Refinement of Copper(II) Azide with 1‐Alkyl‐5H‐tetrazoles: Adaptable Energetic Complexes

A concept for stabilizing highly sensitive and explosive copper(II) azide with 1‐N‐substituted tetrazoles is described. It was possible to stabilize the system by the use of highly endothermic, nitrogen‐rich ligands. The sensitivities of the resulting energetic copper coordination compounds can be tuned further by variation of the alkyl chain of the ligands and by phlegmatization of the complexes with classical additives during the synthesis. It is demonstrated, using the compound based on 1‐methyl‐5H‐tetrazole ([Cu(N3)2(MTZ)], 1) that this class of complexes can be applied as a potential replacement for both lead azide (LA) and lead styphnate (LS). The complex was extensively investigated according to its chemical (elemental analysis, single‐crystal and powder X‐ray diffraction, IR spectroscopy, scanning electron microscopy) and physico‐chemical properties (differential thermal analysis, sensitivities towards impact, friction, and electrostatic discharge) compared to pure copper(II) azide

OZM Ball Drop Impact Tester (BIT‐132) vs. BAM Standard Method – a Comparative Investigation

Safety, performance, cost efficient synthesis and toxicity are the most important aspects of modern explosives. Sensitivity measurements are performed in accordance with different protocols all around the world. Sometimes the BAM drop hammer does not accurately reflect the sensitivity of an energetic material, in particular the sensitivity of primary explosives. Therefore, we present here preliminary results obtained using the novel ball drop tester (BIT‐132), manufactured by OZM research, following MIL‐STD‐1751 A (method 1016). The ball drop impact sensitivity tester is a device in which a free‐falling steel ball is dropped onto an unconfined sample, and is expected to produce more realistic results than the currently commonly used BAM method. The results obtained using the probit analysis were compared to those from the BAM drop hammer and friction tester. The following sensitive explosives were investigated: HMTD, TATP, TAT, Tetrazene, MTX‐1, KDNBF, KDNP, K2DNABT, Lead Styphnate Monohydrate, DBX‐1, Nickel(II) Hydrazine Nitrate, Silver Acetylide, AgN3, Pb(N3)2 RD‐1333, AgCNO, and Hg(CNO)2

Copper(II) Chlorate Complexes: The Renaissance of a Forgotten and Misjudged Energetic Anion

A convenient synthetic route toward new copper­(II) chlorate complexes with potential use in modern advanced ignition or initiation systems is described. Obtained compounds were not only accurately characterized (XRD, IR, UV/Vis EA and DTA) but also investigated for their energetic character (sensitivities, initiation capability and laser ignition). The copper 4-aminotriazolyl chlorate complex showed excellent initiation of PETN, while also being thermally stable and safe to handle. Solid-state UV–Vis measurements were performed to get a possible insight toward the laser initiation mechanism. In contrast to expectations, the presented copper­(II) chlorate energetic coordination compounds show manageable sensitivities that can be tamed or boosted by the appropriate choice of nitrogen-rich ligands

Di(1<i>H</i>-tetrazol-5-yl)methane as Neutral Ligand in Energetic Transition Metal Complexes

The synthesis of di­(1<i>H</i>-tetrazol-5-yl)­methane (<b>1</b>, 5-DTM), starting from commercially available sodium azide and malononitrile, is described. This tetrazole was characterized and investigated for use as a neutral nitrogen-rich ligand in various energetic transition metal complexes: ([CuCl₂­(5-DTM)₂]·​2H₂O (<b>2</b>), [Co­(H₂O)₂­(5-DTM)₂]­Cl₂ (<b>3</b>), [Ni­(H₂O)₂­(5-DTM)₂]­Cl₂ (<b>4</b>), [Co­(H₂O)₂­(5-DTM)₂]­(NO₃)₂ (<b>6</b>), [Ni­(H₂O)₂­(5-DTM)₂]­(NO₃)₂ (<b>7</b>), [Zn­(H₂O)₂­(5-DTM)₂]­(NO₃)₂ (<b>8</b>), {[Cu₃­(SO₄)₂­(5-DTM_–H)₂­(H₂O)₄­(5-DTM)₂]·​2H₂O}_∞ (<b>9</b>), [Cu­(H₂O)₂­(5-DTM)₂]­(NO₃)₂ (<b>11</b>), [Cu­(NO₃)₂­(5-DTM)₂]·​2H₂O (<b>12</b>), [Cu­(NO₃)₂­(5-DTM)₂] (<b>13</b>), [Cu­(H₂O)₂­(5-DTM)₂]­(ClO₄)₂ (<b>14</b>), and [Cu­(ClO₄)₂­(5-DTM)₂] (<b>15</b>). Obtained coordination compounds were characterized using single crystal X-ray diffraction (except for <b>7</b> and <b>13</b>), IR spectroscopy, elemental analysis, and differential thermal analysis. The sensitivities to external stimuli (impact, friction, electrostatic discharge) were determined. Complexes <b>12</b> and <b>13</b> were tested for their ignitability by laser irradiation

Nitrogen-Rich Copper(II) Bromate Complexes: an Exotic Class of Primary Explosives

Because of the ongoing very challenging search for potential replacements of the currently used toxic lead-based primary explosives, new synthetic strategies have to be developed. In particular, the smart concept of energetic coordination compounds (ECC) has proven to hold great potential to solve this difficult and complex problem. The herein-described approach combines the exotic and neglected class of copper­(II) bromate ECC with different environmentally friendly nitrogen-rich heterocycles, which exhibit the energetic properties of powerful primary explosives. The concept is the simple adjustment of the energetic properties of the complexes through alteration of the corresponding azoles. Six new copper­(II) bromate complexes with reasonable sensitivities are featured in this study, which were synthesized in a practical and straightforward fashion, assured through easy access to copper­(II) bromate obtained by metathesis reaction. Obtained compounds were comprehensively characterized through various analytical methods such as low-temperature X-ray diffraction, IR spectroscopy, and elemental analysis. Their sensitivities toward impact and friction were assessed through BAM standard techniques, together with their sensitivity against electrostatic discharge. Evaluation of the energetic properties of the newly synthesized compounds included examination of the respective thermal stabilities by differential thermal analysis. Furthermore, the complexes were tested regarding their behavior toward laser irradiation. Additionally, to receive insight into a possible correlation between the laser-investigated compounds’ optical absorption and their ability to ignite by exposure to laser irradiation, UV–vis–near-IR spectra were recorded

Copper(II) Chlorate Complexes: The Renaissance of a Forgotten and Misjudged Energetic Anion

A convenient synthetic route toward new copper­(II) chlorate complexes with potential use in modern advanced ignition or initiation systems is described. Obtained compounds were not only accurately characterized (XRD, IR, UV/Vis EA and DTA) but also investigated for their energetic character (sensitivities, initiation capability and laser ignition). The copper 4-aminotriazolyl chlorate complex showed excellent initiation of PETN, while also being thermally stable and safe to handle. Solid-state UV–Vis measurements were performed to get a possible insight toward the laser initiation mechanism. In contrast to expectations, the presented copper­(II) chlorate energetic coordination compounds show manageable sensitivities that can be tamed or boosted by the appropriate choice of nitrogen-rich ligands