Hydrogenative rearrangement of biomas s-derived furfurals(furfural and 5-hydroxymethyl furfural) to C_(5) cyclic compounds(such as cyclopentanones and cyclopentanols) offers an expedient reaction route for acquiring O...Hydrogenative rearrangement of biomas s-derived furfurals(furfural and 5-hydroxymethyl furfural) to C_(5) cyclic compounds(such as cyclopentanones and cyclopentanols) offers an expedient reaction route for acquiring O-containing value-added chemicals thereby replacing the traditional petroleum-based approaches.The scope for developing efficient bifunctional catalysts and establishing mild reaction conditions for upgrading furfurals to cyclic compounds has stimulated immense deliberation in recent years.Extensive efforts have been made toward developing catalysts for multiple tandem conversions,including those with various metals and supports.In this scientific review,we aim to summarize the research progress on the synergistic effect of the metal-acid sites,including simple metal-supported acidic supports,adjacent metal acid sites-supported catalysts,and in situ H_(2)-modified bifunctional catalysts.Distinctively,the catalytic performance,catalytic mechanism,and future challenges for the hydrogenative rearrangement are elaborated in detail.The methods highlighted in this review promote the development of C_(5) cyclic compound synthesis and provide insights to regulate bifunctional catalysis for other applications.展开更多
Two novel energetic coordination compounds Zn2（DAT）5（H2O）3（TNR）2 and Co2（DAT）5（H2O）3（TNR）2 were synthesized and their structures were characterized by elemental analysis and FT-IR spectroscopy.The crystal ...Two novel energetic coordination compounds Zn2（DAT）5（H2O）3（TNR）2 and Co2（DAT）5（H2O）3（TNR）2 were synthesized and their structures were characterized by elemental analysis and FT-IR spectroscopy.The crystal structures were determined by single-crystal X-ray diffraction.The results reveal that the compounds have similar molecular structures and the crystals belong to the triclinic system,space group P with a = 11.491（3）,b = 13.564（3）,c = 15.496（3） ,V = 2180.4（8） 3,C17H28 Zn2N36O19,Mr = 1203.02 g·mol-1,Dc = 1.832 g·cm-3,μ（MoKα） = 1.221 mm-1,F（000） = 1223,Z = 2,R = 0.0596 and wR = 0.1514 for 11289 observed reflections（I 〉 2σ（I）） for Zn2（DAT）5（H2O）3（TNR）2 and a = 11.5291（13）,b = 13.4894（15）,c = 15.4852（17） ,V = 2164.8（4） 3,C17H28Co2N36O19,Mr = 1190.14 g·mol-1,Dc = 1.826 g·cm-3,μ（MoKα） = 0.888 mm-1,F（000） = 1211,Z = 2,R = 0.0576 and wR = 0.1431 for 11218 observed reflections（I 〉 2σ（I）） for Co2（DAT）5（H2O）3（TNR）2,respectively.The thermal decomposition characteristics of the com-pounds were investigated using differential scanning calorimetry and thermal gravimetry-diffediffer-rential thermal gravimetry.The results of thermal decomposition processes were similar for the two compounds.Both undergo four-step decomposition after the loss of coordinated H2O molecules.The final solid residues for the two DAT complexes were the corresponding metal oxides.The kinetic parameter of the first exothermic process of the compounds was studied by applying the Kissinger and Ozawa-Doyle methods.The thermodynamic parameters of the activation could be calculated.Sensitivity tests revealed that Co2（DAT）5（H2O）3（TNR）2 was more sensitive than Zn2（DAT）5（H2O）3（TNR）2.展开更多
报告一例常染色体隐性遗传发病的骨质疏松症-假性胶质瘤综合征。先证者女性,23岁,父母非近亲结婚,出生后发现双目失明,婴儿期因发现右眼视网膜母细胞瘤行右眼球摘除术,9岁开始反复发生轻微外力骨折,诊断为成骨不全。查体发现脊柱侧凸畸...报告一例常染色体隐性遗传发病的骨质疏松症-假性胶质瘤综合征。先证者女性,23岁,父母非近亲结婚,出生后发现双目失明,婴儿期因发现右眼视网膜母细胞瘤行右眼球摘除术,9岁开始反复发生轻微外力骨折,诊断为成骨不全。查体发现脊柱侧凸畸形、胸廓畸形、双上肢肘外翻、四肢关节韧带松弛。双能X线吸收检测仪(dual energy X-ray absorptiometry,DXA)骨密度明显低于同龄人,腰椎1-4骨密度Z值-5,左髋骨密度Z值-1.8。X线摄片示全身骨小梁稀疏。Sanger测序显示低密度脂蛋白受体相关蛋白-5(lowdensity lipoprotein receptor-related protein 5,LRP5)基因的6号外显子和23号外显子发生复合杂合突变,导致p.Pro382Leu+p.Cys1611LeufsX33。本文通过文献复习对该病的临床表现和诊疗特点进行讨论及总结,以期帮助临床医生提高对这一疾病的认识。展开更多
