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991.
Richard D. Adams Fang Fang Mark D. Smith Qiang Zhang 《Journal of organometallic chemistry》2011,696(17):2904-2909
A reinvestigation of the reaction of Ir(CO)Cl(PPh3)2, 1 with HSnPh3 has revealed that the oxidative-addition product Ir(CO)Cl(PPh3)2(H)(SnPh3), 2 has the H and SnPh3 ligands in cis-related coordination sites. Compound 2 reacts with a second equivalent of HSnPh3 by a Cl for H ligand exchange to yield the new compound H2Ir(CO)(SnPh3)(PPh3)2, 3. Compound 3 contains two cis- related hydride ligands. Under an atmosphere of CO, 1 reacts with HSnPh3 to replace the Cl ligand with SnPh3 and one of the PPh3 ligands with a CO ligand and also adds a second equivalent of CO to yield the 5-coordinate complex Ir(CO)3(SnPh3)(PPh3), 4. Compound 4 reacts with HSnPh3 by loss of CO and oxidative addition of the Sn-H bond to yield the 6-coordinate complex HIr(CO)2(SnPh3)2(PPh3), 5 that contains two trans-positioned SnPh3 ligands. 相似文献
992.
Sb2S3/Bi2S3 doped TiO2 were prepared with the coordination compounds [M(S2CNEt)3] (M=Sb, Bi; S2CNEt=pyrrolidinedithiocarbamate) as precursors via gel-hydrothermal techniques. The doped TiO2 were characterized by XRD, SEM, XPS and UV-vis diffuse reflectance means. The photocatalyst based on doped TiO2 for photodecolorization of 4-nitrophenol (4-NP) was examined. The optimal Bi2S3/Sb2S3 content, pH and different doped techniques have been investigated. Photocatalytic tests reveal that M2S3 doped TiO2 via the gel-hydrothermal route performs better photocatalytic activity for photodegradation reaction of 4-nitrophenol (4-NP). 相似文献
993.
The reactivity of five di-n-butyltin(IV) complexes, n-Bu2Sn(OR)2 (1), n-Bu2SnO (3), [n-Bu2Sn(OR)]2O (4), (n-Bu2SnO)2(CO2) (6) and (n-Bu2SnO)6[(n-Bu2SnOR)2(CO3)]2 (7) (R = CH3), with CO2, suggested as possible catalyst precursors and key-intermediates for the direct synthesis of dimethyl carbonate from carbon dioxide and methanol, has been investigated using high-pressure 119Sn{1H} NMR (HP-NMR) spectroscopy. Four of the five precursors studied, i.e. 3, 4, 6 and 7 give rise to an identical 119Sn{1H} NMR pattern which can be explicitly attributed to the fingerprint of the dimeric form of the 1-methoxy-3-methylcarbonatotetrabutyldistannoxane {5}2. However, with 1, a new pair of signals is observed in addition to the characteristic 119Sn{1H} NMR resonances of the dimeric hemicarbonato species {2}2 and {5}2, which can be attributed to the in situ formation of an unprecedented species suggested to be the trinuclear carbonato di-n-butyltin(IV) complex, 8. 相似文献
994.
Marius Widerøe Truls Norby Rolf Willestofte Berg 《Journal of solid state chemistry》2011,184(7):1890-1894
A new metal oxyhydride; neodymium oxyhydride, NdHO, has been synthesized from a reactant mixture of metal hydride (CaH2 or NdH3) and neodymium oxide (Nd2O3). The unit cell dimensions decrease smoothly in the series from LaHO, CeHO, PrHO to NdHO, in line with the lanthanide contraction. The crystal structure of NdHO is described on the basis of Rietveld refinement on neutron powder diffraction data:
- Space group: P4/nmm (no. 129, D4h7).
- Axis lengths: a=7.8480(5) Å, c=5.5601(8) Å.
- Volume: V=342.46(6) Å3.
995.
