Energetic Complexes Research Articles

Synthesis, crystal structure, and thermal properties of energetic complex Cu(II) and Ag(I) based on 3-amino-4-(4,5-diamino-1,2,4-triazole-3yl)-furazan

High nitrogen compounds have received much attention due to their great potential as high energy density materials, and the selection of high nitrogen heterocyclic rings as ligands for energetic coordination compounds (ECCs) play a leading role in regulating the energy properties of ECCs. Furazan is rarely used as a building block for the development of high-energy metal ligands. In this study, a new type of high nitrogen ligand 3-amino-4-(4,5-diamino-1,2,4-triazole-3yl)-furazan (ATF) was selected and four kinds of high energy coordination polymers [Cu(II)(ATF)2·4H2O](NO3)2·2H2O (1), [Cu(II)(ATF)2·4H2O](ClO4)2·2H2O (2), [Ag(I)(ATF)2]ClO4·H2O (3) and [Ag(I)(ATF)2NO3] (4) were prepared by water solvent volatilization method and characterized for the first time. The single crystal XRD confirmed that there were abundant hydrogen bond interactions in the four complexes, resulting in dense aggregation with densities of 1.680 ∼ 2.089 g·cm−3. Meanwhile, theoretical calculations show that the detonation velocities of the four ECCs, 7578 ∼ 8192 m·s−1. In terms of thermal stability, the decomposition temperatures of the four ECCs (Td: 253 ∼ 288 °C) showed higher thermal stability during the rapid heating process than the reported ECCs (Cu(PZCA)2(ClO4)2, [Ag+(daf)NO3−]n and CHHP). Both shock and friction sensitivities are greater than 20 J and 300 N. This new structural motif is a promising high-energy material. Moreover, they can promote the combustion decomposition of ammonium perchlorate (AP) well, and the promotion effect of 1 and 2 is better than that of 3 and 4. In the field of explosives and propellants, four ECCs can be attractive candidates.

Glycine-magnesium nitrate tetrahydrate: A unique energetic complex for direct combustion synthesis of nanosized MgO

While numerous combustion methods have been explored for the synthesis of magnesium oxide (MgO), this study presents a unique approach that intentionally overcomes the inherent diffusion limitations associated with traditional combustion synthesis. This was achieved by forming a fuel and oxidizer complex from a 1:1 mol ratio of magnesium nitrate:glycine using the solvent evaporation method. Single crystal x-ray diffraction (SC-XRD) confirmed complex formation. DSC-TGA indicated that the complex reactivity is altered from a physical mixture and exothermically decomposes after partial dehydration. The resulting complex was then combusted to form MgO. The product morphology, as revealed by SEM, showed agglomerated foam-like structures with nanoscale particles on the order of 10 nm. This work demonstrates the potential for a host of metal nitrate-glycine complexes and opens possibilities for tailored applications from fertilizer delivery to catalyst formation.

Customized Green Energetic Tetra(Imidazole)Copper(II) Nitrate (Cu-Im) Complex/Ammonium Nitrate Co-crystal: A Novel Reactive Halogen-Free Oxidizer with Superior Stability and Decomposition Kinetics

