New Application of Hydroxyl Groups: Ligands for High Density Metal Organic Frameworks

Energetic metal organic frameworks (MOFs) with energetic anions as ligands can be used as new-generation explosives. Many powerful anions have been introduced into energetic MOFs to improve the properties; however, the hydroxyl as a common group for energetic MOFs has rarely been studied. In this article, we present two examples of energetic MOFs ([Cu(atz)(NO₃)(OH)]_n) and [Zn(ata)(OH)] (atz=4-amino-1,2,4-triazole; ata=5-amino-1H-tetrazole) with the hydroxyl group as the ligand. Crystal structure analyses reveal that the two compounds possess compact two-dimensional (2-D) structures with densities up to 2.41 g cm⁻³ and 2.54 g cm⁻³, respectively. These two compounds have excellent physicochemical properties. The results demonstrate that a hydroxyl group as the ligands could commendably increase the densities of energetic MOFs, thereby enhancing the detonation performance. It is anticipated this work will open a new direction for the development of energetic MOFs.