Highly-thermostable lanthanide–organic coordination frameworks with N-protonated 2,6-dihydroxypyridine-4-carboxylate exhibiting unusual 3-D mixed-connected network topology?

CrystEngComm Pub Date: 2011-09-06 DOI: 10.1039/C1CE05465A

Abstract

A series of three-dimensional (3-D) lanthanide–organic frameworks (LnOFs), with the general formula [Ln2(H–L)3(H2O)]∞ (H–L = N-protonated 2,6-dihydroxypyridine-4-carboxylate; LnIII = LaIII for 1, PrIII for 2, NdIII for 3, and SmIII for 4), have been synthesized under hydrothermal conditions. X-Ray diffraction and energy dispersive X-ray spectroscopy (EDS) analyses reveal that complexes 1–4 are isostructural and exhibit the unique 3-D coordination framework with (4,5,7)-connected network topology, in which the H–L ligands adopt the μ4- and μ5-bridging fashions. Remarkably, thermogravimetric analysis of the crystalline materials shows their exceptionally high thermal stability (up to 530 °C), which should originate from the dense nature of the packing lattices and the unusual network structures.

Graphical abstract: Highly-thermostable lanthanide–organic coordination frameworks with N-protonated 2,6-dihydroxypyridine-4-carboxylate exhibiting unusual 3-D mixed-connected network topology
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