New Dinuclear Mn(II) Phenanthroline Adipato Complex: Synthesis and Structural and Thermal Characterization of Mn2(phen)2(H2O)2(C6H8O4)2

Reaction of freshly precipitated Mn(OH)2−2x(CO3)x · yH2O, adipic acid and phenanthroline in CH3OH/H2O afforded a new dinuclear Mn(II) complex, Mn2(phen)2(H2O)2(C6H8O4)2 1, aside the known [Mn(phen)2(H2O)(C6H8O4)]·7H2O 2. Single crystal X-ray analyses showed that complex 1 consists of the centrosymmetric dinuclear molecules resulting from two [Mn(phen)(H2O)] moities bridged by two twisted tridentate adipato ligands. The Mn atoms are each in severely distorted octahedral geometry defined by two N atoms of one phen ligand, three carboxyl O atoms of two adipato ligands and one H2O molecule with d(Mn–N) = 2.246 and 2.296 Å and d(Mn–O) = 2.066 – 2.339 Å. The complex molecules are assembled via π–π stacking interactions into 2D layers, which are held together by both strong O–H· · ·O and weak C– H· · ·O hydrogen bonds. The thermal behavior of 1 and 2 upon heating in argon stream is discussed.