溶剂分子的存在会严重降低能量金属-有机框架(EMOFs)材料的爆热和稳定性,开发无溶剂的EMOFs已成为制备高能量密度材料的有效策略。本文将高能的2,3-二(5-1H-四唑基)吡嗪(H2DTPZ)配体与银离子作用在水热条件下制备了一例无溶剂的EMOF [Ag...溶剂分子的存在会严重降低能量金属-有机框架(EMOFs)材料的爆热和稳定性,开发无溶剂的EMOFs已成为制备高能量密度材料的有效策略。本文将高能的2,3-二(5-1H-四唑基)吡嗪(H2DTPZ)配体与银离子作用在水热条件下制备了一例无溶剂的EMOF [Ag2(DTPZ)]n(1)(含氮量:32.58%),并借助元素分析、红外光谱、X射线衍射以及热分析等技术对其组成和结构进行了表征。化合物1中,DTPZ2-配体构型高度扭转并以八齿配位模式桥联Ag+离子形成三维框架结构(ρ=2.812 g·cm-3),配体大的位阻效应和强的配位能力有效阻止了溶剂分子与金属配位或占据框架空腔;同时,不同配体四唑环间强的π–π堆积作用(质心-质心距离为0.34461(1) nm),使得化合物1呈现高的热稳定性(Te=619.1 K, Tp=658.7K)。热分析研究表明化合物1分解主要发生一步快速失重并伴有剧烈的放热,呈现出潜在的含能特质。通过差示扫描量热(DSC)技术对化合物1的热分解过程进行了非等温热动力学分析(基于Kissinger和Ozawa-Doyle方法)并获得了相应热动力学参数(活化能Ea=272.1 k J·mol^-1,Eo=268.9 k J·mol^-1;lgA=19.67 s^-1)。进一步基于升温速率趋于0时的分解峰温和外延起始温度,计算得到了相关热力学参数(活化焓?H≠=266.9 k J·mol^-1,活化熵?S≠=125.4 J·mol^-1·K-1,活化自由能?G≠=188.3 k J·mol^-1)以及热爆炸临界温度(Tb=607.1 K)和自加速分解温度(TSADT=595.8 K),结果表明该化合物具有良好的热安全性,其分解属非自发的熵驱动过程。借助精密转动弹热量计测定了化合物1的恒容燃烧能(Qv)并计算得其标准摩尔生成焓为(2165.99±0.81) k J·mol^-1。爆轰和安全性能测试表明,化合物1对撞击和摩擦均不敏感,爆热值达10.15 k J·g^-1,远高于常见硝铵类炸药奥克托金(HMX)、黑索金(RDX)和2,4,6-三硝基甲苯(TNT),是一例有前景的高能钝感含能材料。展开更多
The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of...The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of Dy_(2)(L_1)_(2)(L_(2))_(2)(CH_(3)OH)_(2)·CH_(2)Cl_(2)·CH_(3)OH(1) and Dy_(2)(L_1)_(2)(L_(3))_(2)(CH_(3)OH)_(2)·CH_(3)CN(2),where L_1,L_(2) and L_(3) represent the deprotonated form of 4-tert-butyl-2-(7-methoxybenzo[d]oxazol-2-yl)phenol,(E)-1-(((3,5-di-tert-butyI-2-hydroxyphenyI)imino)methyl)naphthalen-2-ol and(E)-2,4-di-tertbutyl-6-((2-hydroxybenzylidene)amino)phenol.The tiny difference of the core structure of 1 and 2 is derived from the steric hindrance of Schiff base ligands L_(2) and L_(3).Dynamic magnetic measurements reveal that 1 and 2 show frequency-dependent out-of-phase alternating-current susceptibility signal peaks at different temperatures under zero dc field,diagnostic of single-molecule magnet behavior.The experimental derived energy barrier to magnetization reversal for 1 and 2 is 108(1),47(2) and 33(3) K.Ab initio CASSCF calculations performed on 1 and 2 suggest that the origin of the difference in magnetic properties originates from the variation in the single-ion anisotropy that arises due to minor structural variation.Further,the equation to calculate the effective energy barrier for Dy_(2) proposed earlier is found to yield an excellent agreement with the experimental results.Solid state fluorescence measurements performed on 1 and 2 demonstrate that both exhibit two ligands centered components of fluorescent emissive,in addition,with different emitting colors and chromaticity coordinates.The discrepancy of fluorescence and single molecule magnet behavior showed by 1 and 2 can be attributed to the steric hindrance effect of Schiff base ligands.展开更多