Five coordination compounds, namely [Ni2(5-Fnic)2(H2 O)4](1), [Ni(5-Fnic)(μ-5-Fnic)(H2 biim)]n(2), {[Cd((μ-5-Fnic)2(H2 O)2]×4,4’-bipy}n(3), [Pb2(μ-5-Fnic)2(μ3-5-Fnic)2(H2 O)2]n(4), and [Pb(5-Fnic)2(4,4’-bip...Five coordination compounds, namely [Ni2(5-Fnic)2(H2 O)4](1), [Ni(5-Fnic)(μ-5-Fnic)(H2 biim)]n(2), {[Cd((μ-5-Fnic)2(H2 O)2]×4,4’-bipy}n(3), [Pb2(μ-5-Fnic)2(μ3-5-Fnic)2(H2 O)2]n(4), and [Pb(5-Fnic)2(4,4’-bipy)(H2 O)](5), have been constructed hydrothermally using 5-FnicH(5-FnicH = 5-fluoronicotinic acid), H2 biim(H2 biim = 2,2’-biimidazole), 4,4’-bipy(4,4’-bipy = 4,4’-bipyridine), NiCl2×6 H2 O, CdCl2×H2 O and PbCl2. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses(TGA), and single-crystal X-ray diffraction analyses. Structures of 1~5 range from discrete 0 D monomers(1 and 5) to 1 D coordination polymers(2 and 4) and 2 D metal-organic network(3). A broad structural diversity of 1~5 is guided by the type of the metal(Ⅱ) node and the introduction of auxiliary ligands. The magnetic(for 2) and luminescent(for 3~5) properties were also investigated and discussed.展开更多
The crystal structure, magnetic and magnetocaloric properties of(Ho_(1-x) Y_(0.5))_5 Pd_2 compounds are investigated. All the compounds crystallize in a cubic Dy_5 Pd_2-type structure with the space group Fd3 m and un...The crystal structure, magnetic and magnetocaloric properties of(Ho_(1-x) Y_(0.5))_5 Pd_2 compounds are investigated. All the compounds crystallize in a cubic Dy_5 Pd_2-type structure with the space group Fd3 m and undergo a second order transition from spin glass(SG) state to paramagnetic(PM) state. The spin glass transition temperatures T_g decrease from 26 K for x = 0 to 13 K for x = 0.5. In the PM region, the reciprocal susceptibilities for all the compounds obey the Curie–Weiss law. The paramagnetic Curie temperatures(θp) for Ho_5 Pd_2,(Ho_(0.75) Y_(0.25)_5 Pd_2, and(Ho_(0.5) Y_(0.5))_5 Pd_2 are determined to be 32 K, 30 K, and 22 K, respectively, and the corresponding effective magnetic moments(μeff) are10.8 μB/Ho, 10.3 μB/RE, and 7.5 μB/RE, respectively. Magnetocaloric effect(MCE) is anticipated according to the Maxwell relation, based on the isothermal magnetization curves. For a magnetic field change of 0–5 T, the maximum values of the isothermal magnetic entropy change-?SMof the(Ho_(1-x)Y_x)_5 Pd_2(x = 0, 0.25, and 0.5) compounds are determined to be 11.5 J·kg^(-1)·K^(-1), 11.1 J·kg^(-1)·K^(-1), and 8.9 K J·kg^(-1)·K^(-1), with corresponding refrigerant capacity values of 382.3 J·kg^(-1), 336.2 J·kg^(-1), and 242.5 J·kg^(-1), respectively.展开更多
The development of 5-aminosalicylic acid (5-ASA) therapy as a life long treatment for ulcerative colitis is reviewed from its origins in the 1940s to the present day. The drug was designed to treat rheumatoid arthriti...The development of 5-aminosalicylic acid (5-ASA) therapy as a life long treatment for ulcerative colitis is reviewed from its origins in the 1940s to the present day. The drug was designed to treat rheumatoid arthritis,but was found helpful in the management of nine patients with ulcerative colitis. This discovery preceded the emergence of the clinical trial as a tool for assessing a new drug's efficacy; as a result it lacked scientific rigour and was selective in its presentation of results. Nevertheless it identified the future cornerstone of therapy in ulcerative colitis. In 1962,the first double blind controlled trial of sulphasalazine was conducted on 40 patients. Outcome measures were subjective and included symptoms and an assessment of the rectal mucosa. In 1973,the first two papers on the role of sulphasalazine in maintenance of remission were published. Both used placebo controls and had a stratified design. Outcomes were measured using "an intention to treat" approach. The British study of 64 