A high reactive pentacoordinate organic silicon complex was at first prepared by reaction of natural silica with ethylene glycol and potassium hydroxide. Then a novel tetracoordinate silicon was synthesized by reactin...A high reactive pentacoordinate organic silicon complex was at first prepared by reaction of natural silica with ethylene glycol and potassium hydroxide. Then a novel tetracoordinate silicon was synthesized by reacting the pentacoordinate silicon with HCl. The product was characterized and analyzed by FTIR, NMR and TG/DTG.展开更多
以5,5′-联四唑-1,1′-二羟基二水化合物（H2BTO·2H2O）和2-甲基咪唑为原料合成了一种新的5,5′-联四唑-1,1′-二氧-2-甲基咪唑含能离子盐（M2BTO）。采用X-射线单晶衍射、FT-IR、1 H NMR、13 C NMR和元素分析进行了结构表征;利用...以5,5′-联四唑-1,1′-二羟基二水化合物（H2BTO·2H2O）和2-甲基咪唑为原料合成了一种新的5,5′-联四唑-1,1′-二氧-2-甲基咪唑含能离子盐（M2BTO）。采用X-射线单晶衍射、FT-IR、1 H NMR、13 C NMR和元素分析进行了结构表征;利用差示扫描量热分析（DSC）和热重-微分热重分析（TG-DTG）研究了该含能离子盐的热分解过程及其非等温分解反应动力学;利用Kamlet-Jacobs经验公式对其爆速、爆压参数进行了理论计算;采用WL-1型撞击感度测试仪测定了M2BTO的特性落高H50;采用Kissinger法和Ozawa法计算了其反应活化能。结果表明,M2BTO晶体属于三斜晶系,P-1空间群,晶胞参数为：a=0.538 60（5）nm,b=0.726 76（6）nm,c=1.111 49（11）nm,V=401.00（6）×10^-3nm3,ρ=1.534g/cm3,Z=1;M2BTO分解峰值温度为542.1K,TG曲线上只存在一个失重阶段,该阶段位于503.5-568.2K,失重为78.2%,表明其有较好的热稳定性;表观活化能为134.7kJ/mol（Kissinger法）和136.7kJ/mol（Ozawa法）,二者一致性较好,指前因子1n（A/s-1）=29.33;其爆速、爆压的理论计算值分别为7 104m/s、20.23GPa,特性落高（H50）大于61.0cm。展开更多
Transition-metal catalyzed cross-coupling is one of the basic strategies for the C-C bond formation.However,it is difficult to achieve satisfactory results when terminal alkynes with electron-withdrawing group such as...Transition-metal catalyzed cross-coupling is one of the basic strategies for the C-C bond formation.However,it is difficult to achieve satisfactory results when terminal alkynes with electron-withdrawing group such as propiolate esters are used.The reason behind this might be the easy polymerization of this type of alkynes in the presence of base.A tetrahydroxydiboron and copper sulfate co-promoted cross-coupling/cyclization of propiolate esters and o-iodobenzoic acid for the facile and efficient construction of phthalides is described.Preliminary mechanism study indicates that tetrahydroxydiboron can inhibit the polymerization of propiolate esters and increase the reaction rate.This method is characterized by high regio-and stereoselectivities,mild reaction conditions,short reaction time,broad substrate scope,and excellent functional group compatibility.展开更多
文摘A high reactive pentacoordinate organic silicon complex was at first prepared by reaction of natural silica with ethylene glycol and potassium hydroxide. Then a novel tetracoordinate silicon was synthesized by reacting the pentacoordinate silicon with HCl. The product was characterized and analyzed by FTIR, NMR and TG/DTG.
文摘以5,5′-联四唑-1,1′-二羟基二水化合物（H2BTO·2H2O）和2-甲基咪唑为原料合成了一种新的5,5′-联四唑-1,1′-二氧-2-甲基咪唑含能离子盐（M2BTO）。采用X-射线单晶衍射、FT-IR、1 H NMR、13 C NMR和元素分析进行了结构表征;利用差示扫描量热分析（DSC）和热重-微分热重分析（TG-DTG）研究了该含能离子盐的热分解过程及其非等温分解反应动力学;利用Kamlet-Jacobs经验公式对其爆速、爆压参数进行了理论计算;采用WL-1型撞击感度测试仪测定了M2BTO的特性落高H50;采用Kissinger法和Ozawa法计算了其反应活化能。结果表明,M2BTO晶体属于三斜晶系,P-1空间群,晶胞参数为：a=0.538 60（5）nm,b=0.726 76（6）nm,c=1.111 49（11）nm,V=401.00（6）×10^-3nm3,ρ=1.534g/cm3,Z=1;M2BTO分解峰值温度为542.1K,TG曲线上只存在一个失重阶段,该阶段位于503.5-568.2K,失重为78.2%,表明其有较好的热稳定性;表观活化能为134.7kJ/mol（Kissinger法）和136.7kJ/mol（Ozawa法）,二者一致性较好,指前因子1n（A/s-1）=29.33;其爆速、爆压的理论计算值分别为7 104m/s、20.23GPa,特性落高（H50）大于61.0cm。
基金Project supported by the National Natural Science Foundation of China(No.22271214)。
文摘Transition-metal catalyzed cross-coupling is one of the basic strategies for the C-C bond formation.However,it is difficult to achieve satisfactory results when terminal alkynes with electron-withdrawing group such as propiolate esters are used.The reason behind this might be the easy polymerization of this type of alkynes in the presence of base.A tetrahydroxydiboron and copper sulfate co-promoted cross-coupling/cyclization of propiolate esters and o-iodobenzoic acid for the facile and efficient construction of phthalides is described.Preliminary mechanism study indicates that tetrahydroxydiboron can inhibit the polymerization of propiolate esters and increase the reaction rate.This method is characterized by high regio-and stereoselectivities,mild reaction conditions,short reaction time,broad substrate scope,and excellent functional group compatibility.
