Journal of Molecular Catalysis A: Chemical最新文献

{"title":"Preface to Special Issue: C–H functionalization in modern molecular catalysis","authors":"Dalmo Mandelli (Guest Editor), Alexander M. Kirillov (Managing Guest Editor)","doi":"10.1016/j.molcata.2016.11.024","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.024","url":null,"abstract":"","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.11.024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2220018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mild oxidative C−H functionalization of alkanes and alcohols using a magnetic core-shell Fe3O4@mSiO2@Cu4 nanocatalyst","authors":"Marina V. Kirillova ,&nbsp;Carla I.M. Santos ,&nbsp;Wenyu Wu ,&nbsp;Yu Tang ,&nbsp;Alexander M. Kirillov","doi":"10.1016/j.molcata.2016.06.028","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.06.028","url":null,"abstract":"<div><p>A new hybrid Fe₃O₄@mSiO₂@Cu₄ material was constructed by loading a bio-inspired tetracopper(II) coordination compound [Cu₄(μ₄-O){N(CH₂CH₂O)₃}₄(BOH)₄][BF₄]₂ (Cu₄) onto the Fe₃O₄@mSiO₂ core-shell nanoparticles (NPs) composed of a magnetite (Fe₃O₄) core and mesoporous silica (mSiO₂) shell with perpendicularly aligned channels. The obtained Fe₃O₄@mSiO₂@Cu₄ magnetic nanoparticles were characterized by transmission electron microscopy (TEM), FT-IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and field-dependent magnetization. This hybrid material acts as a magnetically recoverable C−H functionalization nanocatalyst, namely for the mild oxidation, by <em>t</em>-butyl hydroperoxide at 50–70<!--> <!-->°C in acetonitrile medium, of cycloalkanes (cyclopentane, cyclohexane, cycloheptane, and cyclooctane) to the corresponding alcohols and ketones (with up to ∼15% yields based on cycloalkane; TON 335). A related oxidation process using cyclohexanol as a more reactive substrate leads to the formation of cyclohexanone in up to ∼25% yield (TON 570). The Fe₃O₄@mSiO₂@Cu₄ nanocatalyst can be recycled five times without an appreciable loss of activity. The bond-, regio-, and stereoselectivity parameters were investigated in the oxidation of different alkane substrates (<em>n</em>-hexane, <em>n</em>-heptane, <em>n</em>-octane, methylcyclohexane, adamantane, <em>cis</em>- and <em>trans</em>-1,2-demethylcyclohexane), and the obtained results were compared with the homogeneous systems based on the Cu₄ catalyst. In particular, the high bond selectivity parameters detected in the oxidation of methylcyclohexane (1°:2°:3° of 1:8:142) and adamantane (2°:3° of 1:21) catalyzed by Fe₃O₄@mSiO₂@Cu₄ suggest that the reactions possibly occur in hydrophobic pockets of the nanocatalyst.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.06.028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2220019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of shell thickness of Pd core-porous SiO2 shell catalysts on direct synthesis of H2O2 from H2 and O2","authors":"Myung-gi Seo ,&nbsp;Ho Joong Kim ,&nbsp;Sang Soo Han ,&nbsp;Kwan-Young Lee","doi":"10.1016/j.molcata.2016.11.021","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.021","url":null,"abstract":"<div><p>In our previous study, we applied Pd@SiO₂ core-shell catalysts to hydrogen peroxide synthesis and obtained a higher yield of hydrogen peroxide than that obtained with the use of general supported-catalysts (Pd/SiO₂). As an extension of the previous study on Pd@SiO₂ catalysts, the effects of the core-shell thickness on the hydrogen peroxide synthesis reaction were examined in this study. A shell below a certain thickness in the core-shell structure of the Pd nanocatalyst results in a decrease in the catalytic activity. Overall, a volcano curve is observed for the hydrogen peroxide production rate as a function of the shell thickness. Through N₂-adsorption and desorption, TEM, CO-chemisorption, and XRD analyses, we identify the causes for the improved direct hydrogen peroxide synthesis yields and later optimize the shell thickness for the efficient utilization of Pd.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.11.021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2878510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights on the CH Bond activation by Transition Metal Complexes from Groups 8–10 Bearing (P-N) Chelates","authors":"Vanessa R. Landaeta ,&nbsp;Rafael E. Rodríguez-Lugo","doi":"10.1016/j.molcata.2016.08.011","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.08.011","url":null,"abstract":"<div><p>C<img>H bond catalytic activation/functionalization has been matter of great interest, since these transformations could establish new grounds from the synthetic perspective, and could serve to propose alternative and greener methods for the production of organic molecules. In this sense, the development of efficient catalytic systems for C<img>H bond activation becomes of great importance, and understanding the principles that govern such transformations, either stoichiometric or catalytic, is essential. To study such processes from the mechanistic or catalytic point of view requires of the design of ligands and catalysts able of performing C<img>H bond activation. (P,N)-chelates have arisen as alternative ligands to develop new catalytic systems, due to their combination of different donor atoms, and the ability to tune their steric and electronic characteristics and to create potential vacant sites at the metal center due to hemilability.