Energetic Copper Research Articles

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

A copper(II)-based quadridentate chelate [Cu(BNATE)·2H2O] has been prepared and systematically studied. It has excellent near-infrared laser sensitivity and detonation performance, and low mechanical sensitivity.

Effects of energetic copper ions irradiation on the structural and physical properties of Fe–Ni invar alloy

Effects of energetic copper ions irradiation on the structural and physical properties of Fe–Ni invar alloy

Synthesis, characterization and thermal decomposition kinetics of energetic copper complex based on 3,5 dinitrobenzoic acid and 1,10 phenanthroline

Synthesis, characterization and thermal decomposition kinetics of energetic copper complex based on 3,5 dinitrobenzoic acid and 1,10 phenanthroline

Synthesis, characterization and reaction kinetics of an energetic copper (II) complex based on 3,5 dinitrobenzoic acid and 2, 2' bipyridine

Synthesis, characterization and reaction kinetics of an energetic copper (II) complex based on 3,5 dinitrobenzoic acid and 2, 2' bipyridine

NIR light-driven deflagration of energetic copper complexes through photothermal effect

Energetic coordination complexes constructed from non-explosive and stable nitro bearing ligands and Cu2+ have been presented, and are laser-ignitable on the basis of the coordination-induced photothermal conversion.

Low-Power Laser Ignition of an Antenna-Type Secondary Energetic Copper Complex: Synthesis, Characterization, Evaluation, and Ignition Mechanism Studies.

In recent years, development of new energetic compounds and formulations, suitable for ignition with relatively low-power lasers, is a highly active and competitive field of research. The main goal of these efforts is focused on achieving and providing much safer solutions for various detonator and initiator systems. In this work, we prepared, characterized, and studied thermal and ignition properties of a new laser-ignitable compound, based on the 5,6-bis(ethylnitroamino)-N'2,N'3-dihydroxypyrazine-2,3-bis(carboximidamide) (DS3) proligand. This new energetic proligand was prepared in three steps, starting with 5,6-bis(ethylamino)-pyrazine-2,3-dicarbonitrile. Crystallography studies of the DS3-derived Cu(II) complex (DS4) revealed a unique stacked antenna-type structure of the latter compound. DS4 has an exothermal temperature of 154.5 °C and was calculated to exhibit a velocity of detonation of 6.36 km·s-1 and a detonation pressure of 15.21 GPa. DS4 showed properties of a secondary explosive, having sensitivity to impact, friction, and electrostatic discharge of 8 J, 360 N, and 12 mJ, respectively. In order to study the mechanism of ignition by a laser (using a diode laser, 915 nm), we conducted a set of experiments that enabled us to characterize a photothermal ignition mechanism. Furthermore, we found that a single pulse, with a time duration of 1 ms and with a total energy of 4.6 mJ, was sufficient for achieving a consistent and full ignition of DS4. Dual-pulse experiments, with variable time intervals between the laser pulses, showed that DS4 undergoes ignition via a photothermal mechanism. Finally, calculating the chemical mechanism of the formation of the complex DS4 and modeling its anhydrous and hydrated crystal structures (density functional theory calculations using Gaussian and HASEM software) allowed us to pinpoint a more precise location of water molecules in experimental crystallographic data. These results suggest that DS4 has potential for further development to a higher technology readiness level and for integration into small-size safe detonator systems as for many civil, aerospace, and defense applications.