patients used both subjective and objective criteria to assess outcomes. Patients on placebo had a relapse rate four times patients on active treatment and this founded the basis for a life long approach to therapy with 5-ASA compounds in ulcerative colitis. However,in 1985,a small "on demand" study of 32 patients suggested this approach might be as effective as continuous treatment. Some support for this view came from an Italian study which showed no benefit to continued treatment for those in remission for two years or more. The central problem these studies identify is that of adherence to treatment in the long-term. Few studies have considered patients' attitudes to continuous therapy and it is an area that needs further investigation.展开更多
o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ket...o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ketones to afford 2,3-dihydro-1H-1,5-benzodiazepines in good yields under mild and neutral conditions.展开更多
The equilibrium structures and electronic structure of LaNi5-xGax （x=0, 0.5, 1.0） compounds have been investigated by all-electron calculations. Based on the full geometry optimization, the densities of states and e...The equilibrium structures and electronic structure of LaNi5-xGax （x=0, 0.5, 1.0） compounds have been investigated by all-electron calculations. Based on the full geometry optimization, the densities of states and electron densities of LaNi5-xGax are plotted and analyzed. It is clear that the substitution of Ga at the Ni site leads to a progressive filling of the Ni-d bands, the ionic interaction between Ni and Ni, with Ga plays a dominant role in the stability of LaNi5-xGax compounds. The smaller the shift of EF toward higher energy region, the more stable the compounds will be. The increased contribution of the Ni-d-Ga-d interactions near EF and the low energy metal-gallium bonding bands indicate that the compounds become more stable. The results are compared with experimental data and discussed in light of previous studies.展开更多
Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction m...Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction method. It crystallizes in the triclinlc space group P1 with unit cell parameters a= 10.199(5),b=12.116(7), c=14.207(6)A;a=69.47(5),β=72. 38(3),γ= 85.89(4);V= 1569. 9A3, Dc= 1.98 g/cm2; Z=4. Least-square refinement led to final R value of 0. 0539 and Rw value of 0. 0553, based on 3548 independent observed reflections.展开更多
The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)...The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)M have Peierls distorted structures, while those with even valence electrons are favorable to the formation of regular structures. The Band structures show that both LU and HO bands are d-bands for all of the polydecker sandwich compounds studied.展开更多
Additions of diethyl phosphite to α-nitroalkenes followed by the introduction of trimethylchlorosilane and an activated alkene, gave the corresponding title compounds via regioselective 1,3-dipolar cycloaddition in m...Additions of diethyl phosphite to α-nitroalkenes followed by the introduction of trimethylchlorosilane and an activated alkene, gave the corresponding title compounds via regioselective 1,3-dipolar cycloaddition in moderate yield.展开更多
The [Zr6(μ2-Cl)12Cl6H4]3- ion with C4v Symmetry in the title compounds has been calculated by DV-Xα program. The calculated results show that ther is almost no available covalence bonding between zirconium ato...The [Zr6(μ2-Cl)12Cl6H4]3- ion with C4v Symmetry in the title compounds has been calculated by DV-Xα program. The calculated results show that ther is almost no available covalence bonding between zirconium atoms and significant Zr 4d AO compositions in the MOs. but there are much stronger Zr-Cl(bridging) bonding. All analysis results suggest that these compounds would be the cluster with Zr6Cl12 cage linked by Zr-Cl bridging bonding plus six Cl teminal ligands rather than the hexazirconium cluster in view of the chemical bonding.展开更多
