To minimize the loading level of the char-forming phosphorus based flame retardants in the poly（lactic acid） （PLA） with reduced flammability, we have developed the flame-retarded PLA nanocomposites by melt blendin...To minimize the loading level of the char-forming phosphorus based flame retardants in the poly（lactic acid） （PLA） with reduced flammability, we have developed the flame-retarded PLA nanocomposites by melt blending method incorporating organically modified montmorillonite （OMMT） and aluminium diethylphosphinate （A1Pi） additives. The influence of A1Pi and OMMT on flame retardancy and thermal stability of PLA was thoroughly investigated by means of the limiting oxygen index （LOI）, UL94 test, cone calorimeter, X-ray diffraction （XRD）, thermogravimetric analysis and scanning electronic microscopy （SEM）. The experimental results show that the PLA/A1Pi/OMMT system has excellent fire retardancy. The LOI value increases from 19% for pristine PLA to 28% for the flame-retarded PLA. Cone calorimeter analysis of the PLA/A1Pi/OMMT exhibits a reduction in the peak heat release rate values by 26.2%. Thermogravimetric analysis and SEM of cone calorimeter residues indicate that OMMT significantly enhances the thermal stability, promotes char-forming and suppresses the melt dripping. The research of this study implies that the combining of the flame retardant and organoclay results in a synergistic effect. In addition, the flame-retarded PLA nanocomposite also exhibits notable increase in the impact strength and the elongation at break.展开更多
The oxygen evolution reaction(OER)is a key process in water splitting for hydrogen production,yet its sluggish kinetics pose significant challenges for catalyst development.In this work,we present the first systematic...The oxygen evolution reaction(OER)is a key process in water splitting for hydrogen production,yet its sluggish kinetics pose significant challenges for catalyst development.In this work,we present the first systematic study on isostructural 2D coordination polymers(CPs)based on 1,10-ferrocenediyl-bis(H-phosphinic)acid,with cobalt,manganese,and cadmium metals as electrocatalysts for OER.These polymers were synthesized via a facile solution reaction,yielding crystalline materials with excellent structural integrity.The electrocatalytic performance of CPs composites,prepared with carbon and phosphonium ionic liquid,was evaluated in 0.1 M KOH using a three-electrode system.Notably,the Co-and Cd-based CPs demonstrated exceptional OER activity,achieving an overpotential as low as 236–255 mV at 10 mA cm^(-2),surpassing those of many previously reported CP-based OER catalysts.Furthermore,these materials exhibited high stability over prolonged electrolysis,maintaining their activity without significant degradation.This work not only introduces a new class of ferrocenyl phosphinatebased CPs as highly active and durable OER catalysts but also provides valuable insights into their structureactivity relationships,paving the way for future advancements in electrocatalysis.展开更多
Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron...Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.展开更多
The chemo-,regio-,and enantio-controlled synthesis of P-chiral phosphines in a general and efficient manner remains a significant synthetic challenge.In this study,a Pd-catalyzed hydrofunctionalization is developed fo...The chemo-,regio-,and enantio-controlled synthesis of P-chiral phosphines in a general and efficient manner remains a significant synthetic challenge.In this study,a Pd-catalyzed hydrofunctionalization is developed for the highly selective synthesis of P-stereogenic alkenylphosphinates and alkenylphosphine oxides via conjugate addition of enynes.Notably,this methodology is suitable for both phosphine oxide and phosphinate nucleophiles,providing a versatile approach for the construction of diverse P-chiral organophosphosphorus compound.展开更多
Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical p...Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical properties[1-3].While transition metals such as Au,Ag,Pt,and Pd dominate the core composition,surface ligands are predominantly limited to phosphines,thiols,alkynes,and carbenes.Among these,N-heterocyclic carbenes(NHCs)have emerged as a superior ligand class due to their dual capacity for strongσ-donation andπ-back bonding,which stabilizes diverse metal oxidation states and enhances metal-ligand interactions.Notably,NHC-protected clusters exhibit exceptional thermal stability attributed to CH-π/π-πinteractions and enlarged HOMO-LUMO gaps compared to thiol or phosphine analogues.Despite progress,synthetic limitations persist due to NHCs'sensitivity under harsh conditions.Current methods rely on direct reduction of metal-carbene precursors or ligand exchange reactions,with heterogeneous NHC-capped systems remaining unexplored.展开更多
Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the ...Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.展开更多
A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively m...A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively mild conditions.Valuable chiral 1,2,3,4-tetrahydroquinoxalines could be obtained with high yields and excellent enantioselectivities(35 examples,up to>99%ee).展开更多
A mild,green,convenient and scalable N-bromosuccinimide(NBS)promoted direct phosphorylation strategy of secondary phosphine oxides and alcohols for the synthesis of various phosphinate esters was developed.A variety o...A mild,green,convenient and scalable N-bromosuccinimide(NBS)promoted direct phosphorylation strategy of secondary phosphine oxides and alcohols for the synthesis of various phosphinate esters was developed.A variety of substrates are well-tolerated and the desirable compounds were afforded in moderate to excellent yields(up to 92%).This reaction is conducted at room temperature without the addition of any oxidant and metal catalyst,which provides a new strategy for the synthesis of phosphinate esters.展开更多