A 3D mixed-valence Co（Ⅲ）-Co（Ⅱ） compound [Co9（bta）10（Hbta）2（H2O）10]n·[22（H2O）]n （1） （H2bta=N,N-bis（1H-tetrazole-5- yl）-amine） was hydrothermally synthesized by reaction of Co（NO3）2·6H2O ...A 3D mixed-valence Co（Ⅲ）-Co（Ⅱ） compound [Co9（bta）10（Hbta）2（H2O）10]n·[22（H2O）]n （1） （H2bta=N,N-bis（1H-tetrazole-5- yl）-amine） was hydrothermally synthesized by reaction of Co（NO3）2·6H2O with H2bta·H2O. Compound 1 consists of three kinds of distorted-octahedral [CoⅡ（N4O2）] paramagnetic nodes which are separated by [CoⅢ（bta）2（Hbta）]2-/[CoⅢ（bta）3]3- dia- magnetic linkers to generate a 3D porous metal-organic framework （MOF） with alternative …Co（Ⅲ）…Co（II）… array and channels incorporating water molecules. Under an applied magnetic field of 4000 Oe, compound 1 exhibits slow relaxation of magnetization at low temperatures, giving AE/kB=30.O0 K and ι0=2.0×10^-8 s.展开更多
基金supported by the National Natural Science Foundation of China(21727805,21673180,21703135,21803042)Natural Science Basic Research Program of Shaanxi(2017JZ002,2018JM5180,2019JQ-249,2019JQ-067)+1 种基金the Project of Shaanxi Key Laboratory of Chemical Reaction Engineering(14JS112)the 64th China Postdoctoral Science Foundation Funded Project(2018M643706)。
文摘溶剂分子的存在会严重降低能量金属-有机框架(EMOFs)材料的爆热和稳定性,开发无溶剂的EMOFs已成为制备高能量密度材料的有效策略。本文将高能的2,3-二(5-1H-四唑基)吡嗪(H2DTPZ)配体与银离子作用在水热条件下制备了一例无溶剂的EMOF [Ag2(DTPZ)]n(1)(含氮量:32.58%),并借助元素分析、红外光谱、X射线衍射以及热分析等技术对其组成和结构进行了表征。化合物1中,DTPZ2-配体构型高度扭转并以八齿配位模式桥联Ag+离子形成三维框架结构(ρ=2.812 g·cm-3),配体大的位阻效应和强的配位能力有效阻止了溶剂分子与金属配位或占据框架空腔;同时,不同配体四唑环间强的π–π堆积作用(质心-质心距离为0.34461(1) nm),使得化合物1呈现高的热稳定性(Te=619.1 K, Tp=658.7K)。热分析研究表明化合物1分解主要发生一步快速失重并伴有剧烈的放热,呈现出潜在的含能特质。通过差示扫描量热(DSC)技术对化合物1的热分解过程进行了非等温热动力学分析(基于Kissinger和Ozawa-Doyle方法)并获得了相应热动力学参数(活化能Ea=272.1 k J·mol^-1,Eo=268.9 k J·mol^-1;lgA=19.67 s^-1)。进一步基于升温速率趋于0时的分解峰温和外延起始温度,计算得到了相关热力学参数(活化焓?H≠=266.9 k J·mol^-1,活化熵?S≠=125.4 J·mol^-1·K-1,活化自由能?G≠=188.3 k J·mol^-1)以及热爆炸临界温度(Tb=607.1 K)和自加速分解温度(TSADT=595.8 K),结果表明该化合物具有良好的热安全性,其分解属非自发的熵驱动过程。借助精密转动弹热量计测定了化合物1的恒容燃烧能(Qv)并计算得其标准摩尔生成焓为(2165.99±0.81) k J·mol^-1。爆轰和安全性能测试表明,化合物1对撞击和摩擦均不敏感,爆热值达10.15 k J·g^-1,远高于常见硝铵类炸药奥克托金(HMX)、黑索金(RDX)和2,4,6-三硝基甲苯(TNT),是一例有前景的高能钝感含能材料。
基金Project supported by National Natural Science Foundation of China (21601143)Natural Science Foundation of Shaanxi Province (2021JM309)+2 种基金Open Funds of the State Key Laboratory of Rare Earth Resource of Changchun Institute of Applied Chemistry (RERU2021012)Science and Technology Innovation Team Program of Shaanxi Province (2022TD-32) and DST/SERB (CRG/2018/000430,DST/SJF/CSA03/2018-10SB/SJF/2019-20/12)。
