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

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′-(1,2cyclohexanediylethylene)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.