Synthesis, crystal structure and thermal analysis of three supramolecular architectures containing Mn(II)/Fe(II) built by 4,4ʹ-bipyridyl N,Nʹ-dioxide and pseudohalides

Abstract

Three new 3D supramolecular architectures of Mn(II) and Fe(II), [Fe(dca)₂(dpyo)₂ (H₂O₂] (<b>1</b>), [Mn(SCN)₂ (dpyo)(H₂O)(MeOH)] (<b>2</b>) and [Fe(SCN)₂(dpyo)(H₂O)₂].(H₂O) (<b>3</b>), [dca = dicyanamide ion; dpyo = 4,4'-bipyridine N,N'-dioxide] have been synthesized and characterized by single crystal X-ray diffraction study and thermal analysis. The structure of <b>1</b> reveals centrosymmetric mononuclear complex of N₂O₄ octahedral coordination sphere comprising <i>trans </i>located nitrogens from two nitrile dca, two oxygens from water molecules and two oxygens from dpyo. The mononuclear fragments through H-bonding as well as π-π interactions result in a 3D supramolecular network. The X-ray diffraction analyses of 2 and 3

reveal that they are isomorphous, taking into account that in the former the methanol ligand is replaced by two water molecules. Both the structures have 1D chains which undergo intermolecular H-bonding interaction resulting in 3D supramolecular networks. Complex <b>1</b> is thermally more stable than the other two whereas only the deaquated species of <b>2</b> is thermally isolable in solid state.