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91.
Tao Wang Juan Du Yong Sun Xing Tang Zuo-Jun Wei Xianhai Zeng Shi-Jie Liu Lu Lin 《中国化学快报》2021,32(3):1186-1190
Catalytic transfer hydroge nation(CTH) of furfural(FF) to furfu ryl alcohol(FFA) has received great intere st in recent years.He rein,Cu-Cs bimetallic supported catalyst,CuCs(2)-MCM,was developed for the CTH of FF to FFA using formic as hydrogen donor.CuCs(2)-MCM achieved a 99.6% FFA yield at an optimized reaction conditions of 170℃,1 h.Cu species in CuCs(2)-MCM had dual functions in catalytically decomposing formic acid to generate hydrogen and hydrogenating FF to FFA.The doping of Cs made the size of Cu particles smaller and improved the dispersion of the Cu active sites.Impo rtantly,the Cs species played a favorable role in enhancing the hydrogenation activity as a promoter by adjusting the surface acidity of Cu species to an appropriate level.Correlation analysis showed that surface acidity is the primary factor to affect the catalytic activity of CuCs(2)-MCM. 相似文献
92.
Yunqie Deng Linjing Yang Yakun Wang Lili Zeng Jiayuan Yu Bo Chen Xiaoli Zhang Weijia Zhou 《中国化学快报》2021,32(1):511-515
Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co2P HMs).The obtained Ru NCs/Co2P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm2 in 0.5 mol/L H2SO4 and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co2P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm2 in 0.5 mol/L H2SO4,which is below that of the commercial RuO2 electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm2 at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V). 相似文献
93.
Nb2O5/C nanosheets are successfully prepared through a mixing process and followed by heating treatment.Such Nb2O5/C based electrode exhibits high rate performance and remarkable cycling ability, showing a high and stable specific capacity of ~380 mAh g-1 at the current density of 50 mA g-1(much higher than the theoretical capacity of Nb2O5).Further more,at a current density of 500 mA g-1,the nanocomposites electrode still exhibits a specific capacity of above 150 mAh g-1 after 100 cycles.These results suggest the Nb2O5/C nanocomposite is a high performance anode material for lithium-ion batteries. 相似文献
94.
Yong Guo Mei-Wei Huang Xiao-Lin Fu Chao Liu Qing-Yun Chen Zhi-Gang Zhao Ben-Zhong Zeng Jiong Chen 《中国化学快报》2017,28(4):719-728
This review summarizes the recent advances in the catalytic syntheses of CF_3S-containing organic molecules using various nucleophilic or electrophilic trifluoromethylthiolating reagents.C-halogen and C—H bonds in various molecules have been transformed to C—SCF_3 bonds by transition-metal-catalyzed reactions,such as cross-coupling of aryl halides.Enantioselective reactions controlled by chiral metal complexes or chiral organocatalysts have afforded many trifluoromethylthiolated chiral architectures,such as β-ketoesters and oxindoles.Very recently,visible-light-induced photoredox trifluoromethylthiolations have been developed,providing versatile CF_3S-containing structures efficiently. 相似文献
95.
建立水杨酸钠紫外分光光度法测定烟草中总氮含量的方法。烟草样品经硫酸铜–硫酸钾–浓硫酸消化,用水杨酸钠–二氯异氰尿酸钠显色后用紫外分光光度计检测,并对波长、显色剂用量和反应时间等实验条件进行了优化。总氮的质量浓度在5~60 mg/L范围内与其吸光度呈良好的线性关系,线性相关系数为0.998 8,方法的检出限为0.14 mg/L。样品分析结果的相对标准偏差为3.22%(n=6),样品加标回收率为99.30%~101.62%。该方法具有较高的精密度和准确度,尤其适用于样品量少时对烟草中总氮的测定。 相似文献
96.
97.
