碳布生长二维Ni-Mn MOF用于柔性超级电容器

通过溶剂热法在碳布(CC)表面生成二维Ni-Mn层状双金属氢氧化物，利用溶剂热法将其转化为二维Ni-Mn金属有机骨架(Ni-Mn MOF)，产物形貌保持良好。探究了不同Ni、Mn元素物质的量之比、反应温度和反应时间对材料形貌、结构及性能的影响。当Ni、Mn元素物质的量之比为9∶1、反应温度为120℃、反应时间为12 h时，Ni-Mn MOF/CC电极的电化学性能最佳。在电流密度为1 mA·cm^-2时，该电极的面积比电容高达4 007.5 mF·cm^-2，同时该电极具有良好的循环稳定性。将该电极应用于柔性对称超级电容器中，该柔性对称超级电容器可180°弯折，且在10 mA·cm^-2的电流密度下进行5 000次循环后电容保留率为83.6%，具有良好的循环稳定性和柔韧性。     

Zn掺杂Co9S8纳米材料的制备及其在超级电容器和电催化析氢中的应用

采用原位溶剂热生长法设计合成了锌掺杂Co₉S₈纳米颗粒。各种表征技术和性能测试结果表明：锌掺杂Co₉S₈纳米颗粒的孔尺寸为18 nm,比表面积为23 m²·g^-1;同时微量的锌掺杂显著增强了Co₉S₈的电催化析氢（HER）活性及电容器性能。在HER性能测试中,当电流密度为10 mA·cm^-2时电位为-361 mV,电流密度最高可达38.26 mA·cm^-2,且具有优异的循环稳定性。同时在电容器性能测试中具有较高的比电容,当电流密度为1 A·g^-1时,质量比电容和面积比电容分别为235.48 F·g^-1和812.4 mF·cm^-2。     

一种高容量的层状Co-MOF基超级电容器电极材料

通过简单的溶剂热反应合成了一种钴基层状MOF（[Co（4,4''-bpy）（tfbdc）（H₂O）₂],Co-BTH,4,4''-bpy=4,4''-联吡啶,H₂tfbdc=四氟对苯二甲酸）,并考察了其作为超级电容器电极材料的性能。研究结果表明：Co-BTH电极具有良好的赝电容性能,包含高比电容和较好的倍率性能。在1 A·g^-1电流密度下和1 mol·L^-1 KOH溶液中,其比电容最大可达2 316 F·g^-1。在2 A·g^-1的电流密度下,循环1 000次后,电极的比电容仍然还有847 F·g^-1。良好的赝电容性能与Co-BTH的层状结构和小尺寸的纳米片有关。     

空心六边形镍钴硫化物/RGO复合物的合成及其超级电容性能

通过两步法制备了一种空心六边形镍钴硫化物（HHNCS）与还原氧化石墨烯（RGO）的纳米复合材料HHNCS/RGO。利用XRD,SEM,TEM和Raman光谱等对复合物进行表征,发现镍钴硫化物为空心六边形结构,并且均匀地附着在RGO的表面。该纳米复合物用作超级电容器电极表现出优异的电化学性能。在电流密度为1 A·g^-1时比电容为927 F·g^-1;当电流密度增大到20 A·g^-1时,比电容仍高达724 F·g^-1,表明材料拥有较好的倍率性能。此外,在电流密度5 A·g^-1下循环2000次后比电容保留有初始值的93%,显示出优异的循环稳定性。HHNCS/RGO优异的电容性能主要是由于RGO的存在不仅增强了材料的导电性,而且作为理想的载体分散HHNCS纳米片。HHNCS/RGO纳米复合物优异的电化学性能使其在超级电容器电极材料领域具有应用前景。     

表面官能团化增强碳纳米笼超级电容器性能

以具有多级孔结构、高比表面积、良好导电性等特征的碳纳米笼（CNCs）为前体,采用硝酸氧化法在CNCs表面引入含氧官能团。以CNCs为超级电容器电极材料,在相同电流密度下,官能团化样品的比电容显著高于纯CNCs;在1A·g^-1下比电容最高可达到255F·g^-1,比纯CNCs的188F·g^-1增加了34%,这表明表面含氧官能团化能够显著提高CNCs的超级电容器比电容。在100A·g^-1的大电流密度下,硝酸氧化后CNCs的比电容保持在111~167F·g^-1,表明具有良好的耐大电流充放电性能。在10A·g^-1的电流密度下循环10000圈后,CNC-6M样品的比电容由196F·g^-1下降到176F·g^-1,样品的比电容仍保留90%,具有良好的循环稳定性。表面含氧官能团化CNCs所表现出的这种优异的超级电容器性能归因于CNCs的多尺度分级孔结构、高比表面积、良好的导电性、表面亲水性含氧官能团化带来的浸润性提高和引入的赝电容。     