文摘The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of Dy_(2)(L_1)_(2)(L_(2))_(2)(CH_(3)OH)_(2)·CH_(2)Cl_(2)·CH_(3)OH(1) and Dy_(2)(L_1)_(2)(L_(3))_(2)(CH_(3)OH)_(2)·CH_(3)CN(2),where L_1,L_(2) and L_(3) represent the deprotonated form of 4-tert-butyl-2-(7-methoxybenzo[d]oxazol-2-yl)phenol,(E)-1-(((3,5-di-tert-butyI-2-hydroxyphenyI)imino)methyl)naphthalen-2-ol and(E)-2,4-di-tertbutyl-6-((2-hydroxybenzylidene)amino)phenol.The tiny difference of the core structure of 1 and 2 is derived from the steric hindrance of Schiff base ligands L_(2) and L_(3).Dynamic magnetic measurements reveal that 1 and 2 show frequency-dependent out-of-phase alternating-current susceptibility signal peaks at different temperatures under zero dc field,diagnostic of single-molecule magnet behavior.The experimental derived energy barrier to magnetization reversal for 1 and 2 is 108(1),47(2) and 33(3) K.Ab initio CASSCF calculations performed on 1 and 2 suggest that the origin of the difference in magnetic properties originates from the variation in the single-ion anisotropy that arises due to minor structural variation.Further,the equation to calculate the effective energy barrier for Dy_(2) proposed earlier is found to yield an excellent agreement with the experimental results.Solid state fluorescence measurements performed on 1 and 2 demonstrate that both exhibit two ligands centered components of fluorescent emissive,in addition,with different emitting colors and chromaticity coordinates.The discrepancy of fluorescence and single molecule magnet behavior showed by 1 and 2 can be attributed to the steric hindrance effect of Schiff base ligands.
基金supported by the National Natural Science Foundation of China(21373162,21127004,21173168,21203149,21463020)the Natural Science Foundation of Shaanxi Province(11JS110,FF10091,SJ08B09)
文摘A 3D mixed-valence Co（Ⅲ）-Co（Ⅱ） compound [Co9（bta）10（Hbta）2（H2O）10]n·[22（H2O）]n （1） （H2bta=N,N-bis（1H-tetrazole-5- yl）-amine） was hydrothermally synthesized by reaction of Co（NO3）2·6H2O with H2bta·H2O. Compound 1 consists of three kinds of distorted-octahedral [CoⅡ（N4O2）] paramagnetic nodes which are separated by [CoⅢ（bta）2（Hbta）]2-/[CoⅢ（bta）3]3- dia- magnetic linkers to generate a 3D porous metal-organic framework （MOF） with alternative …Co（Ⅲ）…Co（II）… array and channels incorporating water molecules. Under an applied magnetic field of 4000 Oe, compound 1 exhibits slow relaxation of magnetization at low temperatures, giving AE/kB=30.O0 K and ι0=2.0×10^-8 s.