AbstractAmmonium nitrate (AN) is the most promising affordable green oxidizer for solid propellants; however, its endothermic phase transitions and endothermic decomposition restrict its applications. This work shaded the light on multifunctional energetic complex tetra(imidazole)copper (II) nitrate (Cu-Im) with combustion enthalpy of 15.57 KJ/g as a high energy dense material, phase stabilizer, and catalyst for AN-based propellant. The Cu-Im complex was synthesized via a green simple solvent-free melt-assisting technique. As-synthesized Cu-Im complex demonstrated a highly pure crystalline structure with thermal stability up to 200 °C. Cu-Im complex was integrated into AN via an evaporative crystallization technique. The phase transitions and the thermal behavior of the developed Cu-Im complex/AN cocrystal were investigated via DSC and TGA. The Cu-Im complex stabilized the phase transition of AN up to 88.48 °C via an evolved strong hydrogen bonding system within the Cu-Im complex/AN cocrystal. Moreover, the energetic Cu-Im complex offered a significant decrease in the endothermic phase transition peaks associated with IV↔II, and II↔I by 38.81%, and 25.28% respectively. Additionally, AN strong endothermic melting was decreased by 45.32%. The Cu-Im complex converts the AN endothermic thermal decomposition peak with + 1400 J/g into an intensive exothermic peak with the release of -2241 J/g. The Cu-Im complex exhibited a superior catalytic effect via the decrease in AN decomposition temperature by 48.85 °C. Cu-Im complex offered a remarkable reduction in apparent activation energy of AN decomposition by 56.24% and 48.12% via Kissinger’s model and integral iso-conversional nonlinear Vyazovkin method (VYA) respectively. The superior catalytic performance of the Cu-Im complex was attributed to the evolution of CuO nanoparticles during its decomposition. The electron-deficient Lewis acid copper ions have a large affinity to electron lone pair of nitrogen; this effect could support the conversion of NH3 to N2 and H2. This catalytic action could boost the decomposition enthalpy of AN. Consequently, the developed Cu-Im/AN cocrystal could be considered a potential green substitute for perchlorate-based oxidizers.

Energetic transition metal complexes based on 1‐allylimidazole and nitrocyanamide: Syntheses, characterizations and catalytic performances on the thermal decomposition of ammonium perchlorate

AbstractTo explore combustion catalysts for solid propellants, four novel energetic coordination compounds were prepared with the anion of nitrocyanamide (NCA) as the ligand and 1‐allyl‐imidazole (AIM) as the ligand, and transition metals Mn, Co, Ni, and Cu as the central ions. The structures of these compounds were [Mn(AIM)4] (NCA)2 (1), [Co(AIM)4](NCA)2 (2), [Ni(AIM)4](NCA)2 (3), [Cu(AIM)4](NCA)2 (4). The results showed that all of the compounds possessed high energy density, and compound 2 had a mass energy density (Eg) of 17.9 kJ g−1 and a volume energy density (Ev) of 25.59 kJ cm−3. The catalytic effect of these compounds on the thermal decomposition of ammonium perchlorate (AP) was studied using DSC. The addition of 5 % catalyst to AP samples advanced the high‐temperature decomposition temperature and significantly increased the heat release. Compound 4 exhibited the best catalytic performance, with an increased heat release of 1739 J g−1, decomposition temperature advanced by 88.2 °C, and activation energy reduced to 74.74 kJ mol−1. These results demonstrate the potential of these compounds as combustion catalysts for solid propellants.

High‐pressure studies of Mn2(C2H6N6)4(NO3)4·2H2O by Raman scattering, infrared absorption, and synchrotron X‐ray diffraction

AbstractMn2(C2H6N6)4(NO3)4·2H2O (Mn) as one of the energetic coordination complexes was chosen for high‐pressure research. In this work, Mn was analyzed by in situ Raman scattering, infrared absorption, and synchrotron angle‐dispersive X‐ray diffraction (ADXRD) technologies up to ~20 GPa at room temperature. The vibrational modes of Mn at ambient pressure were comprehensively resolved based on the experimental results. Detailed spectral analyses revealed that Mn underwent three pressure‐induced phase transitions at 0.5, 2.5, and 5.7 GPa, respectively. ADXRD experiments confirmed the existence of these three phase transitions in Raman and infrared spectra analyses. Based on the analysis of the vibrational spectra and the changes of lattice parameters under pressure, it can be considered that the deformation of the 3‐hydrazino‐4‐amino‐1, 2, 4‐triazole (HATr) ligand led to the first phase transition, and the distortion of the triazole ring induced the second phase transition, and the rearrangement of the hydrogen bonds resulted in the third phase transition. In addition, it can be inferred from Raman spectra and ADXRD data that Mn may have experienced the abnormal expansion during the first phase transition. This work may lay the foundation for further investigating the structure and properties of energetic coordination complexes under pressure.

