Three unprecedented high-connected 3D lanthanide–organic frameworks based on benzene-1,2,4,5-tetracarboxylic acid

•Three novel Lanthanide coordination polymers are reported.•A coordination mode of benzene-1,2,4,5-tetracarboxylic acid is first reported.•Scarce hexamer water clusters are reported.•A topological type of sqc37 is first reported for a coordination network.

Three unprecedented high-connected 3D lanthanide coordination polymers based on benzene-1,2,4,5-tetracarboxylic acid (H4bta), {[Ln2(bta)1.5(H2O)4] · 3H2O}n (Ln = La (1) and Ce (2)) and [Pr(bta)0.5(H2bta)0.5(H2O)]n (3), have been synthesized under hydrothermal conditions. Complexes 1 and 2 show trinodal (4,4,10)-connected 3D network structures consisting of tetranuclear metal clusters bridged by bta4 − ligands, and a chair conformation hexamer water cluster can be found within the cage enclosed by eight neighboring tetranuclear metal clusters in the two complexes. While 3 consists of 2D {Pr(bta)0.5}n layers linked by H2bta2 − ligands, resulting in an unprecedented trinodal (4,6,10)-connected 3D topological network. The organic ligand exhibits five kinds of coordination modes, in which one of them is reported for the first time. Moreover, the luminescent properties of 1–3 have also been investigated.

Graphical abstractTwo kinds of unprecedented high-connected 3D lanthanide–organic frameworks based on benzene-1,2,4,5-tetracarboxylic acid have been hydrothermally synthesized, and a chair conformation hexamer water cluster could be found within the cage enclosed by eight neighboring tetranuclear metal clusters in framework 1.Figure optionsDownload full-size imageDownload as PowerPoint slide