This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via ...This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via phosphine and silver catalysis.These approaches exhibit high regioselectivity,atom econ-omy and broad functionality tolerance.展开更多
An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles.The key pre-aromatic spirocyclic inte...An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles.The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer(SET)process of Togni's reagentⅡpromoted by the tertiary phosphine resulted in an intriguing and alternative tactic for the cleavage of C–C bonds.By using inexpensive tertiary phosphine as the catalyst,this skeleton-reorganizing approach of N-containing heteroaryl ketones allows a streamlined assembly of complex N-fused heterocycles with broad functional group tolerance.展开更多
Tertiary phosphines and their oxides react with oxalyl bromide to generate corresponding quaternary phosphonium salts,which can be further transformed as active intermediates to facilitate the bromination of alcohols ...Tertiary phosphines and their oxides react with oxalyl bromide to generate corresponding quaternary phosphonium salts,which can be further transformed as active intermediates to facilitate the bromination of alcohols and the dibromination of unsaturated hydrocarbons.This chemical process carries substantial research significance in the field of organic synthesis.In this study,two types of triaryl phosphine oxides and benzyl diaryl phosphine oxides containing alkyne groups were designed and synthesized.These compounds were then subjected to reaction with oxalyl bromide,resulting in the formation of novel benzophosphonium tribromides and trans-phosphoryl dibromoalkenes,respectively.These findings demonstrate variations from their reactions with oxalyl chloride.Furthermore,the benzophosphonium tribromide obtained can act as an alternative reagent for bromine,enabling the direct bromination of aromatics compounds,olefin,alkyne and acetophenone derivatives.展开更多
Phosphine-catalyzed[5+1]annulation reaction of Morita-Baylis-Hillman(MBH)carbonates with 1,3-dicarbonyl compounds has been developed,producing biologically interesting spirocyclohexene derivatives in high yields with ...Phosphine-catalyzed[5+1]annulation reaction of Morita-Baylis-Hillman(MBH)carbonates with 1,3-dicarbonyl compounds has been developed,producing biologically interesting spirocyclohexene derivatives in high yields with moderate to excellent diastereoselectivities.The annulation was achieved through sequential 1,6-conjugate addition/nucleophilic substution reaction of phosphine ylides with dinucleophiles.展开更多
Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reacti...Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reaction conditions,and good functional group compatibility,offering a straightforward and efficient preparation route for terminal vinyl phosphine oxides.展开更多
A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman...A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman(MBH)carbonates under the catalysis of Pd/Synphos,which then undergo Michael addition/N-allylic alkylation with 1-azadienes.A spectrum of eight-membered N-heterocycles featuring a trisubstituted exo-cyclic double bond is furnished efficiently with moderate to good E/Z selectivity and moderate atroposelectivity.In addition,moderate enantioselectivity can be realized by using a chiral ligand or with the assistant of a chiral quaternary ammonium salt.展开更多
Rh/SiO2 catalysts with tethered-phosphines with different alkyl spacer lengths have been prepared,tested and characterized.Lengthening the alkyl spacer of the tethered-phosphine improved the flexibility of tethered-ph...Rh/SiO2 catalysts with tethered-phosphines with different alkyl spacer lengths have been prepared,tested and characterized.Lengthening the alkyl spacer of the tethered-phosphine improved the flexibility of tethered-phospine,promoted the formation of active species and enhanced the activity of hydroformylation over other tethered-phosphine modified Rh/SiO2 catalysts.展开更多
The neutral palladium（Ⅱ） complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-imidazolyl]dichloropalladium（Ⅱ）（1A） ligated by thiazolylimidazolyl-based phosphine（L1） in which thiazolylimidazolyl acted as an...The neutral palladium（Ⅱ） complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-imidazolyl]dichloropalladium（Ⅱ）（1A） ligated by thiazolylimidazolyl-based phosphine（L1） in which thiazolylimidazolyl acted as an S- and N-donor provider with weak coordinating nature,and the ionic complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-3-methylimidazolium]dichloropalladium（Ⅱ） trifluoromethanesulfonate（2A） ligated by thiazolylimidazolium-based phosphine（L2） after quaternization of L1 using methyl trifluoromethanesulphonate were synthesized.It was found that the introduced positive charges and strong electron-withdrawing effect in 2A not only led to changes in the configuration and structural stability of the complex,but also lowered its catalytic performance in carbonylative Sonogashira reactions.These effects reveal the important role of the N-donor in 1A.In addition,as an ionic palladium complex,2A combined with the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate could be recycled eight times as the catalyst in carbonylative Sonogashira reactions without detectable metal leaching.展开更多
