Synthesis and crystal structures of N,N'-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine and its dinuclear manganese(III) complex with antibacterial activities

Abstract

A new dinuclear manganese complex, [Mn₂L₂(N₃)₂], was prepared by reaction of bis-Schiff base N,N'-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine (H₂L) with manganese acetate and sodium azide in methanol. Both the Schiff base and the complex were characterized by physico-chemical methods and single crystal X-ray determination. The Schiff base crystallized in the orthorhombic space group Pbca with unit cell dimensions a = 7.3191(7) Å, b = 6.0948(6) Å, c = 35.382(3) Å, V = 1578.3(3) ų, Z = 4, R₁ = 0.0481, wR₂ = 0.1488. The manganese complex crystallized in the monoclinic space group P2₁/c with unit cell dimensions a = 8.802(1) Å, b = 14.928(2) Å, c = 14.478(2) Å, β = 105.517(2)°, V = 1833.0(4) ų, Z = 2, R₁ = 0.0768, wR₂ = 0.1640. There are crystallographic inversion centers in both the ligand and the complex. The ligand coordinates to Mn through all the phenolate oxygens and imino nitrogens. The two Mn in the complex are bridged by two phenolate oxygens with separation of 3.549(1) Å. Each Mn is octahedral with four donors of the Schiff base ligand defining the equatorial plane, and with one azido nitrogen and one phenolate oxygen of an adjacent Schiff base ligand occupying the axial positions. The Schiff base and the complex were tested in vitro for their antibacterial activities.

Keywords:

• Schiff base
• Manganese
• Synthesis
• Crystal structure
• Antibacterial activity

Acknowledgement

The authors gratefully acknowledge the financial support by the Research Program of Universities of Inner Mongolia Autonomous Region (NJ10245).