Competition between C-C and C-H Activation in Reactions of Neutral Nickel Atom with Cycloalkanes （n = 3-7）

A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. （n = 3-7） is carried out. For the Ni ＋ CnH2, （n = 3, 4） reactions, the major and minor reaction channels involve C-C and C-H bond activations, respectively, whereas Ni atom prefers the attacking of C-H bond over the C-C bond in CnH2n （n = 5=7）. The results are in good agreement with the experimental study. In all cases, intermediates and transition states along the reaction paths of interest are characterized, It is found that both the C-H and C-C bond activation processes are proposed to proceed in a one-step manner via one transition state. The overall C-H and C-C bond activation processes are exothermic and involve low energy barriers, thus transition metal atom Ni is a good mediator for the activity of cycloalkanes CnH2n （n = 3 -7）.

Study on Synthesis and Herbicidal Activity of Heterocyclic Compounds Containing P-P Bond

N,N′-diphenylurea reacted with phosphorus trichloride and phenyl dichlorophosphane giving the heterocyclic compounds 1 and 2 with a direct phosphorus-phosphorus bond (P-P bond), respectively. The new compounds were characterized by elementary analysis, NMR and IR spectra. The results of preliminary bioassay showed that these heterocycles possess selective herbicidal activity at 1.5 kg/hm2.

Density Functional Studies of the Reaction of Ytterbium Monocation with Fluoromethane:C-F Bond Activation and Electron-Transfer Reactivity

The potential energy surface and reaction mechanism corresponding to the reaction of ytterbium monocation with fluoromethane, which represents a prototype of the activation of C-F bond in fluorohydrocarbons by bare lanthanide cations, have been investigated for the first time by using density functional theory. A direct fluorine abstraction mechanism was revealed, and the related thermochemistry data were determined. The electron-transfer reactivity of the reaction was analyzed using the two-state model, and a strongly avoided crossing behavior on the transition state region was shown. The present results support the reaction mechanism inferred from early experimental data and the related thermochemistry data can provide a guide for further experimental researches.

Effects of a decade of organic fertilizer substitution on vegetable yield and soil phosphorus pools, phosphatase activities, and the microbial community in a greenhouse vegetable production system

Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus(P)in agricultural production.However,few studies have comprehensively evaluated the effects of longterm organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.A 10-year(2009–2019)field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools,phosphatase activities and the microbial community,and identify factors that regulate these soil P transformation characteristics.Four treatments included 100%chemical N fertilizer(4 CN),50%substitution of chemical N by manure(2 CN+2 MN),straw(2 CN+2 SN),and combined manure with straw(2 CN+1 MN+1 SN).Compared with the 4 CN treatment,organic substitution treatments increased celery and tomato yields by 6.9-13.8%and 8.6-18.1%,respectively,with the highest yields being in the 2 CN+1 MN+1 SN treatment.After 10 years of fertilization,organic substitution treatments reduced total P and inorganic P accumulation,increased the concentrations of available P,organic P,and microbial biomass P,and promoted phosphatase activities(alkaline and acid phosphomonoesterase,phosphodiesterase,and phytase)and microbial growth in comparison with the 4 CN treatment.Further,organic substitution treatments significantly increased soil C/P,and the partial least squares path model(PLS-PM)revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.Partial least squares(PLS)regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices.

