The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-m...The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy（FTIR）, Solid carbon nuclear magnetic resonance spectroscopy（CNMR））, silicon-29 nuclear magnetic resonance spectroscopy（Si NMR））, and X-ray diffraction spectroscope（（XRD） were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb（II） from the aqueous solution. The Pb（II）-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy（FTIR））,scanning electron microscopy（SEM））, and X-ray photoelectron spectroscopy（（XPS））. From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb（II）. Kinetic studies indicated that the adsorption of Pb（II）followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb（II） ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly（acrylic acid）-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb（II） adsorbent.展开更多
Dear Editor,This letter presents an organoid segmentation model based on multi-axis attention with convolution parallel block.MACPNet adeptly captures dynamic dependencies within bright-field microscopy images,improvi...Dear Editor,This letter presents an organoid segmentation model based on multi-axis attention with convolution parallel block.MACPNet adeptly captures dynamic dependencies within bright-field microscopy images,improving global modeling beyond conventional UNet.展开更多
Inspired by the freezing tolerance performances found in living creatures, an effect approach is presented to develop novelantifreezing polymeric organohydrogel actuators. Through construction of a bilayer hydrogel in...Inspired by the freezing tolerance performances found in living creatures, an effect approach is presented to develop novelantifreezing polymeric organohydrogel actuators. Through construction of a bilayer hydrogel including a nonresponsivepolyacrylamide (PAAm) layer and a pH-responsive polyacrylic acid (PAA) layer in the presence of a mixed solvent of water andglycerol, organohydrogel actuators that could produce various shape deformations at subzero temperatures have been achieved,and the actuating speed could be tuned by adjusting the temperature and the ratio between glycerol and water. Moreover, aseries of application demonstrations including a weightlifting robot, artificial valve, and robotic arm have been displayed. Inaddition, by introducing the ionic compound KI into the glycerol-based organogel, flexible conductors that could perform stablesensing performance over a wide range of temperatures from -30℃ to 60℃ have been developed.展开更多
The introduction of bifunctional groups into low-cost adsorbents for selective adsorption of Ag(I) through synergistic effect will have a profound impact on the recovery of precious metals. Organo silica nanosheets(or...The introduction of bifunctional groups into low-cost adsorbents for selective adsorption of Ag(I) through synergistic effect will have a profound impact on the recovery of precious metals. Organo silica nanosheets(organo-Si NSs) functionalized by series of azole derivatives(2-mercaptoimidazole(MI), 2-mercaptobenzimidazole(MBT) and 1H-1,2,4-triazole-3-thiol(MTT)), are fabricated and employed for selective removal of Ag(I). The structures of the organo-Si NSs are investigated using several characterization methods. The results of batch adsorption experiments display that the maximum adsorption amounts are 70.3, 103.2 and 139.5 mg·g^(-1) on MI-Si NSs, MBI-Si NSs and MTT-Si NSs for Ag(I) ions, and reach rapid equilibrium within 10–30 min. The adsorption processes are chemisorption and fit pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Notably, MTT-Si NSs is greatly selective for Ag(I) in multicomponent system, and the distribution coefficient value of Ag(I) ions reaches 2331.26 ml·g^(-1). The reusability of organo-Si NSs is verified by four cycles of regeneration tests with 0.1 mol·L^(-1) HNO_(3) as the eluent. A combination of experimental, structural along with theoretical analysis is conducted to proclaim the structure-adsorptivity relationship:(i) The adsorption mechanisms are attributed to complexation.(ii) The amino group and sulfhydryl group of MTT-Si NSs as well as MBISi NSs may have synergistic impacts on Ag(I) capture.(iii) The differences in adsorption behavior and selectivity of the three organo-Si NSs are mainly related to the form of function groups, charge density and steric hindrance of adsorbent. This work not only sheds light on the promise of functionalized organo-Si NSs for the rapid and selective removal/enrichment of Ag(I) ions in complex water systems,but also provides new insights for designing cost-effective Si NSs-based adsorbents.展开更多
