Solvent-free synthesis of new open-framework metal oxalates with different 4-connected topologies

•New metal oxalates were prepared under solvent-free conditions.•Open-framework structures display sra, lon, and dia topologies.•In situ formation of a new organic structure-directing agent

Three open-framework metal oxalates, formulated as (Hdbu)[In2(OH)(ox)3] (1), (Hthfa)[Eu2(Hthfa)(H2O)(ox)4]⋅ 3H2O (2), and (Hepc)[Bi(ox)2] (3), were prepared under solvent-free conditions, where dbu = 1,8-diazabicyclo[5.4.0]undec-7-ene, ox = oxalate, thfa = tetrahydrofurfurylamine, and epc = 4-ethylpiperazine-1-carbaldehyde. Topological analyses reveal that these compounds have different 4-connected networks with sra (for 1), lon (for 2), and dia (for 3) topologies. Compound 2 displays a bright red luminescence as a result of excitation at 397 nm.

Graphical abstractThree new open-framework metal oxalates were synthesized under solvent-free conditions. These compounds display 4-connected sra, lon, and dia topologies. The in situ formation of a new organic structure-directing agent is noteworthy.Figure optionsDownload full-size imageDownload as PowerPoint slide