Syntheses, crystal structures and magnetic properties of four tetrahydrofuran-2,3,4,5-tetracarboxylato bridged transition metal complexes with N-donor heteroaromatic co-ligands

Four tetrahydrofuran-2,3,4,5-tetracarboxylato complexes, Cu(bpy)(H2THFTC) (1), [Cu(phen)(H2THFTC)]center dot 0.5H(2)O (2), [Mn(phen)(H2THFTC)]center dot 0.5H(2)O (3) and [Co-4(H2O)(4)(phen)(4)(THFTC)(2)]center dot 4H(2)O (4) (H4THFTC = tetrahydrofuran-2,3,4,5-tetracarboxylic acid, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine) were synthesized in aqueous solution or under hydrothermal conditions, and characterized. In compounds 1-3, the metal centers are bridged by tetrahydrofuran-2,3,4,5-tetracarboxylate anions to form 1D chains, which are further assembled into 2D supramolecular layers based on interchain pi center dot center dot center dot pi interactions. Compound 4 consists of tetranuclear [Co-4(H2O)(4)(phen)(4)(THFTC)(2)] complex molecules and lattice water molecules. The complex molecules are interconnected into hydrogen-bonded chains along the [100] direction, and interdigitation of phen ligands with interchain pi center dot center dot center dot pi stacking interactions assembles the hydrogen-bonded chains into 2D supramolecular layers parallel to the (010) plane. Variable-temperature magnetic measurements show an overall weak ferromagnetic behavior for complexes 1 and 2 and antiferromagnetic behavior for complexes 3 and 4.