Dear Editor,Human cell-based and personalized in vitro cartilage models are urgently needed for osteoarthritis treatment in pre-clinical regenerative medicine development.Cellular self-assemblies and condensations of ...Dear Editor,Human cell-based and personalized in vitro cartilage models are urgently needed for osteoarthritis treatment in pre-clinical regenerative medicine development.Cellular self-assemblies and condensations of the appropriate stem cells could initiate the formation of transient tissue structures programmed for specific organogenesis processes.1 This recapitulation of developmental events has previously been demonstrated for the formation of cardiac,epithelial and liver organoids.However,there has been very limited progress in the development of human cartilage organoids for osteoarthritis(OA).2 Here,we describe the fabrication of functional bioengineered cartilage organoid suitable for OA treatment.Briefly,agarose microwell inserts for formation of a high number of synovial mesenchymal stromal cell(SMSC)organoids with homogeneous size distribution were created as previously described by Leijten et al.33D-cultured SMSC organoids were generated and phenotypically analyzed for potential applications in OA modeling and treatment(Fig.1a).展开更多
The title compound （E）-ethyl 2-fluoro-2-（3-oxoisobenzofuran-1（3H）-ylidene） aceta- te was synthesized as an unexpected product by the reaction ofphthalyl dichloride with bis-silylenol ether, which is not in accor...The title compound （E）-ethyl 2-fluoro-2-（3-oxoisobenzofuran-1（3H）-ylidene） aceta- te was synthesized as an unexpected product by the reaction ofphthalyl dichloride with bis-silylenol ether, which is not in accordance with our previous studies. The title compound was characterized by single-crystal X-ray diffraction, 1H NMR, 13C NMR, 19F NMR, GCMS, HRMS and IR. The crystal （C12HgFO4, Mr = 236.19） belongs to the monoclinic system, space group P21/c, a = 19.1609（8）, b = 7.9831（3）, c = 13.7715（6） A, V= 2106.13（15） A3, Z= 8, Dx = 1.490 Mg m-3, MoKa radiation, 2 = 0.71073 A,μ = 0.12 mm-1, F（000） = 976, the final R = 0.025 and wR = 0.1300 for 4505 observed reflections with I〉 2σ（I）.展开更多
Reaction of（C5Me4SiMe3）Y（CH2SiMe）2（THF） with two equivalents of iPrN=C=NiPr in hexane at room temperature afforded a mixed-ligand yttrium complex（C5Me4SiMe3）（iPrN）2CCH2SiMe32Y.X-ray diffraction revealed that...Reaction of（C5Me4SiMe3）Y（CH2SiMe）2（THF） with two equivalents of iPrN=C=NiPr in hexane at room temperature afforded a mixed-ligand yttrium complex（C5Me4SiMe3）（iPrN）2CCH2SiMe32Y.X-ray diffraction revealed that the center metal was nine-coordinated by one cyclopentadienyl ring and two amidinate ligands, and adopted a four-legged piano stool geometry.展开更多
The retinal organoid is a vital model for studying retinal development and related diseases, especially for the human retina(Jin et al., 2019). The retina constitutes an integral part of the central nervous system(CNS...The retinal organoid is a vital model for studying retinal development and related diseases, especially for the human retina(Jin et al., 2019). The retina constitutes an integral part of the central nervous system(CNS) and originates from neuroectodermal cells during organogenesis.展开更多
Metal organophosphonates have been explored in energy-related fields due to their high chemical and thermal stability as a type of uniformly precursor,but only few of pristine metal organophosphonate are directly used...Metal organophosphonates have been explored in energy-related fields due to their high chemical and thermal stability as a type of uniformly precursor,but only few of pristine metal organophosphonate are directly used for oxygen evolution reaction(OER)catalysts.Here,a mixedvalence iron phosphonate(Fe_(3)-ppat)has been constructed and applied to OER catalysis considered the potential active sites in pillars Fe^(Ⅱ)(-H_(2)O)_(4)(COO)_(2)and inorganic layers Fe^(Ⅲ)(μ_(2)–OH)PO_(3).Specifically,isostructural trimetallic framework Fe_(1.7)Co_(0.3)Ni_(1.0)-ppat possesses a minimum overpotential(291 mV),small Tafel slope(91.65 mV dec^(-1)),and high stability up to 83 h.The enhanced catalytic performance could be mainly ascribed to the synergistic effect of Ni^(Ⅱ)equivalent occupancy in pillars and Co/Fe^(Ⅲ)in layers.展开更多
New synthesis of multi-layer 3 D chiral molecules has been developed under novel conditions to give better outcomes.The aggregation-induced emission(AIE),UV irradiation/excitation,charge transfer(CT)and local excited(...New synthesis of multi-layer 3 D chiral molecules has been developed under novel conditions to give better outcomes.The aggregation-induced emission(AIE),UV irradiation/excitation,charge transfer(CT)and local excited(LE)ππ*transitions have been investigated on a representative individual enantiomer of pseudo C_2 asymmetry which was made possibly by differentiating moieties on phosphorous on N-phosphonyl ring of chiral sandwich framework.Meanwhile,a new tandem C–N/C–C coupling reaction was unexpectedly rendered providing a novel access to special benzo[a]carbazoles.展开更多
