A dinuclear complex [(Me3P)3Ru(μ-OH)3Ru(PMe3)3]+[OPh]− (1) (0.5 mol%) catalyzes E-selective dimerization of phenylacetylene, which involves the C–H bond cleavage of phenylacetylene and resulting stereospecific C–C bond forming reaction, at 100 °C for 2 h to give (E)-1,4-diphenylbut-3-en-1-yne in quantitative yield (E/Z = 91/9). Similar reactions using 4-nitro-, 4-cyano-, 4-trifluoromethyl-, 4-acetyl-, and 4-methylphenylacetylene give the corresponding enynes. The kinetic study for dimerization of phenylacetylene shows the second-order and first-order reactions with regard to the phenylacetylene and 1 concentrations, respectively, suggesting this reaction to be catalyzed by a dinuclear ruthenium complex. Addition of PMe3 to the catalytic system strongly discourages the dimerization. These features are consistent with the scenario, where dissociation of a PMe3 ligand from 1 gives a coordinatively unsaturated diruthenium species and one of the ruthenium centers performs as a reaction site for the enyne formation and the other ruthenium center behaves as a spectator in the catalysis.
{"title":"E-Selective dimerization of phenylacetylene catalyzed by cationic tris(μ-hydroxo)diruthenium(II) complex and the mechanistic insight: The role of two ruthenium centers in catalysis","authors":"Sayori Kiyota, Hirofumi Soeta, Nobuyuki Komine, Sanshiro Komiya , Masafumi Hirano","doi":"10.1016/j.molcata.2016.08.027","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.08.027","url":null,"abstract":"<div><p>A dinuclear complex [(Me<sub>3</sub>P)<sub>3</sub>Ru(μ-OH)<sub>3</sub>Ru(PMe<sub>3</sub>)<sub>3</sub>]<sup>+</sup>[OPh]<sup>−</sup> (<strong>1</strong>) (0.5 mol%) catalyzes <em>E</em>-selective dimerization of phenylacetylene, which involves the C–H bond cleavage of phenylacetylene and resulting stereospecific C–C bond forming reaction, at 100<!--> <!-->°C for 2<!--> <!-->h to give (<em>E</em>)-1,4-diphenylbut-3-en-1-yne in quantitative yield (<em>E</em>/<em>Z</em> <!-->=<!--> <!-->91/9). Similar reactions using 4-nitro-, 4-cyano-, 4-trifluoromethyl-, 4-acetyl-, and 4-methylphenylacetylene give the corresponding enynes. The kinetic study for dimerization of phenylacetylene shows the second-order and first-order reactions with regard to the phenylacetylene and <strong>1</strong> concentrations, respectively, suggesting this reaction to be catalyzed by a dinuclear ruthenium complex. Addition of PMe<sub>3</sub> to the catalytic system strongly discourages the dimerization. These features are consistent with the scenario, where dissociation of a PMe<sub>3</sub> ligand from <strong>1</strong> gives a coordinatively unsaturated diruthenium species and one of the ruthenium centers performs as a reaction site for the enyne formation and the other ruthenium center behaves as a spectator in the catalysis.</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.2016.08.027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2660117","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.11.008
Kyung Soo Park , Jeong Hwa Kim , So Hyun Park , Dong Ju Moon , Hyun-Seog Roh , Chan-Hwa Chung , Soong Ho Um , Joon-Hwan Choi , Jong Wook Bae
Direct activation of CH4 to oxygenates and unsaturated light hydrocarbons was investigated using Fe-modified ZSM-5 and Ferrierite (FER) for a partial oxidation of CH4 with N2O oxidant. The amount of active α-oxygen sites and number of Bronsted acid sites on the Fe-modified zeolites were well correlated with CH4 conversion rate and product distributions. The amount of α-oxygen sites was largely changed according to preparation method such as wet impregnation or ion-exchange of iron precursor and types of zeolites. A large number of Bronsted acid sites and α-oxygen sites on the Fe-modified FER revealed a higher oxygenate formation such as methanol and dimethyl ether (DME) with COx, and a larger number of strong acid sites on Fe-modified ZSM-5 was also responsible for a higher selectivity to light hydrocarbons by a successive dehydration of oxygenates formed. The different catalytic performances were verified through proper measurements of the amount and type of acidic sites as well as the α-oxygen sites measured by N2O pulse chemisorption. The Fe-modified FER prepared by impregnation method possessed a larger amount of α-oxygen sites due to abundant Bronsted acid sites, which was responsible for a higher rate of CH4 conversion to oxygenates with the help of N2O decomposition on the α-oxygen sites originated from iron oxide nanoparticles.
