A new lanthanum coordination polymer built from a semi‐rigid tripodal carboxylic acid ligand: synthesis, crystal structure and properties.

By employing the semi‐rigid multidentate carboxylic acid ligand 4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoic acid (denoted H3L), a new lanthanum coordination polymer, namely poly[[bis(dimethylformamide)(μ6‐4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoato)lanthanum(III)] dimethylformamide tetrasolvate 0.25‐hydrate], {[La(C33H27O9)(C3H7NO)2]·4C3H7NO·0.25H2O}n or {[La(L)(DMF)2]·4(DMF)·0.25(H2O)}n (DMF is dimethylformamide) (1), was prepared and characterized by single‐crystal X‐ray diffraction, elemental analysis, thermogravimetric analysis, IR spectroscopy and photoluminescence studies. The asymmetric unit contains one LaIII cation, one anionic L3− ligand, two coordinated DMF molecules, four free DMF molecules and one‐quarter of a free water molecule. Compound 1 possesses (3,6)‐connected two‐dimensional kgd topology sheets consisting of secondary building units of La2 clusters and L3− ligands, which further stack into three‐dimensional supramolecular networks through π–π interactions. Compound 1 exhibits a photoluminescence emission at room temperature, with a peak at 410 nm, owing to a ligand‐centred excited state. [ABSTRACT FROM AUTHOR]