Synthesis of monosubstituted N-arylamidines by divalent diaminobisphenolate ytterbium complex catalyzed addition of amines to nitriles

Divalent ytterbium complex YbL^（ONNO）（THF）2 （L^（ONNO）= Me2NCH2CH2N（CH2-2-O-3,5-C6H2（^1Bu）2）2） （1） has first been found to serve as a catalyst for addition of amines to nitriles to give monosubstituted N-arylamidine in moderate to good yields. The aromatic amines and nitriles showed better activity. The outcome of the addition reaction was greatly affected by the structure of divalent ytterbium complexes. The reaction mechanism was proposed and the benzonitrile-coordinated divalent ytterbium phenoxide Yb（OAr）2（C6H5CN）（THF）2 （Ar = 2,6-di^tBu-4-MeC6H3） was isolated as one of the intermediates.     

Aluminum chloride: A highly efficient catalyst for addition of amines to carbodiimides to synthesize substituted guanidines

A catalytic addition of amine N H bonds to carbodiimides using aluminum chloride as a Lewis acid catalyst is developed.The reaction proceeds under mild conditions without solvent to afford a series of substituted guanidines in good to excellent yields using a wide range of amines as substrates.Evidence of the proposed mechanism is provided by in situ infrared spectroscopy.     

Synthesis of a novel multi-SO3H functionalized strong Brønsted acidic ionic liquid and its catalytic activities for acetalization

The novel multi-SO3H functionalized strong Bronsted acidic ionic liquid has been prepared and its catalytic activities were investigated through the acetalization. The results showed that the novel catalyst was very efficient for the reaction with the average yield over 90% under solvent-free condition at room temperature. Operational simplicity, without need of any solvent, a small amount of usage, low cost of the catalyst used, high yields, applicability to large-scale reactions and reusability are the key features of this methodology. The novel catalyst also has great potential for the green process.     

Facile and efficient one-pot synthesis of 2-arylbenzoxazoles using hydrogen tetrachloroaurate as catalyst under oxygen atmosphere

In this paper, we presented a novel method for the facile and efficient one-pot synthesis of 2-arylbenzoxazoles, which were directly synthesized from 2-aminophenol and aldehydes catalyzed by hydrogen tetrachloroaurate (HAuCl₄·4H₂O) under an oxygen atmosphere with anhydrous tetrahydrofuran (THF) as solvent or in solvent-free condition. The results show that this method could bring excellent yields as high as 96%. THF was proven to be the best choice among several solvents screened and the reaction was tolerated with a variety of aromatic aldehydes possessing electron-donating or withdrawing groups. The advantages of the present method lie in catalytic process using economic and environmentally benign dioxygen as oxidant.     

苯环上取代基及烷化剂醇对还原—烷基化合成N—烷基芳胺的影响

研究了骨架镍催化下,芳香硝基化合物和醇进行还原烷基化合成Ｎ－单烷基芳胺衍生物时,苯环上取代基位置和性质以及作为烷化剂的醇的结构变化对Ｎ－烷化反应的作用;证明苯环上给电子基促进反应进行,吸电子基则减缓还原烷基化。该工艺适用于除Ｎ－甲基化处的其他Ｎ－直链烷基化。     

硫酸铁水合物催化下醇脱水成烯反应

研究了在硫酸铁水合物催化下,不同叔醇脱水成烯反应,结果表明该催化剂对叔醇脱水成烯的反应有较好的催化效果,生成烯烃的产率为85～97％。     

Ferric chloride-catalyzed decarboxylative alkylation of β-keto acids with benzylic alcohols

β-Keto acids are unstable to heat,acids,and bases,and have rarely been employed as carbon nucleophiles for the formation of carbon-carbon bonds.In this context,an efficient decarboxylative alkylation reaction of β-keto acids with benzylic alcohols has been developed,for the first time,through sequential cleavage of carbon-oxygen and carbon-carbon bonds.In the presence of 10 mol% of ferric chloride,a range of β-keto acids smoothly undergo decarboxylative alkylation with benzylic alcohols to give structurally diverse unsymmetric ketones in moderate to excellent yields and with extremely high regioselectivity.Preliminary mechanistic studies indicate that the reaction proceeds through an SN1 alkylation followed by decarboxylation.     