What is the most favorite and original chemistry developed in your research group?Our research focuses on the field of asymmetric organocatalysis and natural product synthesis.Our work draws upon and impacts the desig...What is the most favorite and original chemistry developed in your research group?Our research focuses on the field of asymmetric organocatalysis and natural product synthesis.Our work draws upon and impacts the design and synthesis of N-and P-containing bifunctional ion pair catalysts from a-amino acids,and their applications as organocatalysts or ligands in asymmetric synthesis.展开更多
Adult tissue-derived organoids allow for the expansion and maintenance of primary epithelial cells in a near-native state.These 3D and self-organizing organotypic cultures derived from adult tissues have been increasi...Adult tissue-derived organoids allow for the expansion and maintenance of primary epithelial cells in a near-native state.These 3D and self-organizing organotypic cultures derived from adult tissues have been increasingly used in fundamental and translational research.A key feature of this organoid system is that it recapitulates the stem cell lineage and thus,the differentiated cell-type heterogeneity of the in vivo tissue of origin.展开更多
Summary of main observation and conclusion Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize a-keto acetals directly.Using 02 as oxidant and alcohol as solvent an...Summary of main observation and conclusion Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize a-keto acetals directly.Using 02 as oxidant and alcohol as solvent and alkoxylation reagent,the reaction is practical from industrial viewpoint.Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn-elim-ination regenerating the catalytically active organoselenium species.展开更多
Instantaneous free radicals can be formed easily in the homolytic processes of carbon-metal bond of organo-metallic compounds and these processes are used as a source of free radicals. The active free radical with sho...Instantaneous free radicals can be formed easily in the homolytic processes of carbon-metal bond of organo-metallic compounds and these processes are used as a source of free radicals. The active free radical with short lifetime and low concentration is hardly展开更多
The considerable utility of organoboranes in synthesis is firmly established,which is in a large part due to the power of the Suzuki-Miyaura cross-coupling reaction for con・structing C-C bonds.Therefore,discovering si...The considerable utility of organoboranes in synthesis is firmly established,which is in a large part due to the power of the Suzuki-Miyaura cross-coupling reaction for con・structing C-C bonds.Therefore,discovering simple new routes to form desirable organoboranes continues to be of significant import.Methodologies that directly transform C-H into C-B are particularly desirable,especially if borylation occurs with excellent site selectivity and without precious metal catalysts due to their low crustal abundance,high cost and toxicity.展开更多
Although it has long been acknowledged that geometrical factors, such as size and shape of ligands, play an important role in molecular structures of coordination and organo-metallic compounds, they have been complete...Although it has long been acknowledged that geometrical factors, such as size and shape of ligands, play an important role in molecular structures of coordination and organo-metallic compounds, they have been completely neglected in quantitative treatment. There are possible approaches to the steric effects based on the well-developed molecular展开更多
In the structure research of Ziegler-Natta catalyst the most effective method is the isolation of the active species from a homogeneous catalyst solution. Six Ln (Ln=La, Ce, Pr, Nd, Sm and Eu) and Al-containing bimeta...In the structure research of Ziegler-Natta catalyst the most effective method is the isolation of the active species from a homogeneous catalyst solution. Six Ln (Ln=La, Ce, Pr, Nd, Sm and Eu) and Al-containing bimetallic complexes were isolated in our laboratory from homogeneous catalyst systems composed展开更多
基金supported by the USM short-term grant (Ac No.: 8044043)by the USM fellowship scheme for PhD study (to M. Irani)Water Program at University of Wyoming
文摘The purpose of this work is to remove Pb（II） from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy（FTIR）, Solid carbon nuclear magnetic resonance spectroscopy（CNMR））, silicon-29 nuclear magnetic resonance spectroscopy（Si NMR））, and X-ray diffraction spectroscope（（XRD） were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb（II） from the aqueous solution. The Pb（II）-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy（FTIR））,scanning electron microscopy（SEM））, and X-ray photoelectron spectroscopy（（XPS））. From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb（II）. Kinetic studies indicated that the adsorption of Pb（II）followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb（II） ions was 430 mg/g. Thus, the waste linear low-density polyethylene-g-poly（acrylic acid）-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb（II） adsorbent.
