Synthesis, crystal structures and magnetic properties of two heterometallic {Ln8Cr4} (Ln = Gd3+ and Tb3+) complexes with one-dimensional wave chain structure

Two isomorphic heterometallic 3d-4f cluster-based materials, formulated [Gd8Cr4(IN)(18)(mu(3)-O)(2)(mu(3)-OH)(6)(mu(4)-O)(4)(H2O)(10)]center dot 13H(2)O (1) and [Tb8Cr4(IN)(18)(mu(3)-O)(2)(mu(3)-OH)(6)(mu(4)-O)(4)(H2O)(10)]center dot 13H(2)O (2) (abbreviation: {Ln(8)Cr(4)}: Ln = Gd3+ (1); Tb3+ (2); HIN = isonicotinic acid), were achieved by hydro-/solvothermal method through using the ligand HIN. X-ray diffraction analysis illustrates eight lanthanide ions (Ln = Gd3+, Tb3+) and four transition-metal ions (Cr3+) of {Ln(8)Cr(4)} were constructed from two classical "drum-like" {Ln(4)Cr(2)} structures associated by organic ligands HIN, displaying a one-dimensional wave chain structure, which is rare. The magnetic properties of {Gd8Cr4} were inspected and showed the existence of antiferromagnetic coupling interactions between contiguous metal ions. On top of this, the magnetic entropy change of Delta S-m can attain 23.40 J kg(-1) K-1 (44.90 mJ cm(-3) K-1) at about 3 K and Delta H = 7 T. Besides, fluorescence measurements of {Tb8Cr4} display typical characteristic Tb-based luminescence.