{"title":"Direct activation of CH4 to oxygenates and unsaturated hydrocarbons using N2O on Fe-modified zeolites","authors":"Kyung Soo Park , Jeong Hwa Kim , So Hyun Park , Dong Ju Moon , Hyun-Seog Roh , Chan-Hwa Chung , Soong Ho Um , Joon-Hwan Choi , Jong Wook Bae","doi":"10.1016/j.molcata.2016.11.008","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.008","url":null,"abstract":"<div><p>Direct activation of CH<sub>4</sub> to oxygenates and unsaturated light hydrocarbons was investigated using Fe-modified ZSM-5 and Ferrierite (FER) for a partial oxidation of CH<sub>4</sub> with N<sub>2</sub>O oxidant. The amount of active α-oxygen sites and number of Bronsted acid sites on the Fe-modified zeolites were well correlated with CH<sub>4</sub> conversion rate and product distributions. The amount of α-oxygen sites was largely changed according to preparation method such as wet impregnation or ion-exchange of iron precursor and types of zeolites. A large number of Bronsted acid sites and α-oxygen sites on the Fe-modified FER revealed a higher oxygenate formation such as methanol and dimethyl ether (DME) with COx, and a larger number of strong acid sites on Fe-modified ZSM-5 was also responsible for a higher selectivity to light hydrocarbons by a successive dehydration of oxygenates formed. The different catalytic performances were verified through proper measurements of the amount and type of acidic sites as well as the α-oxygen sites measured by N<sub>2</sub>O pulse chemisorption. The Fe-modified FER prepared by impregnation method possessed a larger amount of α-oxygen sites due to abundant Bronsted acid sites, which was responsible for a higher rate of CH<sub>4</sub> conversion to oxygenates with the help of N<sub>2</sub>O decomposition on the α-oxygen sites originated from iron oxide 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.2016.11.008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2878506","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.09.005
Oksana V. Nesterova , Dmytro S. Nesterov , Agnieszka Krogul-Sobczak , M. Fátima C. Guedes da Silva , Armando J.L. Pombeiro
The complexes of copper [Cu(κONN’-HL)(NO3)(DMF)](NO3)∙H2O (1) and [Cu(κONN’-HL)Cl2]∙½DMSO (2), and of manganese [Mn(κON-HL)2Cl2]Cl (3) and [Mn(κON-HL)2(NO3)2](NO3)∙H2O (4) were synthesized by reactions of the respective chloride or nitrate salt with a non-aqueous solutions of the Schiff base aminoalcohol HL (product of condensation of salicylic aldehyde and aminoethylpiperazine) and characterized by X-ray diffraction analysis. The catalytic investigations disclosed a prominent activity of the copper compounds 1 and 2 towards oxidation of cyclohexane with hydrogen peroxide in the presence of various promoters (nitric, hydrochloric, oxalic acids and pyridine), under mild conditions. The unusual promoting effect of pyridine on the catalytic activity of the copper catalysts allowed to achieve yields up to 21% based on cyclohexane. Chromatographic studies revealed that cyclohexyl hydroperoxide is a main reaction product and chlorocyclohexane (in the presence of HCl as promoter) was also detected, suggesting a free radical reaction pathway with hydroxyl radicals as attacking species. Complexes 1 and 2 act also as catalysts in the oxidation of 1-phenylethanol with tert-butylhydroperoxide, showing acetophenone yields up to 62% and TON (turnover numbers) up to 620 in the presence of the K2CO3 promoter.