Response characteristics of combustion pressure exponent of propellants: compensation effect of three energetic potassium lead complexes with Co, Cu, Ni

Response characteristics of combustion pressure exponent of propellants: compensation effect of three energetic potassium lead complexes with Co, Cu, Ni

Chemical compatibility of energetic metal complexes with polymers by thermal analytical techniques

Energetic metal complexes have been established to be effective combustion catalyst for energetic composites and propellants with improved performance. Chemical compatibility is an important aspect in the development of novel energetic composites which are related to safe processing, handling, and storage. In the present paper, the compatibility of energetic metal complexes [Zn(atrz)(DNBA)2(H2O)2]n (complex 1) and [Cd(atrz)(DNBA)2(H2O)2]n (complex 2) with Viton A and epoxy resin as polymer binder are studied by thermal analytical techniques. The compatibility was studied through vacuum stability test (VST), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) according to standardization agreement (STANAG) 4147 method. Furthermore, physicochemical methods including powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR) are used to support the thermal analytical methods. The VST results indicate that the volume of gases evolved for complex 1/Viton A, complex 1/epoxy resin, complex 2/Viton A, and complex 2/epoxy resin is found to be 0.545 mL/g, 0.86 mL/g, 0.403 mL/g, and 0.884 mL/g, respectively, indicating high compatibility with one another. According to the STANAG 4147 criteria, the DSC/DTG data demonstrate that the difference in Tmax is less than 2 °C for all the admixtures, suggesting that the polymer binders under investigation are compatible with complexes. TG results demonstrate that the mass loss difference is less than 4 % for all admixtures, indicating good compatibility. The essential additional information offered by the supplementary non-thermal FTIR and PXRD techniques confirm that no reaction occurs between metal complex and polymer. SEM micrographs exhibit that metal complex crystals are embedded in the polymer matrix.

Metal-Determined Explosive Characteristics of M(NO3)2(1-AT)x of Thermal and Laser Ignition (M2+ = Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+; x = 2 or 3).

Optical and thermal ignition are two common pathways to initiate the explosion of primary explosives, where laser ignition is a more reliable and safer initiation method. Caused by the current-applied laser igniter with the wavelength of 1064 or 915 nm, the energetic complexes with strong absorption in the near-infrared (NIR) region are possibly applied as laser-ignited explosives. Recently, [Cu(NO3)2(1-AT)3] complex has been synthesized with excellent NIR absorption properties, where 1-amino-5H-tetrazole (1-AT) has been proved to be a promising laser-ignited energetic ligand. To confirm the structure-thermal/optical explosive characteristics, based on the structure of synthesized [Cu(NO3)2(1-AT)3], the commonly used transition-metal cations (M2+ = Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+) have been selected to construct the series of complexes of M(NO3)2(1-AT)x (x = 2 or 3) theoretically. Car-Parrinello molecular dynamics (CPMD) method has been applied to unveil the role of center metals in the initiation and growth pathways. Time-dependent density functional theory (TD-DFT) method is used to explore their charge-transfer (CT) characteristics. The optical characteristic of the metal complex is mainly determined by the behaviors of the 3d electrons of center metals in excitation, where the activity of β-d electrons is an important factor to affect the NIR characteristic of complexes.

Assembly of 1D Helical Energetic Coordination Polymers Using a Flexible Bridged Furazan-triazole Cation.