分子筛限域单位点钴体系催化芳香族化合物C-H键自调节高效氧化

通过芳香族化合物的碳-氢键活化与选择氧化,可以将廉价芳香烃类原料转化为高附加值含氧产品,因此,该反应在基础研究和工业生产中均受到广泛关注.传统的苯乙酮生产工艺存在毒性底物使用、催化剂回收困难、反应条件苛刻以及产物收率低等问题.通过大量的研究探索,科研人员进一步改进其生产工艺,利用环烷酸钴作为均相催化剂,实现了无溶剂条件下分子氧直接选择氧化乙苯生成苯乙酮.相比均相催化,多相催化在催化剂回收和产物分离方面具有优势,更适合工业化生产.因此,开发用于乙苯选择氧化制苯乙酮的高效稳定多相催化体系非常重要,但具有较大挑战.本文采用原位配体保护的水热合成法将钴配合物(钴-二乙烯三胺)封装在Y型分子筛中,并经进一步焙烧去除配体成功制得Co@Y分子筛催化剂.在无溶剂、无添加剂的条件下,单位点Co作为Co@Y分子筛催化剂的活性位点可催化乙苯选择氧化生成苯乙酮.X射线粉末衍射、透射电镜、紫外可见光吸收光谱和固体核磁共振谱等结果表明,该单位点Co(Co^(2+))通过与骨架氧原子作用稳定限域在Y型分子筛中.为明确Co@Y分子筛催化剂中单位点Co在乙苯氧化反应中所起的重要作用,本文还对比了不同后合成方法所制备的Y分子筛(Co/Y,Co-Y)催化剂及工业环烷酸钴催化剂的催化性能.结果表明,在相同反应条件下,Co@Y分子筛催化剂表现出最高的催化性能,也说明在乙苯氧化反应过程中Co@Y分子筛催化剂的单位点Co有别于上述其他催化剂的活性位点.此外,在Co@Y催化剂热过滤实验中未检测出Co物种浸出,表明Co@Y分子筛催化乙苯氧化反应为多相催化过程,并且在多次循环测试后,Co@Y催化剂结构和反应活性均未发生明显变化.这两项实验均表明Co@Y催化剂具有高稳定性.值得注意的是,在乙苯氧化反应过程中观察到自加速现象,为此进行了对比实验(添加苯甲醛或1-苯乙醇的对比实验)和反应动力学分析.结果表明,痕量苯甲醛或1-苯乙醇的加入会显著改变Co@Y催化剂在乙苯氧化反应中的催化行为,痕量苯甲醛的加入可将反应表观活化能从69.7降至53.7 kJ/mol.本文也通过第一性原理密度泛函理论(DFT)计算系统研究了Co@Y分子筛催化剂单位点Co处乙苯选择氧化反应机理及反应过程中自加速现象产生的原因.DFT计算结果结合上述对比实验和反应动力学分析结果表明,加入痕量苯甲醛或者1-苯乙醇后部分乙苯会直接氧化生成苯乙酮,而非通过乙苯→1-苯乙醇→苯乙酮的途径生成苯乙酮.DFT计算结果也阐明反应过程中自加速现象的产生源于单位点Co处活性氧物种(O^(*))的生成.该活性氧物种在乙苯、苯甲醛和1-苯乙醇的氧化途径中均能自发生成,并且该物种类似“引发剂”促使后续更多链式反应的发生,在乙苯氧化反应过程中具有非常重要的作用.综上所述,本文为理解芳香族化合物碳-氢键选择氧化实验现象与催化作用机制提供了有益见解,可为理性设计开发更高效的催化剂提供新思路.

Highly Active and Stable Ni_2P/SiO_2 Catalyst for Hydrogenation of C_9 Petroleum Resin

Catalytic hydrogenation is an appropriate method for the improvement of C9 petroleum resin（C9PR） quality. In this study, the Ni2P/SiO2（containing 10% of Ni） catalyst prepared by the temperature-programmed reduction（TPR） method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity（LHSV） was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values（250 mg Br/100g） within 300h, showing the high activity and stability of Ni2P/SiO2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction（XRD）, BET surface area（BET） analysis, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, Fourier transform infrared（FTIR） pyridine adsorption, and X-ray photoelectron spectroscopy（XPS）. Compared with the traditional sulfurated-Ni W catalysts, Ni2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni2P/SiO2 catalyst. The stability of Ni2P/SiO2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni2P nanoparticles and weak surface acidity for the Ni2P/SiO2 catalyst.

Efficient Photolytic Halogenation and Oxidation of Unactivated Alkyl sp^(3) C—H Bonds with Iodine(III)

A metal-free,green,and sustainable functionalization of unactivated alkyl sp^(3) C—H bonds is reported using iodine(III)as a feasible dehydrogenation agent under visible light or KBr,and alkyl chlorides,bromides,alcohols,and ketones could be constructed by addition of different coupling reagents.Cheap and safe iodobenzene diacetate was used to form a radical to activate the alkyl sp^(3) C—H bond in a highly efficient manner,which can construct different alkylation products by adding corresponding coupling reagents.

Ni–Al Bimetal-Catalyzed Tertiary C(sp^(3))–H Activation for Dual C–H Annulation of Formamides with Alkynes

3d-Metal-catalyzed tertiary C(sp^(3))–H bond activation has been a formidable challenge.Herein,a tertiary C(sp^(3))–H bond is smoothly activated by Ni–Al bimetallic catalysts for dual C–H annulation of formamides with alkynes,delivering a series of δ-lactams with a quaternary carbon up to 98%yield.Various tertiary C(sp^(3))–H bonds such as noncyclic,monocyclic and bridged-ring tertiary C(sp^(3))–H bonds are all compatible with the reaction.

