A Pair of Manganese(III) Schiff-Base Enantiomers: Synthesis, Crystal Structure and Magnetic Characterization

Abstract

<em>Based-on the quasi-planar tetra-dentate Schiff-base ligand, a pair of manganese(III) Schiff-base enantiomers formulated as {[Mn(R,R-3-MeOSalcy)(H₂O)(CH₃OH)]ClO₄}₂ (1) and {[Mn(S,S-3-MeOSalcy)(H₂O)(CH₃OH)]ClO₄}₂ (2) (3-MeOSalcy = N,N′-(1,2-cyclohexanediylethylene)bis(3-methoxysalicylideneiminato)dianion) have been synthesized and characterized by element analysis. Single X-ray structure analysis showed that the coordination sphere of the Mn(III) ion is an elongated octahedron with the four equatorial positions occupied by N₂O₂ unit from the Schiff-base ligand and two O atoms of the coordinated solvent molecules completing the additional two axial sites. The mononuclear manganese(III) Schiff-base compounds are self-complementary into a supramolecular dimer structure through the coordinated solvent ligand from one complex and the free O₄ compartment from the neighboring complex. Investigation of the magnetic susceptibility of the manganese complexes reveals the overall weak antiferromagnetic interactions between the adjacent mental centers.</em>