[Objective] This study aimed to investigate the killing effect of mixed fumi- gation of phosphine and carbon dioxide on eggs of Lasioderma serricorne F. [Method] The outside-storage phosphine generator was placed in a...[Objective] This study aimed to investigate the killing effect of mixed fumi- gation of phosphine and carbon dioxide on eggs of Lasioderma serricorne F. [Method] The outside-storage phosphine generator was placed in a tabernacled smoke box, and the mortality rates of L. serricome F. eggs in the smoke box under conditions of different aluminium phosphide usage amount and different fumigation time were studied. In addition, the times needed by tabernacle and smoke box cen- ter to reach the phosphine concentration peak were recorded. [Result] The optimum conditions for killing the eggs of L. serricorne were as follows： temperature of （27± 2） ℃, relatively humidity of （45±5）%, aluminium phosphide usage amount of 1.5 g/m3 and effective exposure time of 96 h. The killing effect of mixed fumigation of phos- phine and carbon dioxide was increased with the extension of fumigation time. The increased usage amount of aluminium phosphide showed no significant effect on killing effect. The tabernacle space and smoke box center all required relatively short time to reach the phosphine concentration peak. If the tabernacle had a good airtightness, the overall fumigation time could be shortened. [Conclusion] The fumi- gation method is reliable, and it can be used for the control of L. serricorne F. in tobacco storage.展开更多
[Objective] This study aimed to investigate the effects of phosphine on germination and physiological characteristics of rice seeds. [Method] Simulation envi- ronments were conducted to study the effects of high-level...[Objective] This study aimed to investigate the effects of phosphine on germination and physiological characteristics of rice seeds. [Method] Simulation envi- ronments were conducted to study the effects of high-level phosphine on germination status and physiological characteristics of rice seeds and explore the early environ- mental and ecological effects of phosphine on rice growth in phosphorus cycle of paddy field. [Result] Experimental results showed that the increase of phosphine con- centration in the environment resulted in the decrease of germination rate and ger- mination potential by 11.11% and 19.71%, respectively. In addition, the activities of catalase （CAT） and peroxidase （POD） were reduced to 94.35% and 92.61%, respec- tively; the content of malondialdehyde （MDA） was maximally increased by 29.11%, indicating that both germination potential and growth condition of rice seeds were in- hibited under conditions of high-level phosphine. [Conclusion] This study provided theoretical basis for investigating the effects of phosphine on germination of rice seeds under natural environment.展开更多
We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experi...We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experimentally and fitted by the Toth equation, and the isosteric heat of PH_3 adsorption was calculated by the Clausius-Clapeyron Equation. The exhausted MWAC was regenerated by water washing and air drying. Moreover, the properties of five different samples were characterized by N_2 adsorption isotherm, SEM/EDS, XPS, and FTIR. The results showed that the maximum PH_3 equilibrium adsorption capacity was 595.56 mg/g. The MWAC had an energetically heterogeneous surface due to values of isosteric heat of adsorption ranging from 43 to 90 kJ/mol. The regeneration method provided an effective way for both adsorption species recycling and exhausted carbon regeneration. The high removal efficiency and big equilibrium adsorption capacity for PH_3 adsorption on the MWAC were related to its large surface area and high oxidation activity in PH_3 adsorption-oxidation to H_3 PO_4 and P_2 O_5. Furthermore, a possible PH_3 adsorption mechanism was proposed.展开更多
A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its cataly...A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800℃ to 400-500 ℃. The decomposition rate of phosphine achieved 100%.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51203118)the Shanghai Automotive Industry Science and Technology Development Foundation(No.1006)
文摘To minimize the loading level of the char-forming phosphorus based flame retardants in the poly（lactic acid） （PLA） with reduced flammability, we have developed the flame-retarded PLA nanocomposites by melt blending method incorporating organically modified montmorillonite （OMMT） and aluminium diethylphosphinate （A1Pi） additives. The influence of A1Pi and OMMT on flame retardancy and thermal stability of PLA was thoroughly investigated by means of the limiting oxygen index （LOI）, UL94 test, cone calorimeter, X-ray diffraction （XRD）, thermogravimetric analysis and scanning electronic microscopy （SEM）. The experimental results show that the PLA/A1Pi/OMMT system has excellent fire retardancy. The LOI value increases from 19% for pristine PLA to 28% for the flame-retarded PLA. Cone calorimeter analysis of the PLA/A1Pi/OMMT exhibits a reduction in the peak heat release rate values by 26.2%. Thermogravimetric analysis and SEM of cone calorimeter residues indicate that OMMT significantly enhances the thermal stability, promotes char-forming and suppresses the melt dripping. The research of this study implies that the combining of the flame retardant and organoclay results in a synergistic effect. In addition, the flame-retarded PLA nanocomposite also exhibits notable increase in the impact strength and the elongation at break.