基于氧化偶联方法实现C(sp3)-N键构建的开放性实验设计

基于现有有机合成科研平台,设计利用氧化偶联方法实现C(sp3)-N键构建的本科生开放性实验。在无催化剂的条件下,利用过硫酸钠为氧化剂实现二甲基亚砜C(sp3)-H键与苯并三氮唑N-H之间的脱氢氧化偶联反应来构建C(sp3)-N键。对该反应中催化剂、氧化剂和反应温度等条件进行了优化,确定了最优的反应条件。本开放性实验,将有机合成的新方法与有机波普分析融入实验教学,不仅开拓了学生的科研眼界,而且满足了学生个性化探索实践的需求。

POLYMER-SUPPORTED LEWIS ACID CATALYSTS. Ⅵ. POLYSTYRENE-BONDED STANNIC CHLORIDE CATALYST

A polystyrene-bonded stannic chloride catalyst was synthesized by the method of lithium polystyryl combined with stannic chloride. This catalyst is a polymeric organometallic compound containing 0.25 mmol Sn (Ⅳ)/g catalyst. The catalyst showed sufficient stability and catalytic activity in organic reaction such as esterification, acetalation and ketal formation, and it could be reused many times without losing its catalytic activity.

STUDIES OF QUANTUM CHEMISTRY CALCULATION ON VALENCE-BOND STRUCTURE AND HYDRATION ACTIVTY OF C_(12)A_7

The structure, chemical bonds and hydra-tion activity of C12A were studied by SCC-DV-Xa method of computational quantum chemistry. The calculated results show that Ca-O bond will be first broken off when C12A hydrates, the reactivity of Al(2)O4 tetrahedron is superior to that of Al(1)O4 tet, thedron and the rupture of the Al-O-Al chain composed of two types of AlO4 tetrahedra under the action of water lies in the very weak Al(2)-O(2) bonds. the Al-O bond strength of C12A7 is between C3A and C11A7·CaF2.

Phytochemical Characterization of Three Plants and Their Antisickling Activity in the Management of Sickle Cell Disease

Natural plant products have been used by the population of the south-eastern part of Côte d’Ivoire in the management of sickle cell anemia. This study was aimed at investigating the antisickling activity of the hydro-ethanolic extract of a combination of the leaves of J. secunda, J. gossypiifolia and P. nigrescens. These three plants species were used in the Ivorian traditional herbal medicine. Preliminary phytochemistry was carried out using standard methods. As for the sickling reversal test, the Hb SS blood sickling was induced with 2% sodium metabisulfite. After 120 minutes of incubation, the plant extract was added. Every 30 minutes for a period of 120 minutes, a drop of the prepared solution was observed at (40×) magnification and the percentage of reversion calculated. The phytochemical analysis revealed the presence of Alkaloids, Flavonoids, Polyphenols, Catechic Tannins, Sterols and Polyterpenes. The results of the reversal test showed that the percentage of sickling reversal effect of the combination of the plants (75.00 ± 4.33b,c) was highly superior than the negative control (10.17 ± 0.55d) but was significantly (p < 0.05) the same as the percentage of the individual plant (J. secunda: 83.50 ± 2.33a;J. gossypiifolia: 78.00 ± 3.67b,c and P. nigrescens: 77.83 ± 2.89b,c) and the positive control (80.66 ± 2.22a,b). From the results, the extracts J. secunda, J. gossypiifolia and P. nigrescens have shown to be therapeutically beneficial to the population. Their use is also justified in the management of sickle cell disease in the south-eastern part of Côte d’Ivoire.

Fe－Mn－C－P系高锰熔体的热力学研究

测定了１４００℃时Ｆｅ－Ｍｎ－Ｃ－Ｐ系高锰熔体中碳的溶解度为：Ｎ＿Ｃ＝０．１９６１＋０．１１８３Ｎ＿（Ｍｎ）－０．８５２５Ｎｐ；计算得到Ｍｎ与Ｃ，Ｐ与Ｃ的活度相互作用系数为：ε＿Ｃ￣（Ｍｎ）＝－１．６７，ρ＿Ｃ￣（Ｍｎ）＝０．２９，ε＿Ｃ￣Ｐ＝１１．００，ρ＿Ｃ￣Ｐ＝１０．８２；估算了高锰熔体中Ｍｎ，Ｐ和溶剂铁的活度系数。

