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Evolution of Routes for Asymmetric Total Synthesis of Cyclocitrinol Enabled by Type Ⅱ [5+2] Cycloaddition

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Chinese Journal of chemistry 2021年第5期39卷 1247-1254页

作者： Jianlei Wu Junyang Liu Jian-Hong Fan Zhi-Dong Xie Hukun Qin Chuang-Chuang Shenzhen key laboratory of Small Molecule Drug Discovery and Synthesis Department of ChemistryGuangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhenGuangdong 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhenGuangdong 518055China

The asymmetric total synthesis of an unusual C25 steroid containing a unique bicyclo[4.4.1]undecene A/B ring system,resulting in the synthesis of cyclocitrinol(1)and its isomer △^(8,14)-cyclocitrinol(38),is *** attempts to construct the synthetically challenging bicyclo[4.4.1]undecene A/B ring system using a type Ⅱ[5+2]cycloaddition showed that a chiral substituent at the allylic position of the alkene(C6,cyclocitrinol numbering)controlled the stereoselective outcome of the cycloaddition ***-stage migration of the tetrasubstituted C8-C14 double bond in △^(8,14)-cyclocitrinol(38)to obtain cyclocitrinol(1)proved challenging,inspiring an alternative *** chiral β-CH_(2)OR group on the allylic substituent at C6 played a pivotal role both in controlling the diastereoselectivity of the type Ⅱ[5+2]cycloaddition and retaining the C6 substituent under lithium-amine conditions.

关键词： Asymmetric Total synthesis Cyclocitrinol TypeⅡ[5+2] Cycloaddition

Insights into spin polarization regulated exciton dissociation and charge separation of C_(3)N_(4)for efficient hydrogen evolution and simultaneous benzylamine oxidation

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Nano Research 2023年第7期16卷 8845-8852页

作者： Gen Li Xiaomei Sun Peng Chen Meiyang Song Tianxiang Zhao Fei Liu Shuang-Feng Yin provincial Guizhou key laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China College of chemistry and Chemical Engineering Advanced Catalytic Engineering Research Center of the Ministry of EducationState Key Laboratory of Chemo/Biosensing and ChemometricsHunan UniversityChangsha 410082China

The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic ***,owing to the huge difference in dielectric properties between ferromagnetic oxide and polymers,the photogenerated excitons with spin states are often limited to the ferromagnetic oxide wells,which leads to unsatisfactory *** this paper,a single-atom Co-doped C_(3)N_(4)photocatalyst is successfully synthesized for photocatalytic water splitting and simultaneous oxidation of *** a tiny external magnetic field(24.5 mT),the hydrogen production rate could reach at 3979.0μmol·g^(-1)·h^(-1),which is about 340 times that of C_(3)N_(4).Experimental results and theoretical calculations indicate that the interaction of Co d and N p orbital changes the symmetry center of C_(3)N_(4),resulting in an increase in dielectric constant and spin ***,magnetic fields further promote parallel electron spin,and the increased number of charges with the parallel spin-down state is likely to dissociate under the action of an external magnetic *** the other hand,the Co-N bond provides a huge built-in electric field and active site for strengthening the charge transfer and surface *** work not only deepens the understanding of spin polarization,but also enriches methods to accelerate electron-hole separation.

关键词： low magnetic field C_(3)N_(4) spin polarization photocatalytic hydrogen evolution benzylamine oxidation

Heterostructured Co_(3)O_(4)-SnO_(2)composites containing oxygen vacancy with high activity and recyclability toward NH_(3)BH_(3)dehydrogenation

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Rare Metals 2023年第9期42卷 3013-3023页

作者： Hui-Ze Wang You-Xiang Shao Yu-Fa Feng Yu-Jie Tan Qing-Yu Liao Xiao-Dong Chen Xue-Feng Zhang Zhao-Hui Guo Hao Li School of chemistry and Materials Engineering Huizhou UniversityHuizhou516007China guangdong provincial key laboratory for Electronic Functional Materials and Devices Huizhou UniversityHuizhou516007China

