Synthesis, characterization, and luminescence properties of magnesium coordination networks using a thiophene-based linker

By varying the solvents and temperatures under solvothermal conditions, two new magnesium based coordination networks were synthesized using 2,5-thiophenedicarbxoylate as a linker. Mg3(TDC)3(DMF)3 [1; TDC = 2,5 thiophenedicarboxylate; space group P21/c, a = 17.747(4) Å, b = 9.805(2) Å, c = 21.359(4) Å, β = 103.13(3)°] is constructed by a combination of magnesium polyhedral trimers, which are connected by the TDC2− linkers to form a 3-D network. Coordinated DMF molecules are present within the channels. Mg(TDC)(H2O)2 [2; space group Pnma, a = 7.296(4) Å, b = 17.760(4) Å, c = 6.6631(3) Å] is formed by 1-D chains of magnesium octahedra connected by the TDC2− linker. Water molecules are coordinated at the axial positions of the magnesium octahedra. Compound 1 is formed using DMF as the synthesis solvent at 180 °C, while compound 2 is formed using ethanol as the synthesis solvent at 100 °C. Both compounds show enhanced photoluminescence intensity when excited at 397 nm compared to the free TDC ligand, suggesting a charge transfer between the ligand and the magnesium metal center.

Two new magnesium coordination networks were synthesized using 2,5-thiophenedicarboxylic acid as an organic linker. Solvent and temperature were used as synthetic variables to direct the synthesis of each network. The luminescence properties of the networks show enhanced properties compared to the free linker.Figure optionsDownload as PowerPoint slideHighlights
► Two new magnesium based coordination networks were synthesized.
► Temperature and solvent are used as variables resulting in different structures.
► The networks show strong luminescence properties.