Two Co(II) coordination polymers (CPs), namely [Co(L)(tp)] n (1) and [Co(L)0.5(tbip)·H2O] n (2), (L = 1,6-bis(2-methylbenzimidazolyl) hexane, H2tp = terephthalic acid, H2tbip = 5-tert-butyl isophthalic acid), were hydrothermally synthesized and characterized by physicochemical and spectroscopic methods. CP 1 possesses a 2D (4,4) corrugated layer structure, which further extends into a 3D supramolecular framework by π–π stacking interactions, while CP 2 has a 1D ladder-like chain structure and combines into a 2D layer via O–H?O hydrogen-bonding interactions. The thermal stabilities, luminescence and electrochemical properties of both CPs, as well as photocatalytic activities for the decomposition of methylene blue, were presented. The photocatalytic mechanism was investigated by introducing t-butyl alcohol, EDTA-2Na and benzoquinone as ?OH, (hole)+ and ·O2? scavengers, respectively. 相似文献
98.
Maosheng Wan Li Hua Yiwen Zeng Peifu Jiao Dengyu Xie Zhangfa Tong Guirong Wu Yongxiao Zhou Quan Tang Fuwang Mo 《Cellulose (London, England)》2017,24(8):3209-3218
Four novel stilbene-twelve alkyl quaternary ammonium salts 5a–d were synthesized. All synthesized compounds were characterized by FT-IR, 1H-NMR and elemental analysis. Compounds 5a–d showed efficient whitening effect on cotton fiber and high fastness. Furthermore, compound 5c showed better stability to light than C186 in aqueous solution. The preliminary biological experiment demonstrated compounds 5a–d possessed significant antibacterial activities. Among them, compound 5d turned out to be the most active compound against Candida albicans with MIC50 4 μg/mL as well as E. coli with MIC50 16 μg/mL. 相似文献
99.
Hierarchy of equations to calculate the linear spectra of molecular aggregates: Time‐dependent and frequency domain formulation 下载免费PDF全文
Pan‐Pan Zhang Zeng‐Zhao Li Alexander Eisfeld 《International journal of quantum chemistry》2017,117(14)
In a recent publication (Ritschel et al., J. Chem. Phys. 2015, 142, 034115) we have derived a hierarchy of coupled differential equations in time domain to calculate the linear optical properties of molecular aggregates. Here, we provide details about issues concerning the numerical implementation. In addition we present the corresponding hierarchy in frequency domain. 相似文献
100.
Crystal Structures of Bacterial (6‐4) Photolyase Mutants with Impaired DNA Repair Activity 下载免费PDF全文
Kalinga Bowatte Dennis Kwiatkowski Esther Mittmann Heba Qasem Norbert Krauß Xiaoli Zeng Zhong Ren Patrick Scheerer Xiaojing Yang Tilman Lamparter 《Photochemistry and photobiology》2017,93(1):304-314
PhrB from Agrobacterium fabrum is the first prokaryotic photolyase which repairs (6‐4) UV DNA photoproducts. The protein harbors three cofactors: the enzymatically active FAD chromophore, a second chromophore, 6,7‐dimethyl‐8‐ribityllumazine (DMRL) and a cubane‐type Fe‐S cluster. Tyr424 of PhrB is part of the DNA‐binding site and could provide an electron link to the Fe‐S cluster. The PhrBY424F mutant showed reduced binding of lesion DNA and loss of DNA repair. The mutant PhrBI51W is characterized by the loss of the DMRL chromophore, reduced photoreduction and reduced DNA repair capacity. We have determined the crystal structures of both mutants and found that both mutations only affect local protein environments, whereas the overall fold remained unchanged. The crystal structure of PhrBY424F revealed a water network extending to His366, which are part of the lesion‐binding site. The crystal structure of PhrBI51W shows how the bulky Trp leads to structural rearrangements in the DMRL chromophore pocket. Spectral characterizations of PhrBI51W suggest that DMRL serves as an antenna chromophore for photoreduction and DNA repair in the wild type. The energy transfer from DMRL to FAD could represent a phylogenetically ancient process. 相似文献