There has been a resurged interest in the synthesis of metal-organic frameworks because of their potential applications in energy production and drug delivery. Although diimides are insoluble in aqueous solutions, the addition of phosphonic acid allows the complex to be water soluble, which greatly increases their application. Therefore, the creation of a hybrid metal-organic complex by the addition of phosphonic groups to diimide ligands can result in a polar porous compound. In this project the ligand design included the use of dianhydrides including pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, and biphenyl-tetracarboxylic acid dianhydride. These dianhydride precursors were refluxed under argon with aminomethyl phosphonic acid. The methods were repeated with imidazole and dimethylformamide as the solvents and subsequently purified. The results of the IR spectroscopy, 1H NMR, 13C-NMR, and absorbance indicated successful design of the ligands. The metal phosphonate complexes were prepared under hydrothermal conditions with phosphonate based diimide ligands, metal salts, sodium hydroxide, and hydrofluoric acid in an autoclave for a week. Future work in analysis of the compounds and their use in protonation for energy are being explored.
Medina, Kenya V. and Pius, Adelani, "Synthesis of Phosphonate-Based Diimide Ligands" (2022). St. Mary's University Honors Theses and Projects. 12.