Several [Gd-M] Heterometal–Organic Frameworks with [Gd_n] as Nodes: Tunable Structures and Magnetocaloric Effect

Abstract

Tunable structures and magnetocaloric effect (MCE) of seven MOFs with [Gd n ] as nodes are explored. The [Gd n ] node is realized from mononuclear [Gd] to binuclear paddle-wheel [Gd 2 ], tetranuclear tetrahedral [Gd 4 ], and pentanuclear trigonal bipyramidal [Gd 5 ]. Meanwhile, the magnetic entropy changes from 19.4 to 46.0 J·kg –1 ·K –1 . The results reveal that the effect of magnetic density on MCE plays a dominant role for Gd 3+ -based compounds, and high spin ground state of Mn 2+ ( S = 5/2) is more favorable to achieve high MCE than that with Zn 2+, Co 2+, and Ni 2+ (Co 2+, S = 3/2; Ni 2+, S = 1). To our knowledge, it is the first report that MCE is controlled by various clusters as nodes in MOFs.