Dinitromethyltetrazole (DNMT)-based energetic coordination polymers (ECPs) as lead-free primary explosives and laser initiators

The development of lead-free primary explosives is urgent from industrial and military aspects. Herein, a typical energetic molecule with the dinitromethyl group and tetrazole ring was selected as the ligand for different alkali metals (Na, K, Rb, and Cs) to achieve a series of energetic coordination polymers (ECPs), namely, ECP 1 to ECP 4. The DNMT molecule showed outstanding coordination ability with metal ions to form diverse metal complexes and coordination frameworks. It was found that the conformation of the energetic ligand as well as the framework structure can be tuned by the deprotonation of DNMT and the corresponding metal centers. Interestingly, a rare metal-pi(tetrazole) coordinate bond was also observed in ECP 3, which is valuable for designing new ECPs and energetic metal complexes (EMCs). A new method has been developed for predicting the energetic properties of EMCs and ECPs. The calculation results indicate that the DNMT-based ECPs have good detonation performance and can be used as lead-free primary explosives. Moreover, the perforated lead plate test reveals the extensive application of the DNMT-based ECPs in emerging laser-initiated explosives. Compared to pure DNMT, the DNMT-based ECPs show significantly enhanced thermal stability. The mechanisms behind different detonation performances and thermal stabilities among the DNMT-based ECPs were also discussed. All the results will be valuable for the future development of ECPs in the applications of lead-free primary explosives. A series of energetic coordination polymers has been synthesized by incorporating dinitromethyltetrazole with alkali metals (Na, K, Rb and Cs), which have potential applications in laser initiating high explosives.