掺硅MlNi5系稀土贮氢合金电化学性能

对ＭｌＮｉ３．５Ｃｏ０．７５－ｘＳｉｘＡｌ０．２Ｍｎ０．５５的显微组织结构及电化学性能进行了系统的研究。当ｘ＝０．１,０．２时,合金的放电容量较大、活化速度快、大电流放电容量较高、放电电压稳定。Ｘ射线分析和扫描电镜观察表明该系合金由ＬａＮｉ３与Ｌａ２Ｎｉ７两相组成,且随Ｓｉ含量的提高,非贮氢相ＬａＮｉ７相增加。     

富镧混合稀土贮氢合金分离氢中Kr,Xe性能的研究

叙述Ｍ１Ｎｉ４．５Ａｌ０．５贮氢合金分离氢中氪、氙的基本原理，分了分离时氢中氪、浓度与分离温度的关系。结果表明，当Ｔ为２９８Ｋ时，贮氢合金Ｎ１Ｎｉ４．５Ａｌ０．５与ＴｉＦｅ０．８６Ｍｎ０．１的分离性能基本相似，分离浓度与放氢体积符合Ｎ＝ａｅ＾－ｂｒ方程。     

TiO2负载非晶态合金NiB催化剂的制备、表征及HDS动力学研究

用等体积浸渍－还原法制备了负载型的ＮｉＢ／ＴｉＯ２（Ｂ／Ｎｉ＝５：１摩尔比）非晶态合金,并在相同条件下制备了ＮｉＢ／Ａｌ２Ｏ３（Ｂ／Ｎｉ＝５：１摩尔比）与之对照。用ＸＲＤ,ＳＥＭ和ＴＥＭ等表征方法比较了样品的非晶性质,在脉冲反色谱装置上以噻吩的ＨＤＳ反应为探针测定了ＮｉＢ／ＴｉＯ２、ＮｉＢ／Ａｌ２Ｏ３的反应活性,进行了动力学研究。结果证明,ＮｉＢ／ＴｉＯ２的低温活性远高于ＮｉＢ／Ａｌ２Ｏ３,其原因     

含锡AB5型非化学计量贮氢合金Ⅰ.合金的结构

采用Ｘ射线衍射法研究了ＬａＮｉ５．１５,Ｌａ（ＮｉＳｎ）５．１４,Ｌａ（ＮｉＳｎＣｏ）５．１２,Ｌａ（ＮｉＳｎＭｎ）５．１２,ＬＡ（ＮｉＳｎＣｏＭｎＡｌ）５．１０５种ＡＢ５型非化学计量贮氢合金的结构。发现主物相中并未产生第二物相,ＡＢ５型贮氢合金中Ｂ原子数发生正偏移时,晶胺体积减小,当Ｂ侧含有取代元素时,这种变化更加明显。对于非化学计量贮氢合金而言,少量Ｓｎ取代Ｎｉ后,晶胞体积大大提高。Ｍｎ,Ｃｏ     

LaNi5-xMx高温氢化的歧化行为

采用Ｘ射线衍射、差热分析及电化学方法，研究了吸氢合金ＬａＮｉ５－ｘ－Ｍｘ（Ｍ＝Ｍｎ，Ｃｏ，Ｆｅ，Ｃｒ，Ａｌ）在高温氢化反应时的歧化行为及其反应产物的电化学性能。ＬａＮｉ５－ｘＭｘ在２．５ＭＰａ氢压和５５０℃以上保温一地间后可发生明显的歧化反应，并析出纳米相镍。歧化反应的程度与加热温度、时间、第三组元Ｍ及合金的生成焓关系密切。电化学交换电流密度测定表明，经歧化反应得到的含纳米相镍的复相组织与原始合金     

NO_x储存催化剂Pt/BaAl_2O_4-A1_2O_3的XAFS研究

采用共沉淀－浸渍法在不同载体焙烧温度下,制备了不同Ａｌ／Ｂａ原子比的Ｐｔ／ＢａＡｌ２Ｏ４－Ａ１２Ｏ３系列样品。用ＸＲＤ,ＸＡＮＥＳ,ＥＸＡＦＳ,以及ＮＳＣ（ＮＯ_ｘ　ｓｔｏｒａｇｅ ｃａｐａｃｉｔｙ）测定等手段对样品的微观结构和ＮＯ_ｘ储存性能进行了详细的表征．样品中Ｂａ物种是以ＢａＡｌ２Ｏ４和ＢａＣＯ３两种混合物相的形式存在,且伴随着载体焙烧温度和Ｂａ含量的降低,ＢａＡｌ２Ｏ４物相的分散度变高,ＮＯ_ｘ储存活性也随之提高,这表明ＢａＡｌ２Ｏ４相的分散度与样品的ＮＯ_ｘ储存性能密切相关,小颗粒的ＢａＡｌ２Ｏ４相是ＮＯ_ｘ的主要储存活性中心．在样品中,Ｐｔ物种以金属原子簇形式存在．分散度很高,其Ｐｔ—Ｐｔ壳层配位数较标样Ｐｔ粉有显著下降,Ｐｔ—Ｐｔ键长变短,出现了纳米收缩现象．高分散的小颗粒金属Ｐｔ原于簇为捕获和氧化ＮＯ_ｘ的主要活性中心．     