文摘The oxygen evolution reaction(OER)is a key process in water splitting for hydrogen production,yet its sluggish kinetics pose significant challenges for catalyst development.In this work,we present the first systematic study on isostructural 2D coordination polymers(CPs)based on 1,10-ferrocenediyl-bis(H-phosphinic)acid,with cobalt,manganese,and cadmium metals as electrocatalysts for OER.These polymers were synthesized via a facile solution reaction,yielding crystalline materials with excellent structural integrity.The electrocatalytic performance of CPs composites,prepared with carbon and phosphonium ionic liquid,was evaluated in 0.1 M KOH using a three-electrode system.Notably,the Co-and Cd-based CPs demonstrated exceptional OER activity,achieving an overpotential as low as 236–255 mV at 10 mA cm^(-2),surpassing those of many previously reported CP-based OER catalysts.Furthermore,these materials exhibited high stability over prolonged electrolysis,maintaining their activity without significant degradation.This work not only introduces a new class of ferrocenyl phosphinatebased CPs as highly active and durable OER catalysts but also provides valuable insights into their structureactivity relationships,paving the way for future advancements in electrocatalysis.
文摘Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.
基金the National Natural Science Foundation of China(NSFC,No.22271241),Yunnan Key Laboratory of Chiral Functional Substance Research and Application(No.202402AN360010)Research Grants Council of Hong Kong(GRF,No.12303422)HKBU KRPS grant for financial support.
文摘The chemo-,regio-,and enantio-controlled synthesis of P-chiral phosphines in a general and efficient manner remains a significant synthetic challenge.In this study,a Pd-catalyzed hydrofunctionalization is developed for the highly selective synthesis of P-stereogenic alkenylphosphinates and alkenylphosphine oxides via conjugate addition of enynes.Notably,this methodology is suitable for both phosphine oxide and phosphinate nucleophiles,providing a versatile approach for the construction of diverse P-chiral organophosphosphorus compound.
文摘Ligand-stabilized metal nanoclusters with atomic precision have garnered significant attention for applications in catalysis,biomedicine,and nanoelectronics due to their tunable structures and unique physicochemical properties[1-3].While transition metals such as Au,Ag,Pt,and Pd dominate the core composition,surface ligands are predominantly limited to phosphines,thiols,alkynes,and carbenes.Among these,N-heterocyclic carbenes(NHCs)have emerged as a superior ligand class due to their dual capacity for strongσ-donation andπ-back bonding,which stabilizes diverse metal oxidation states and enhances metal-ligand interactions.Notably,NHC-protected clusters exhibit exceptional thermal stability attributed to CH-π/π-πinteractions and enlarged HOMO-LUMO gaps compared to thiol or phosphine analogues.Despite progress,synthetic limitations persist due to NHCs'sensitivity under harsh conditions.Current methods rely on direct reduction of metal-carbene precursors or ligand exchange reactions,with heterogeneous NHC-capped systems remaining unexplored.
