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, [Ce1.3(PTA)2(Oxa)2(Gly)(H2O)2]·(Gly)4H2O (1) and [Ce2.6(PTA)4(Oxa)2(H2O)10]·(MeOH)7H2O (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 PTAH3, 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.