Syntheses, Structures and Properties of 3d-4f Heterometallic Coordination Polymers Based on Tetradentate Metalloligand and Lanthanoid Ions

Abstract

Based on tetradentate metalloligand L Cu ([Cu(2,4-pydca) 2 ], 2,4-pydca = pyridine-2,4-dicarboxylate) and lanthanides (Sm 3+ , Dy 3+), two 3d-4fheterometalliccoordination polymers, namely, {[Sm 2 (DMSO) 4 (CH 3 OH) 2 ][L Cu ] 3 •7DMSO•2CH 3 OH} n 1 and {[Dy 2 (DMSO) 3 (CH 3 OH)][L Cu3 (DMSO)]•4DMSO•CH 3 OH} n 2 (DMSO = dimethyl sulfoxide), have been synthesized and well characterized by elemental analysis, Fourier-transform infrared spectroscopy, thermogravimetric and single-crystal X-ray diffraction analysis. Single-crystal X-ray analysis reveals that both 1 and 2 crystallize in the triclinic crystal system with P-1 space group and possess the 3D framework structures, which are constructed from metalloligands L Cu connecting with {Sm 2 } and {Dy 2 } clusters, respectively. The 3D structure of 1 has a 6-connected single-nodal topology with the point symbol {4 9 × 6 6 }, while 2 features a different framework with the point symbol of {4 12 × 6 3 }. Thermogravimetric analysis exhibits that the skeleton of both 1 and 2 collapse after 350˚C. Magnetic properties of 1 and 2 have also been investigated.

Porous Lanthanide Metal–Organic Frameworks Using Pyridine-2,4-dicarboxylic Acid as a Linker: Structure, Gas Adsorption, and Luminescence Studies

“…However, pyridine-2,4-dicarboxylate (2,4-pdc) has been little employed, by itself, as a ligand for Ln-based MOFs. Only a few examples have been reported on Ln-based MOFs, for which oxalate ions are coursed as other ligands, , and also on 3d–4f heterometallic MOFs, for which 2,4-pdc is coordinated to transition ions but not to Ln ions. − On the other hand, for 3d transition and main-group ions, 2,4-pdc has been prosperously employed, particularly in the construction of porous MOFs because of its easy formation of nodes provided by octahedral or square-pyramidal coordination to the 3d transition ions, then accomplishing rectangular 3D networks. − …”