Energetic copper(ii) quadridentate chelate: a novel green laser-sensitive primary explosive

Abstract

Laser-sensitive primary explosives (LSPEs) have long been a focus of attention as the material foundation for safer and more efficient laser-initiation technology. However, LSPEs often have poor safety due to their structural characteristics, which greatly limits the development and application of laser initiating technology. In this work, we introduced the concept of multidentate chelates into LSPEs and innovatively propose the concept of energetic quadridentate chelates. To achieve this highly creative idea, we synthesized an energetic flexible chelating ligand, namely, 1,2-bis(3-nitroamino-1,2,4-triazol-5-yl)ethane (BNATE), and prepared a novel metal quadridentate chelate, namely, [Cu(BNATE)·2H₂O] (1), by chelating it with Cu²⁺. Through a series of tests, including X-ray single-crystal diffraction analysis, thermogravimetric analysis, and differential scanning calorimetry (TG-DSC), and evaluation of the safety and detonation performance, it was proven that this compound adhered to the high stability characteristics of the chelate, and its safety and detonation performance were superior to previous LSPEs. Moreover, through laser-initiation experiments, it was determined that the compound had excellent photosensitivity and a lower laser-initiation threshold. To explain the reason why the chelate structure is specifically sensitive to a laser, diffuse reflection ultraviolet and TD-DFT simulations were conducted, which not only demonstrated experimentally that chelation had a good enhancement effect on the laser photosensitivity but also confirmed the mode of electron transfer in the quadridentate chelate structure.