2p-4f MOFs based on naphthalene-1,4,5,8-tetracarboxylate with magnetocaloric effect and slow magnetic relaxation properties

Abstract A family of new three-dimensional (3D) 2 p -4 f metal-organic frameworks (MOFs), namely [Na 2 Ln(L)(OH)(H 2 O) 3 ] n (H 4 L = naphthalene-1,4,5,8-tetracarboxylic acid, Ln = Gd ( 1 ), Tb ( 2 ) and Dy ( 3 )) have been synthesized by using hydrothermal method and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction and IR spectra. Complexes 1 – 3 are isostructural and crystallize in the space group Cmca of orthorhombic system. Their crystal structures can be described as a kind of homeomorphism configurations with 3D framework. Magnetic measurements indicated that complex 1 exhibits antiferromagnetic behavior and magnetocaloric effect with −Δ S m max  = 28.8 J kg −1  K −1 (Δ H  = 7 T and T  = 2 K), and complex 2 exhibits field-induced slow magnetic relaxation behaviors.