Two coordination polymers based on semicarbazone Schiff base and azide: synthesis, crystal structure, electrochemistry, magnetic properties and biological activity

Abstract

[Mn(L)(μ_1,1–N₃)₂]_{2 n} [Mn(H₂O)₂(μ_1,1–N₃)₂] _n (1) and [Cd(HL)(μ_1,1–N₃)₂] _n (2) have been synthesized from HL (HL: pyridine-2-carbaldehyde semicarbazone) and azide ligands, characterized by FT-IR, UV–vis spectroscopy and X-ray crystallography. Single crystal X-ray diffraction revealed that 1 is a coordination polymer consisting of two infinite 1-D chains: chain A with [Mn(L)(μ_1,1–N₃)₂]_{2 n} and chain B with [Mn(H₂O)₂(μ_1,1–N₃)₂] _n . In both chains, Mn centers are connected via two double end-on (EO) azide bridges. 2 is a coordination polymer consisting of a 1-D infinite chain, where Cd centers are connected via two double EO azide bridges. The electrochemistry of HL, 1 and 2 were studied by cyclic voltammetry. Magnetic susceptibility measurements indicate bulk ferromagnetic coupling for 1 below 5 K. Antimicrobial activities of both compounds 1 and 2 were greater than HL, with the strongest effect for 2 consistent with its larger radius and electronegativity of Cd(II) ions.

Keywords:

• Semicarbazone ligand
• Azide ligand
• Coordination polymer
• X-ray structure
• Antimicrobial activity

Acknowledgements

We gratefully acknowledge the financial support of the Tabriz University Research council and are also very much obliged to Dr. Babak Mirtamizdoust and Mr. Majid Sadeghi for their assistance. We also acknowledge support of the project Praemium Academiae of the Academy of Sciences of the Czech Republic. As well, this work is supported by Slovak Grant Agency VEGA-1/0159/09 and by the ERDF EU (European Union European regional development fund) grant under contract No. ITMS26220120005.