Synthesis, Crystal Structure and Catalytic Performance of a novel Five‐Coordinated Energetic Copper(II) Compound

AbstractEnergetic copper (II) compound was synthesized based on 2,4,6‐trinitrobenzoic acid (TNBA) and imidazole (IMI), which characterized by elemental analysis and FT‐IR characterization. Single‐crystal X‐ray diffraction analysis revealed that [Cu(IMI)2(H2O)(TNBA)2] (1) belongs to monoclinic, pertains to P21/c space group, β=95.230(2)° and Dc=1.790 g cm−3. The five bonds formed by the central copper atom are derived from the two oxygen atoms and nitrogen atoms in the two TNBA and IMI ligands, and the oxygen atom in the water molecule, which present a novel five‐coordination model and a unique pyramid structure and show a typical single tooth coordination pattern. Catalytic effects on the thermal decomposition of ammonium perchlorate (AP), RDX and HMX of complexe 1 were investigated in detail by employing the DSC technique. Complex 1 shows an outstanding catalytic activity. The non‐isothermal kinetics parameters were calculated by the Kissinger's, Ozawa's and Starink's method, respectively. In the end, impact sensitivity was also determined by standard method. All the experimental data results supported the potential applications of the energetic complexes as additives of solid rocket propellants.

A Smart Access to the Dinitramide Anion - The Use of Dinitraminic Acid for the Preparation of Nitrogen-Rich Energetic Copper(II) Complexes.

Dinitraminic acid (HN(NO2)2, HDN) was prepared by ion exchange chromatography and acid‐base reaction with basic copper(II) carbonate allowed the in situ preparation of copper(II) dinitramide, which was reacted with twelve nitrogen‐rich ligands, for example, 4‐amino‐1,2,4‐triazole, 1‐methyl‐5H‐tetrazole, di(5H‐tetrazolyl)‐methane/‐ethane/‐propane/‐butane. Nine of the complexes were investigated by low‐temperature X‐ray diffraction. In addition, all compounds were investigated by infrared spectroscopy (IR), differential thermal analysis (DTA), elemental analysis (EA) and thermogravimetric analysis (TGA) for selected compounds. Furthermore, investigations of the materials were carried out regarding their sensitivity toward impact (IS), friction (FS), ball drop impact (BDIS) and electrostatic discharge (ESD). In addition, hot plate and hot needle tests were performed. Complex [Cu(AMT)4(H2O)](DN)2, based on 1‐amino‐5‐methyltetrazole (AMT), is most outstanding for its detonative behavior and thus also capable of initiating PETN in classical initiation experiments. Laser ignition experiments at a wavelength of 915 nm were performed for all substances and solid‐state UV‐Vis spectra were recorded to apprehend the ignition mechanism.

Rapid ignition of “green” bipropellants enlisting hypergolic copper (II) promoter-in-fuel

Ionic liquid-with-promoter fuels and H2O2 oxidizer require optimization and further exploration of inexpensive initiators that can be understood at the molecular level; it is advantageous when exacting structural characterization comparisons can also be made. For the first time, hypergolic energetic copper(II) complexes viz. [CuII(1-H-imidazole)4(BH3CN)][BH3CN] (Cu-P1) and [CuII(1-methyl imidazole)4(BH3CN)2] (Cu-P2) were developed as new ‘promoters’ for “green” space vehicle propulsion. Cu-P1 and Cu-P2 exhibited ignition delay times (IDTs) of 3.75 and 8.5 ms, respectively, with 95% H2O2. The superior solubility of Cu-P1 in ionic and non-ionic fuels helped to promote the hypergolic ignition of green liquid fuels. The ionic liquid, 1-ethyl-3-methyl imidazolium cyanoborohydride ([EMIM][BH3CN]), non-ionic tetraglyme, and mixtures thereof (1:1, wt/wt%) were employed. A 13 wt% of Cu-P1 in [EMIM][BH3CN] improved the IDT from >1000 ms to 9.50 ms with 95% H2O2 and from >5000 ms to 21.25 ms with 70% H2O2. Hence, the development of a suitable energetic promoter, soluble in ionic liquid, gained significant attention for “green” bipropellant development. Interestingly, tetraglyme is non-hypergolic with H2O2; a 13 wt% Cu-P1 induced the hypergolic ignition with an IDT of 9.0 ms (95% H2O2). Moreover, the fuel mixture of [EMIM][BH3CN] and tetraglyme (1:1, wt/wt%) with 13 wt% Cu-P1 also revealed the shortest IDT of 7.75 ms (95% H2O2) and 16.5 ms (70% H2O2). The superior ignition performance, reasonable viscosity and density, long-term stability of promoter in the fuel, and comparable theoretical performance of hypergolic propellants are advantages of our approach.