Ammonia borane(NH_(3)BH_(3),AB)has been regarded as a promising chemical hydrogen storage material owing to its high hydrogen density and superior ***,the development of low-cost and high-efficient heterogeneous catalysts for the dehydrogenation of AB has attracted considerable scholarly *** this study,heterostructured Co_(3)O_(4)-SnO_(2)catalysts containing oxygen vacancy(V_(o))with different Co/Sn atomic ratios(designated as V_(o)-Co-Sn_(5:x))were synthesized via a simple coprecipitation-calcination method under mild reaction *** catalyst containing an optimized Co/Sn atomic ratio of 5:2(V_(o)-Co-Sn_(5:2))exhibited robust catalytic performance with a turnover frequency value of 17.6mol_(H2)·mol^(-1)_(metal)·min^(-1).Moreover,82.6%of the original activity of the catalyst was retained after 14 catalytic cycles,indicating the high stability of the *** characterization combined with the density functional theory(DFT)calculation confirmed the transfer of electrons from Co_(3)O_(4)to Sn O_(2)and the distribution of the separated charges on SnO_(2)-Co_(3)O_(4)*** transfer of electrons and the distribution of charges facilitated the adsorption and activation of water on the catalyst,thus accelerating the dissociation of H_(2)O molecule(the ratedetermining step of AB hydrolysis).It was found that the V_(o)adjusted the electron structure of the catalysts rather than acted as active *** findings will provide researchers with useful information for designing cheap and highly efficient catalysts for catalytic AB hydrolysis.

关键词： Ammonia borane(AB) Cobalt-tin composite oxide Heterocatalysis Hydrogen production Oxygen vacancy

A highly durable catalyst based on CoxMn3-xO4 nanosheets for low-temperature formaldehyde oxidation

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Nano Research 2016年第12期9卷 3881-3892页

作者： Yongchao Huang Kaihang Ye Haibo Li Wenjie Fan FengyiZhao Yuanming Zhang Hongbing Ji MOE of the key laboratory of Bioinorganic and Synthetic chemistry KLGHEI of Environment and Energy Chemistry The Key Lab at Low-carbon Chemistry and Energy Conservation of Guangdong Province School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 China Country department of chemistry Jinan University Guangzhou 510632 China

Cost-effective catalysts for the oxidation of volatile organic compounds （VOCs） are critical to energy conversion applications and environmental protection. The main bottleneck of this process is the development of an efficient, stable, and cost-effective catalyst that can oxidize HCHO at low temperature. Here, an advanced material consisting of manganese cobalt oxide nanosheet arrays uniformly covered on a carbon textile is successfully fabricated by a simple anodic electrodeposition method combined with post annealing treatment, and can be directly applied as a high-performance catalytic material for HCHO elimination. Benefiting from the increased surface oxygen species and improved redox properties, the as-prepared manganese cobalt oxide nanosheets showed substantially higher catalytic activity for HCHO oxidation. The catalyst completely converted HCHO to CO2 at temperatures as low as 100 ℃, and exhibited excellent catalytic stability. Such impressive results are rarely achieved by non-precious metal-based catalysts at such low temperatures.

关键词： CoxMn3-xO4 nanosheet formaldehyde catalytic oxidation mechanism

catalytic enantioselective domino alkenylation-alkynylation of alkenes: stereoselective synthesis of 5–7 membered azacycles and carbocycles

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Science China chemistry 2023年第6期66卷 1701-1706页

作者： Zhaoming Ma Lantian Sun Jianrong Steve Zhou State key laboratory of Chemical Oncogenomics Guangdong Provincial Key Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China department of chemistry Hong Kong Baptist UniversityHong KongChina

Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as *** new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and ***,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.

关键词： membered cycles synthesis

Iron(Fe,Ni,Co)-based transition metal compounds for lithium-sulfur batteries:Mechanism,progress and prospects

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Journal of Energy chemistry 2022年第10期31卷 513-532,I0013页

作者： Junhao Li Zhangshi Xiong Yujie Wu Hao Li Xinyan Liu Hongjie Peng Yuying Zheng Qiang Zhang Quanbing Liu Guangzhou key laboratory of Clean Transportation Energy chemistry Guangdong Provincial Key Laboratory of Plant Resources BiorefinerySchool of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina School of chemistry and Materials Engineering Huizhou UniversityHuizhou 516007GuangdongChina University of Electronic Science and Technology of China Chengdu 611731SichuanChina Beijing key laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of ***,the shuttle effects of lithium polysulfides(Li PSs)and sluggish redox kinetics lead to their materials capacity loss and cycle stability deterioration,which restrains LSBs *** compounds as additions can improve the electrochemical performance of the Li-S system,through the trap of Li PSs and accelerate the conversion of the soluble Li *** of them,the iron group elements(Fe,Ni,Co)-based compounds are the promising materials for the LSBs,due to their unique outer electronic structure and its tunable properties,low cost,abundant in the earth,environmental benignity,controllable and scalable prepared,and so *** this review,we have made a summary for iron-based compounds to capture Li PSs according to lithium bond,sulfur bond and magnetic *** type of iron-based compound including oxides,sulfides,nitrides,phosphides,carbides,and so on,and we have investigated the electrocatalytic mechanism of these ***,some improvement strategies are proposed,such as the engineering of the special micro/nanostructure,defect concentrations,band structures,and *** hope to shed an in-depth light on the rationally design and fabrication of robust,commercial and stable materials for high-performance LSBs.

