystatalline Cu(II) complexes showed anisotropic
signal. Conductivity measurements support the non electrolytic nature of the complexes.
Magnetic moment data suggest that reported complexes are paramagnetic and of high spin
type. All the examined complexes have also been tested in vitro against a number of
pathogenic fungi. Results indicated that the complexes exhibited good antifungal activities.

Keywords: Macrocyclic, octahedral, antifungal, tetragonal, anisotropic.

DOI:  10.3126/jncs.v25i0.3284

Journal of Nepal Chemical Society Volume 25, 2010 pp 46-52