Abstract
The complexes of Manganese(II) with 1,10-phenanthroline using the nitrate, thiocyanate and dicyanamide as co-ligands have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermal analysis and room temperature magnetic susceptibility measurements. The magnetic moments of the complexes are consistent with high spin (d5) octahedral geometry. Single-crystal X-ray analysis confirmed the complexes to be [Mn(Phen)2(NO3)2] (1), [Mn(Phen)2(N3)2)] (2), and [Mn(Phen)2(dca)2)] (3). Complexes 1 and 2 crystallize in an orthorhombic crystal system with space group Pbcn while complex 3 crystallizes in the monoclinic crystal system with space group P21/c. The complexes have been screened for in vitro antibacterial and antifungal activities by the disc diffusion method. The minimum inhibitory concentration values indicate that the complexes showed greater activity against the fungi strains tested compared to that of the reference antifungal.
Highlights
There has been sustained interest in the coordination chemistry of 1,10-phenanthroline (Bencini and Lippolis 2010)
The magnetic moments of the complexes are consistent with high spin (d5) octahedral geometry
Interest in the coordination chemistry of Mn(II) compounds has increased due to their significant role as redox sites in biological systems such as pyruvate carboxylase, oxaloacetate decarboxylase, superoxide dismutases and diamine oxidases (Wieghardt 1989)
Summary
There has been sustained interest in the coordination chemistry of 1,10-phenanthroline (Bencini and Lippolis 2010). The use of mixed ligands having different donor atoms to synthesise complexes, can lead to changes in their physical and chemical properties. Metal complexes of these heterocyclic aromatic ring systems are electron-deficient and can undergo π-π stacking interactions as π-acceptors (Pook, Hentrich et al 2015). The azide anion exhibits different coordination modes with transition metal ions, leading to a wide variety of fascinating structures (discrete molecules to 3-D arrays) (Chen, Jiang et al 2009, Lazari, Stamatatos et al 2009). The coordination modes (Scheme 2a) range from monodentate to bridging bi-, tri- and tetra-dentate (Batten and Murray 2003, Lazari, Stamatatos et al 2009, Adhikary and Koner 2010)
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