Two new energetic coordination compounds with 1D helical chain structures have been synthesized. First, the polyamine precursor 4,5-diamino-2-((4-amino-1,2,5-oxadiazole-3-yl)methyl)-2,4-dihydro-3H-1,2,4-triazole-3-imino chloride salt (TATAF-Cl) is obtained by incorporating 4-(chloromethyl)-1,2,5-oxadiazol-3-amine with 4H-1,2,4-triazole-3,4,5-triamine. Using a simple hydrothermal method, two energetic complexes, Ag(TATAF)(ClO4)2 (ECP-1) and Ag(TATAF)(NO3)2·H2O (ECP-2), with a helical 1D MOF structure of furazan and triazole were synthesized. Compounds ECP-1 and ECP-2 have relatively high nitrogen and oxygen content (N + O%: 52.04%, 61.04%), excellent crystal density (2.229 g cm-3, 2.116 g cm-3 at 298 K) and high heat of detonation (1.18 kcal g-1, 1.06 kcal g-1), good detonation performance (P: 35.34 GPa, 29.52 GPa; Dv: 8412 m s-1, 7794 m s-1), and moderate sensitivity (IS: 8 J, 13 J; FS: 72 N, 64 N). Structurally, the Ag+ of the two ECPs is coordinated with two energetic cations, two perchlorates, or one nitrate via tetragonal coordination to form a single helical structure that is interspersed up and down in two directions.

Energetic coordination polymers (ECPs) based on tetrazole N-oxides: green nitrogen-rich energetic complexes of variable dimensions.

In recent years, it has been demonstrated that the energetic properties of many tetrazole-containing compounds can be enhanced through the formation of the corresponding N-oxides. The introduction of N-O groups increases the oxygen balance of tetrazole compounds, while providing additional coordination sites and enriching the coordination modes between tetrazole compounds and metal ions. The introduction of O atoms alters the polarity of the substance from N to N-O, the packing and density increase and therefore the detonation velocity (VD) and pressure (P) also increase. Based on this, energetic coordination polymers (ECPs) with tetrazole N-oxides serving as ligands possess extremely high research value. In this paper, we aim to summarize the existing ECPs based on tetrazole N-oxides briefly and discuss their advantages, emphasizing their excellent stability and application prospects.

Structure and performance regulation of energetic complexes through multifunctional molecular self-assembly.

The design of novel energetic compounds constitutes a pivotal research direction within the field of energetic materials. However, exploring the intricate relationship between their molecular structure and properties, in order to uncover their potential applications, remains a challenging endeavor. Therefore, employing multi-molecule assembly techniques to modulate the structure and performance of energetic materials holds immense significance. This approach enables the creation of a new generation of energetic materials, fueling research and development efforts in this field. In this study, a series of coordination compounds are synthesized by utilizing tetranitroethide (TNE) as an anion, which possesses a high nitrogen and oxygen content. The synthesis involves the synergistic modification between metal ions and small molecule ligands. Characterization of the obtained compounds is carried out using various techniques, including single crystal X-ray diffraction, IR spectroscopy, elemental analysis, and simultaneous TG-DSC analysis. Additionally, the energy of formation for these compounds is calculated using bomb calorimetry, based on the heat of combustion. The detonation performances of the compounds are determined through calculations using the EXPLO 5 software, and their sensitivities to external stimuli are evaluated.

Construction of Energetic Complexes Based on LLM-105 and Transition Metal Cations (Ni, Co, Mn, and Cu)

Energetic complexes represent a crucial research direction for the design and synthesis of novel energetic materials. In this work, 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), a significant explosive compound with exceptional comprehensive properties, was selected as the ligand for coordinating with various metal ions. Four novel energetic complexes, Ni(C4H3N6O5)2·DMF (1), Co(C4H3N6O5)2·2DMF (2), Mn(C4H3N6O5)3·3/2DMF (3), and Cu3(C4H2N6O5)3·3DMF (4) were successfully synthesized, and their crystal structures were identified by a single-crystal X-ray diffraction technique. The structural analyses illustrated that LLM-105 can form either a mononuclear metal complex after the deprotonation of one amino group or a trinuclear metal complex after the deprotonation of two amino groups. Compound 1 exhibits a planar quadrilateral geometry, while both compounds 2 and 3 display distorted octahedral configurations. Compound 4 has three metal centers and exhibits two coordination configurations of distorted tetragonal pyramid geometry and planar quadrilateral geometry. The detonation performances of compounds 1–4 were also theoretically calculated, revealing their favorable explosive properties. These findings emphasize the diverse coordination modes of LLM-105 and the structural variability and adjustability of its complexes, offering valuable insights for regulating both the structure and performance of the LLM-105 complex as well as researching its deprotonation.

