Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spec...Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spectrophotometric method. The results show that the complexing properties of the ligands in comparison with those of DTPA are affected by converting two carboxyl groups to amide groups. The relaxation studies have shown that the relaxivity of the chelates is similar to that of Gd DTPA, indicating that in solution all the chelates have one water molecule directly coordinated to the metal ion. Only one water molecule in inner coordination sphere suggests the coordination of the carboxamide oxygen to gadolinium ion, which agrees with the FT IR results.展开更多
The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, ...The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.展开更多
Lithium aluminium amide [LiAI（NHR）4] 5 obtained by treating the primary amine 4 with LiAlH4 could promote the ring opening of epoxide 2 and led to high regioselective product of racemic bis[2-（6-fluoro-2-chromanyl...Lithium aluminium amide [LiAI（NHR）4] 5 obtained by treating the primary amine 4 with LiAlH4 could promote the ring opening of epoxide 2 and led to high regioselective product of racemic bis[2-（6-fluoro-2-chromanyl）-2-hydroxyethyl]amine methanesulfonic acid salt 7.展开更多
凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂...凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂、双(氟磺酰)亚胺锂为导电盐、碳酸乙烯酯/碳酸甲乙酯混合溶剂为增塑剂的GPE。通过热重分析对聚甲基丙烯酸甲酯(PMMA)基GPE的热力学性质进行了表征,采用计时安培法和电子扫描显微镜研究了PMMA基GPE对Al集流体的稳定性。研究结果表明,PMMA基GPE在室温拥有较高的电导率,达到6.61 mS/cm,同时可以将碳酸酯电解液的挥发温度由100.3℃提高至138.1℃。PMMA基GPE在高电位下对Al箔显示出良好的稳定性,4.3 V vs.Li/Li+以下不会发生铝箔腐蚀,而且在商用石墨/LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)软包电池中展现出良好的循环稳定性和容量保持能力,循环1000次后容量保持率为93.4%。展开更多
Facile and rapid polycondensation reactions of N,N'-(pyromellitoyl)-bis-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h were developed by using a domestic microwave oven in...Facile and rapid polycondensation reactions of N,N'-(pyromellitoyl)-bis-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h were developed by using a domestic microwave oven in the presence of a small amount of polar organic medium such as o-cresol. The polycondensation reactions proceeded rapidly, compared with the conventional solution polycondensation, and was completed within 7-10 min, producing a series of novel optically active poly(amide-imide)s 3a-h with high yield and inherent viscosity of 0.35-0.65 dL/g. All of the above polymers were fully characterized by FT-IR, elemental analyses, inherent viscosity (η inh ), solubility test and specific rotation. Some structural characterization and physical properties of these optically active poly(amide-imide)s are reported.展开更多
Diacetates 1 and N-[(1-benzotriazol-l-yl)alkyl]amides 2, both masked forms of aldehydes, could undergo deprotection and condensation with cycloalkanones in a one-pot procedure promoted by samarium(III) iodide (SmI3) ...Diacetates 1 and N-[(1-benzotriazol-l-yl)alkyl]amides 2, both masked forms of aldehydes, could undergo deprotection and condensation with cycloalkanones in a one-pot procedure promoted by samarium(III) iodide (SmI3) to afford α,α'-bis(substituted benzylidene) cycloalkanones in good yields.展开更多
文摘Five DTPA bis(amide)s have been synthesized and characterized by means of 1 H NMR , FT IR and elemental analyses. The stability constants of their Gd 3+ complexes have been measured using a simple spectrophotometric method. The results show that the complexing properties of the ligands in comparison with those of DTPA are affected by converting two carboxyl groups to amide groups. The relaxation studies have shown that the relaxivity of the chelates is similar to that of Gd DTPA, indicating that in solution all the chelates have one water molecule directly coordinated to the metal ion. Only one water molecule in inner coordination sphere suggests the coordination of the carboxamide oxygen to gadolinium ion, which agrees with the FT IR results.
基金Project supported by the Beijing S&T Project,China(Grant No.Z13111000340000)the National Basic Research Program of China(Grant No.2012CB932900)the National Natural Science Foundation of China(Grants Nos.51325206 and 51421002)
文摘The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using Li FSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction（XRD）, scanning electron microscopy（SEM）, Raman spectroscopy, x-ray photoelectron spectroscopy（XPS）, and transmission electron microscopy（TEM）. It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.
基金the National 863 Program(No.2003AA323030)the National Natural Science Foundation of China(No.50272069 and No.20472090)for financial support.
文摘Lithium aluminium amide [LiAI（NHR）4] 5 obtained by treating the primary amine 4 with LiAlH4 could promote the ring opening of epoxide 2 and led to high regioselective product of racemic bis[2-（6-fluoro-2-chromanyl）-2-hydroxyethyl]amine methanesulfonic acid salt 7.
文摘凝胶聚合物电解质(GPE)是当前最具商业化应用前景之一的准固态电解质,可以缓解甚至解决锂离子电池存在的漏液、挥发、燃烧等潜在安全问题。本文通过高温原位固化技术制备了一种以甲基丙烯酸甲酯为单体、聚乙二醇二甲基丙烯酸酯为交联剂、双(氟磺酰)亚胺锂为导电盐、碳酸乙烯酯/碳酸甲乙酯混合溶剂为增塑剂的GPE。通过热重分析对聚甲基丙烯酸甲酯(PMMA)基GPE的热力学性质进行了表征,采用计时安培法和电子扫描显微镜研究了PMMA基GPE对Al集流体的稳定性。研究结果表明,PMMA基GPE在室温拥有较高的电导率,达到6.61 mS/cm,同时可以将碳酸酯电解液的挥发温度由100.3℃提高至138.1℃。PMMA基GPE在高电位下对Al箔显示出良好的稳定性,4.3 V vs.Li/Li+以下不会发生铝箔腐蚀,而且在商用石墨/LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)软包电池中展现出良好的循环稳定性和容量保持能力,循环1000次后容量保持率为93.4%。
基金This project was supported by the Research Affairs Division of Arak University.
文摘Facile and rapid polycondensation reactions of N,N'-(pyromellitoyl)-bis-L-leucine diacid chloride 1 with eight different derivatives of hydantoin compounds 2a-h were developed by using a domestic microwave oven in the presence of a small amount of polar organic medium such as o-cresol. The polycondensation reactions proceeded rapidly, compared with the conventional solution polycondensation, and was completed within 7-10 min, producing a series of novel optically active poly(amide-imide)s 3a-h with high yield and inherent viscosity of 0.35-0.65 dL/g. All of the above polymers were fully characterized by FT-IR, elemental analyses, inherent viscosity (η inh ), solubility test and specific rotation. Some structural characterization and physical properties of these optically active poly(amide-imide)s are reported.
文摘Diacetates 1 and N-[(1-benzotriazol-l-yl)alkyl]amides 2, both masked forms of aldehydes, could undergo deprotection and condensation with cycloalkanones in a one-pot procedure promoted by samarium(III) iodide (SmI3) to afford α,α'-bis(substituted benzylidene) cycloalkanones in good yields.
