A two-dimensional coordination polymer constructed from binuclear copper(II) metalloligands and manganese(II) ions: Synthesis, crystal structure and magnetic properties

Abstract

The self-assembly process between the binuclear [Cu2(HL)(L)]− complex and the manganese(II) ion affords a two-dimensional coordination polymer of formula [Mn{Cu2(HL)(L)}2(H2O)2]n (1) (H3L=3-hydroxyiminomethylsalicylic acid) where parallel ladder-like motifs of defective double cubanes of bis(phenoxo)dicopper(II) units as rods and anti-syn carboxylato bridges as rungs act as ligands towards tetraaqua-manganese(II) entities through the deprotonated oxime groups. The topology of 1 is compared with the one of another compound, [Mn{Cu2(HL)(L)}2(H2O)4]·4H2O·2DMF (1′) which was obtained in different conditions by Okawa et al. (J. Chem. Soc., Dalton Trans. (2001) 3119). Magnetic susceptibility measurements of 1 in the temperature range 2.0–300K are practically determined by the occurrence of a very large antiferromagnetic coupling between the two copper(II) ions through the double phenoxido bridge [J=−765(5)cm−1, the spin Hamiltonian being defined as H=−JSCu1·SCu2], a value which is as expected in the light of a recent magneto-structural correlation for bis(phenoxido)dicopper(II) complexes.