</p><p>This mini review summarizes the advances from 2005 to 2015 in the field of C<img>H bond activation at transition metal centers from groups 8–10 bearing (P,N)-chelating ligands. Even when the examples of inter- or intramolecular C<img>H bond activation using transition metal complexes with the (P,N) ligands described herein do not engage yet in catalytic applications, their understanding becomes of great importance and sets the basis for future developments in this field.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.08.011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2879560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrophilic RhI catalysts for arene H/D exchange in acidic media: Evidence for an electrophilic aromatic substitution mechanism","authors":"Michael S. Webster-Gardiner ,&nbsp;Paige E. Piszel ,&nbsp;Ross Fu ,&nbsp;Bradley A. McKeown ,&nbsp;Robert J. Nielsen ,&nbsp;William A. Goddard III ,&nbsp;T. Brent Gunnoe","doi":"10.1016/j.molcata.2016.07.045","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.07.045","url":null,"abstract":"<div><p>A series of new rhodium (I) complexes supported by bidentate nitrogen-donor ligands with varying electronic and steric properties were synthesized <em>in situ</em> and evaluated for catalytic arene C–H/D activation. In trifluoroacetic acid (HTFA), these complexes are proposed to mediate H/D exchange of arene C–H/D bonds by an electrophilic aromatic substitution mechanism that involves Rh-mediated activation of HTFA (or DTFA). DFT calculations support the proposed pathway for the H/D exchange reactions.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.07.045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2882022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive study on electrochemical and photocatalytic activity of SnO2-ZnO/clinoptilolite nanoparticles","authors":"Hadis Derikvandi ,&nbsp;Alireza Nezamzadeh-Ejhieh","doi":"10.1016/j.molcata.2016.11.011","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.011","url":null,"abstract":"<div><p>Mechanically prepared clinoptilolite nanoparticles (NC) and coupling were used for increasing photocatalytic activity of ZnO and SnO₂. The raw and modified catalysts were characterized by XRD, FTIR, SEM-EDX, X-ray mapping, DRS, electrochemical impedance spectroscopy (EIS) and BET techniques. The calcined catalysts at 600<!--> <!-->°C for 2<!--> <!-->h showed the best photocatalytic activity in metronidazole (MZ) aqueous solution. Based on the EIS results, this catalyst has the best charge transfer efficiency with respect to other catalysts calcined at lower and higher temperatures. This caused to lower e/h recombination and hence higher photodegradation activity. The mole ratio of ZnO/SnO₂ affects the degradation activity of the catalysts so the best activities were obtained for the ZnO_2.4-SnO_2(2.0)/NC (ZS-NC) and ZnO_3.3-SnO_2(2.0)/NC (Z₂S-NC) catalysts at pH 3. Cyclic voltammograms of the modified carbon paste electrodes with ZS-NC and Z₂S-NC showed increased peak current in phosphate buffer which confirm formation of the ZnO and SnO₂ semiconductors inside NC. Also, peak current dependence of the modified electrode to MZ concentration confirmed that the degradation extent of MZ can be estimated by electrochemical methods.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.11.011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2660122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selectivity control in one-pot myrtenol amination over Au/ZrO2 by molecular hydrogen addition","authors":"Yu. S. Demidova ,&nbsp;E.V. Suslov ,&nbsp;I.L. Simakova ,&nbsp;E.S. Mozhajcev ,&nbsp;D.V. Korchagina ,&nbsp;K.P. Volcho ,&nbsp;N.F. Salakhutdinov ,&nbsp;A. Simakov ,&nbsp;D. Yu. Murzin","doi":"10.1016/j.molcata.2016.10.034","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.10.034","url":null,"abstract":"<div><p>The one-pot myrtenol amination was studied over Au (3<!--> <!-->wt.%)/ZrO₂ catalyst under mixed N₂/H₂ atmosphere (9<!--> <!-->bar). The effect of hydrogen addition was explored with the aim to increase selectivity to the target amines. Hydrogen addition timing depending on myrtenol conversion and hydrogenation temperature affected selectivity to the reaction products. Hydrogen addition (1<!--> <!-->bar) after almost complete myrtenol conversion at 100<!--> <!-->°C increased the yield to amine up to 68% preserving C<img>C bond in the initial myrtenol structure. Hydrogen addition at 180<!--> <!-->°C irrespective of the myrtenol conversion level provoked reduction of both C<img>C and C<img>N bonds with formation of two diastereomers (yield up to 93%), with <em>trans</em>-isomer formation being preferred when hydrogen was added at almost complete myrtenol conversion. It was shown, that in the presence of a gold catalyst controlled hydrogenation of competitive C<img>C and C<img>N groups can be performed during one-pot alcohol amination by regulation of the reaction conditions.