Synthesis, crystal structure, and properties of energetic copper(II) compound based on 3,5-dinitrobenzoic acid and imidazole

Energetic copper(II) compound was synthesized based on 3,5-dinitrobenzoic acid (HDNBA) and imidazole (IMI), and characterized by elemental analysis and FTIR characterization. Single-crystal X-ray diffraction analysis revealed that [Cu(IMI)2(DNBA)2] (1) belongs to monoclinic, pertains to P21/c space group, β= 96.195(2) and Dc= 1.742 g cm–3. Cu(II) ion was coordinated to a plane tetragon, by two oxygen atoms and two nitrogen atoms from different DNBA ions and IMI ligands, which of them present typical monodentate coordination mode. Differential scanning calorimetry (DSC) was applied to assess the thermal decomposition behavior of 1. The non-isothermal kinetics parameters were calculated by the Kissinger’s method, Ozawa’s method and Starink’s method, respectively. Impact sensitivity and friction Sensitivity were also determined by standard method. In the end, the catalytic effects on the decomposition of ammonium perchlorate (AP), HMX and RDX of 1 were studied by DSC. All results supported the potential applications of the energetic complex 1 as additive of solid rocket propellant.

N‐Fluoromethylated (Amino)Tetrazoles: Manipulating Thermal and Energetic Properties

Fluoroiodomethane was allowed to react with the sodium salts of 5H‐tetrazole and 5‐aminotetrazole to give in each case the two corresponding isomers 1‐fluoromethyl‐5H‐tetrazole (1a) and 2‐fluoromethyl‐5H‐tetrazole (1b), as well as 1‐fluoromethyl‐5‐aminotetrazole (2a) and 2‐fluoromethyl‐5‐aminotetrazole (2b). The new tetrazoles were isolated and characterized by spectroscopic methods (IR, Raman, multinuclear NMR), mass spectrometry, and in the case of fluoromethyl‐5‐aminotetrazole the crystal structures of both isomers were obtained and discussed. Differential thermal analysis (DTA) gave insight in how a FCH2 moiety attached to a tetrazole effects the thermal behavior compared to its CH3 analog. In addition, the detonation parameters were calculated and compared to those of the corresponding methyltetrazoles. In addition, the preparation of energetic copper complexes of the new ligands was attempted. Complexes of copper(II) perchlorate and chlorate are crystallographically described and their energetic properties discussed.

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.

Copper (II) complexes of 1-methyl-5-aminotetrazole with different energetic anions: syntheses, crystal structures and properties

ABSTRRACT Three energetic copper (II) complexes, [Cu(1-MAT)2(HDNBA)2](DNBA)2 (1), [Cu(1-MAT)2](PA)2 (2) and [Cu(1-MAT)4(H2O)2](ClO4)2 (3) [1-MAT: 1-methyl-5-aminotetrazole; HDNBA: 3,5-dinitrobenzoic acid; PA: picric acid] were synthesized and characterized. The X-ray single-crystal diffraction results illustrate that the structure of the coordination compounds 1, 2 and 3 belong to the P21/c, P21212 and C2/m space group, respectively. The central copper ion forms a hexacoordinated octahedral structure with N and O atoms. All of them possess good thermal stability, with the thermal decomposition temperatures of 254°C (1), 272°C (2) and 322°C (3), respectively, due to their plenty of coordination bonds, intramolecular and intermolecular H-bonds. According to the results of impact sensitivity and friction sensitivity, these compounds are insensitive to impact (>40 J) and friction (>360 N), except the impact sensitivity of 3 is 2.7 J. The measured constant volume combustion energies of 1, 2 and 3 are 13480, 3537 and 7442 kJ mol−1, respectively.

