Mohd Yawer

Lanthanide-based entangled coordination polymers connected by thiophene-2,5-dicarboxylate: solvothermal syntheses, crystal structures, luminescence and magnetic properties

Nine novel coordination polymers (CPs) with the formulas [M6(TDA)9(DEF)5(H2O)3]n [M = Ce (1), Pr (2), Nd (3), Sm (4)], [Eu4(TDA)6(DEF)3(H2O)2]n (5), [Gd2(TDA)3(DEF)2]n·H2O (6), [Tb2(TDA)3(DEF)2]n·0.5H2O (7), [Dy2(TDA)3(DEF)2]n·H2O (8) and [Yb2(TDA)3(DEF)2]n·0.5H2O (9) (TDA = 2,5-thiophenedicarboxylate anion and DEF = diethylformamide) have been synthesized at different temperatures in a DEF–H2O 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 Pna21 and form 3D frameworks with large volumes 10 378.1(5), 10 230.5(5), 10 171.9(5) and 10 077.1(11) A3, 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 P21 and P2/c, respectively, forming a 3D network. The TDA ligand exhibits two coordination modes [(κ1-κ1)–(κ1-κ1)-μ4 and (κ2-κ1-μ2)–(κ1-κ1)-μ5] which interconnect the metal ions to generate 3D novel metal–organic frameworks. The luminescence properties of 4, 5, 7 and 8, and the magnetic properties of 6–8 were investigated.

Synthesis, crystal structure, and porosity of 1D coordination polymer of neodymium(III) with isonicotinic acid and dimeric complex of neodymium(III) with nicotinic acid

A 1D coordination polymer [Nd3(INA)9(H2O)6]n (I) and a dimeric complex with mononuclear asymmetric unit [Nd(NA)3(H2O)2] (II) (HINA = isonicotinic acid and HNA = nicotinic acid) were synthesized. The compounds were characterized by elemental analyses, infrared spectroscopy and single crystal X-ray diffraction studies (CIF file CCDC nos. 938976 (I) and 939061 (II). X-ray crystal structure analysis reveals that both compounds exhibit rich structural chemistry. Compounds I and II belong to the monoclinic system with space group P21/c. Thermogravimetric analysis has been performed to investigate their thermal stability. The coordination polymer I has meso-porous structure with average diameter of pores (∼4 nm) and BET surface area 13.62 m2/g.