The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68...The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68-91%yields.This supported rhodium complex can be reused several times without noticeable loss of activity.Our system not only solves the basic problems of catalyst separation and recovery,but also avoids the use of phosphine ligands.展开更多
The hydroaminomethylation of 1-dodecene catalyzed by water soluble rhodium complex RhCl(CO)(TPPTS)2 in the presence of surfactant CTAB was investigated. High reactivity and selectivity for tertiary amine were achieved...The hydroaminomethylation of 1-dodecene catalyzed by water soluble rhodium complex RhCl(CO)(TPPTS)2 in the presence of surfactant CTAB was investigated. High reactivity and selectivity for tertiary amine were achieved under relatively mild conditions.展开更多
The catalytic performances of four HRh(CO)(PPh3)3-diphosphine (BISBI,BDPX, BDNA and BINAP) systems in 1-dodecene hydroformylation were investigated and compared with HRh(CO)(PPh3)3-PPh3 system. The catalyst system HR...The catalytic performances of four HRh(CO)(PPh3)3-diphosphine (BISBI,BDPX, BDNA and BINAP) systems in 1-dodecene hydroformylation were investigated and compared with HRh(CO)(PPh3)3-PPh3 system. The catalyst system HRh(CO)(PPh3)3-BISBI exhibited very high regioselectivity for the formation of linear aldehyde.展开更多
Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethy...Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethylphosphine to give Cp t Rh(PMe 3)Cl 2(2) in high yield. 2 reacts with ammonium polysulfide, (NH 4) 2S x to give cyclooligosulfido half-sandwich complexes Cp t Rh(PMe 3)(S n )( n =4(4a),6(4b)). Desulfurization of 4b by excess PPh 3 results in cyclotetrasulfido product 4a, while 4a takes up sulfur from polysulfide to convert cyclohexasulfido product 4b. The reaction of 2 with Et 4NI gives diiodide complex 3 which is determined by single crystal X-ray crystallographic analysis.展开更多
Microbial synthesis utilizes sustainable resources to produce valuable chemicals,as a potential alternative to petroleum-based chemical industry.Although metabolic engineering is an efficient method to enhance the bio...Microbial synthesis utilizes sustainable resources to produce valuable chemicals,as a potential alternative to petroleum-based chemical industry.Although metabolic engineering is an efficient method to enhance the biosynthesis efficacy of microorganisms,it requires complicated biological procedures.Herein,we report a facile intracellular catalysis system for augmenting the production of bio-based material in microorganism.Covalent linking of oligo(p-phenylenevinylene)(OPV)and cyclopentadienyl rhodium(Ⅲ)bipyridine offers intracellular metal catalyst(OPV-Rh).The OPV-Rh complex displayed certain resistance to toxic biomolecules,which guaranteed its catalytic activity in complicated biological systems.With uptake by Gramnegative bacterium Ralstonia eutropha H16(R.eutropha H16),the OPV-Rh complex promotes the transformation of intracellular NADP+to NADPH,which further enhances the biosynthesis of polyhydroxybutyrate(PHB)by this microorganism.This work demonstrates that synthetic metal catalyst can be employed for regulating microbial biosynthesis intracellularly.展开更多
A C2-symmetrical aryl diphosphite derived from chiral binaphthol was prepared and its rhodium complex was used as catalysts in the asymmetric hydroformylation of olefins. High catalytic activity and good regioselectiv...A C2-symmetrical aryl diphosphite derived from chiral binaphthol was prepared and its rhodium complex was used as catalysts in the asymmetric hydroformylation of olefins. High catalytic activity and good regioselectivity were observed. Up to 31.2% ee and 38.1% ee were achieved for the hydroformylation of 4-fluoro-styrene and vinyl acetate respectively. The influences of ligand-to-metal ratio, reaction temperature and the pressure of syn-gas on the enantioselectivity and regioselectivity were also studied.展开更多
A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coo...A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coordinated donor) atoms which enable to improve its stability by intramolecular substitution reaction. Its synthesis, characteristic and catalytic reaction were discussed here.展开更多
In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using th...In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2DZ level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and trans- structure exchange linkage of catalysis reactive species, the two pathways, cis- and trans-cata- lyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither cis-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.展开更多
