The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion ...The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion are quite rare.Herein,two fluorescent probes for cyclo-N-5anion were designed.Sensor 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent changes.Sensor 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition performance.Isothermal titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:2.Both sensors display typical aggregation-induced emission(AIE)features and good water-solubility.The sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to N-5anion.In addition,the probes also have good selectivity of N-5anion salts.The research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.展开更多
Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the ...Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.展开更多
In recent decades,pentazolate salts have gained considerable attention as high energy density materials(HEDMs).Using the machine-learning accelerated structure searching method,we predicted four pentazolate salts stab...In recent decades,pentazolate salts have gained considerable attention as high energy density materials(HEDMs).Using the machine-learning accelerated structure searching method,we predicted four pentazolate salts stabilized with tetravalent metals(Ti-N and Zr-N).Specifically,the ground state MN_(20)(M=Ti,Zr)adopts the space-group P 4/mcc under ambient conditions,transforming into the I-4 phase at higher pressure.Moreover,the I-4-MN_(20)becomes energetically stable at moderate pressure(46.8 GPa for TiN_(20),38.7 GPa for ZrN_(20)).Anharmonic phonon spectrum calculations demonstrate the dynamic stabilities of these MN_(20)phases.Among them,the P 4/mcc phase can be quenched to 0 GPa.Further ab-initio molecular dynamic simulations suggest that the N_(5)rings within these MN_(20)systems can still maintain integrity at finite temperatures.Calculations of the projected crystal orbital Hamilton population and reduced density gradient revealed their covalent and noncovalent interactions,respectively.The aromaticity of the N_(5)ring was investigated by molecular orbital theory.Finally,we predicted that these MN_(20)compounds have very high energy densities and exhibit good detonation velocities and pressures,compared to the HMX explosive.These calculations enrich the family of pentazolate compounds and may also guide future experiments.展开更多
The search for high energy density materials(HEDMs)in polymeric nitrogen compounds has gained considerable attention.Previous theoretical predictions and experiments have revealed that metal ions can be used to stabil...The search for high energy density materials(HEDMs)in polymeric nitrogen compounds has gained considerable attention.Previous theoretical predictions and experiments have revealed that metal ions can be used to stabilize the pentazolate(N-5)anion.In this work,by employing a machine learning-accelerated crystal structure searching method and first-principles calculations,we found that the new pentazolate salts,CaN(10)and BaN(10),are energetically favorable at high pressures.Phonon dispersion calculations reveal that they are quenchable at ambient pressure.Ab initio molecular dynamics simulations verify their dynamic stability at finite temperature.Bader charge and electron localization function illustrates that alkaline earth atoms serve as electron donors,contributing to the stability of N5 rings.Bonding calculations reveal covalent bonds between nitrogen atoms and weak interactions between N5 rings.Similar to other pentazolate salts,these polymeric nitrides have high energy densities of approximately 2.35 kJ/g for CaN(10)and 1.32 kJ/g for BaN(10).The predictions of CaN(10)and BaN(10)structures indicate that these salts are potential candidates for green nitrogen-rich HEDMs.展开更多
Subject Code:E04With the support by the National Natural Science Foundation of China,a major breakthrough has been made by the group led by Prof.Lu Ming(陆明)from Nanjing University of Science&Technology.The relat...Subject Code:E04With the support by the National Natural Science Foundation of China,a major breakthrough has been made by the group led by Prof.Lu Ming(陆明)from Nanjing University of Science&Technology.The related research achievement entitled“A series of energetic metal pentazolate hydrates”was published展开更多
Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we p...Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we present a new strategy to utilize deflagration reactions of cobalt pentazolate in combination with explosive poly(ionic liquid)(EPIL)for the preparation of Co@N-doped carbon materials with homogeneously distributed cobalt nanoparticle encapsulated by the layers of N-doped carbon sheets.The resultant5%Co(N5)2-EPIL-900 exhibits high electrocatalytic activities,excellent stability and tolerance to CH3 OH towards oxygen reduction reaction(ORR).Moreover,the present approach provides a novel routine for preparation of functional materials from energetic and newly-emerging cyclo-N5--derived compounds.展开更多