{"title":"Synthesis, crystal structures and catalytic activity of Cu(II) and Mn(III) Schiff base complexes: Influence of additives on the oxidation catalysis of cyclohexane and 1-phenylehanol","authors":"Oksana V. Nesterova , Dmytro S. Nesterov , Agnieszka Krogul-Sobczak , M. Fátima C. Guedes da Silva , Armando J.L. Pombeiro","doi":"10.1016/j.molcata.2016.09.005","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.09.005","url":null,"abstract":"<div><p>The complexes of copper [Cu(κ<em>ONN</em>’-HL)(NO<sub>3</sub>)(DMF)](NO<sub>3</sub>)∙H<sub>2</sub>O (<strong>1</strong>) and [Cu(κ<em>ONN</em>’-HL)Cl<sub>2</sub>]∙½DMSO (<strong>2</strong>), and of manganese [Mn(κ<em>ON</em>-HL)<sub>2</sub>Cl<sub>2</sub>]Cl (<strong>3</strong>) and [Mn(κ<em>ON</em>-HL)<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub>](NO<sub>3</sub>)∙H<sub>2</sub>O (<strong>4</strong>) were synthesized by reactions of the respective chloride or nitrate salt with a non-aqueous solutions of the Schiff base aminoalcohol HL (product of condensation of salicylic aldehyde and aminoethylpiperazine) and characterized by X-ray diffraction analysis. The catalytic investigations disclosed a prominent activity of the copper compounds <strong>1</strong> and <strong>2</strong> towards oxidation of cyclohexane with hydrogen peroxide in the presence of various promoters (nitric, hydrochloric, oxalic acids and pyridine), under mild conditions. The unusual promoting effect of pyridine on the catalytic activity of the copper catalysts allowed to achieve yields up to 21% based on cyclohexane. Chromatographic studies revealed that cyclohexyl hydroperoxide is a main reaction product and chlorocyclohexane (in the presence of HCl as promoter) was also detected, suggesting a free radical reaction pathway with hydroxyl radicals as attacking species. Complexes <strong>1</strong> and <strong>2</strong> act also as catalysts in the oxidation of 1-phenylethanol with <em>tert</em>-butylhydroperoxide, showing acetophenone yields up to 62% and TON (turnover numbers) up to 620 in the presence of the K<sub>2</sub>CO<sub>3</sub> promoter.</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.2016.09.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2171632","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}
Lewis base, N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated o-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated o-alkynoylphenols, which achieved the diversity oriented synthesis of γ-benzopyranones, 4aa–4eg, with 93–99% yields.
{"title":"Pd catalyzed couplings of “superactive esters” and terminal alkynes: Application to flavones and γ-benzopyranones construction","authors":"Dandan Yang, Zhenhua Wang, Xiu Wang, Huaming Sun, Zunyuan Xie, Juan Fan, Guofang Zhang, Weiqiang Zhang, Ziwei Gao","doi":"10.1016/j.molcata.2016.10.030","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.10.030","url":null,"abstract":"<div><p>Lewis base, <em>N</em>-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated <em>o</em>-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated <em>o</em>-alkynoylphenols, which achieved the diversity oriented synthesis of <em>γ</em>-benzopyranones, 4aa–4eg, with 93–99% yields.</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.2016.10.030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2878503","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.10.033
G.J. Lichtenegger , M. Maier , M. Hackl , J.G. Khinast , W. Gössler , T. Griesser , V.S.Phani Kumar , H. Gruber-Woelfler , P.A. Deshpande
Palladium substituted CeO2, SnO2 and their mixed oxides have been synthesized in quantitative yields out of non-toxic and inexpensive precursors using a simple and rapid single step solution combustion method. The resulting oxides, especially the mixed oxides Ce0.79Sn0.20Pd0.01O2-δ, Sn0.79Ce0.20Pd0.01O2-δ and Sn0.99Pd0.01O2-δ proved to be highly active (TOF > 12,000 h−1) for Suzuki-Miyaura cross-couplings of phenylboronic acid with various bromoarenes. The reactions were carried out in ambient air at moderate temperatures using environmentally friendly aqueous ethanol solutions as reaction solvents. Minimal amounts of palladium in the product solution ( < 0.14 mg/L), the reaction kinetics as well as catalyst poisoning tests support the thesis that the reaction proceeds via dissolved palladium species in a homogeneous reaction mechanism. Nevertheless, the synthesized catalysts could be reused for at least five times with only minor changes in activity and no changes in the crystal structure, indicating the high potential of the investigated catalysts as quasi-heterogeneous CC coupling catalysts.