基金support from the National Natural Science Foundation of China (Nos. 22178158, 52162014 and 22065024)Science and Technology Project of Education Department of Jiangxi Province (No. GJJ2200402)+3 种基金Jiangxi Provincial Natural Science Foundation (No. 20224BAB213023)the Outstanding Youth Science Fund Project of Jiangxi Province (No. 20224ACB213008)the Jiangxi Provincial Double Thousand Talents Plan-Youth Program (No. S2021GDQN0947)Natural Science Foundation of Chongqing (No. 2023NSCQ-MSX0052)
文摘Hydrogenative rearrangement of biomas s-derived furfurals(furfural and 5-hydroxymethyl furfural) to C_(5) cyclic compounds(such as cyclopentanones and cyclopentanols) offers an expedient reaction route for acquiring O-containing value-added chemicals thereby replacing the traditional petroleum-based approaches.The scope for developing efficient bifunctional catalysts and establishing mild reaction conditions for upgrading furfurals to cyclic compounds has stimulated immense deliberation in recent years.Extensive efforts have been made toward developing catalysts for multiple tandem conversions,including those with various metals and supports.In this scientific review,we aim to summarize the research progress on the synergistic effect of the metal-acid sites,including simple metal-supported acidic supports,adjacent metal acid sites-supported catalysts,and in situ H_(2)-modified bifunctional catalysts.Distinctively,the catalytic performance,catalytic mechanism,and future challenges for the hydrogenative rearrangement are elaborated in detail.The methods highlighted in this review promote the development of C_(5) cyclic compound synthesis and provide insights to regulate bifunctional catalysis for other applications.
基金supported by the National Natural Science Foundation of China (NSAF: 10776002)the project of State Key Laboratory of Science and Technology (No. QNKT11-06, YBKY10-03)the Program for New Century Excellent Talents in University (NCET-09-0051)
文摘Two novel energetic coordination compounds Zn2（DAT）5（H2O）3（TNR）2 and Co2（DAT）5（H2O）3（TNR）2 were synthesized and their structures were characterized by elemental analysis and FT-IR spectroscopy.The crystal structures were determined by single-crystal X-ray diffraction.The results reveal that the compounds have similar molecular structures and the crystals belong to the triclinic system,space group P with a = 11.491（3）,b = 13.564（3）,c = 15.496（3） ,V = 2180.4（8） 3,C17H28 Zn2N36O19,Mr = 1203.02 g·mol-1,Dc = 1.832 g·cm-3,μ（MoKα） = 1.221 mm-1,F（000） = 1223,Z = 2,R = 0.0596 and wR = 0.1514 for 11289 observed reflections（I 〉 2σ（I）） for Zn2（DAT）5（H2O）3（TNR）2 and a = 11.5291（13）,b = 13.4894（15）,c = 15.4852（17） ,V = 2164.8（4） 3,C17H28Co2N36O19,Mr = 1190.14 g·mol-1,Dc = 1.826 g·cm-3,μ（MoKα） = 0.888 mm-1,F（000） = 1211,Z = 2,R = 0.0576 and wR = 0.1431 for 11218 observed reflections（I 〉 2σ（I）） for Co2（DAT）5（H2O）3（TNR）2,respectively.The thermal decomposition characteristics of the com-pounds were investigated using differential scanning calorimetry and thermal gravimetry-diffediffer-rential thermal gravimetry.The results of thermal decomposition processes were similar for the two compounds.Both undergo four-step decomposition after the loss of coordinated H2O molecules.The final solid residues for the two DAT complexes were the corresponding metal oxides.The kinetic parameter of the first exothermic process of the compounds was studied by applying the Kissinger and Ozawa-Doyle methods.The thermodynamic parameters of the activation could be calculated.Sensitivity tests revealed that Co2（DAT）5（H2O）3（TNR）2 was more sensitive than Zn2（DAT）5（H2O）3（TNR）2.
