Green synthesis and characterization of cobalt oxide nanoparticles and its electrocatalytic behavior

Green synthesis of pure cobalt oxide nanoparticles (CoO-NPs) in aqueous medium has been carried out using gelatin. The main advantage of using gelatin as a stabilizing agent is that it provides long-term stability for nanoparticles by preventing particles agglomeration. The particles have been characterized using X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EADX), and thermogravimetric analysis (TGA). TEM image shows the formation of CoO-NPs with average particle size of 28 nm which agrees well with the XRD data. Cobalt oxide nanoparticles modified carbon paste electrode (CoO-NPs/CPE) displayed excellent electrochemical catalytic activities towards the oxidation of glucose. The electrocatalytic response showed a wide linear range of 7–1000 µM, as well as its experimental limit of detection can be achieved 5.3 µM. The modified electrode for glucose determination is of the property of simple preparation, good stability and high sensitivity.     

A novel one step synthesis of a dihydropentalene

1,4-Dipyrrolidinocyclohexa-1, 3-diene 4 reacts with dimethyl acetylenedicarboxylate i an unexpected manner to produce the substituted dihydropentalene 6.     

Facile synthesis of nickel cobalt sulfide nano flowers for high performance supercapacitor applications

A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g^?1 at a scan rate of 5 mV s^?1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg^?1 at power density of 495 W kg^?1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future.     

水热法制备磷酸镍及其光催化性能评价

采用水热合成法以Ni(NO3)2·6H2O为镍源、KH2PO4为磷源合成了磷酸镍,并详细研究了用水热法合成磷酸镍过程中Ni/P摩尔比、晶化温度及溶液酸碱度对磷酸镍光催化降解染料亚甲基蓝的影响,优化了合成条件。通过X-射线粉末衍射(XRD)、扫描电子显微镜(SEM)、红外吸收光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)和热重-差热(TG-DTA)和N2吸附等技术对其晶相组成、表面形貌、官能团结构、光吸收特性、热稳定性和比表面积进行了表征。合成材料通过对亚甲基蓝的光催化降解性能进行评价,当制备条件Ni/P摩尔比为3:2、反应温度为110℃、p H为碱性时晶化36 h合成的材料其光催化性能最佳。     

不对称二亚胺异双核钴镍催化剂的合成及乙烯聚合研究

合成了不对称异双核钴镍催化剂MN5CoNi.该催化剂经AlEt3,MMAO,AlEt3/[PhMe2NH][B(C6F5)4](B)或MMAO/B活化后用于乙烯聚合.异双核催化剂与相应的等摩尔双组分混合单核催化剂相比,以TEA作助催化剂时,异双核催化剂的Co和Ni中心的活性都远低于双组分混合体系,且Ni中心生成的聚乙烯含量低于双组分混合体系,异双核催化剂中的Co和Ni中心同时被抑制.以MMAO作助催化剂时,异双核催化剂的活性虽低于双组分混合体系,但是异双核催化剂中的两种金属中心的活性都有了较大的提高,且Ni中心生成的聚乙烯含量高于后者.同时考察了活性随时间变化,发现异双核催化剂中活性衰减比双组分混合体系慢,说明异双核体系中Co和Ni中心在MMAO活化下比双组分混合体系的金属中心更稳定.当以TEA/B作助催化剂时,异双核催化剂中Co和Ni中心的活性有所提高,但仍远低于双组分混合体系,且Ni中心生成的聚乙烯含量低于后者,说明Ni被选择性抑制.当使用MMAO/B作助催化剂时,结果与MMAO类似.     

A one step synthesis of 1,4-benzodiazepines: synthetic studies on neothramycin

A one step synthesis of 1,4-benzodiazepines from o-haloanilines and amino acids was achieved by use of palladium catalyzed carbonylation, by which application a synthesis of the model compounds(23a and 23b) of Neothramycin (A and B) was described. An efficient chemoselective reduction of the amide was provided.     

A one step synthesis of 1-alkylpyrazolo[5,4-d]pyrimidines

A new synthesis of 1-alkylpyrazolo[5,4-d]pyrimidines is described. The reaction of 4,6-dichloropyrimidine-5-carbaldehyde with various substituted hydrazines provides such compounds in a single step from commercially available starting materials. This method has advantages over methods currently described in the literature for the construction of such ring systems.     

A new one pot and solvent-free synthesis of nickel porphyrin complex

Abstract

A new one pot and solvent-free synthesis of nickel porphyrin complex is described. This is prepared by condensing pyrrole, benzaldehyde, nickel (II) chloride, and 1,8-diazabicyclo [5.4.0] undec-7-ene as a base. This new method allows higher yields, reduced reaction times, ease of handling, and follows principles of green chemistry. The same complex is also prepared by an alternative route, i.e. first, the porphyrin is prepared and then the insertion of metal ion.     