Precise Regulation of Combustion Characteristics of High-Energy Composite Propellants by Incorporation of CL-20 Crystals Intercalated with Energetic Burn Rate Modifiers.

In this study, a 2D structured triaminoguanidine-glyoxal polymer with a high nitrogen content has been coordinated with metal ions to produce energetic metal complexes (TAGP-Ms) employed as energetic burn rate inhibitors. The metal ions (Ba2+, K+, and Ca2+) are elaborately selected based on their ability of suppressing the burn rate of composite propellants. The CL-20 crystals were intercalated with prepared TAGP-Ms materials via a solvent-antisolvent method for realization of the precise control on burning behaviors of studied propellants. The influence of TAGP-Ms inhibitors on thermal decomposition and combustion characteristics of high-energy composite propellants was evaluated using thermal analysis and a combustion diagnostic method. Results of TGA/DSC-FTIR measurements suggest that the thermal decomposition of CL-20-containing composite propellants was found to be constrained by varied degrees as a result of TAGP-Ms additions, in which the TAGP-K displays a stronger effect on suppressing the thermal decomposition of CL-20 compared with that of other TAGP-Ms. The FTIR spectra indicate that the primary gaseous phase products are composed of N2O, H2O, and CO2 in CL-20 decomposition, as well as by HCl, H2O, NO2, and N2O in the decomposition of AP for all studied composite propellants. The combustion characterizations show that the TAGP-K-containing composite propellant exhibits a significantly reduced rate of heat release but is associated with a higher flame radiation intensity increased by 4.2% compared with that of the reference propellant, which clearly implies that the TAGP-K is capable of suppressing the energy release rate while ensuring the high energetic features of propellants to be well maintained. Moreover, the burn rate pressure exponents are considerably decreased by ∼10% for the TAGP-K-containing propellants in comparison with those of propellants with the typical formulation, which strongly suggests that TGAP-Ms are promising candidates for tuning the combustion behaviors of composite propellants by influencing the decomposition processes of CL-20 and AP collectively.

Metal-Free Hybrid Energetic Composites Based on Donor-Acceptor π-Conjugated Organic Energetic Catalysts with Enlightening the Laser Ignition Performance of Multi-Scale Ammonium Perchlorate.

Photosensitive materials, such as energetic complexes, usually have high sensitivity and cause heavy-metal pollution, whereas others, like carbon black and dye, do not contain energy, which affects energy output and mechanical properties. In this work, donor-acceptor π-conjugated energetic catalysts, denoted as D-n, are designed and synthesized. Nonmetallic hybrid energetic composites are prepared by assembling the as-synthesized catalysts into multiscale ammonium perchlorate (AP). Composites containing catalysts and APs can be successfully ignited without the involvement of metals. The new ignition mechanism is further analyzed using experimental and theoretical analyses such as UV-vis-near-infrared (NIR) spectra, electron-spin resonance spectroscopy, and energy-gap analysis. The shortest ignition delay time is 56ms under the experimental condition of a NIR wavelength of 1064nm and a laser power of 10W. At the voltage of 1kV and the electric field of 500V mm-1 , the laser-ignition delay time of D-2/AP hybrid composite decreases from 56 to 35ms because D-2 also exhibits organic semiconductor-like properties. D-2/AP and D-12/AP can also be used to successfully laser ignite other common energetic materials. This study can guide the development of advanced metal-free laser-ignitable energetic composites to address challenges in the field of aerospace engineering.

