Variable Dimensionality of Europium(III) and Terbium(III) Coordination Compounds with a Flexible Hexacarboxylate Ligand.

A reaction between 4,4',4″-(benzene-1,3,5-triyltris(oxy))triphthalic acid (H 6 L) and lanthanide(III) nitrates (Ln = Eu 3+ , Tb 3+ ) in water under the same conditions gave a molecular coordination compound [Tb(H 4.5 L) 2 (H 2 O) 5 ]∙6H 2 O in the case of terbium(III) and a one-dimensional linear coordination polymer {[Eu 2 (H 3 L) 2 (H 2 O) 6 ]∙8H 2 O} n in the case of europium(III). The crystal structures of both compounds were established by single-crystal X-ray diffraction, and they were further characterized by powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. The compounds demonstrated characteristic lanthanide-centered photoluminescence. The lanthanide-dependent dimensionality of the synthesized compounds, which are the first examples of the coordination compounds of hexacarboxylic acid H 6 L demonstrates its potential as a linker for new coordination polymers.