Bimetal nickel–cobalt phosphide directly grown on commercial graphite substrate by the one-step electrodeposition as efficient electrocatalytic electrode

It is challenging to find a method to obtain a catalyst with low cost and efficient multifunctional performances. Herein, in order to obtain the electrode with high-performance water splitting and non-enzymatic glucose detection, the commercial graphite sheet (GS) with excellent durability and electroconductivity was used as substrate material, and the non-noble ternary component Ni–Co–P catalyst with hierarchical architecture was fabricated on GS via a co-electrodeposition. The catalyst only required low overpotentials of 44.6, 76.5 and 49 mV to drive the current density of 10 mA cm⁻² alongside with the smaller Tafel slopes of 39.2, 44.8 and 112 mV dec⁻¹ for hydrogen evolution reaction (HER) in 1.0 M KOH, 0.5 M H₂SO₄ and 1.0 M PBS solution, respectively. For oxygen evolution reaction (OER), the catalyst demonstrated a low overpotential of 304 mV to achieve the current density of 20 mA cm⁻² with excellent Tafel slope of 89.8 mV dec⁻¹ in alkaline solution. Furthermore, the Ni–Co–P/GS electrode serving as non-enzymatic glucose sensor exhibited the superior electrocatalytic activity with an ultrahigh sensitivity of 7400 μA mM⁻¹ cm⁻², low detection limit of 0.425 μM (S/N = 3), and wide linear range (1–1200 μM).     

用于邻苯基苯酚合成的Pt-K/Al2O3脱氢催化剂(Ⅱ):催化剂失活机制

采用热重-差热分析(TG-DTA)、元素分析、氢氧滴定(HOT)、扫描电镜能谱分析(SEM-EDS)、透射电镜(TEM)等对Pt-K催化剂可能的失活机制进行研究。结果表明:积碳并非Pt-K催化剂失活的主要原因;脱氢催化剂上铂颗粒的尺寸在运转过程中没有明显的增大,即铂中心烧结也不是催化剂失活的主要原因;Pt-K催化剂在运转过程中铂分散度明显下降而且无法通过再生恢复;Pt-K/Al2O3催化剂的失活极有可能源自催化剂运转过程中钾物种对铂中心的过度覆盖作用。     

新型含吡啶基手性配体的合成

改进了高收率、高选择性的手性叔丁基亚磺酰亚胺与2-吡啶基格氏试剂的不对称加成方法,合成了11个含吡啶基胺类手性配体,建立了手性叔丁基亚磺酰亚胺与2-吡啶基格氏试剂的不对称加成立体构型的预测模型.     

水杨醛亚胺的微波驱动无溶剂合成

为寻求简单快速合成金属催化剂配体化合物西佛碱的方法,利用微波驱动的有机反应具有快速高效的优点,于无溶剂、616W微波功率驱动下,20s~4 min快速高效合成了6种水杨醛亚胺类化合物.化合物的化学结构经IR,NMR和元素分析测试加以证实.     

Magnetic field induced synthesis of (Ni,Zn)Fe2O4 spinel nanorod for enhanced alkaline hydrogen evolution reaction

Recently, the introduction of external fields(light, thermal, magnetism, etc.) during electrocatalysis reactions gradually becomes a new strategy to modulate the catalytic activities. In this work, an external magnetic field was innovatively employed for the synthesis progress of(Ni, Zn)Fe₂O₄spinel oxide(M-(Ni, Zn)Fe₂O₄). Results indicated the magnetic field(≤250 m T) would affect the morphology of catalyst due to the existing Fe ions, inducing the M-(...     

Synthesis of Li_4Ti_5O_(12) nanostructural anode materials with high charge–discharge capability

This study demonstrates a facile and efficient hydrothermal method to prepare spindle titanate(Li4Ti5O12 denoted as LTO)and/or carbon-LTO nanocomposites(CLTO),in which the LTO or C-LTO microspheres have diameters of a few micrometers,composed of numerous nanosheets with thickness of*30 nm and edge length of hundreds of nanometers.The morphology and size control of these nanoparticles could be achieved by varying experimental parameters including concentration of titanium butoxide,lithium hydroxide,and cetyltrimethylammonium bromide,as well as reaction temperature and time.These micro-nanostructures were characterized by several advanced techniques,such as transmission electron microscopy,scanning electron microscopy,X-ray diffraction,energy dispersive spectroscopic analysis,surface area,and electrochemical measurements.The LTO and C-LTO microstructures were examined in the charge–discharge capacity at a rate of 50 C,as well as the stability after 100 cycles at a rate of 10 C.The excellent capability may be attributed to good conductivity,large surface area,and stable assembly structure of such micro-nanostructures,which could be explored as a promising anode material for lithium-ion batteries.     