Nanoscale Homogeneous Energetic Copper Azides@Porous Carbon Hybrid with Reduced Sensitivity and High Ignition Ability.

Research on green primary explosives with lead-free and excellent ignition performance is of significance for practical applications. In this work, we have developed a novel, green, and facile strategy for synthesizing copper azide@porous carbon hybrids (CA@PC) based on ionic cross-linked hydrogel with low-cost cellulose derivatives as the starting material, in which the CA nanoparticles are uniformly distributed in the porous carbon skeletons. The detailed characterizations and control experiments demonstrated that such an outstanding performance originates from the excellent electric conductivity of nanoscale carbon cages. With the favorable unique structures, the as-prepared hybrids can greatly benefit a new type of energetic materials, which exhibit a very low electrostatic sensitivity of 1.06 mJ. Interestingly, the hybrids possess a high ignition ability, and the flame sensitivity can even achieve 47 cm, superior to those well-developed CA-based materials reported previously. This work paves the way toward the design and development of next-generation highly efficient energetic materials.

Synthesis, Crystal Structure, and Properties of Energetic Copper(II) Complex based on 3,5-Dinitrobenzoic Acid and 1,5-Diaminotetrazole

Energetic copper(II) complexes based on 3,5-dinitrobenzoic acid (HDNBA) and 1,5-diaminotetrazole (DAT), Cu(DNBA)(2)(H2O)(2) (1) and Cu(DAT)(2)(DNBA)(2) (2) were synthesized and characterized by elemental analysis, IR spectroscopy, single-crystal and powder X-ray diffraction. In both complexes, Cu-II was coordinated to a plane tetragon, by four oxygen atoms from two DNBA(-) ions and two coordinated H2O molecules for 1, and by two oxygen atoms and two nitrogen atoms from different DNBA(-) ions and DAT ligands for 2. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were employed to measure the thermal decomposition processes and non-isothermal kinetics parameters of the complexes. The thermal decomposition onset temperatures of 1 and 2 are 321 and 177 degrees C. The apparent activation energies of the first exothermic decomposition peaks of 1 and 2 are 247.2 and 185.2 kJmol(-1). Both 1 (35 J, > 360 N) and 2 (12.5 J, > 360 N) are less sensitive than RDX. The catalytic effects on the decomposition of ammonium perchlorate (AP) of 1 and 2 were studied by DSC. All results supported the potential applications of the energetic complexes as additives of solid rocket propellants.

Cocrystallization of photosensitive energetic copper(II) perchlorate complexes with the nitrogen-rich ligand 1,2-Di(1H-tetrazol-5-yl)ethane.

Two recently introduced concepts in the design of new energetic materials, namely complexation and cocrystallization, have been applied in the synthesis and characterization of the energetic copper(II) compound "[Cu(dt-5-e)2(H2O)](ClO4)2," which consists of two different complex cations and can be described as a model energetic ionic cocrystal. The presence of both the N-rich 1,2-di(1H-tetrazol-5-yl)ethane ligand and oxidizing perchlorate counterion results in a new type of energetic material. The ionic complex cocrystal consists of a mononuclear and a trinuclear complex unit. It can be obtained by precipitation from perchloric acid or by dehydration of the related mononuclear coordination compound [Cu(dt-5-e)2(H2O)2](ClO4)2·2H2O at 70 °C in the solid state. The transformation starting at 60 °C was monitored by X-ray powder diffraction and thermal analysis. The energetic ionic cocrystal was shown to be a new primary explosive suitable for laser ignition. The different coordination spheres within the ionic cocrystal (octahedral and square pyramidal) were shown by UV/vis/NIR spectroscopy to result in excellent light absorption.

