Two new β-octamolybdate supported rare earth metal complexes: [NH 4] 2[{Gd(DMF) 7} 2(β-Mo 8O 26)][β-Mo 8O 26] and [NH 4][La(DMF) 7(β-Mo 8O 26)

Abstract

Two novel β-octamolybdate supported rare earth metal complexes, [NH 4] 2[{Gd(DMF) 7(β-Mo 8O 26)}][β-Mo 8O 26] 1 and [NH 4][La(DMF) 7(β-Mo 8O 26)] 2, were obtained from the reaction of (NH 4) 6Mo 7O 24·4H 2O with LnCl 3 (Ln=Gd for 1 and La for 2) at low pH values in the mixed solvents of H 2O/DMF or H 2O/DMF/CH 3CN. The single X-ray diffraction studies reveal that 1 consists of discrete centrosymmetric heterometallic decanuclear [{Gd(DMF) 7} 2-β-Mo 8O 26] 2+, [β-Mo 8O 26] 4− and two amino cations. In each decanuclear [{Gd(DMF) 7} 2-β-Mo 8O 26] 2+ cation, the β-octamolybdate moiety is linked to two eight-coordinated Gd III cations, which is coordinated by seven DMF ligands and one terminal oxygen atom of molybdenum center. Compound 2 is built up from DMF coordinated La III fragment and β-octamolybdate unit joined together through two terminal oxygen atoms of two molybdenum atoms. Ferromagnetic behavior is observed for 1 from the magnetic measurement, which might result from the exchange interaction through the bridging β-[Mo 8O 26] 4− ligand or the presence of zero-field splitting.