文摘报告一例常染色体隐性遗传发病的骨质疏松症-假性胶质瘤综合征。先证者女性,23岁,父母非近亲结婚,出生后发现双目失明,婴儿期因发现右眼视网膜母细胞瘤行右眼球摘除术,9岁开始反复发生轻微外力骨折,诊断为成骨不全。查体发现脊柱侧凸畸形、胸廓畸形、双上肢肘外翻、四肢关节韧带松弛。双能X线吸收检测仪(dual energy X-ray absorptiometry,DXA)骨密度明显低于同龄人,腰椎1-4骨密度Z值-5,左髋骨密度Z值-1.8。X线摄片示全身骨小梁稀疏。Sanger测序显示低密度脂蛋白受体相关蛋白-5(lowdensity lipoprotein receptor-related protein 5,LRP5)基因的6号外显子和23号外显子发生复合杂合突变,导致p.Pro382Leu+p.Cys1611LeufsX33。本文通过文献复习对该病的临床表现和诊疗特点进行讨论及总结,以期帮助临床医生提高对这一疾病的认识。
基金supported by Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2015,2018)the Natural Science Foundation of Guangdong Province(No.2016A030313761)+3 种基金the Pearl River Scholar Foundation of Guangdong Industry Polytechnic(RC2015-001)the Opening Foundation of MOE Key Laboratory of MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of Chemistry Sun Yat-Sen University(2016)Innovation Team Project on University of Guangdong Province(2017GKCXTD001,2017GWCXTD002)Outstanding youth fund project of Guangdong Industry Polytechnic(QN 2018-007)
文摘Five coordination compounds, namely [Ni2(5-Fnic)2(H2 O)4](1), [Ni(5-Fnic)(μ-5-Fnic)(H2 biim)]n(2), {[Cd((μ-5-Fnic)2(H2 O)2]×4,4’-bipy}n(3), [Pb2(μ-5-Fnic)2(μ3-5-Fnic)2(H2 O)2]n(4), and [Pb(5-Fnic)2(4,4’-bipy)(H2 O)](5), have been constructed hydrothermally using 5-FnicH(5-FnicH = 5-fluoronicotinic acid), H2 biim(H2 biim = 2,2’-biimidazole), 4,4’-bipy(4,4’-bipy = 4,4’-bipyridine), NiCl2×6 H2 O, CdCl2×H2 O and PbCl2. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses(TGA), and single-crystal X-ray diffraction analyses. Structures of 1~5 range from discrete 0 D monomers(1 and 5) to 1 D coordination polymers(2 and 4) and 2 D metal-organic network(3). A broad structural diversity of 1~5 is guided by the type of the metal(Ⅱ) node and the introduction of auxiliary ligands. The magnetic(for 2) and luminescent(for 3~5) properties were also investigated and discussed.
基金Project supported by the National Basic Research Program of China(Grant No.2014CB643703)the National Key Research and Development Program of China(Grant No.2016YFB0700901)+1 种基金the National Natural Science Foundation of China(Grant Nos.51261004 and 51761007)Guangxi Natural Science Foundation,China(Grant No.2018GXNSFAA294051)
文摘The crystal structure, magnetic and magnetocaloric properties of(Ho_(1-x) Y_(0.5))_5 Pd_2 compounds are investigated. All the compounds crystallize in a cubic Dy_5 Pd_2-type structure with the space group Fd3 m and undergo a second order transition from spin glass(SG) state to paramagnetic(PM) state. The spin glass transition temperatures T_g decrease from 26 K for x = 0 to 13 K for x = 0.5. In the PM region, the reciprocal susceptibilities for all the compounds obey the Curie–Weiss law. The paramagnetic Curie temperatures(θp) for Ho_5 Pd_2,(Ho_(0.75) Y_(0.25)_5 Pd_2, and(Ho_(0.5) Y_(0.5))_5 Pd_2 are determined to be 32 K, 30 K, and 22 K, respectively, and the corresponding effective magnetic moments(μeff) are10.8 μB/Ho, 10.3 μB/RE, and 7.5 μB/RE, respectively. Magnetocaloric effect(MCE) is anticipated according to the Maxwell relation, based on the isothermal magnetization curves. For a magnetic field change of 0–5 T, the maximum values of the isothermal magnetic entropy change-?SMof the(Ho_(1-x)Y_x)_5 Pd_2(x = 0, 0.25, and 0.5) compounds are determined to be 11.5 J·kg^(-1)·K^(-1), 11.1 J·kg^(-1)·K^(-1), and 8.9 K J·kg^(-1)·K^(-1), with corresponding refrigerant capacity values of 382.3 J·kg^(-1), 336.2 J·kg^(-1), and 242.5 J·kg^(-1), respectively.