In this study,based on two attractive energetic compounds pentazole(PZ) and tetraazacubane(TAC),a new family of high energy and high nitrogen compounds pentazolyltetraazacubanes were designed.Then,a different number o...In this study,based on two attractive energetic compounds pentazole(PZ) and tetraazacubane(TAC),a new family of high energy and high nitrogen compounds pentazolyltetraazacubanes were designed.Then,a different number of NH2 or NO2 groups were introduced into the system to further adjust the property.The structures,properties,and the structure-property relationship of designed molecules were investigated theoretically.The results showed that all nine designed compounds have extremely high heat of formation(HOF,1226-2734 kJ/mol),good density(1,73-1.88 g/cm3),high detonation velocity(8.30-9.35 km/s),high detonation pressure(29.8-39.7 GPa) and acceptable sensitivity(△V:41-87 A3).These properties could be effectively positive adjusted by replacing one or two PZ rings by NH2 or/and NO2 groups,especially for the energy and sensitivity performance,which were increased and decreased obviously,respectively.As a result,two designed pentazolyltetraazacubanes were predicted to have higher energy and lower sensitivity than the famous high energy compound in use 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane,while two others have better co mbination property than 1,3,5-Trinitro-1,3,5-triazacyclohexane.In all,four new pentazolyltetraazacubanes with good combination performance were successfully designed by combining PZ with TAC,and the further property adjustment strategy of introducing a suitable amount of NH2/NO2 groups into the system.This work may help develop new cage energetic compounds.展开更多
Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3...Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3-amino-1,2,4-triazole C2H4N4(ATz) were crystallized into NaN5 and two novel energetic coordination polymers(CPs),(NaN5)5[(CH6-N3)N5](N5)3–(1) and(NaN5)2(C2H4N4)(2) were prepared respectively via a self-assembly process. The crystal structure reveals the co-existence of the chelating pentazole anion and organic component in the solid state. In polymer 1, Na+and N5– were coordinated to form a cage structure in which guanidine cation [C(NH2)3]+ was trapped;for polymer 2, a mixedligand system was observed;N5 – and ATz coordinate separately with Na+and form two independent but interweaved nets. In this way, coordination polymer has been successfully utilized to modify specific properties of energetic materials through crystallization. Benefiting from the coordination and weak interactions, the decomposition temperatures of both polymers increase from 111°C(1D structure [Na(H2 O)(N5)]?2 H2 O) to 118.4 and 126.5°C respectively. Moreover, no crystallized H2 O was generated in products to afford the anhydrous compounds of pentazole salts with high heats of formation( >800 kJ mol–1). Compared to traditional energetic materials, the advantage in heats of formation is still obvious for the cyclo-N5– based CPs, which highlights cyclo-N5– as a promising energetic precursor for high energy density materials(HEDMs).展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.22175093 and 22007047)the Natural Science Foundation of Jiangsu Province(Grant No.BK20200474)the China Postdoctoral Science Foundation(Grant No.2022M721615)。
文摘The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion are quite rare.Herein,two fluorescent probes for cyclo-N-5anion were designed.Sensor 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent changes.Sensor 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition performance.Isothermal titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:2.Both sensors display typical aggregation-induced emission(AIE)features and good water-solubility.The sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to N-5anion.In addition,the probes also have good selectivity of N-5anion salts.The research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Nat-ural Science Foundation of China(Grant Nos.12174143,11634004,11847094,and 11804384)JLU Science and Technology Innovative Research Team(Grant No.2017TD-01)。
文摘Pentazolate compounds have attracted extensive attention as high energy density materials.The synthesis and recovery of pentazolate compounds is of great importance for their potential applications.Here,we report the synthesis of Pmn2_(1)-NaN_(5)and Pm-Na_(2)N_(5)through compressing and laser heating pure NaN_(3)at~60 GPa.Upon decompression,the pressureinduced structural transition from Pmn2_(1)-NaN_(5)into Cm-NaN_(5)is observed in the pressure range of 14-23 GPa for the first time.The cyclo-N_(5)^(-)can be traced down to 4.7 GPa at room temperature and recovered to ambient pressure under low temperature condition(up to 160 K).The Pm-Na_(2)N_(5)is suggested to decompose into the P4/mmm-NaN_(2)at 23 GPa,and be stable at ambient conditions.This work provides insight into the high-pressure behaviors of pentazolate compounds and an alternative way to stabilize energetic polynitrogen compounds.
