A Pair of 2D MOFs Based on [Tm2] Secondary Building Units: Syntheses, Structural Variation and Magnetic Properties

摘要

A pair of 2D MOFs, [Tm-4(ipO)(4)(H2O)(4)] (1) and [Tm-2(ipO)(2)(DMF)(H2O)] (2), have been solvothermally synthesized using 2-hydroxyisophthalic acid (H(3)ipO) ligand. Both of them are structurally characterized by single-crystal X-ray diffraction, IR, TGA and PXRD. They all consist of [Tm-2] Secondary Building Units (SBUs), in which two Tm-III ions are double bridged by the O-phenol from ipO(3-) ligands. It is interesting that the tiny change of the reaction solvents has resulted in structural dissimilarity between them. Two types of centrosymmetric SBUs, namely, [Tm-2(ipO)(2)] and [Tm-2(ipO)(2)(H2O)(2)], are observed in 1. While 2 is built by the SBUs of [Tm-2(ipO)(2)(DMF)(H2O)], in which two Tm-III centers show distinct coordination geometries. Furthermore, the difference in the linkages between the SBUs of two MOFs are also found, though two MOFs show rather similar 2D framework structures. The mesurements of variable temperature magnetic susceptibility revealed the occurrence of weak antiferromagnetic interaction between the Tm-III centers in two systems.

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