Seven-, eight-, and ten-coordinated cerium(III) with highly connective pyridine-2,4,6-tricarboxylate, oxalate, and glycine ligands

Abstract

Two new 3-D Ce(III) coordination polymers, [Ce 1.3 (PTA) 2 (Oxa) 2 (Gly)(H 2 O) 2 ]·(Gly)4H 2 O (1) and [Ce 2.6 (PTA) 4 (Oxa) 2 (H 2 O) 10 ]·(MeOH)7H 2 O (2) (PTA = 2,4,6-pyridinetricarboxylate, oxa = oxalate and Gly = glycine), were synthesized. The oxalate in 1 and 2, generated in situ from the cleavage and chemical rearrangement of PTAH 3 , assembled into mixed-ligand networks to generate 3-D frameworks. Single crystal analysis reveals that in both complexes, Ce(III) shows coordination numbers of 7 and 10 in 1 and 8 and 10 in 2. PTA adopts four kinds of coordination modes. These complexes were further characterized using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.

Ionothermal Synthesis of Cadmium Coordination Polymers: Ionic Liquid Effects on the Synthesis, Structural, and Thermal Characterization

“…This reaction, which typically takes place in the presence of a catalyst and an oxidizing agent [23], could take place due to the synergistic effect of Cd 2+ , NO 3 – and [Bmim][BF 4 ], as it has been previously described by Xie et al [12]. On the other hand, there is an in situ formation of oxalate ligands, which could be the product of the hydrolysis of 4-methylpyridine, as it has been previously observed in solvothermal conditions for pyridine derivatives [24]. Finally, there is an in situ hydrolysis of the BF 4 – anion, which gives rise to F – ions, which coordinates to Cd 2+ .…”

Investigation of the preparation and reactivity of metal–organic frameworks of cerium and pyridine-2,4,6-tricarboxylate

“…The DMF molecules, coordinated to the Ce centres, fill any void space that may otherwise be present, and are found to be disordered, modelled as being present in two different orientations, with occupancy of 70:30. for the later lanthanides the smaller size of the Ln 3+ cations with increasing atomic number may results in lower coordination numbers, even for an isostructural series, where the water content may be variable. 23 We also note that PTC has been used as a ligand in combination with a second ligand to form extended coordination networks with cerium, such as with oxalate or glycine, 24 but structural comparison with these materials is not straightforward due to the influence of the second ligand on the architecture of the structure.…”