Self-assembly Hybridization of CL-20 and Hydrazone-based Polymeric Carbon Nitrides for High Performance Explosive

A strategy for desensitization of the highly sensitive explosive CL-20 with polymeric carbon nitrides is described. The hybrid energetic material (MHGP-CL-20) was synthesized via a self-assembly approach, where CL-20 molecules are immobilized on the hydrazone-based polymeric carbon nitrides. The good detonation performances (detonation velocity 9608 m·s−1, detonation pressure 42.8 GPa) show that MHGP-CL-20 retains the excellent performance of CL-20 to the greatest extent. More importantly, its sensitivities were effectively reduced with the impact sensitivity (IS) 10 J and the friction sensitivity (FS) 160 N, which is much lower compared with raw ε-CL-20 (IS: 4 J; FS: 94 N). In addition, its specific impulse was improved to 276.6 s, higher than that of ε-CL-20 (272.4 s). By preparing solid composite propellants, the burning rate of the propellant grain PMC20 based on MHGP-CL-20 is higher than PC20 based on ε-CL-20. The addition of hybrid energetic complex could keep the stability of combustion and improve the burning rate of solid propellant. The combination of PCNs material and CL-20 sustains the excellent performance of CL-20 and reduces the sensitivity effectively. The preparation of hybrid energetic material MHGP-CL-20 finds a new balance in the contradictory system of high energy and low sensitivity.

Accelerated thermal decomposition of ammonium perchlorate by electron transfer from dinuclear rare-earth EMOFs

Energetic metal-organic framework materials (EMOFs) are a class of energetic complexes formed by constructing energetic organic compounds with metal ions, which have garnered considerable attention due to their potential catalytic role in promoting the thermal decomposition of ammonium perchlorate (AP). However, how to improve the catalytic effect is still long-standing issue for EMOFs. Based on the electron transfer between rare earth metal ions with positive holes in the d, f-orbital and ammonium perchlorate ions, three rare earth EMOFs (La2(tza)3(H2O)6·4H2O, Ce2(tza)3(H2O)6·3H2O, and Nd2(tza)3(H2O)6·4H2O) were synthesized by solution evaporation method and their effects on the thermal decomposition of AP were investigated. The three EMOFs are binuclear isomorphic and form thermally stable (Tdet > 630.0 K) 3D structures through extensive hydrogen bonds. In addition, the introduction of lanthanide metals can enhance the electron transfer ability of EMOFs and promote the electron transfer of AP/EMOFs mixtures, which is beneficial to modulate the catalytic performance of EMOFs for the AP thermal decomposition. The addition of the three EMOFs caused the high-temperature decomposition peak of AP towards the low-temperature. Meanwhile, the temperature of the high-temperature decomposition peak was advanced by 46.8 K ∼ 59.8 K, and the activation energy (Ea) was reduced by 85.02 ∼ 117.71 kJ/mol, which could significantly improve the thermal decomposition performance of AP. Most importantly, compared to the other two EMOFs, the cation in Nd2(tza)3(H2O)6·4H2O has the highest effective nuclear charge number in the f orbital and strongest electron transfer ability, which can reduce the Ea of AP to 96.85 kJ/mol. Overall, the strategy of construction EMOFs by increase the electron transfer ability can provide guidance for the exploration of novel and efficient energetic catalysts.