Thermolysis, Nonisothermal Decomposition Kinetics, Specific Heat Capacity and Adiabatic Time-to-Explosion of [Cu(NH3)4](DNANT)2 (DNANT= Dinitroacetonitrile)

A new energetic copper complex of dinitroacetonitrile (DNANT), [Cu(NH3)4](DNANT)2, was first synthesized through an unexpected reaction. The thermal decomposition of [Cu(NH3)4](DNANT)2 was studied with DSC and TG/DTG methods. The gas products were analyzed through a TG-FTIR-MS method. The nonisothermal kinetic equation of the exothermic process is dα/dT = 10(10.92)/β4(1 - α)[-ln(1 - α)](3/4) exp(-1.298 × 10(5)/RT). The self-accelerating decomposition temperature and critical temperature of thermal explosion are 217.9 and 221.0 °C. The specific heat capacity of [Cu(NH3)4](DNANT)2 was determined with a micro-DSC method, and the molar heat capacity is 512.6 J mol(-1) K(-1) at 25 °C. Adiabatic time-to-explosion of Cu(NH3)4(DNANT)2 was also calculated to be about 137 s.

Syntheses and characterizations of two new energetic copper–amine-DNANT complexes and their effects on thermal decomposition of RDX

Abstract Two novel copper complexes of dinitroacetonitrile (DNANT), Cu(NH3)4(DNANT)2 (1) and Cu(en)2(DNATN)2 (2), have been synthesized for the first time through an unique reaction, and structurally characterized. The single-crystal X-ray structural analysis shows that the Cu2+ cations in the two complexes share a similar four-coordinated structure, which however does not directly involve the main energetic DNANT− anion. The differential scanning calorimetry (DSC) study reveals that the two complexes have higher thermal stability and lower sensitivity than the analogous FOX-7 complexes, and exhibit good catalytic action to the decomposition of RDX.

Copper Azide Confined Inside Templated Carbon Nanotubes

AbstractThe currently used primary explosives, such as lead azide and lead styphnate, present serious health hazards due to the toxicity of lead. There is a need to replace them with equally energetic but safer‐to‐handle and more environmentally friendly materials. Copper azide is more environmentally acceptable, but very sensitive and detonates easily from electrostatic charges during handling. If the highly sensitive copper azide is encapsulated within conducting containers, such as anodic aluminum oxide (AAO)‐templated carbon nanotubes (CNTs), its sensitivity can be tamed. This work describes a technique for confining energetic copper azide within CNTs. ∼5 nm colloidal copper oxide nanoparticles are synthesized and filled into the 200 nm diameter CNTs, produced by template synthesis. The Cu‐O inside the CNTs is reduced in hydrogen to copper, and reacted with hydrazoic acid gas to produce copper azide. Upon initiation, the 60 μm long straight, open‐ended CNTs guide decomposition gases along the tube channel without fracturing the nanotube walls. These novel materials have potential for applications as nano‐detonators and green primary explosives; they also offer new opportunities for understanding the physics of detonation at the nanoscale.

Energetic Nitrogen-Rich Cu(II) and Cd(II) 5,5′-Azobis(tetrazolate) Complexes

Copper(II) and cadmium(II) complexes of 5,5'-azobis(tetrazolate) (ABT) were synthesized at ambient temperature. The anhydrous copper(II) and cadmium(II) salts (1) and (3) are very impact sensitive. The energetic copper(II) and cadmium(II) ABT coordination complexes, tetraammine copper 5,5'-azobis(tetrazolate) dihydrate [Cu(NH(3))(4)]ABT(H(2)O)(2) (2) and diammine dihydrate cadmium 5,5'-azobis(tetrazolate) [Cd(NH(3))(2)(H(2)O)(2)]ABT (4) were prepared and then structured by single crystal X-ray diffraction. Their vibrational spectra (IR) were measured and compared with the calculated frequencies. Thermal stabilities were obtained from differential scanning calorimetry measurements and sensitivity toward impact was determined by BAM standards. The energies of combustion of 2 and 4 were based on oxygen bomb calorimetry values and were used to calculate the corresponding heats of formation.