{"title":"Suzuki-Miyaura coupling reactions using novel metal oxide supported ionic palladium catalysts","authors":"G.J. Lichtenegger , M. Maier , M. Hackl , J.G. Khinast , W. Gössler , T. Griesser , V.S.Phani Kumar , H. Gruber-Woelfler , P.A. Deshpande","doi":"10.1016/j.molcata.2016.10.033","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.10.033","url":null,"abstract":"<div><p>Palladium substituted CeO<sub>2</sub>, SnO<sub>2</sub> and their mixed oxides have been synthesized in quantitative yields out of non-toxic and inexpensive precursors using a simple and rapid single step solution combustion method. The resulting oxides, especially the mixed oxides Ce<sub>0.79</sub>Sn<sub>0.20</sub>Pd<sub>0.01</sub>O<sub>2-δ</sub>, Sn<sub>0.79</sub>Ce<sub>0.20</sub>Pd<sub>0.01</sub>O<sub>2-δ</sub> and Sn<sub>0.99</sub>Pd<sub>0.01</sub>O<sub>2-δ</sub> proved to be highly active (TOF<!--> <!-->><!--> <!-->12,000<!--> <!-->h<sup>−1</sup>) for Suzuki-Miyaura cross-couplings of phenylboronic acid with various bromoarenes. The reactions were carried out in ambient air at moderate temperatures using environmentally friendly aqueous ethanol solutions as reaction solvents. Minimal amounts of palladium in the product solution (<!--> <!--><<!--> <!-->0.14<!--> <!-->mg/L), the reaction kinetics as well as catalyst poisoning tests support the thesis that the reaction proceeds via dissolved palladium species in a homogeneous reaction mechanism. Nevertheless, the synthesized catalysts could be reused for at least five times with only minor changes in activity and no changes in the crystal structure, indicating the high potential of the investigated catalysts as quasi-heterogeneous C<img>C coupling catalysts.</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.2016.10.033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1737688","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.11.009
Huong T.T. Nguyen, Duc N.A. Doan, Thanh Truong
Herein, nickel-based metal-organic framework, Ni-MOF-74, was synthesized by a solvothermal method and its properties was characterized by a host of techniques. Ni-MOF-74 exhibited exceptional catalytic activity toward the direct arylation of azoles via CH activation while other Ni-MOFs, nickel-based heterogeneous systems, and homogeneous counter parts displayed lower activity. Optimal conditions involved the use of Li2CO3 or KCl salts in diglyme solvent in 18 h and no additional ligand is required. This is the first and unprecedented report using KCl salt as promoter for arylation of heterocycles. By avoiding the use of strong bases and oxidants, optimized conditions are compatible with wide range of functional groups and heterocycles. Furthermore, by taking advantage of large aperture size of Ni-MOF-74, we are able to utilize optimized conditions to successfully synthesize several bioactive arylated azole derivatives. Previous studies using heterogeneous catalysts to approach these bioactive compounds are not performed in the literature. Leaching tests indicated that homogeneous catalysis via leached active nickel species is unlikely. Thus, the catalyst was facilely separated from the reaction mixture and reused several times without significant degradation of the catalytic reactivity.
{"title":"Unprecedented salt-promoted direct arylation of acidic sp2 CH bonds under heterogeneous Ni-MOF-74 catalysis: Synthesis of bioactive azole derivatives","authors":"Huong T.T. Nguyen, Duc N.A. Doan, Thanh Truong","doi":"10.1016/j.molcata.2016.11.009","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.11.009","url":null,"abstract":"<div><p>Herein, nickel-based metal-organic framework, Ni-MOF-74, was synthesized by a solvothermal method and its properties was characterized by a host of techniques. Ni-MOF-74 exhibited exceptional catalytic activity toward the direct arylation of azoles via C<img>H activation while other Ni-MOFs, nickel-based heterogeneous systems, and homogeneous counter parts displayed lower activity. Optimal conditions involved the use of Li<sub>2</sub>CO<sub>3</sub> or KCl salts in diglyme solvent in 18<!--> <!-->h and no additional ligand is required. This is the first and unprecedented report using KCl salt as promoter for arylation of heterocycles. By avoiding the use of strong bases and oxidants, optimized conditions are compatible with wide range of functional groups and heterocycles. Furthermore, by taking advantage of large aperture size of Ni-MOF-74, we are able to utilize optimized conditions to successfully synthesize several bioactive arylated azole derivatives. Previous studies using heterogeneous catalysts to approach these bioactive compounds are not performed in the literature. Leaching tests indicated that homogeneous catalysis via leached active nickel species is unlikely. Thus, the catalyst was facilely separated from the reaction mixture and reused several times without significant degradation of the catalytic reactivity.</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.2016.11.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2595835","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.07.015
Ana Paula C. Ribeiro , Emmanuele Fontolan , Elisabete C.B.A. Alegria , Maximilian N. Kopylovich , Roberta Bertani , Armando J.L. Pombeiro
3d metal (Cu, Fe, Co, V) containing composite catalysts for the solvent-free microwave-assisted transformation of 1-phenylethanol to acetophenone with tert-butyl hydroperoxide (TBHP) as oxidant were prepared by ball milling. The influence of multiwalled carbon nanotubes (CNTs) and graphene oxide (GO) additives on the catalytic activity of the catalysts was studied. CNTs or GO were mixed by ball milling with the metal salts (CoCl2), oxides (CuO, Fe2O3, V2O5) or binary systems (Fe2O3-CoCl2, CoCl2-V2O5, CuO-Fe2O3). For CoCl2-based catalytic systems, addition of small amounts (0.1–5%) of CNTs or GO leads to significant improvement in catalytic activity, e.g. 1% of the CNTs additive allows to rise yields from 28 to 77%, under the same catalytic conditions. The CoCl2-5%CNTs composite is the most active among the studied ones with 85% yield and TON of 43 after 1 h.