直接甲醇燃料电池阳极催化剂PtRu/MWCNTs的水热合成及其电催化行为

采用水热法合成了PtRu/MWCNTs阳极催化剂,并以循环伏安、线性扫描、计时电流和交流阻抗等电化学测试研究了其对甲醇的电催化氧化,结果表明,水热合成的PtRu/MWCNTs较之同样条件下合成的PtRu/Vu lcan XC-72有更好的对甲醇氧化的催化活性和更强的抗毒化能力。     

New polynuclear cobalt trimethylacetate complexes: synthesis and structure

Extraction of polymer (1), formed in the reaction of CoCl₂ with KOOCBu^t, with boiling hexane gives crystals of hexamer Co₆(μ₃-OH)₂(OOCBu¹)₁₀(HOOCBu¹)₄ (2). According to data of X-ray study, four Co¹¹ atoms in the hexanuclear molecule2 have an octahedral ligand environment and two Co¹¹ atoms have a tetrahedral one. Dissolution of polymer1 in EtOH results in its splitting into Co₄(μ₃-OH)₂(OOCBu¹)₆(HOEt)₆ tetramers (3). In molecule3, two asymmetric dimeric (η²-OOCBu^t)(EtOH)Co(μ-OOCBu^t)Co(HOEt)₂ fragments are bound by two tridentate bridging OH groups. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1773–1778, September, 1999.     

Chemical identification of icosahedral structure for cobalt and nickel clusters

Reactions of bare and hydrogenated cobalt and nickel clusters with ammonia and with water are used to determine cluster geometrical structure. Saturation measurements determine the total number of ammonia binding sites on cluster surfaces. A pattern of minima in the number of such sites is found to correlate with the sequence of closed shells and subshells expected for icosahedral packing in the 50- to 120-atom size range (50- to 200-atom range for hydrogenated clusters). In many cases there are 12 sites at the minima, the number that would be expected for preferred ammonia binding sites on closed (sub)shells of icosahedral clusters. The equilibrium adsorption of a single water molecule provides a sensitive measure of changes in cluster-water binding energy. A pattern of binding energy maxima is found, once again correlating with icosahedral structure, but for clusters having one metal atom more than the closed (sub)shells. In general, hydrogenation enhances the patterns of minima and maxima. These observations are explained in terms of the expected nature of ammonia and water binding to icosahedral clusters.     

A simple and efficient automatable one step synthesis of triazolopyridines from carboxylic acids

Triazolopyridines can be rapidly and efficiently synthesized from a variety of carboxylic acids with 2-hydrazinopyridines in one simple step. The use of commercially available PS-PPh₃ resin combined with microwave heating delivered the product triazolopyridines in good yields and purities.     

原位合成氧化镍硼/石墨炔杂化材料用于提高光/电催化产氢性能

当今世界面临严峻的能源紧缺和环境污染问题,发展高效无污染的清洁能源替代传统化石能源成为近几十年科研工作者的研究热点.其中,氢能由于具有高燃烧值和产物无污染等优点成为理想的替代能源.光/电催化水分解产生氢气是最有效的制氢方法之一.目前,高活性的产氢催化剂仍以贵金属为主,但贵金属价格高昂和稀缺性等限制了其大规模应用,因此,...     

A one step derivatization of controlled pore glass for oligonucleotide solid-phase synthesis

A one step anchoring of various diols on bare controlled pore glass (CPG) support via an adsorption mechanism allowed us to synthesize different (oligonucleotide-3′-diol) conjugates with high purity, through standard phosphoramidite chemistry. Diol loading on CPG proved to be efficient and reproducible. This methodology virtually allows the synthesis of any 3′-modified oligonucleotide, using any reporter molecule containing a diol moiety adsorbed on the CPG. Moreover, vicinal diol as glycol or glycerol enabled the release of some part of oligonucleotide-3′-OH.     

A novel one step synthesis of pyrano (2,3-d) pyrimidines

A novel and one step synthesis of pyrano(2,3-d) pyrimidines is described. It utilises the reaction of different thiobarbituric acid with ketones.     

A one step synthesis of thiadiazolo[2,3-b]quinazoline derivatives

Diazotized anthranilic acid and its methyl ester react with substituted phenacyl thiocyanates 3 to give in both cases the corresponding thiadiazolo[2,3-b]quinazolines 7a-e . A mechanism is proposed and it is substantiated by alternate synthesis of 7a from the hydrazidoyl chlorides 9a,b and potassium thiocyanate.     

A simple and efficient one step synthesis of benzoxazoles and benzimidazoles from carboxylic acids

Benzoxazoles or benzimidazoles can be rapidly and efficiently synthesized from a variety of carboxylic acids with 2-aminophenols or 1,2-phenylenediamines in one simple step, respectively. The use of commercially available PS-PPh₃ resin combined with microwave heating delivered a variety of benzoxazoles and benzimidazoles in high yields and purities.