基金supported by the Xinjiang Tianchi Talents Program(E33B9401)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2023D01E15)+1 种基金the National Natural Science Foundation of China(62302495)the National Natural Science Foundation of China(62373348)。
文摘Dear Editor,This letter presents an organoid segmentation model based on multi-axis attention with convolution parallel block.MACPNet adeptly captures dynamic dependencies within bright-field microscopy images,improving global modeling beyond conventional UNet.
基金This work was supported by the National Natural Science Foundation of China(51873223,51773215,and 21774138)the National Key Research and Development Program of China(2018YFB1105100)+3 种基金the Key Research Program of Frontier Science,Chinese Academy of Sciences(QYZDBSSW-SLH036)the Natural Science Foundation of Ningbo(2018A610035)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017337,2019297)the Ningbo Science and Technology Bureau(2016C50009).
文摘Inspired by the freezing tolerance performances found in living creatures, an effect approach is presented to develop novelantifreezing polymeric organohydrogel actuators. Through construction of a bilayer hydrogel including a nonresponsivepolyacrylamide (PAAm) layer and a pH-responsive polyacrylic acid (PAA) layer in the presence of a mixed solvent of water andglycerol, organohydrogel actuators that could produce various shape deformations at subzero temperatures have been achieved,and the actuating speed could be tuned by adjusting the temperature and the ratio between glycerol and water. Moreover, aseries of application demonstrations including a weightlifting robot, artificial valve, and robotic arm have been displayed. Inaddition, by introducing the ionic compound KI into the glycerol-based organogel, flexible conductors that could perform stablesensing performance over a wide range of temperatures from -30℃ to 60℃ have been developed.
基金the National Natural Science Foundation of China (21776306)。
文摘The introduction of bifunctional groups into low-cost adsorbents for selective adsorption of Ag(I) through synergistic effect will have a profound impact on the recovery of precious metals. Organo silica nanosheets(organo-Si NSs) functionalized by series of azole derivatives(2-mercaptoimidazole(MI), 2-mercaptobenzimidazole(MBT) and 1H-1,2,4-triazole-3-thiol(MTT)), are fabricated and employed for selective removal of Ag(I). The structures of the organo-Si NSs are investigated using several characterization methods. The results of batch adsorption experiments display that the maximum adsorption amounts are 70.3, 103.2 and 139.5 mg·g^(-1) on MI-Si NSs, MBI-Si NSs and MTT-Si NSs for Ag(I) ions, and reach rapid equilibrium within 10–30 min. The adsorption processes are chemisorption and fit pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Notably, MTT-Si NSs is greatly selective for Ag(I) in multicomponent system, and the distribution coefficient value of Ag(I) ions reaches 2331.26 ml·g^(-1). The reusability of organo-Si NSs is verified by four cycles of regeneration tests with 0.1 mol·L^(-1) HNO_(3) as the eluent. A combination of experimental, structural along with theoretical analysis is conducted to proclaim the structure-adsorptivity relationship:(i) The adsorption mechanisms are attributed to complexation.(ii) The amino group and sulfhydryl group of MTT-Si NSs as well as MBISi NSs may have synergistic impacts on Ag(I) capture.(iii) The differences in adsorption behavior and selectivity of the three organo-Si NSs are mainly related to the form of function groups, charge density and steric hindrance of adsorbent. This work not only sheds light on the promise of functionalized organo-Si NSs for the rapid and selective removal/enrichment of Ag(I) ions in complex water systems,but also provides new insights for designing cost-effective Si NSs-based adsorbents.