{"title":"The influence of multiwalled carbon nanotubes and graphene oxide additives on the catalytic activity of 3d metal catalysts towards 1-phenylethanol oxidation","authors":"Ana Paula C. Ribeiro , Emmanuele Fontolan , Elisabete C.B.A. Alegria , Maximilian N. Kopylovich , Roberta Bertani , Armando J.L. Pombeiro","doi":"10.1016/j.molcata.2016.07.015","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.07.015","url":null,"abstract":"<div><p>3<em>d</em> metal (Cu, Fe, Co, V) containing composite catalysts for the solvent-free microwave-assisted transformation of 1-phenylethanol to acetophenone with <em>tert</em>-butyl hydroperoxide (TBHP) as oxidant were prepared by ball milling. The influence of multiwalled carbon nanotubes (CNTs) and graphene oxide (GO) additives on the catalytic activity of the catalysts was studied. CNTs or GO were mixed by ball milling with the metal salts (CoCl<sub>2</sub>), oxides (CuO, Fe<sub>2</sub>O<sub>3</sub>, V<sub>2</sub>O<sub>5</sub>) or binary systems (Fe<sub>2</sub>O<sub>3</sub>-CoCl<sub>2,</sub> CoCl<sub>2</sub>-V<sub>2</sub>O<sub>5</sub>, CuO-Fe<sub>2</sub>O<sub>3</sub>). For CoCl<sub>2</sub>-based catalytic systems, addition of small amounts (0.1–5%) of CNTs or GO leads to significant improvement in catalytic activity, e.g. 1% of the CNTs additive allows to rise yields from 28 to 77%, under the same catalytic conditions. The CoCl<sub>2</sub>-5%CNTs composite is the most active among the studied ones with 85% yield and TON of 43 after 1<!--> <!-->h.</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.2016.07.015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2171633","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.09.020
Claudia Rodrigues , Fabio G. Delolo , Jakob Norinder , Armin Börner , André L. Bogado , Alzir A. Batista
In this work, the catalytic activity of ruthenium II and III complexes containing chloride, pyridine, phosphine and CO ligands was investigated in the hydroformylation – hydrogenation and hydroformylation – acetalization reactions. The complexes mer-[RuCl3(dppb)(H2O)](1), mer-[RuCl3(dppb)(4-Vpy)](2), mer-[RuCl3(dppb)(4-tBupy)](3), mer-[RuCl3(dppb)(py)](4), mer-[RuCl3(dppb)(4-Phpy)](5), mer-[RuCl3(dppb)(4-Mepy)](6), cis-[RuCl2(CO)2(dppb)](7), trans-[RuCl2(CO)2(dppb)](8), RuCl3·xH2O(9), [RuCl2(PPh3)3](10) and [RuCl2(PPh3)2(dppb)](11) were used as supplied or synthesized as previously described in the literature {Where PPh3 = triphenylphosphine, dppb = 1,4-bis(diphenylphosphino)butane, py = pyridine, 4-Mepy = 4-methylpyridine, 4-Vpy = 4-vinylpyridine, 4-tBupy = 4-tert-butylpyridine and 4-Phpy = 4-phenylpyridine}. These complexes were used as a pre-catalysts in a hydroformylation catalytic system to produce CC, CO and CO bonds, where 1-decene resulted in a formation of respective alcohol and dimethyl acetals. Several reactions were performed in order to find the best reaction conditions presenting the best conversion (64% after 24 h). The 1-decene was also used as a substrate in two type tandem reactions labeled as: hydroformylation – hydrogenation (HH) and hydroformylation – acetalization (HA) reactions. The relationship between Ru – catalyst/substrate was 1:100, without free ligands or additives, in a controlled temperature and pressure. All the products of catalytic reactions HH and HA were analyzed by CG-FID with good yields.
