Light Metal Li/K-Based Energetic Coordination Polymers: Structural Effect on Detonation Performance

It is the current development trend to contribute green high-energy coordination polymers (CPs) with light metal to realize effective energy density. In this study, self-assembly of a ligand 3-(tetrazol-5-yl)­triazole (H₂tztr) with the light metal Li produces Li–CP [Li₂(Htztr)₂(H₂O)₄] (<b>1a</b>). Further structure recombination generates the polymorph (<b>1b</b>) in the presence of HNO_3, which displays better detonation performance. Nevertheless, the detonation performance is affected by multiple water molecules, which may take some energy away because they evaporate at lower temperatures. Hence, we selected K­(I) with the larger radius to replace Li­(I), expecting that more ligands participate in coordination, which not only increases energetic units but also avoids a large amount of coordinated H₂O molecules. Compound [K­(Htztr)­(H₂O)]_<i>n</i> (<b>2</b>) with a two-dimensional structure was prepared by facile synthesis, which effectively reduces coordinated H₂O molecules. Particularly, <b>2</b> possesses outstanding detonation performance with excellent thermostability and low sensitivity (<i>T</i>_dec = 325 °C, Δ<i>H</i>_det = 4.255 kcal·g^–1, <i>D</i> = 9.742 km·s^–1, and <i>P</i> = 42.659 GPa) among reported energetic CPs. This finding demonstrates a systemic study about calculations of detonation properties and offers an efficient approach to enhancing detonation performance by light metals as nodes to construct ECPs with one-step release of energy