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.

Solvothermal synthesis of six novel coordination polymers of Ln(iii) containing 3,5-pyridinedicarboxylic acid.

Nine novel coordination polymers (CPs) with the formulas [M 6 (TDA) 9 (DEF) 5 (H 2 O) 3 ] n [M = Ce (1), Pr (2), Nd (3), Sm (4)], [Eu 4 (TDA) 6 9) (TDA = 2,5-thiophenedicarboxylate anion and DEF = diethylformamide) have been synthesized at different temperatures in a DEF-H 2 O solvent system under solvothermal conditions. All the compounds were characterized by single crystal X-ray diffraction analysis (XRD), Fourier transformation vibrational spectroscopy (FT-IR) and thermal analysis (TGA). Structural analyses of CPs 1-4 reveal that the polymers crystallize in the orthorhombic space group Pna2 1 and form 3D frameworks with large volumes 10 378.1(5), 10 230.5(5), 10 171.9(5) and 10 077.1(11) Å 3 , respectively. The M(III) ions of CPs 1-4 exhibit nine and eight coordination numbers with diverse geometries. Structural analyses of CPs 5 and 6-9 unveil that the polymers crystallize in the monoclinic system, with space groups P2 1 and P2/c, respectively, forming a 3D network. The TDA ligand exhibits two coordination modes [(κ 1 -κ 1 )-(κ 1 -κ 1 )-μ 4 and (κ 2 -κ 1 -μ 2 )-(κ 1 -κ 1 )-μ 5 ] which interconnect the metal ions to generate 3D novel metalorganic frameworks. The luminescence properties of 4, 5, 7 and 8, and the magnetic properties of 6-8 were investigated.

No abstract

Ten isomorphous coordination polymers (CPs) with the formula [Ln2(ATPA)3(DEF)2]n Ln=Ce (1), Pr(2), Nd (3), Eu (5), Gd (6) and [Ln(ATPA)1.5(DEF)]n Ln=Sm (4), Tb (7), Dy (8), Ho (9) and Y(10) (H2ATPA=2‐aminoterepthalic acid and DEF=diethyl formamide) have been synthesized by the self assembly of Ln(III) ions, 2‐aminoterepthalate and DEF under solvothermal condition. These polymers have been systematically characterized by single‐crystal X‐ray diffraction, FTIR, PXRD, thermogravimetric (TGA) and elemental analyses. Structure analyses of CPs 1–10 reveal that all CPs crystallize in the monoclinic space group C2/c system and form 3D framework with difference in coordination numbers. The CPs 1 & 2 exhibit eight coordination numbers whereas CPs 3–10 show seven coordination number with different geometries. TGA indicate thermal stability and robustness of the synthesized CPs. The Sm (4), Eu (5), Tb (7) and Dy (8) polymers emit strong ligand sensitized characteristic f‐f luminescence. Analyses of magnetic susceptibility data of CPs 4, 6, 7 & 8 at variable temperatures and applied magnetic fields reveal weak ferromagnetic interactions at low temperatures.