A Series of Lanthanide-Based Metal–Organic Frameworks Derived from Furan-2,5-dicarboxylate and Glutarate: Structure-Corroborated Density Functional Theory Study, Magnetocaloric Effect, Slow Relaxation of Magnetization, and Luminescent Properties

Abstract

Herein, through a dual-ligand strategy, we report eight isorecticular lanthanide(III) furan-2,5-dicarboxylic acid metal−organic frameworks (Ln-MOFs) with the general formula {[Ln(2, Gd (3), Tb (4), Dy (5), Ho (6), Er (7), and Yb (8); 2,5-FDA 2− = furan-2,5-dicarboxylate and Glu 2− = glutarate; x = 0.5 for 1, 2, and 4 and x = 0 for 3 and 5−8], synthesized under solvothermal conditions by using an N,N′-dimethylformamide/H 2 O mixed solvent system. Crystallographic data reveal that all eight Ln-MOFs 1−8 crystallize in the orthorhombic Pnma space group. All of the MOFs are isostructural as well as isomorphous with distorted monocapped squareantiprismatic geometry around the Ln1 metal center. In Ln-MOFs 1−8, the 2,5-FDA 2− and Glu 2− ligands exhibit μ 2 -κ 4 ,η 1 :η 1 :η 1 :η 1 and μ 3 -κ 5 ,η 2 :η 1 :η 1 :η 1 coordination modes, respectively. Topologically, assembled Ln-MOFs 1−8 consist of the 2D cem topological type. The designed Ln-MOFs 1−8 are further explored for structure-corroborated density functional theory study. Meanwhile, room temperature photoluminescence properties of Ln-MOFs 2 and 4 and magnetic properties of Ln-MOFs 3 and 5 have been explored in detail. A highly intense, ligand-sensitized, Ln 3+ f−f photoluminescence emission is exhibited by Ln-MOFs 2 [Eu 3+ (red emission)] and 4 [Tb 3+ (green emission)]. Magnetic studies suggest weak antiferro-and ferromagnetic interactions between adjacent Gd III ions in Ln-MOF 3, thereby displaying a large magnetocaloric effect. The magnetic data measured at T = 2 K and ΔH = 30 kOe depict that the −ΔS m value per unit mass reaches 32.1 J kg −1 K −1 , which is larger than most of the Gd III -based complexes reported. The alternating-current susceptibility measurements on Ln-MOF 5 revealed that out-of-phase signals are frequency-and temperature-dependent under both 0 and 2 kOe direct-current fields, thereby suggesting a typical slow magnetic relaxation behavior with two relaxation processes. This is further supported by the Cole−Cole plots at 2.4−6 K.

Building a Shp: A New Rare-Earth Metal-Organic Framework and Its Application in a Catalytic Photo-Oxidation Reaction

“…[13][14][15][16] Rare-earth (RE) metals, which include scandium, yttrium and the fifteen lanthanides, have been used to synthesize a diverse library of MOFs, including many with unique structures and properties driven by the high coordination numbers and geometries of RE-metals. [17][18][19][20] Like other classes of MOFs, RE-MOFs have been reported with several different secondary building units (SBUs), including inorganic nodes that are metal ions, 21,22 chains, [23][24][25] or clusters. 5,[26][27][28][29] In 2013, Eddaoudi et al showed that the use of fluorinated modulators, such as 2-fluorobenzoic acid, favors the formation of RE-cluster nodes, instead of the ion or chain nodes that tend to preferentially form in the presence of carboxylic acid linkers.…”

Gd(iii)-Based inorganic polymers, metal–organic frameworks and coordination polymers for magnetic refrigeration

“…[11][12][13][14] Therefore, Gd(III)-based inorganic polymers, MOFs, and CPs with possible large magnetic and physical densities as well as weak magnetic interactions have received much attention from researchers. [15][16][17] To obtain Gd(III)-based inorganic polymers, MOFs, and CPs with a large ΔS m under low fields, a key point is to choose suitable Gd III -ion sources and ligands. 18,19 Gd III salts, including Gd(NO 3 ) 3 , GdCl 3 , Gd 2 (SO 4 ) 3 , GdPO 4 , and Gd 2 (CO 3 ) 3 , are the most common Gd III -ion sources because of their relatively good solubility in common solvents.…”

Building a Shp: A New Rare-Earth Metal-Organic Framework and Its Application in a Catalytic Photo-Oxidation Reaction

“…[13][14][15][16] Rare-earth (RE) metals, which include scandium, yttrium and the fifteen lanthanides, have been used to synthesize a diverse library of MOFs, including many with unique structures and properties driven by the high coordination numbers and geometries of RE-metals. [17][18][19][20] Like other classes of MOFs, RE-MOFs have been reported with several different secondary building units (SBUs), including inorganic nodes that are metal ions, 21,22 chains, [23][24][25] or clusters. 5,[26][27][28][29] In 2013, Eddaoudi et al showed that the use of fluorinated modulators, such as 2-fluorobenzoic acid, favors the formation of RE-cluster nodes, instead of the ion or chain nodes that tend to preferentially form in the presence of carboxylic acid linkers.…”