A novel terbium metal–organic framework for luminescence sensing of pyridine: Synthesis, structure, selectivity, sensitivity and recyclability

Self-Assembled Lanthanide Phosphinate Square Grids (Ln = Er, Dy, and Tb): Dy4 Shows SMM/SMT and Tb4 SMT Behavior

Tetranuclear [2 × 2] square-grid-like LnIII clusters have been synthesized by reacting LnCl3·6H2O salts with bis[α-hydroxy(p-bromophenyl)methyl]phosphinic acid [R2PO2H, where R = CH(OH)PhBr] and pivalic acid. Single-crystal X-ray diffraction studies show the formation of [Me4N]2[Ln4(μ2-η1:η1-PO2R2)8(η2-CO2But)4(μ4-CO3)] [Ln = Er (1), Dy (2), and Tb (3)]. Direct-current studies reveal significant ferromagnetic interactions between DyIII in 2 and TbIII in 3 and an antiferromagnetic interaction between ErIII in 1. Dynamic magnetic susceptibility measurements confirm a single-molecule magnet (SMM) behavior in both 0 and 1200 Oe applied magnetic fields for 2. Complexes 2 and 3 show single molecular toroic (SMT) behavior with a mixed magnetic moment.

Lanthanide-MOFs as multi-responsive photoluminescence sensor for sensitively detecting Fe3+, Cr2O72- and nitrofuran antibiotics

Fast and selective detection of contaminants plays a key role in meeting human health and environmental concerns. Herein, two groups of isostructural lanthanide MOFs, [Ln(Hpta)(oxalic acid)]·H2O (1-Eu, 2-Gd) and [Ln(pta)(oxalic acid)0.5(H2O)2]·2H2O (3-Eu, 4-Gd) (H2pta = 2-(4-pyridyl)-terephthalic acid, C2O4- = oxalic acid), were synthesized by solvothermal method. Single crystal X-ray diffraction reveals that 1 and 2 are 3D neutral frameworks, while 3 and 4 consist of 2D layers with parallelogram holes and stack into 3D networks through O-H⋯N and O-H⋯O hydrogen bonding interactions. All complexes remain crystalline and stable below 400 °C, suggesting preeminent thermostability. Noteworthily, only 3 shows excellent chemical stability in water and organic solvent. Therefore, the solid-state fluorescence spectrum was used to characterize 3 which exhibited intense red luminescence. The N active sites in the pore channels of 3 are conducive to displaying a distinct quenching effect for Fe3+ cations in aqueous solutions, Cr2O72- anions in DMF and DMA solutions, and nitrofuran antibiotics in the DMF solvent. Overall, 3 is a prospective luminescent sensor for detecting Fe3+, Cr2O72- and nitrofuran antibiotics.

A novel 3D terbium metal-organic framework as a heterogeneous Lewis acid catalyst for the cyanosilylation of aldehyde

A novel 3D lanthanide(iii) metal-organic framework (MOF) (namely Tb-MOF), was synthesized by self-assembly from Tb(iii) ion nitrate and the rigid organic ligand H₂sbdc (H₂sbdc = 5,5-dioxo-5H-dibenzo[b,d]thiophene-3,7-dicarboxylic acid), and could work as an efficient heterogeneous catalyst for the cyanosilylation of aromatic aldehydes at room temperature. The obtained Tb-MOF has been characterized and analysed in detail by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis and so on. The pores of Tb-MOF provided a microenvironment that was beneficial for the substrates to be close to the Lewis acid catalytic sites. The IR spectrogram and the fluorescence titration proved that the substrates could be activated inside the channel of Tb-MOF. The heterogeneous Tb-MOF catalyst with fine catalytic efficiency exhibited a high TON (TON = 460), and could be recycled at least three times without significantly reducing its activity.