Novel 3D lanthanide-organic frameworks with an unusual infinite nanosized ribbon [Ln3(μ3-OH)2(-CO2)6]n+ (Ln = Eu, Gd, Dy): syntheses, structures, luminescence, and magnetic properties

Three novel lanthanide-organic frameworks, [Ln(3)(mu(3)-OH)(2)L-2(HCO2)(3)(H2O)(2)]center dot H2O (Ln = Eu (1), Gd (2), Dy (3); H2L = 3,3`-dimethoxy-4,4`-biphenyldicarboxylic acid), have been prepared by the solvothermal reaction of Ln(NO3)(3)center dot 6H(2)O and H2L in DMF/H2O mixed solvent. Crystallographic data show that 1-3 are isomorphous and crystallize in the monoclinic space group P2(1)/c. Each complex contains a rare infinite nanosized ribbon [Ln(3)(mu(3)-OH)(2)(-CO2)(6)](n)(+) with three crystallographically distinct Ln(III) ions: two nine-coordinated and one eight-coordinated. The nanosized ribbons are interconnected through HCO2- anions and L-2(-) linkers to yield a 3D framework. Furthermore, 1 exhibits strong red luminescence upon 343 nm excitation. The investigation of the magnetic properties shows the weak antiferromagnetic coupling between Gd(III) ions in 2 but ferromagnetic coupling between the Dy(III) ions in 3.