琥珀酸构建具有超级电容器性能的混合金属有机骨架

采用简单的溶剂热法合成了混合金属有机骨架材料（MOF （Ni,Co））,然后通过X射线衍射、FT-IR、扫描电子显微镜、X射线光电子能谱和N₂吸附-脱附对制备的材料进行了表征,并进一步研究了其作为超级电容器电极材料的性能。结果表明,具有独特的纳米花状结构的MOF （Ni_1.2Co_0.8）可以提供更多的电活性位点,从而具有优异的电化学性能,在1 A·g^-1时的比电容为850 F·g^-1。同时本研究工作说明MOF （Ni）电极材料在掺杂适量钴元素后,可增强电极内部电子/离子转移,降低活性物质和电解液之间的接触电阻,提高导电性,增强电化学性能。     

CoFeOx/MoO2准平行纳米阵列电极的析氢性能

利用CoFe层状双金属氢氧化物(CoFe LDH)准平行纳米片阵列作为载体前驱体,通过原位负载及煅烧方式,实现了含有氧空位的 MoO₂纳米颗粒在纳米片阵列表面的生长。电化学研究结果表明,所得 CoFeO_x/MoO₂纳米阵列电极具有高析氢反应(HER)催化活性。该电极在10和1 000 mA·cm^-2时的HER过电位分别为40和217 mV。在50 mA·cm^-2的电流密度下,该电极可以稳定运行125 h。     

一种基于二维钴基配位聚合物[KCo(pa)(OH)]n的高容量超级电容器电极材料

采用溶剂热反应合成了一种二维钴基配位聚合物[KCo (pa)(OH)]_n(Co-pa,H₂pa=邻苯二甲酸),并对其进行了红外光谱、热重分析、粉末X射线衍射、X射线光电子能谱、扫描电镜和氮气吸附-脱附等温线表征。当Co-pa作为超级电容器电极材料时,Co-pa电极展示了较高的放电比容量、较好的循环稳定性和倍率性能。在1和10 A·g^-1电流密度下,其比电容分别为910和400F·g^-1。在2 A·g^-1下循环2 000次后,其电容保持率为81.2%。较好的赝电容性能与Co-pa的小尺寸纳米棒形貌、Co-pa包含的钴离子、邻苯二甲酸根阴离子及层状结构有关。     

双金属离子调控型镍钴氧化物纳米片用于非对称超级电容器

通过水热-煅烧两步法制备了系列镍钴氧化物（NCO）纳米片。通过改变前驱体溶液中的镍、钴离子物质的量之比,进而调控NCO纳米片中的过渡金属离子比例。NCO纳米片的晶相、形貌和结构利用X射线衍射、扫描电子显微镜和X射线光电子能谱表征。此外,对NCO纳米片的电化学性能进行测试。结果表明,NCO-2（Ni_1.95Co₁O_x）纳米片在0.5 A·g^-1电流密度下,比电容为1 096.88 F·g^-1,且经过5 000次循环后具有78.26%的循环稳定性。以NCO-2为正极、活性碳为负极构成的非对称超级电容器,在功率密度为576 W·kg^-1时,能量密度为57.70 Wh·kg^-1。     

泡沫镍负载NiMoO4/NiMoS4复合材料的制备及其电化学性能

以泡沫镍作为基底，采用水热法原位生长出具有片状结构的NiMoO₄活性材料，然后通过水热硫化制备出NiMoO₄/NiMoS₄复合材料，研究了水热时间和硫脲添加量对样品形貌和电化学性能的影响。电化学结果表明，NiMoO₄/NiMoS₄电极在电流密度为 1 A·g^-1时，比电容为 1 560.7 F·g^-1，在电流密度为 40 A·g^-1时循环 2 000次后，比电容仍为初始比电容的 76.7%。将 NiMoO₄/NiMoS₄电极材料与活性炭(AC)分别作为正、负极组装的非对称超级电容器(ASC)在 400 W·kg^-1的功率密度下可提供 29.0 Wh·kg^-1的能量密度。     

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.     

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.     

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.