Chlorido‐Bridged Mn^II Schiff‐Base Complex with Ferromagnetic Exchange Interactions

Abstract

Abstract The preparation, crystal structure, and magnetic properties of the μ‐Cl‐bridged dinuclear complex [Mn(HL)(μ‐Cl)Cl] 2 ( 1 ) with the Schiff‐base ligand HL, 2‐methyl‐6‐[(pyridine‐2‐ylmethylene)amino]phenol, is reported. Structural studies show that 1 is binuclear with a pair of chlorine atoms bridging the manganese atoms in a central Mn 2 Cl 2 plane, the intramolecular Mn ··· Mn separation being 3.694 Å. Each manganese atom in 1 is six‐coordinate with two nitrogen atoms (one imine nitrogen and one pyridine nitrogen) and one phenolic oxygen from the neutral tridentate ligand, and three chlorine atoms (one terminal and two bridging) building an elongated octahedral environment. The two octahedra adopt the unique geometry sharing an equatorial‐to‐axial edge with parallel equatorial planes. The hydrogen bonds between the coordinated Cl – anions and hydroxy groups connect the dimeric coordinated units together forming a one‐dimensional chain. Variable temperature susceptibility measurements in the temperature range of 2.0–300 K reveal a ferromagnetic coupling ( J = +0.94 cm –1 ) in the dimer via the double chlorido bridge, and a weak antiferromagnetic coupling ( zJ ′ = –0.036 cm –1 ) between the dimers through the intermolecular hydrogen bonding. A comparison of the magnetic coupling of 1 with other structurally similar Mn(μ‐Cl) 2 Mn compounds is discussed in detail. Complex 1 may provide useful information for the magneto‐structural correlations of this kind of compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)