机械合金化Mg/MmNi5-x(CoAlMn)x复合储氢合金的组织结构与吸氢特性

运用Ｘ射线衍射、扫描电及粒度分析等方法表征了机械合金化制备Ｍｇ／ＭｎＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ复合储氢合金的结构,通过ＰＣＴ曲线研究了基储氢性能。结果表明,在适当的球磨条件下能够获得纳米晶结构的Ｍｇ／ＭｎＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ复合储氢合金,ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ合金相彘,复合储氢合金的活化性能及储氢量有明显提高。此外,还考察了Ｍｇ含量对复合储氢合金的组织结构及储氢性能的影响。     

Pr_（2－x）Sr_xNiO_（4±δ）的合成、结构和电磁性质

用固相法合成了Ｐｒ＿（２－ｘ）Ｓｒ＿ｘＮｉＯ＿（４±δ）（０．０≤ｘ≤１．０）系列Ｋ＿２ＮｉＦ＿４型化合物，研究了其结构，红外光谱，电磁性质。当０．０≤ｘ＜０．１和ｘ＝１．０时以正交晶系结晶；当０．１≤ｘ＜１．０时以四方晶系结晶；Ｎｉ离子平均价态在＋２至＋３价之间。当ｘ值较小时，样品中含有过量的氧。ＮｉＯ＿６八面体中Ｎｉ￣（３＋）的Ｊａｈｎ－Ｔｅｌｌｅｒ畸变引起ｃ／ａ值在ｘ＝０．５处出现极大，在７７～２５０Ｋ之间，样品磁性质符合居里－外斯定律，并表现出反铁磁相互作用。电学性质的变化可以理解为Ｎｉ￣（３＋）离子电子组态由：变至的结果     

（C_5H_7S_2）_3〔Bi_2Cl_9〕的合成和晶体结构

标题化合物由ＢｉＣｌ３和乙酰丙酮在ＨＣＩ（气）／Ｃ２Ｈ５ＯＨ溶剂中通入Ｈ２Ｓ气体反应而得。晶体属四方晶系，Ｍｒ＝１１３０．７６，空间群Ｐ４１２１２。晶胞参数ａ＝ｂ＝８．８６７（２），ｃ＝４１．５１１（４）Ａ；Ｖ＝３２６４（１）Ａ３，Ｚ＝４，Ｄｃ＝２．３０ｇｃｍ（－３），μ（ＭｏＫα）＝１１８．６０７ｃｍ（－１），Ｆ（０００）＝２１０４．晶体结构由重原子法求得。最终偏离因子Ｒ＝０．０７２。晶体由分立的（Ｃ５Ｈ７Ｓ２）＋阳离子和［Ｂｉ２Ｃｌ９］３－阴离子组成。每个Ｂｉ原子和６个Ｃｌ原子形成畸变的八面体配位。２个［ＢｉＣｌ６］八面体共面构成具有２次轴对称的［Ｂｉ２Ｃｌ９］（３－）配阴离子。还讨论了阳离子种类对Ｂｉ配阴离子结构类型的影响。     

La,Ce,Nd和Pr对RE（NiCoMnTi）5贮氢合金电化学性能的作用机理

系统地研究了稀土（ＲＥ＝Ｌａ１－ｘ－ｙ－ｚＣｅｘＮｄｙＰｒｚ）对贮氢合金ＲＥ（ＮｉＣｏＭｎＴｉ）５电化学性能的影响。结果表明，Ｌａ、Ｃｅ、Ｎｄ和Ｐｒ比例对合金性能有显著影响，ＲＥ＝Ｌａ０．４Ｃｅ０．１Ｎｄ０．２Ｐｒ０．３时，对应合金具有最高放电容量，为２９０ｍＡｈ／ｇ，并有较好的循环寿命。从原子结构和性质角度分析了Ｌａ，Ｃｅ，Ｎｄ和Ｐｒ作用的机理。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.