基金J.S.gratefully acknowledges the financial support from the National Natural Science Foundation of China(12125404,11974162,11834006)the Fundamental Research Funds for the Central Universities.K.X.acknowledges the National Natural Science Foundation of China under 12004185+2 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China under 20KJB140016the Scientific Research Start-up Funds of Nanjing Forestry University(163101110)the financial support from the Project funded by China Postdoctoral Science Foundation(2019M651767).
文摘In recent decades,pentazolate salts have gained considerable attention as high energy density materials(HEDMs).Using the machine-learning accelerated structure searching method,we predicted four pentazolate salts stabilized with tetravalent metals(Ti-N and Zr-N).Specifically,the ground state MN_(20)(M=Ti,Zr)adopts the space-group P 4/mcc under ambient conditions,transforming into the I-4 phase at higher pressure.Moreover,the I-4-MN_(20)becomes energetically stable at moderate pressure(46.8 GPa for TiN_(20),38.7 GPa for ZrN_(20)).Anharmonic phonon spectrum calculations demonstrate the dynamic stabilities of these MN_(20)phases.Among them,the P 4/mcc phase can be quenched to 0 GPa.Further ab-initio molecular dynamic simulations suggest that the N_(5)rings within these MN_(20)systems can still maintain integrity at finite temperatures.Calculations of the projected crystal orbital Hamilton population and reduced density gradient revealed their covalent and noncovalent interactions,respectively.The aromaticity of the N_(5)ring was investigated by molecular orbital theory.Finally,we predicted that these MN_(20)compounds have very high energy densities and exhibit good detonation velocities and pressures,compared to the HMX explosive.These calculations enrich the family of pentazolate compounds and may also guide future experiments.
基金financial support from the National Key R&D Program of China(Grant No.2016YFA0300404)the National Natural Science Foundation of China(Grant Nos.11974162,and 11834006)+1 种基金the Fundamental Research Funds for the Central Universitiesfinancial support from the Project funded by China Postdoctoral Science Foundation(Grant No.2019M651767)。
文摘The search for high energy density materials(HEDMs)in polymeric nitrogen compounds has gained considerable attention.Previous theoretical predictions and experiments have revealed that metal ions can be used to stabilize the pentazolate(N-5)anion.In this work,by employing a machine learning-accelerated crystal structure searching method and first-principles calculations,we found that the new pentazolate salts,CaN(10)and BaN(10),are energetically favorable at high pressures.Phonon dispersion calculations reveal that they are quenchable at ambient pressure.Ab initio molecular dynamics simulations verify their dynamic stability at finite temperature.Bader charge and electron localization function illustrates that alkaline earth atoms serve as electron donors,contributing to the stability of N5 rings.Bonding calculations reveal covalent bonds between nitrogen atoms and weak interactions between N5 rings.Similar to other pentazolate salts,these polymeric nitrides have high energy densities of approximately 2.35 kJ/g for CaN(10)and 1.32 kJ/g for BaN(10).The predictions of CaN(10)and BaN(10)structures indicate that these salts are potential candidates for green nitrogen-rich HEDMs.