P选择素、抗心磷脂抗体及活化蛋白C抵抗预测下肢创伤骨折术后深静脉血栓形成的临床研究

目的:探讨P选择素、抗心磷脂抗体(anticardiolipin antibody,ACA)及活化蛋白C抵抗(activated protein c resistance,APCR)对下肢创伤骨折术后深静脉血栓形成(deep venous thrombosis,DVT)的预测价值。方法:选择接受手术治疗的下肢创伤骨折患者,术后第3天抽取患者静脉血,采用酶联免疫吸附法测定P选择素含量和ACA阳性率,采用Dahlback法测定APCR阳性率。按照《深静脉血栓形成的诊断和治疗指南(第三版)》中DVT的诊断标准判断患者术后2周内是否发生DVT,比较DVT组和无DVT组的血清P选择素含量、血清ACA阳性率及血清APCR阳性率。以是否发生DVT为因变量,以血清P选择素、ACA及APCR为自变量,进行多因素Logistic回归分析。结果:共纳入648例患者,其中31例患者术后2周内发生DVT(DVT组),其余617例均未检出DVT(无DVT组)。2组患者的血清P选择素含量、血清ACA阳性率及血清APCR阳性率比较,差异均有统计学意义(t=26.989,P=0.000;χ^2=0.010,P=0.000;χ^2=12.447,P=0.000)。多因素Logistic回归分析结果显示,血清P选择素、ACA及APCR是下肢创伤骨折术后DVT的危险因素(OR=1.219,P=0.019;OR=1.292,P=0.009;OR=2.430,P=0.012)。结论:P选择素、ACA及APCR是下肢创伤骨折术后DVT的危险因素,可作为预测下肢创伤骨折术后DVT的检测指标。

Fe－Cr－C－P系高铬熔体的热力学研究

实验测出１５５０℃时Ｆｅ－Ｃｒ－Ｃ－Ｐ系高铬熔体中碳的溶解度为：Ｎｃ＝０．２１７８＋０．２４７９Ｎ＿（ｃｒ）－０．９８９１Ｎ＿ｐ计算得到Ｃｒ与Ｃ，Ｐ与Ｃ的活度相互作用系数为：并估算了高铬熔体中（≤３８％Ｃ＿ｒ）铬和磷的活度系数。

P(HB-co-HV)/PVPh的相容性与聚集态结构

采用差热扫描分析、红外光谱、固体核磁、小角Ｘ光散射等方法研究了聚（β－羟基丁酸酯－ｃｏ－β－羟基戊酸酯（Ｐ（ＨＢ－ｃｏ－ＨＶ））／聚（对－羟基苯乙烯）（简称ＰＶＰｈ）共混物的相容性和形态．结果表明两组分间形成较强的分子间氢键，形成完全相容的共混体系．固体核磁结果表明Ｐ（ＨＢ－ｃｏ－ＨＶ）／ＰＶＰｈ（５０／５０）在３．４ｎｍ尺寸上是完全均相的．小角Ｘ光散射结果表明，在等温结晶的共混物中无定形的ＰＶＰｈ分子分散在Ｐ（ＨＢ－ｃｏ－ＨＶ）片晶之间与非晶的Ｐ（ＨＢ－ｃｏ－ＨＶ）分子形成非晶区，从而使非晶区加宽。

锰基Mn-Fe-P-C系热力学性质

1400℃碳溶解度平衡实验测得：锰基Mn－Fe－P－C系碳的溶解度计算式为，Nc=0．2719－0．0940NFe－1．1954Np；整个锰铁熔体浓度范围，即从纯锰到纯铁范围，碳的溶解度计算式有，NC=0．2719－0．0945NFe和Nc==0．1959十0．1044NMn，通过热力学的推导和计算，得到以下一些热力学数据：①铁基体系，锰基体系。

钯催化剂催化交叉偶联反应形成P-C键和复杂含磷化合物的研究进展

综述了利用金属钯催化交叉偶联反应形成P-C键以合成各种复杂的含磷化合物特别是手性膦配体的研究进展;介绍了参加偶联反应的不同价态的P化合物亲核试剂,以及卤代烯烃、卤代芳烃、三氟甲磺酸烯基脂、三氟甲磺酸芳基脂、乙烯基硼酸脂等亲电试剂;探讨了相应的偶联反应的反应条件、反应机理及其在材料、医药、农药等领域的应用.

“原位”生成的d^（10）－Pt（diphos）配合物对sp^3C－H键的活化作用

“原位”生成的ｄ１０－Ｐｔ（ｄｉｐｈｏｓ）配合物对ｓｐ３Ｃ－Ｈ键的活化作用＊帅复华（西南交通大学应用化学技术研究所成都６１００３１）孙光日＊＊张良辅（中国科学院成都有机化学研究所成都６１００４１）关键词Ｃ－Ｈ键活化金属有机配合物原位反应温和条件下，饱...

与两种气相反应速率系数k_c和k_p对应的不同活化能

本文讨论了气相反应的kc、kp与其活化能Ea,c和Ea,p之间的关系,及在对行反应中二种活化能与反应热力学能变、焓变之间的关系。通过误差分析论证,我们在教学中提出对Ea,c和Ea,p两种活化能应注意区分。