In this paper, we used density functional theory(DFT) computations to study the mechanisms of the hydroacylation reaction of an aldehyde with an alkene catalyzed by Wilkinson's catalyst and an organic catalyst 2-a...In this paper, we used density functional theory(DFT) computations to study the mechanisms of the hydroacylation reaction of an aldehyde with an alkene catalyzed by Wilkinson's catalyst and an organic catalyst 2-amino-3-picoline in cationic and neutral systems. An aldehyde's hydroacylation includes three stages: the C–H activation to form rhodium hydride(stage I), the alkene insertion into the Rh–H bond to give the Rh-alkyl complex(stage II), and the C–C bond formation(stage III). Possible pathways for the hydroacylation originated from the trans and cis isomers of the catalytic cycle. In this paper, we discussed the neutral and cationic pathways. The rate-determining step is the C–H activation step in neutral system but the reductive elimination step in the cationic system. Meanwhile, the alkyl group migration-phosphine ligand coordination pathway is more favorable than the phosphine ligand coordination-alkyl group migration pathway in the C–C formation stage. Furthermore, the calculated results imply that an electron-withdrawing group may decrease the energy barrier of the C–H activation in the benzaldehyde hydroacylation.展开更多
Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been...Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from the single-molecule vapor-phase density functional theory (DFT) calculation that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic analysis study confirms that in the solid phase, the two complexes retain the higher D2h symmetry. The vibrational wavenumbers of certain modes associated to free 1,5-cyc- looctadiene were observed to be shifted to lower values upon coordination with rhodium or iridium metals. It was also found theoretically that the metal-olefin interaction is slightly more pronounced for iridium metal.展开更多
The complex [（CF3-BINAP（O））Rh（COD）][ClO4]·Et2O （2, CFa-BINAP（O） = 2- {bis[3,5-bis（trifluoromethyl）phenyl]phosphino } -2 ＇- {bis [3,5-bis（trifluoromethyl）phenyl]phosphinyl } -1,1、-binaphthyl, COD = ...The complex [（CF3-BINAP（O））Rh（COD）][ClO4]·Et2O （2, CFa-BINAP（O） = 2- {bis[3,5-bis（trifluoromethyl）phenyl]phosphino } -2 ＇- {bis [3,5-bis（trifluoromethyl）phenyl]phosphinyl } -1,1、-binaphthyl, COD = 1,5-cyclooctadiene） was obtained directly from the reaction of CF3- BINAP（O） ligand with [Rh（COD）][C104]. Complex 2 has been characterized by single-crystal X-ray diffraction. The crystal adopts space group P21/n with a = 19.0727（4）, b = 15.6275（4）, c = 22.3039（6） A, fl = 112.3570（10）°, V= 6148.2（3） A3, Z = 4, Dc = 1.693 g/cm3, F（000） = 3144, μ（MoKa） = 0.500 mm-1, the final R = 0.0947 and wR = 0.2501. Structural studies reveal that Rh（I） is coordinated by one oxygen and one phosphorus in the same ligand. Asymmetric hydrogenation of acetami- docinnamic acid with compound 2 was also evaluated.展开更多
A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed t...A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed that the catalyst could catalyze the reaction in95.6% conversion with 92.8% selectivity for the normal aldehyde, methyl β-formylisobu-tyrate. Such catalyst also showed high stability during the reaction and could be used repeat-edly.展开更多
基金National Natural Science Foundation of China(No.20862008)Natural Science Foundation of Jiangxi Province(No.2008GQH0034) for financial support
文摘The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68-91%yields.This supported rhodium complex can be reused several times without noticeable loss of activity.Our system not only solves the basic problems of catalyst separation and recovery,but also avoids the use of phosphine ligands.
文摘The hydroaminomethylation of 1-dodecene catalyzed by water soluble rhodium complex RhCl(CO)(TPPTS)2 in the presence of surfactant CTAB was investigated. High reactivity and selectivity for tertiary amine were achieved under relatively mild conditions.
基金We thank the National Basic Research Project of China(G2000048008)for the financial support.
文摘The catalytic performances of four HRh(CO)(PPh3)3-diphosphine (BISBI,BDPX, BDNA and BINAP) systems in 1-dodecene hydroformylation were investigated and compared with HRh(CO)(PPh3)3-PPh3 system. The catalyst system HRh(CO)(PPh3)3-BISBI exhibited very high regioselectivity for the formation of linear aldehyde.
基金Financial support by the National Natural Science Foundation of China and by the Special Funds for Major State Basic Research Projects(G1999064800)is gratefully acknowledged.
文摘Treatment of 1,3-di- t -butylcyclopentadiene with rhodium trichloride in EtOH leads to the formation of binuclear half-sandwich complex [Cp t RhCl( μ -Cl)] 2 (1) (Cp t = η 5- t Bu 2C 5H 3) which reacts with trimethylphosphine to give Cp t Rh(PMe 3)Cl 2(2) in high yield. 2 reacts with ammonium polysulfide, (NH 4) 2S x to give cyclooligosulfido half-sandwich complexes Cp t Rh(PMe 3)(S n )( n =4(4a),6(4b)). Desulfurization of 4b by excess PPh 3 results in cyclotetrasulfido product 4a, while 4a takes up sulfur from polysulfide to convert cyclohexasulfido product 4b. The reaction of 2 with Et 4NI gives diiodide complex 3 which is determined by single crystal X-ray crystallographic analysis.