{"title":"Hydroformylation-hydrogenation and hydroformylation-acetalization reactions catalyzed by ruthenium complexes","authors":"Claudia Rodrigues , Fabio G. Delolo , Jakob Norinder , Armin Börner , André L. Bogado , Alzir A. Batista","doi":"10.1016/j.molcata.2016.09.020","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.09.020","url":null,"abstract":"<div><p>In this work, the catalytic activity of ruthenium II and III complexes containing chloride, pyridine, phosphine and CO ligands was investigated in the hydroformylation – hydrogenation and hydroformylation – acetalization reactions. The complexes <em>mer-</em>[RuCl<sub>3</sub>(dppb)(H<sub>2</sub>O)]<strong>(1)</strong>, <em>mer-</em>[RuCl<sub>3</sub>(dppb)(4-Vpy)]<strong>(2)</strong>, <em>mer-</em>[RuCl<sub>3</sub>(dppb)(4-<em>t</em>Bupy)]<strong>(3)</strong>, <em>mer-</em>[RuCl<sub>3</sub>(dppb)(py)]<strong>(4)</strong>, <em>mer-</em>[RuCl<sub>3</sub>(dppb)(4-Phpy)]<strong>(5)</strong>, <em>mer-</em>[RuCl<sub>3</sub>(dppb)(4-Mepy)]<strong>(6)</strong>, <em>cis-</em>[RuCl<sub>2</sub>(CO)<sub>2</sub>(dppb)]<strong>(7)</strong>, <em>trans-</em>[RuCl<sub>2</sub>(CO)<sub>2</sub>(dppb)]<strong>(8)</strong>, RuCl<sub>3</sub>·xH<sub>2</sub>O<strong>(9)</strong>, [RuCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub>]<strong>(10)</strong> and [RuCl<sub>2</sub>(PPh<sub>3</sub>)<sub>2</sub>(dppb)]<strong>(11)</strong> were used as supplied or synthesized as previously described in the literature {Where PPh<sub>3</sub> <!-->=<!--> <!-->triphenylphosphine, dppb<!--> <!-->=<!--> <!-->1,4-bis(diphenylphosphino)butane, py<!--> <!-->=<!--> <!-->pyridine, 4-Mepy<!--> <!-->=<!--> <!-->4-methylpyridine, 4-Vpy<!--> <!-->=<!--> <!-->4-vinylpyridine, 4-<em>t</em>Bupy<!--> <!-->=<!--> <!-->4-<em>tert</em>-butylpyridine and 4-Phpy<!--> <!-->=<!--> <!-->4-phenylpyridine}. These complexes were used as a pre-catalysts in a hydroformylation catalytic system to produce C<img>C, C<img>O and C<img>O bonds, where 1-decene resulted in a formation of respective alcohol and dimethyl acetals. Several reactions were performed in order to find the best reaction conditions presenting the best conversion (64% after 24<!--> <!-->h). The 1-decene was also used as a substrate in two type tandem reactions labeled as: hydroformylation – hydrogenation (HH) and hydroformylation – acetalization (HA) reactions. The relationship between Ru – catalyst/substrate was 1:100, without free ligands or additives, in a controlled temperature and pressure. All the products of catalytic reactions HH and HA were analyzed by CG-FID with good yields.</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.2016.09.020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2798706","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.10.029
Yang Lv , Fang Hao , Pingle Liu , Shaofeng Xiong , He’an Luo
Different inorganic acids were used to activate sepiolite, and the acid-activated sepiolites supported nickel and potassium bimetallic catalysts were prepared. Nitrogen adsorption-desorption, hydrogen chemisorption, ammonia temperature programmed desorption (NH3-TPD), temperature programmed reduction (TPR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and energy dispersive X-ray (EDX) were used to characterize the catalysts. The catalytic performance of the acid-activated sepiolite supported K-Ni bimetallic catalysts were investigated in 1,6-hexanedinitrile (HDN) hydrogenation in liquid phase. It was revealed that the potassium could increase the alkalinity of the catalyst with the aim of inhibiting the formation of the 1-azacycloheptane (ACH). And the addition of potassium reduces the particle size of nickel and improves its dispersion. Compared with hydrochloric acid and sulfuric acid, nitric acid treatment increases more silanol groups (SiOH) on the sepiolite surface, which is helpful to nickel particles adsorption and dispersion. Nitric acid activated sepiolite supported nickel and potassium bimetallic catalysts (K-Ni/NASEP) present the best catalytic performance, the conversion of HDN comes up to 92.0% under moderate conditions of lower temperature and pressure, the selectivity to 6-aminocapronitrile (ACN) and 1,6-hexanediamine (HDA) is up to 95.2%.