文摘Subject Code:E04With the support by the National Natural Science Foundation of China,a major breakthrough has been made by the group led by Prof.Lu Ming(陆明)from Nanjing University of Science&Technology.The related research achievement entitled“A series of energetic metal pentazolate hydrates”was published
基金financially supported by the National Natural Science Foundation of China(21703218 and21875228)Shenzhen Science and Technology Innovation Committee(JCYJ20151013162733704)
文摘Cyclopentazolate anions(cyclo-N5-)have been receiving ever-increasing attention as component of energetic explosives since recent fulfilment of the first stable sample in solid phase and ambient conditions.Herein,we present a new strategy to utilize deflagration reactions of cobalt pentazolate in combination with explosive poly(ionic liquid)(EPIL)for the preparation of Co@N-doped carbon materials with homogeneously distributed cobalt nanoparticle encapsulated by the layers of N-doped carbon sheets.The resultant5%Co(N5)2-EPIL-900 exhibits high electrocatalytic activities,excellent stability and tolerance to CH3 OH towards oxygen reduction reaction(ORR).Moreover,the present approach provides a novel routine for preparation of functional materials from energetic and newly-emerging cyclo-N5--derived compounds.
基金supported by the Natural Science Foundation of Nanjing Institute of Technology (CKJA201603)the Natural Science Foundation of Jiangsu Province(BK20170761,BK20160774)+3 种基金the Jiangsu Key Laboratory Opening Project of Advanced Structural Materials and Application Technology (ASMA201707)Science Innovation Project for Undergraduates of Jiangsu Province (201811276023Z)Outstanding Scientific and Technological Innovation Team in Colleges and Universities of Jiangsu ProvinceJiangsu Overseas Visiting Scholar Program for University Prominent Young & Middle-aged Teachers and Presidents
文摘In this study,based on two attractive energetic compounds pentazole(PZ) and tetraazacubane(TAC),a new family of high energy and high nitrogen compounds pentazolyltetraazacubanes were designed.Then,a different number of NH2 or NO2 groups were introduced into the system to further adjust the property.The structures,properties,and the structure-property relationship of designed molecules were investigated theoretically.The results showed that all nine designed compounds have extremely high heat of formation(HOF,1226-2734 kJ/mol),good density(1,73-1.88 g/cm3),high detonation velocity(8.30-9.35 km/s),high detonation pressure(29.8-39.7 GPa) and acceptable sensitivity(△V:41-87 A3).These properties could be effectively positive adjusted by replacing one or two PZ rings by NH2 or/and NO2 groups,especially for the energy and sensitivity performance,which were increased and decreased obviously,respectively.As a result,two designed pentazolyltetraazacubanes were predicted to have higher energy and lower sensitivity than the famous high energy compound in use 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane,while two others have better co mbination property than 1,3,5-Trinitro-1,3,5-triazacyclohexane.In all,four new pentazolyltetraazacubanes with good combination performance were successfully designed by combining PZ with TAC,and the further property adjustment strategy of introducing a suitable amount of NH2/NO2 groups into the system.This work may help develop new cage energetic compounds.
基金financially supported by the National Natural Science Foundation of China (11702141, 21771108, and U1530101)
文摘Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3-amino-1,2,4-triazole C2H4N4(ATz) were crystallized into NaN5 and two novel energetic coordination polymers(CPs),(NaN5)5[(CH6-N3)N5](N5)3–(1) and(NaN5)2(C2H4N4)(2) were prepared respectively via a self-assembly process. The crystal structure reveals the co-existence of the chelating pentazole anion and organic component in the solid state. In polymer 1, Na+and N5– were coordinated to form a cage structure in which guanidine cation [C(NH2)3]+ was trapped;for polymer 2, a mixedligand system was observed;N5 – and ATz coordinate separately with Na+and form two independent but interweaved nets. In this way, coordination polymer has been successfully utilized to modify specific properties of energetic materials through crystallization. Benefiting from the coordination and weak interactions, the decomposition temperatures of both polymers increase from 111°C(1D structure [Na(H2 O)(N5)]?2 H2 O) to 118.4 and 126.5°C respectively. Moreover, no crystallized H2 O was generated in products to afford the anhydrous compounds of pentazole salts with high heats of formation( >800 kJ mol–1). Compared to traditional energetic materials, the advantage in heats of formation is still obvious for the cyclo-N5– based CPs, which highlights cyclo-N5– as a promising energetic precursor for high energy density materials(HEDMs).