基金This work was funded by the National Key R&D Program of China(No.2018YFB1105600,No.2018YFA0703000)China National Natural Science Funds(No.51631009,No.81802122)+1 种基金Chinese post-doctoral funding(No.2019M661559)the Funds from Shanghai jiao tong university for the Clinical and Translational Research Center for 3D Printing Technology.
文摘Dear Editor,Human cell-based and personalized in vitro cartilage models are urgently needed for osteoarthritis treatment in pre-clinical regenerative medicine development.Cellular self-assemblies and condensations of the appropriate stem cells could initiate the formation of transient tissue structures programmed for specific organogenesis processes.1 This recapitulation of developmental events has previously been demonstrated for the formation of cardiac,epithelial and liver organoids.However,there has been very limited progress in the development of human cartilage organoids for osteoarthritis(OA).2 Here,we describe the fabrication of functional bioengineered cartilage organoid suitable for OA treatment.Briefly,agarose microwell inserts for formation of a high number of synovial mesenchymal stromal cell(SMSC)organoids with homogeneous size distribution were created as previously described by Leijten et al.33D-cultured SMSC organoids were generated and phenotypically analyzed for potential applications in OA modeling and treatment(Fig.1a).
文摘The title compound （E）-ethyl 2-fluoro-2-（3-oxoisobenzofuran-1（3H）-ylidene） aceta- te was synthesized as an unexpected product by the reaction ofphthalyl dichloride with bis-silylenol ether, which is not in accordance with our previous studies. The title compound was characterized by single-crystal X-ray diffraction, 1H NMR, 13C NMR, 19F NMR, GCMS, HRMS and IR. The crystal （C12HgFO4, Mr = 236.19） belongs to the monoclinic system, space group P21/c, a = 19.1609（8）, b = 7.9831（3）, c = 13.7715（6） A, V= 2106.13（15） A3, Z= 8, Dx = 1.490 Mg m-3, MoKa radiation, 2 = 0.71073 A,μ = 0.12 mm-1, F（000） = 976, the final R = 0.025 and wR = 0.1300 for 4505 observed reflections with I〉 2σ（I）.
基金supported by the National Natural Science Foundation of China (20604023)Zhejiang Provincial Natural Science Foundation (Y406301)Ningbo Municipal Natural Science Foundation (2008A610056)
文摘Reaction of（C5Me4SiMe3）Y（CH2SiMe）2（THF） with two equivalents of iPrN=C=NiPr in hexane at room temperature afforded a mixed-ligand yttrium complex（C5Me4SiMe3）（iPrN）2CCH2SiMe32Y.X-ray diffraction revealed that the center metal was nine-coordinated by one cyclopentadienyl ring and two amidinate ligands, and adopted a four-legged piano stool geometry.
文摘The retinal organoid is a vital model for studying retinal development and related diseases, especially for the human retina(Jin et al., 2019). The retina constitutes an integral part of the central nervous system(CNS) and originates from neuroectodermal cells during organogenesis.
基金supported by the National Natural Science Foundation of China(NSFC 21871167)the National Natural Science Fund for Young Scholars of China(NSFC 21201114)+2 种基金the 1331 Engineering of Shanxi ProvinceScientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2019L0464)Shanxi Province Science Foundation for Youths(201901D211391)。
文摘Metal organophosphonates have been explored in energy-related fields due to their high chemical and thermal stability as a type of uniformly precursor,but only few of pristine metal organophosphonate are directly used for oxygen evolution reaction(OER)catalysts.Here,a mixedvalence iron phosphonate(Fe_(3)-ppat)has been constructed and applied to OER catalysis considered the potential active sites in pillars Fe^(Ⅱ)(-H_(2)O)_(4)(COO)_(2)and inorganic layers Fe^(Ⅲ)(μ_(2)–OH)PO_(3).Specifically,isostructural trimetallic framework Fe_(1.7)Co_(0.3)Ni_(1.0)-ppat possesses a minimum overpotential(291 mV),small Tafel slope(91.65 mV dec^(-1)),and high stability up to 83 h.The enhanced catalytic performance could be mainly ascribed to the synergistic effect of Ni^(Ⅱ)equivalent occupancy in pillars and Co/Fe^(Ⅲ)in layers.