Shiue-Shien Weng Chih-Shueh KeFong-Kuang Chen You-Fu LyuGuan-Ying Lin 《Tetrahedron》2011,67(9):1640-1648
A practical and clean protocol for transesterification catalyzed by a 5 mol % cheap, non-toxic and moisture stable Fe(acac)3 or other iron(III) β-diketonate species in solvent, such as heptane under azeotropic condition is developed. A remarkable rate enhancement was observed upon the addition of 5 mol % of an inorganic base, such as Na2CO3, which suggests that faster formation of a dimeric μ-alkoxy-bridged iron(III) species under alkaline conditions facilitates catalytic turnover. This system provides smooth transesterification over a wide range of structurally diverse esters and alcohols without disturbing functional groups. In addition, the use of iron β-diketonate complexes as catalysts is more environmentally friendly, safer, and economical than other transition-metal catalysts. Preliminary mechanistic studies indicate that the active catalyst is likely a dimeric μ-alkoxy-bridged iron(III) species, as determined by X-ray crystallography of [Fe(dbm)2(O-n-Bu)]2 derived from the alcoholysis of Fe(dbm)3 under alkaline conditions. 相似文献
996.
考虑煤中吡啶六元环与其他杂环的结合形式,对四种典型的吡啶型氮杂环结构及其热解中间产物中各键的Mayer键级进行了计算。通过对比Mayer键级的大小判断热解时最易发生断裂的键,进而对吡啶型氮热解时氮的逸出机理进行了分析。计算结果表明,吡啶型氮热解产生的含氮污染物主要是HCN;由于吡啶环与其他环结合方式的不同,氮的逸出过程也有差异。利用高频炉快速热解装置对吡啶和吖啶两种模型化合物进行了快速热解实验以验证计算结果。结果表明,吡啶和吖啶热解时虽有少量NH3生成,但含氮污染物仍以HCN为主,实验结果可为计算所得的结论提供一定支持。
相似文献
相似文献
997.
998.
生物质焦油模拟物重整制取富氢气体实验研究 总被引:1,自引:0,他引:1
以流化床作为反应器,进行生物质焦油模拟物(苯)催化重整制取富氢气体的实验研究,主要探究实验温度(780℃~900℃)、水蒸气/焦油模拟物质量比S/T (3.0~6.0)、床高(5.0cm~20.0cm)和床料(催化剂)对焦油模拟物重整制取富氢气体过程的影响。实验结果表明,焦油模拟物重整制取富氢气体的理想操作工况分别是温度为860℃~900℃,S/T 值为5.0,床层高度为15.0cm~20.0cm;通过比较,在上述理想操作条件下,合成的碱土金属催化剂(20CaAl)具有较好的催化活性,而其改性后的SCaFeNiAl催化剂具有更好的活性。在SCaFeNiAl作用下,焦油模拟物重整过程的活化能为58.87kJ/mol,指前因子为1.36×107h-1,且获得较好的实验效果,H2体积分数为67.28%,H2产率为303.50g/kg-tar,焦油模拟物转化率为95.93%,总气体产率为5.05m3/kg-tar。 相似文献
999.
The diruthenium compound [Ru2(O2CMe)4]3[Cr(CN)6] may be the only known material that contains two weakly-coupled, magnetically-ordered sublattices occupying the same three-dimensional volume. Due to the strong easy-plane anisotropy on each Ru2 complex, the moment of each sublattice is constrained to one of the eight cubic diagonals. At low fields, the two sublattices are antiferromagnetically aligned by weak dipolar and deformation energies. But above a metamagnetic critical field of about 1000 Oe, the sublattice moments become ferromagnetically aligned and the net magnetization increases dramatically. We have successfully modeled this metamagnetic transition by assuming that the individual sublattice spin configurations are only weakly distorted by the magnetic field. This model suggests that the ground state of each sublattice undergoes a phase transition at a pressure of about 7 kbar. The drop in the sublattice moment and the rise in the sublattice susceptibility above 7 kbar can be explained by a high- to low-spin transition (S = 3/2 to 1/2) on the mixed-valent diruthenium complexes. 相似文献
1000.