A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space g...A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space group P1 with a = 13.054（3）,b = 13.137（3）,c = 15.077（3） ,α = 80.009（9）,β = 77.187（10）,γ = 76.075（11）°,Z = 2,V = 2427.3（9） 3,Dc = 1.565 g/cm3,μ（MoKα） = 2.076 mm-1,F（000） = 1152,the final R = 0.0335 and wR = 0.0664 for 9416 observed reflections（I 2σ（I））.Cluster 2 belongs to the monoclinic system,space group P21/c with a = 13.673（3）,b = 13.342（3）,c = 16.296（4） ,β = 104.385（5）o,Z = 4,V = 2879.7（10） 3,Dc = 1.347 g/cm3,μ（MoKα） = 1.751 mm-1,F（000） = 1176,the final R = 0.0306 and wR = 0.0706 for 6390 observed reflections（I 2σ（I））.The crystal structures of the clusters consist of cen-trosymmetric [RCOOSnnBu2OSnnBu2OH）]2 molecules with an almost planar Sn4O4 framework.Each pair of exo-and endo-cyclic tin atoms was linked by one bridge-OH only.In addition,a novel structure of nBu2SnO different from the previous reports was proposed on the basis of 1H-NMR,TG analysis and X-ray diffraction.展开更多
A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer（RAFT） method and characterized by the gel-per...A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer（RAFT） method and characterized by the gel-permeation chromatography（GPC） and 1H-NMR. And the self-assemblies of these block copolymers with various chain length ratios in the different concentrations in CHCl3 were stable according to the results of DLS and TEM. Additionally, it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.展开更多
By comprehensively determining the lattice parameter, XPS, Mssbauer spectrum, relationship between the resistance and the temperature, oxygen content and the thermal decomposition temperature of the samples of YBa_2Cu...By comprehensively determining the lattice parameter, XPS, Mssbauer spectrum, relationship between the resistance and the temperature, oxygen content and the thermal decomposition temperature of the samples of YBa_2Cu_(3-x)Sn_xO_(7+y) system, it is discovered that Sn occupies the site of Cuin the form of Sn^(4+) oxidation state. The change of crystalline structure as well as T_c are very little for x<0.4. The oxygen content of the samples is increased by the substitution of Sn for Cu, which influences the valence of Cu obviously, and makes the Cu be in the Cu^(3+) state. The experimental results give some important information on understanding the origin of superconductivity from the structure, oxygen deficiency, and electronic state. From analysis, it is suggested that the coupling strength between metals and oxygen determines the superconductivity.展开更多
在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速...在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速20 m L/min;反应时间4 h;反应温度55°C.该条件下,ε-己内酯收率达到98.8%,选择性达到99.0%;采用SEM、XRD等对催化剂的结构进行表征;催化剂重复使用5次仍保持较高活性.展开更多
TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations ...TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.展开更多
基金supported by the National Natural Science Foundation of China (20421202,20372033)
文摘A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space group P1 with a = 13.054（3）,b = 13.137（3）,c = 15.077（3） ,α = 80.009（9）,β = 77.187（10）,γ = 76.075（11）°,Z = 2,V = 2427.3（9） 3,Dc = 1.565 g/cm3,μ（MoKα） = 2.076 mm-1,F（000） = 1152,the final R = 0.0335 and wR = 0.0664 for 9416 observed reflections（I 2σ（I））.Cluster 2 belongs to the monoclinic system,space group P21/c with a = 13.673（3）,b = 13.342（3）,c = 16.296（4） ,β = 104.385（5）o,Z = 4,V = 2879.7（10） 3,Dc = 1.347 g/cm3,μ（MoKα） = 1.751 mm-1,F（000） = 1176,the final R = 0.0306 and wR = 0.0706 for 6390 observed reflections（I 2σ（I））.The crystal structures of the clusters consist of cen-trosymmetric [RCOOSnnBu2OSnnBu2OH）]2 molecules with an almost planar Sn4O4 framework.Each pair of exo-and endo-cyclic tin atoms was linked by one bridge-OH only.In addition,a novel structure of nBu2SnO different from the previous reports was proposed on the basis of 1H-NMR,TG analysis and X-ray diffraction.
基金financially supported by the National Natural Science Foundation of China(Nos.21072099,21202084 and 21372120)
文摘A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer（RAFT） method and characterized by the gel-permeation chromatography（GPC） and 1H-NMR. And the self-assemblies of these block copolymers with various chain length ratios in the different concentrations in CHCl3 were stable according to the results of DLS and TEM. Additionally, it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.
文摘By comprehensively determining the lattice parameter, XPS, Mssbauer spectrum, relationship between the resistance and the temperature, oxygen content and the thermal decomposition temperature of the samples of YBa_2Cu_(3-x)Sn_xO_(7+y) system, it is discovered that Sn occupies the site of Cuin the form of Sn^(4+) oxidation state. The change of crystalline structure as well as T_c are very little for x<0.4. The oxygen content of the samples is increased by the substitution of Sn for Cu, which influences the valence of Cu obviously, and makes the Cu be in the Cu^(3+) state. The experimental results give some important information on understanding the origin of superconductivity from the structure, oxygen deficiency, and electronic state. From analysis, it is suggested that the coupling strength between metals and oxygen determines the superconductivity.
文摘在分子氧-苯甲醛体系,由共沉淀法制备的Fe-Sn-O复合氧化物作为催化剂,催化分子氧化环己酮合成ε-己内酯,通过单因素实验,得到适宜的合成条件:常温常压下,以环己酮用量为5 mmol计;n(苯甲醛)∶n(环己酮)=3∶1;1,2-二氯乙烷20 m L;氧气流速20 m L/min;反应时间4 h;反应温度55°C.该条件下,ε-己内酯收率达到98.8%,选择性达到99.0%;采用SEM、XRD等对催化剂的结构进行表征;催化剂重复使用5次仍保持较高活性.
文摘TiO2-SnO2-SiO2 nanocomposite photocatalysts were prepared with Na2SiO3·9H2O, SnCl4·5H2O and TiCl4 as precursors by chemistry coating processes and supercritical fluid drying (SCFD) method. Characterizations with XRD, TEM, NMR and FTIR showed that in addition to anatase type TiO2, a new active phase(Ti,Sn)O2 was also formed in the range of the studied doping concentration, The catalytic activity was evaluated by photocatalytic degradation of phenol as model reaction. SiO2 remained amphorous at all samples. It could prevent from growth of the size of nanopaticle and transformation from anatase to rutile. Compared with pure TiO2, or TiO2-SnO2 catalyst prepared by Sol-gel method, Nano-composite photo-catalyst showed significant improvement in catalytic activity, the photo-catalytic degradation rate of phenol in 7 h reached 88.7%. Application of the composite catalysts for the photocatalytic decomposition of phenol not only gave the same activity relative to pure ultrafine TiO2, but also reduced cost. The experimental results also proved that the thermal stability of TiO2 was greatly enhanced after mixing with small amount of SiO2. The optimized doping of SiO2 was 20.3%. The photo-catalyst prepared by SCFD combination technology was characterized with smaller particle size, larger surface area and higher activity.