Preparation of low hygroscopicity ADN-based energetic composite microspheres and their performance study

In order to reduce the hygroscopicity of ammonium dinitramide (ADN), four different ADN/nitrocellulose (NC) samples were prepared from acetone solutions using electrostatic spraying, with the concentrations of 2.5, 5, 7.5, and 10 mg ml−1. The morphology was analyzed by scanning electron microscopy, and the samples with regular morphology and uniform size were examined by x-ray powder diffraction and differential scanning calorimetry to investigate the crystal structure and obtain their thermal decomposition properties. Additionally, the mechanical sensitivity and hygroscopicity of the microspheres were also obtained from these studies. The ADN/NC energetic complexes prepared at a concentration of 5 mg ml−1 were found to be spherical, regular in shape, and uniform in size. The apparent activation energy and the critical temperature for thermal explosion were found to be reduced. The impact sensitivities were comparable to those of the raw material, whereas the friction sensitivities were enhanced. Water absorption tests showed that the moisture absorption of the raw ADN was 32.12%, and that of the ADN/NC sample after coating was 3.75%. The moisture absorption of the prepared samples was significantly reduced.

Energetic Coordination Polymers Based on Copper Furazans and 1,2,3-Triazoles: Tuning the Oxygen Balance with Nitramino Functionalities

Four novel energetic complexes comprising furazan/nitramino groups were synthesized through a simple hydrothermal method. Owing to the introduction of an oxygen-containing nitramino group, Cu(DNAF)(NH3)3 (ECP-1), Cu(DNAF)(H2O)3 (ECP-2), Cu(ANFZ)2(H2O)5 (ECP-3), and Cu2(TA)2(H2O)6 (ECP-4) (DNAF = 4,5-dinitraminofurazan, ANFZ = 4-amino-3-nitraminofurazan, TA = 5-nitro-4-nitramino-1,2,3-triazole) possess relatively high oxygen contents and oxygen balance, indicating efficient energy release during the self-sustained redox process. In addition, these energetic coordination polymers (ECPs) possess exceptional crystal density and insensitivity to external stimuli. Compared to the energetic complexes reported previously, the oxygen balance and contents of nitrogen and oxygen atoms of ECP-1–ECP-4 remain at a relatively higher level (OB > −20%, N+O% > 60%), ECP-2 and ECP-4 have excellent positive oxygen balance (10.5% and 5.5%, respectively), and ECP-4 has the highest density (2.22 g/cm3) among these four coordination polymers.

Theoretical design of new insensitive high energy metal complexes based on the double fused-ring insensitive ligands strategy.

In this work, 24 new nitrogen-rich fused-ring energetic metal complexes were designed based on the double fused-ring insensitive ligands strategy. First, 7-nitro-3-(1H-tetrazol-5-yl)-[1,2,4]triazolo[5,1-c][1,2,4]triazin-4-amine and 6-amino-3-(4H,8H-bis([1,2,5]oxadiazolo)[3,4-b:3',4'-e]pyrazin-4-yl)-1,2,4,5-tetrazine-1,5-dioxide were linked together by coordinating with metals cobalt and copper. Then, three energetic groups (NH2, NO2, and C(NO2)3) were introduced into the system to modify the structure and adjust the performance. Then, their structures and properties were investigated theoretically; the effects of different metals and small energetic groups were studied also. Finally, 9 compounds which have both higher energy and lower sensitivity than the famous high energy compound compound 1,3,5,7-tetranitro-1,3,5,7-tetrazocine were selected out. In addition, it was found that copper, NO2, and C(NO2)3 could increase the energy while cobalt and NH2 would be helpful for reducing the sensitivity. Calculations were performed at the TPSS/6-31G(d) level by using the Gaussian 09 software.

Construction of variable dimension green high energy complex and laser response

A high dimensional energetic complex [Co(OH-Tz)2(H2O)2]n was synthesis with tetrazole energetic ligand, and its single crystal structures were obtained. Compared with the previously reported complexes, it has higher density (ρ = 2.135 g·cm−3), higher energy level (D = 7.59 km·s−1) and thermal stability (Tdec = 271 ℃). In addition, the femtosecond laser and high-speed imaging results show that this compound is sensitive to laser stimulation, and under the stimulation of 808 nm femtosecond laser, the detonation process initiated by thermal mechanism can occur when the total laser energy is 224 mJ. Therefore, it is a potential environment-friendly laser detonating material.