Visible-light-driven Ag/Ag3PO4-based plasmonic photocatalysts: Enhanced photocatalytic performance by hybridization with graphene oxide

An efficient visible-light-driven plasmonic photocatalyst with regard to graphene oxide(GO) hybridized Ag/Ag3PO4(Ag/Ag3PO4/GO) nanostructures has been facilely synthesized via a deposition-precipitation method.The synthesized nanostructures have been characterized by means of scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX),X-ray diffraction(XRD),UV-vis spectra,Fourier transform infrared spectra(FT-IR),X-ray photoelectron spectroscopy(XPS),and Raman spectra.It has been disclosed that compared with the bare Ag/Ag3PO4 nanospecies,the GO hybridized nanostructures display enhanced photocatalytic activity for the photodegradation of methyl orange pollutant under visible-light irradiation.It is suggested that the reinforced charge transfer and the suppressed recombination of electron-hole pairs in Ag/Ag3PO4 /GO,the smaller size of Ag/Ag3PO4 nanospecies in Ag/Ag3PO4/GO,all of which are the consequences of the hybridization of GO,are responsible for the enhanced photocatalytic performance.The investigation might open up new opportunities to obtain highly efficient Ag3PO4-based visible-light-driven plasmonic photocatalyst for the photodegradation of organic pollutants.     

光催化烯烃加成/环化合成含氟异喹啉-1,3-二酮

发展了一种光催化活泼烯烃加成/环化合成含氟异喹啉-1,3-二酮的反应.在可见光催化下,多种N-烷基-N-甲基丙烯酰基苯甲酰胺衍生物与全氟碘代丁烷、溴二氟乙酸乙酯发生自由基串联加成环化反应,以67%～80%的产率合成了一系列具有潜在生理活性的含氟取代异喹啉-1,3-二酮衍生物.这为具有潜在药用价值的氟取代异喹啉-1,3-二酮的合成提供了一条绿色、高效、条件温和的途径.     

Enantioselective Chlorocyclization of Olefinic Amides with 1,3-Dichloro- 5, 5-Dimethylhydantoin (DCDMH) Catalyzed by (DHQD)<Subscript>2</Subscript>PHAL

An efficient catalytic asymmetric chlorocyclization of olefinic amides with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using hydroquinidine 1,4-phthalazinediyl diether ((DHQD)₂PHAL) as organocatalyst has been developed. Series of chiral chloro substituted isobenzofuran-1(3H)-imine derivatives were obtained in good yields (up to 85%) and enantioselectivities (up to 70% ee).     

铁催化烯基环丙烷类化合物的三氟甲基化反应

对铁催化的烯基环丙烷类化合物的自由基三氟甲基化反应进行了研究.以中等到良好的收率获得了含三氟甲基的二氢萘衍生物.方法具有反应条件温和,催化剂廉价易得,反应时间短等优点.同时对反应机理进行了初步研究.     

Catalytic self-assembly preparation and characterization of carbon nitride nano-tubes by a solvothermal method

A solvothermal reaction of anhydrous CaNaCl3 and sodium using cyclohexane as solvent and NiCI2 as catalyst precursor has been carried out to prepare carbon nitride nanotubes successfully at 230℃ and 1.8 MPa. The carbon nitride nanotubes were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), electron energy loss spectrum (EELS) and Raman spectrum.SEM and TEM results indicated that the tubes have a length of 20-30 μm, a uniform outer diameter of about 50-60 nm,an inner diameter of 30-40 nm and are highly ordered assembled as bundles. The EELS measurement indicated that the ratio of N/C was about 1.00. The ED and XRD analyses revealed that the tube may have a new CN crystalline structure. The growth mechanism of nanotubes was discussed.     

Nickel-catalyzed alkene ipso-selective reductive hydroamination with nitroarenes

Aromatic amine synthesis via reductive coupling between alkenes and nitroarenes is attractive; however, it remains underdeveloped. Herein, we report a nickel-catalyzed alkene hydroamination with nitroarenes under mild reductive conditions. This reaction exhibited an ipso-selectivity and enabled repaid preparation of aromatic amines with primary and secondary alkyl groups. Many functional groups were well tolerated, providing an efficient approach for drug-like arylamine synthesis.     

Hydrotalcite-supported Pd-Cu catalyst for nitrate adsorption and reduction from water

With the rapid development of industry and agricul- ture, the nitrate contamination in groundwater becomes increasingly serious in many countries [1]. Therefore, the remediation of nitrate-contaminated groundwater is one of the targets urgently confronted…