{"title":"Improved catalytic performance of acid-activated sepiolite supported nickel and potassium bimetallic catalysts for liquid phase hydrogenation of 1,6-hexanedinitrile","authors":"Yang Lv , Fang Hao , Pingle Liu , Shaofeng Xiong , He’an Luo","doi":"10.1016/j.molcata.2016.10.029","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.10.029","url":null,"abstract":"<div><p>Different inorganic acids were used to activate sepiolite, and the acid-activated sepiolites supported nickel and potassium bimetallic catalysts were prepared. Nitrogen adsorption-desorption, hydrogen chemisorption, ammonia temperature programmed desorption (NH<sub>3</sub>-TPD), temperature programmed reduction (TPR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and energy dispersive X-ray (EDX) were used to characterize the catalysts. The catalytic performance of the acid-activated sepiolite supported K-Ni bimetallic catalysts were investigated in 1,6-hexanedinitrile (HDN) hydrogenation in liquid phase. It was revealed that the potassium could increase the alkalinity of the catalyst with the aim of inhibiting the formation of the 1-azacycloheptane (ACH). And the addition of potassium reduces the particle size of nickel and improves its dispersion. Compared with hydrochloric acid and sulfuric acid, nitric acid treatment increases more silanol groups (Si<img>OH) on the sepiolite surface, which is helpful to nickel particles adsorption and dispersion. Nitric acid activated sepiolite supported nickel and potassium bimetallic catalysts (K-Ni/NASEP) present the best catalytic performance, the conversion of HDN comes up to 92.0% under moderate conditions of lower temperature and pressure, the selectivity to 6-aminocapronitrile (ACN) and 1,6-hexanediamine (HDA) is up to 95.2%.</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.2016.10.029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2391732","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}
Pub Date : 2017-01-01DOI: 10.1016/j.molcata.2016.08.014
Ekaterina M. Titova , S.M. Wahidur Rahaman , Elena S. Shubina , Rinaldo Poli , Natalia V. Belkova , Eric Manoury
Complexes [M(P,SR)(diene)X] where (P,SR) = CpFe[1,2-C5H3(PPh2)(CH2SR)] (M = Ir, R = tBu or Bn diene = cod, X = Cl; M = Rh, diene = cod or nbd; X = BF4 or Cl) were used as precatalysts for the redox isomerization of various allylic alcohols (7a–e) to the corresponding saturated ketones (8a–e) and or hydrogenation to the saturated alcohol (9a–e). In optimization studies using 1-phenyl-2-propen-1-ol (7a) in THF and in iPrOH/MeONa, the only observed product was the saturated alcohol 1-phenyl-1-propanol (9a) when working under a 30 bar H2 pressure, but activation for only 1 min under H2 pressure and then continuation under 1 bar of H2 or Ar led to increasing amounts of the allylic isomerization product propiophenone (8a). Continued reaction under H2 converted (8a) into (9a). The Rh precatalysts were more active than the Ir analogues. For the rhodium precatalysts (3) and (4), the redox isomerization reaction could be carried out after precatalyst activation in iPrOH/MeONa under Ar at 82 °C (without H2) with complete conversion in 1 h (1% catalyst loading). However, longer reaction times resulted in slow transfer hydrogenation of (8a) leading to (9a) with low enantiomeric excess. Extension of the H2-free activation of the Rh precatalysts in iPrOH to other allylic alcohol substrates (7b–d) yielded the corresponding ketones with good to excellent yields and excellent chemoselectivities under appropriate conditions.