基金the National Natural Science Foundation of China(21533012,21661132006)。
文摘Microbial synthesis utilizes sustainable resources to produce valuable chemicals,as a potential alternative to petroleum-based chemical industry.Although metabolic engineering is an efficient method to enhance the biosynthesis efficacy of microorganisms,it requires complicated biological procedures.Herein,we report a facile intracellular catalysis system for augmenting the production of bio-based material in microorganism.Covalent linking of oligo(p-phenylenevinylene)(OPV)and cyclopentadienyl rhodium(Ⅲ)bipyridine offers intracellular metal catalyst(OPV-Rh).The OPV-Rh complex displayed certain resistance to toxic biomolecules,which guaranteed its catalytic activity in complicated biological systems.With uptake by Gramnegative bacterium Ralstonia eutropha H16(R.eutropha H16),the OPV-Rh complex promotes the transformation of intracellular NADP+to NADPH,which further enhances the biosynthesis of polyhydroxybutyrate(PHB)by this microorganism.This work demonstrates that synthetic metal catalyst can be employed for regulating microbial biosynthesis intracellularly.
基金Project supported by the Suzhou University and the Hong Kong Polytechnic University ASD Fund and University Grants Committee Area of Excel-lence Scheme in Hong Kong (AoE P/10-01).
文摘A C2-symmetrical aryl diphosphite derived from chiral binaphthol was prepared and its rhodium complex was used as catalysts in the asymmetric hydroformylation of olefins. High catalytic activity and good regioselectivity were observed. Up to 31.2% ee and 38.1% ee were achieved for the hydroformylation of 4-fluoro-styrene and vinyl acetate respectively. The influences of ligand-to-metal ratio, reaction temperature and the pressure of syn-gas on the enantioselectivity and regioselectivity were also studied.
基金Project (No. 29974035) supported by the National Natural Science Foundation of China
文摘A new class of rhodium complexes with high catalytic activity as well as excellent stability, which was used as catalyst for carbonylation of methanol to acetic acid, is reported. It contains free donor (namely un-coordinated donor) atoms which enable to improve its stability by intramolecular substitution reaction. Its synthesis, characteristic and catalytic reaction were discussed here.
文摘In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2DZ level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and trans- structure exchange linkage of catalysis reactive species, the two pathways, cis- and trans-cata- lyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither cis-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.
基金supported by the National Natural Science Foundation of China(21373023,21203006,21072018)
文摘In this paper, we used density functional theory(DFT) computations to study the mechanisms of the hydroacylation reaction of an aldehyde with an alkene catalyzed by Wilkinson's catalyst and an organic catalyst 2-amino-3-picoline in cationic and neutral systems. An aldehyde's hydroacylation includes three stages: the C–H activation to form rhodium hydride(stage I), the alkene insertion into the Rh–H bond to give the Rh-alkyl complex(stage II), and the C–C bond formation(stage III). Possible pathways for the hydroacylation originated from the trans and cis isomers of the catalytic cycle. In this paper, we discussed the neutral and cationic pathways. The rate-determining step is the C–H activation step in neutral system but the reductive elimination step in the cationic system. Meanwhile, the alkyl group migration-phosphine ligand coordination pathway is more favorable than the phosphine ligand coordination-alkyl group migration pathway in the C–C formation stage. Furthermore, the calculated results imply that an electron-withdrawing group may decrease the energy barrier of the C–H activation in the benzaldehyde hydroacylation.
文摘Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from the single-molecule vapor-phase density functional theory (DFT) calculation that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic analysis study confirms that in the solid phase, the two complexes retain the higher D2h symmetry. The vibrational wavenumbers of certain modes associated to free 1,5-cyc- looctadiene were observed to be shifted to lower values upon coordination with rhodium or iridium metals. It was also found theoretically that the metal-olefin interaction is slightly more pronounced for iridium metal.
基金Supported by the National Natural Science Foundation of China(20972159)
文摘The complex [（CF3-BINAP（O））Rh（COD）][ClO4]·Et2O （2, CFa-BINAP（O） = 2- {bis[3,5-bis（trifluoromethyl）phenyl]phosphino } -2 ＇- {bis [3,5-bis（trifluoromethyl）phenyl]phosphinyl } -1,1、-binaphthyl, COD = 1,5-cyclooctadiene） was obtained directly from the reaction of CF3- BINAP（O） ligand with [Rh（COD）][C104]. Complex 2 has been characterized by single-crystal X-ray diffraction. The crystal adopts space group P21/n with a = 19.0727（4）, b = 15.6275（4）, c = 22.3039（6） A, fl = 112.3570（10）°, V= 6148.2（3） A3, Z = 4, Dc = 1.693 g/cm3, F（000） = 3144, μ（MoKa） = 0.500 mm-1, the final R = 0.0947 and wR = 0.2501. Structural studies reveal that Rh（I） is coordinated by one oxygen and one phosphorus in the same ligand. Asymmetric hydrogenation of acetami- docinnamic acid with compound 2 was also evaluated.
文摘A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed that the catalyst could catalyze the reaction in95.6% conversion with 92.8% selectivity for the normal aldehyde, methyl β-formylisobu-tyrate. Such catalyst also showed high stability during the reaction and could be used repeat-edly.
