Synthesis and characterization of a novel Mn(III)-(γ-diketone) complex with catalytic and antifungal activity

A novel Mn(III) complex with γ-diketone having general formula [Mn(hdo)₃], where hdo = hexane-2,5-dione ligand, has been synthesized and characterized using UV–vis, FT-IR, ESI-mass and EPR spectra, elemental analysis, powder X-ray diffraction, SEM, and magnetic susceptibility measurements. The X-ray diffraction studies reveal that it has monoclinic lattice system with C₂/C space group and the unit cell dimensions are a = 9.92245 Å, b = 10.50696 Å, and c = 9.80835 Å. The particle size of this complex has been found to be 32.1 nm. The complex was evaluated for its antifungal activity against Aspergillus flavus, Aspergillus niger, and Aspergillus terreus fungal species. The results indicate that the minimum inhibitory concentration of the synthesized complex was 8 ppm for A. niger while for A. flavus and A. terreus it was 6 ppm. β-Diketone Mn(III) complexes inhibit the fungal growth only partially. This communication is the first report of transformation of a keto-group to an ester group catalyzed by a metal complex.