关键词： Li-S batteries Iron-based compounds Shuttle effect Capture LiPSs Electrocatalysis Rational design

Electrosynthesis of Azobenzenes Directly from Nitrobenzenes

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Chinese Journal of chemistry 2021年第12期39卷 3334-3338页

作者： Yanfeng Ma Shanghui Wu Shuxin Jiang Fuhong Xiao Guo-Jun Deng key laboratory for Green Organic Synthesis and Application of Hunan Province Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of EducationCollege of ChemistryXiangtan UniversityXiangtanHunan 411105China guangdong provincial key laboratory of Luminescence from Molecular Aggregates(South China University of Technology) GuangzhouGuangdong 510640China

The electrochemical reduction strategy of nitrobenzenes is *** chemistry occurs under ambient *** protocol uses inert electrodes and the solvent,DMSO,plays a dual role as a reducing *** synthetic value has been demons... 详细信息

关键词： Azo compounds Nitro reduction Electrochemistry Nitrobenzenes Green chemistry

Imidodiphosphorimidates (IDPis): Catalyst Motifs with Unprecedented Reactivity and Selectivity

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Chinese Journal of chemistry 2023年第6期41卷 685-694页

作者： Jun Kee Cheng Shao-Hua Xiang Bin Tan Shenzhen Grubbs Institute and department of chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhenGuangdong 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhenGuangdong 518055China

The conceptually designed imidodiphosphorimidates(IDPis)have emerged as one of the most potent classes of chiral acid *** are characterized by enzyme-like,highly confined active site and high acidity,which underlie their wide-reaching applications as Bronsted acid catalysts and as precatalysts for silylium Lewis *** carbon-carbon and carbon-heteroatom bond formation reactions that were deemed intractable could now be attained with spectacular reactivity and *** that are small,unbiased and/or possess insufficient reactivity such as simple alkenes could now be *** high structural confinement is particularly invaluable to control stereo-and *** well-defined steric environment offers unique opportunity to control high-energy but structurally unbiased cation intermediates such as the norbonyl *** practical appeals such as good scalability as well as ease and modularity of preparation,the extremely low pre-catalyst loadings required to achieve high turnover and stereoselectivity have also come to define a new frontier in organocatalysis.

关键词： Bronsted acid catalyst Lewis acid catalyst Silylium ACDC Imidodiphosphorimidates Asymmetric organocatalysis

Growth mechanism of palladium clusters on rutile TiO_2 (110) surface

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Journal of Natural Gas chemistry 2012年第5期21卷 544-555页

作者： Weina Zhao Huaxiang Lin Yi Li Yongfan Zhang Xin Huang Wenkai Chen department of chemistry Fuzhou UniversityFuzhou 350116FujianChina Fujian provincial key laboratory of Photocatalysis-State key laboratory Breeding Base Fuzhou UniversityFuzhou 350002FujianChina

Oxide-supported transition metal systems have been the subject of enormous interest due to the improvement of catalytic properties relative to the separate *** in this paper,we embark on a systematic study for Pd n （n=1-5） clusters adsorbed on TiO2 （110） surface based on DFT-GGA calculations utilizing periodic supercell models.A single Pd adatom on the defect-free surface prefers to adsorb at a hollow site bridging a protruded oxygen and a five-fold titanium atom along the [110] direction,while Pd dimer is located on the channels with the Pd-Pd bond parallel to the *** to the transition states （TSs） search,the adsorbed Pd trimer tends to triangular growth mode,rather than linear mode,while the Pd4 and Pd5 clusters prefer three-dimensional （3D） ***,the oxygen vacancy has almost no influence on the promotion of Pd n cluster ***,of particular significance is that the Pd-TiO2 interaction is the main driving force at the beginning of Pd nucleation,whereas the Pd-Pd interaction gets down to control the growth process of Pd cluster as the cluster gets *** is hoped that our theoretical study would shed light on further designing high-performance TiO2 supported Pd-based catalysts.

关键词： density functional theory TiO2 (110) surface palladium cluster adsorption