复合物[M (P, SR)(二烯)X] (P, SR) = CpFe [1, 2-C5H3 (PPh2) (CH2SR)] (M = Ir, R = tBu或Bn二烯=鳕鱼,X = Cl;M = Rh, diene = cod或nbd;X = BF4或Cl)作为预催化剂,将各种烯丙醇(7a-e)氧化还原异构化为相应的饱和酮(8a-e),或氢化为饱和醇(9a-e)。在THF和iPrOH/MeONa中使用1-苯基-2-丙烯-1-醇(7a)的优化研究中,在30 bar H2压力下工作时,唯一观察到的产物是饱和醇-1-苯基-1-丙醇(9a),但在H2压力下激活仅1 min,然后在1 bar H2或Ar下继续激活导致烯丙异构化产物丙烯酮(8a)的数量增加。在H2下继续反应,(8a)转化为(9a)。Rh预催化剂的活性高于Ir类似物。对于铑预催化剂(3)和(4),预催化剂在82℃氩气条件下(不含H2)在iPrOH/MeONa中活化后可进行氧化还原异构化反应,在1 h(1%催化剂负载)内完全转化。然而,较长的反应时间导致(8a)的转移加氢缓慢,导致(9a)具有较低的对映体过量。将iPrOH中Rh预催化剂的无h2活化扩展到其他烯丙醇底物(7b-d),在适当的条件下,可以得到相应的产率良好至优异的酮类,并具有良好的化学选择性。
{"title":"Catalytic redox isomerization of allylic alcohols with rhodium and iridium complexes with ferrocene phosphine-thioether ligands","authors":"Ekaterina M. Titova , S.M. Wahidur Rahaman , Elena S. Shubina , Rinaldo Poli , Natalia V. Belkova , Eric Manoury","doi":"10.1016/j.molcata.2016.08.014","DOIUrl":"https://doi.org/10.1016/j.molcata.2016.08.014","url":null,"abstract":"<div><p>Complexes [M(P,SR)(diene)X] where (P,SR)<!--> <!-->=<!--> <!-->CpFe[1,2-C<sub>5</sub>H<sub>3</sub>(PPh<sub>2</sub>)(CH<sub>2</sub>SR)] (M<!--> <!-->=<!--> <!-->Ir, R<!--> <!-->=<!--> <!-->tBu or Bn diene<!--> <!-->=<!--> <!-->cod, X<!--> <!-->=<!--> <!-->Cl; M<!--> <!-->=<!--> <!-->Rh, diene<!--> <!-->=<!--> <!-->cod or nbd; X<!--> <!-->=<!--> <!-->BF<sub>4</sub> or Cl) were used as precatalysts for the redox isomerization of various allylic alcohols (<strong>7a–e</strong>) to the corresponding saturated ketones (<strong>8a–e</strong>) and or hydrogenation to the saturated alcohol (<strong>9a–e</strong>). In optimization studies using 1-phenyl-2-propen-1-ol (<strong>7a</strong>) in THF and in iPrOH/MeONa, the only observed product was the saturated alcohol 1-phenyl-1-propanol (<strong>9</strong>a) when working under a 30<!--> <!-->bar H<sub>2</sub> pressure, but activation for only 1<!--> <!-->min under H<sub>2</sub> pressure and then continuation under 1<!--> <!-->bar of H<sub>2</sub> or Ar led to increasing amounts of the allylic isomerization product propiophenone (<strong>8a</strong>). Continued reaction under H<sub>2</sub> converted (<strong>8a</strong>) into (<strong>9a</strong>). The Rh precatalysts were more active than the Ir analogues. For the rhodium precatalysts (<strong>3</strong>) and (<strong>4</strong>), the redox isomerization reaction could be carried out after precatalyst activation in iPrOH/MeONa under Ar at 82<!--> <!-->°C (without H<sub>2</sub>) with complete conversion in 1<!--> <!-->h (1% catalyst loading). However, longer reaction times resulted in slow transfer hydrogenation of (<strong>8a</strong>) leading to (<strong>9a</strong>) with low enantiomeric excess. Extension of the H<sub>2</sub>-free activation of the Rh precatalysts in iPrOH to other allylic alcohol substrates (<strong>7b–d</strong>) yielded the corresponding ketones with good to excellent yields and excellent chemoselectivities under appropriate 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.2016.08.014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2879562","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}