文摘The development of 5-aminosalicylic acid (5-ASA) therapy as a life long treatment for ulcerative colitis is reviewed from its origins in the 1940s to the present day. The drug was designed to treat rheumatoid arthritis,but was found helpful in the management of nine patients with ulcerative colitis. This discovery preceded the emergence of the clinical trial as a tool for assessing a new drug's efficacy; as a result it lacked scientific rigour and was selective in its presentation of results. Nevertheless it identified the future cornerstone of therapy in ulcerative colitis. In 1962,the first double blind controlled trial of sulphasalazine was conducted on 40 patients. Outcome measures were subjective and included symptoms and an assessment of the rectal mucosa. In 1973,the first two papers on the role of sulphasalazine in maintenance of remission were published. Both used placebo controls and had a stratified design. Outcomes were measured using "an intention to treat" approach. The British study of 64 patients used both subjective and objective criteria to assess outcomes. Patients on placebo had a relapse rate four times patients on active treatment and this founded the basis for a life long approach to therapy with 5-ASA compounds in ulcerative colitis. However,in 1985,a small "on demand" study of 32 patients suggested this approach might be as effective as continuous treatment. Some support for this view came from an Italian study which showed no benefit to continued treatment for those in remission for two years or more. The central problem these studies identify is that of adherence to treatment in the long-term. Few studies have considered patients' attitudes to continuous therapy and it is an area that needs further investigation.
基金We thank the National Natural Science Foundation of China (Project No.29872010) NSF of Zhejiang province for financial support.
文摘o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ketones to afford 2,3-dihydro-1H-1,5-benzodiazepines in good yields under mild and neutral conditions.
基金This work was financially supported by the National Natural Science Foundation of China （No.60777012）.
文摘The equilibrium structures and electronic structure of LaNi5-xGax （x=0, 0.5, 1.0） compounds have been investigated by all-electron calculations. Based on the full geometry optimization, the densities of states and electron densities of LaNi5-xGax are plotted and analyzed. It is clear that the substitution of Ga at the Ni site leads to a progressive filling of the Ni-d bands, the ionic interaction between Ni and Ni, with Ga plays a dominant role in the stability of LaNi5-xGax compounds. The smaller the shift of EF toward higher energy region, the more stable the compounds will be. The increased contribution of the Ni-d-Ga-d interactions near EF and the low energy metal-gallium bonding bands indicate that the compounds become more stable. The results are compared with experimental data and discussed in light of previous studies.
文摘Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction method. It crystallizes in the triclinlc space group P1 with unit cell parameters a= 10.199(5),b=12.116(7), c=14.207(6)A;a=69.47(5),β=72. 38(3),γ= 85.89(4);V= 1569. 9A3, Dc= 1.98 g/cm2; Z=4. Least-square refinement led to final R value of 0. 0539 and Rw value of 0. 0553, based on 3548 independent observed reflections.
基金Supported by the National Natural Science Foundation of China the Young Teacher's Foundation of the State Education Commission of China
文摘The results of SCF CNDO-CO calculation on polymeric [(η5,μ-2,3-dihydro-1 , 3-di-borolyl)M](M= Cr, Mn, Fe, Co, Ni) indicate that polydecker sandwich compounds with odd valence electrons in each stacking unit (C3B2H5)M have Peierls distorted structures, while those with even valence electrons are favorable to the formation of regular structures. The Band structures show that both LU and HO bands are d-bands for all of the polydecker sandwich compounds studied.
文摘Additions of diethyl phosphite to α-nitroalkenes followed by the introduction of trimethylchlorosilane and an activated alkene, gave the corresponding title compounds via regioselective 1,3-dipolar cycloaddition in moderate yield.
文摘The [Zr6(μ2-Cl)12Cl6H4]3- ion with C4v Symmetry in the title compounds has been calculated by DV-Xα program. The calculated results show that ther is almost no available covalence bonding between zirconium atoms and significant Zr 4d AO compositions in the MOs. but there are much stronger Zr-Cl(bridging) bonding. All analysis results suggest that these compounds would be the cluster with Zr6Cl12 cage linked by Zr-Cl bridging bonding plus six Cl teminal ligands rather than the hexazirconium cluster in view of the chemical bonding.