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.10.034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1737689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iridium-catalysed desilylative acylation of 1-alkenylsilanes","authors":"Maciej Zaranek ,&nbsp;Maciej Skrodzki ,&nbsp;Justyna Szudkowska-Frątczak ,&nbsp;Maciej Dodot ,&nbsp;Ireneusz Kownacki ,&nbsp;Bartosz Orwat ,&nbsp;Piotr Pawluć","doi":"10.1016/j.molcata.2016.10.035","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.10.035","url":null,"abstract":"<div><p>We report the iridium-catalysed desilylative acylation of styryl and dienyl silanes by acid anhydrides to afford (E)-α,β-unsaturated ketones. The [{Ir(μ-Cl)(cod)}₂] catalyst is the first non-rhodium complex successfully applied for this type of transformation. Stoichiometric reaction of [{Ir(μ-Cl)(cod)}₂] with (E)-trimethyl(4-chlorostyryl)silane was carried out to gain insight into the reaction mechanism.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.10.035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2171635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Roles of phosphorous-modified Al2O3 for an enhanced stability of Co/Al2O3 for CO hydrogenation to hydrocarbons","authors":"Seon-Ju Park ,&nbsp;Jae Min Cho ,&nbsp;Chang-Il Ahn ,&nbsp;Yun-Jo Lee ,&nbsp;Ki-Won Jun ,&nbsp;Bong Gyoo Cho ,&nbsp;Jong Wook Bae","doi":"10.1016/j.molcata.2016.11.013","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.013","url":null,"abstract":"<div><p>A phosphorous-modified γ-Al₂O₃ (P-Al₂O₃), where γ-Al₂O₃ support was prepared by sol-gel method with a high surface area of ∼350<!--> <!-->m²/g, has been applied for a preparation of cobalt-supported Co/P-Al₂O₃ catalysts. The Co/P-Al₂O₃ catalysts having a different P/Al molar ratio were investigated to elucidate the roles of phosphorous species on the γ-Al₂O₃ to the catalytic stability and product distribution for CO hydrogenation to hydrocarbons. The γ-Al₂O₃ surface was partially transformed to aluminum phosphates after phosphorous modification, and the newly formed aluminum phosphate phases simultaneously altered the surface hydrophilicity and cobalt dispersion as well. The partial formation of tridymite aluminum phosphate (AlPO₄) phases on the P-Al₂O₃ support eventually enhanced the dispersion of the supported cobalt crystallites and suppressed the aggregation of cobalt nanoparticles by forming the strongly interacted cobalt crystallites on the P-Al₂O₃ surfaces. The phosphorous-modified Fischer-Tropsch synthesis (FTS) catalyst also significantly suppressed heavy hydrocarbon depositions due to an increased surface hydrophilicity originated from partially formed SiO₂-like tridymite AlPO₄ surfaces. A higher stability of the Co/P-Al₂O₃ catalyst at an optimal phosphorous content in the range of 0.5–1.0 mol% was attributed to homogeneously distributed cobalt crystallites and less deposition of heavy hydrocarbons by forming macro-emulsion droplets with the help of trace amount of alcohols formed during FTS reaction. This was confirmed by in-situ analysis of adsorbed intermediates with surface hydrophilicity and some surface characterizations such as crystallite size, reducibility, and electronic state of the supported cobalt nanoparticles.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.11.013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2878508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic oxidation of alkene by cobalt corroles","authors":"Li-Ting Huang,&nbsp;Atif Ali,&nbsp;Hua-Hua Wang,&nbsp;Fan Cheng,&nbsp;Hai-Yang Liu","doi":"10.1016/j.molcata.2016.11.019","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.019","url":null,"abstract":"<div><p>Four cobalt (III) corroles bearing different number of pentafluorophenyl and phenyl groups were synthesized and characterized by elemental analysis, HR-MS, UV–vis, NMR, XPS as well as cyclic voltammetry. The first investigation of cobalt corrole catalyzed oxidation of alkene was conducted by using styrene as substrate. The best yield was obtained in acetonitrile solvent in the air with TBHP oxidant (96% yield based on oxidant, up to 96 TON). Benzaldehyde was detected as the main product by using PhI(OAc)₂, TBHP, KHSO₅, PhIO as oxidants. In contrast, styrene oxide was found to be the major product when using <em>m</em>-CPBA oxidant. Nearly no products could be found by using H₂O₂ oxidant. Possible catalytic oxidation pathway was also discussed based on the obsewrvations of UV–vis changes of the ctatalytic system in the absence of substrate and in-situ HR-MS.</p></div>","PeriodicalId":370,"journal":{"name":"Journal of Molecular Catalysis A: Chemical","volume":null,"pages":null},"PeriodicalIF":5.062,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcata.2016.11.019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2878509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}