基金supported by the National Natural Science Foundation of China(91956110,21672100)Robert A.Welch Foundation(D-1361,USA)+1 种基金financial support from Beijing National Laboratory for Molecular Sciences(BNLMS201910)support from the School of Pharmaceutical Science and Technology(SPST),Tianjin University,Tianjin,China。
文摘New synthesis of multi-layer 3 D chiral molecules has been developed under novel conditions to give better outcomes.The aggregation-induced emission(AIE),UV irradiation/excitation,charge transfer(CT)and local excited(LE)ππ*transitions have been investigated on a representative individual enantiomer of pseudo C_2 asymmetry which was made possibly by differentiating moieties on phosphorous on N-phosphonyl ring of chiral sandwich framework.Meanwhile,a new tandem C–N/C–C coupling reaction was unexpectedly rendered providing a novel access to special benzo[a]carbazoles.
文摘What is the most favorite and original chemistry developed in your research group?Our research focuses on the field of asymmetric organocatalysis and natural product synthesis.Our work draws upon and impacts the design and synthesis of N-and P-containing bifunctional ion pair catalysts from a-amino acids,and their applications as organocatalysts or ligands in asymmetric synthesis.
基金This work was supported by the European Research Council under ERC Advanced Grant Agreement no.67013(H.C.and K.B.)。
文摘Adult tissue-derived organoids allow for the expansion and maintenance of primary epithelial cells in a near-native state.These 3D and self-organizing organotypic cultures derived from adult tissues have been increasingly used in fundamental and translational research.A key feature of this organoid system is that it recapitulates the stem cell lineage and thus,the differentiated cell-type heterogeneity of the in vivo tissue of origin.
基金We thank the Natural Science Foundation of Jiangsu Province(BK20181449)the Jiangsu Provincial Six Talent Peaks Project(XCL-090),the National Natural Science Foundation of China(Nos.21202141,21971065)the Priority Academic Program Devel-opment(PAPD)of Jiangsu Higher Education Institutions.
文摘Summary of main observation and conclusion Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize a-keto acetals directly.Using 02 as oxidant and alcohol as solvent and alkoxylation reagent,the reaction is practical from industrial viewpoint.Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn-elim-ination regenerating the catalytically active organoselenium species.
基金The project supported by the National Natural Science Foundation of China
文摘Instantaneous free radicals can be formed easily in the homolytic processes of carbon-metal bond of organo-metallic compounds and these processes are used as a source of free radicals. The active free radical with short lifetime and low concentration is hardly
基金supported by the Horizon 2020 Research and Innovation Program (769599)
文摘The considerable utility of organoboranes in synthesis is firmly established,which is in a large part due to the power of the Suzuki-Miyaura cross-coupling reaction for con・structing C-C bonds.Therefore,discovering simple new routes to form desirable organoboranes continues to be of significant import.Methodologies that directly transform C-H into C-B are particularly desirable,especially if borylation occurs with excellent site selectivity and without precious metal catalysts due to their low crustal abundance,high cost and toxicity.
基金Project supported by the National Natural Science Foundation of China
文摘Although it has long been acknowledged that geometrical factors, such as size and shape of ligands, play an important role in molecular structures of coordination and organo-metallic compounds, they have been completely neglected in quantitative treatment. There are possible approaches to the steric effects based on the well-developed molecular
文摘In the structure research of Ziegler-Natta catalyst the most effective method is the isolation of the active species from a homogeneous catalyst solution. Six Ln (Ln=La, Ce, Pr, Nd, Sm and Eu) and Al-containing bimetallic complexes were isolated in our laboratory from homogeneous catalyst systems composed