基金the National Natural Science Foundation of China(Nos.22171147 and 21871148)for the financial support。
文摘Polycyclic compounds are widely found in natural products and drug molecules with important biological activities,which attracted the attention of many chemists.Phosphine-catalyzed nucleophilic addition is one of the most powerful tools for the construction of various cyclic compounds with the advantages of atom economy,mild reaction conditions and simplicity of operation.Allenolates,Morita−Baylis−Hillman(MBH)alcohols and their derivatives(MBHADs),electron-deficient olefins and alkynes are very efficient substrates in phosphine mediated annulations,which formed many phosphonium species such asβ-phosphonium enolates,β-phosphonium dienolates and vinyl phosphonium ylides as intermediates.This review describes the reactivities of these phosphonium zwitterions and summarizes the synthesis of polycycle compounds through phosphine-mediated intramolecular and intermolecular sequential annulations.Thus,a systematic summary of the research process based on the phosphine-mediated sequential annulations of allenolates,MBH alcohols and MBHADs,electron-deficient olefins and alkynes are presented in Chapters 2-6,respectively.
基金the financial support of the National Natural Science Foundation of China(No.21672133)the Opening Foundation of Key Laboratory of Applied Surface and Colloid Chemistry,Ministry of Education(No.GK202205011)the Fundamental Research Funds for the Central Universities(Nos.GK202307007 and GK202002003)。
文摘A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively mild conditions.Valuable chiral 1,2,3,4-tetrahydroquinoxalines could be obtained with high yields and excellent enantioselectivities(35 examples,up to>99%ee).
文摘A mild,green,convenient and scalable N-bromosuccinimide(NBS)promoted direct phosphorylation strategy of secondary phosphine oxides and alcohols for the synthesis of various phosphinate esters was developed.A variety of substrates are well-tolerated and the desirable compounds were afforded in moderate to excellent yields(up to 92%).This reaction is conducted at room temperature without the addition of any oxidant and metal catalyst,which provides a new strategy for the synthesis of phosphinate esters.
基金support from the National Natural Science Foundation of China(Nos.21971107,22071101,22271147).
文摘This work describes intermolecular acylfluorination of gem-difluoroenynes using acyl fluorides as both acyl source and fluorine source.Trifluoromethyl-substituted allenones or furans could be selectively achieved via phosphine and silver catalysis.These approaches exhibit high regioselectivity,atom econ-omy and broad functionality tolerance.
基金the financial support from the National Natural Science Foundation of China(Nos.21971205 and 22271231)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-YB-126)+1 种基金Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(No.2022JC-08)Key Research and Invention Program in Shaanxi Province of China(No.2021SF-299)。
文摘An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles.The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer(SET)process of Togni's reagentⅡpromoted by the tertiary phosphine resulted in an intriguing and alternative tactic for the cleavage of C–C bonds.By using inexpensive tertiary phosphine as the catalyst,this skeleton-reorganizing approach of N-containing heteroaryl ketones allows a streamlined assembly of complex N-fused heterocycles with broad functional group tolerance.
文摘Tertiary phosphines and their oxides react with oxalyl bromide to generate corresponding quaternary phosphonium salts,which can be further transformed as active intermediates to facilitate the bromination of alcohols and the dibromination of unsaturated hydrocarbons.This chemical process carries substantial research significance in the field of organic synthesis.In this study,two types of triaryl phosphine oxides and benzyl diaryl phosphine oxides containing alkyne groups were designed and synthesized.These compounds were then subjected to reaction with oxalyl bromide,resulting in the formation of novel benzophosphonium tribromides and trans-phosphoryl dibromoalkenes,respectively.These findings demonstrate variations from their reactions with oxalyl chloride.Furthermore,the benzophosphonium tribromide obtained can act as an alternative reagent for bromine,enabling the direct bromination of aromatics compounds,olefin,alkyne and acetophenone derivatives.
文摘Phosphine-catalyzed[5+1]annulation reaction of Morita-Baylis-Hillman(MBH)carbonates with 1,3-dicarbonyl compounds has been developed,producing biologically interesting spirocyclohexene derivatives in high yields with moderate to excellent diastereoselectivities.The annulation was achieved through sequential 1,6-conjugate addition/nucleophilic substution reaction of phosphine ylides with dinucleophiles.
文摘Cesium carbonate was used as a base to achieve the desulfurization reaction of alkenyl sulfonium salts and phosphine oxides at room temperature,forming C(sp2)—P bonds.This method features simple operation,mild reaction conditions,and good functional group compatibility,offering a straightforward and efficient preparation route for terminal vinyl phosphine oxides.
文摘A[4+4]annulation reaction for the construction of medium-sized N-heterocycles is reported.This process involves the generation of all-carbon 1,4-dipoles containing aπ-allylpalladium complex from Morita-Baylis-Hillman(MBH)carbonates under the catalysis of Pd/Synphos,which then undergo Michael addition/N-allylic alkylation with 1-azadienes.A spectrum of eight-membered N-heterocycles featuring a trisubstituted exo-cyclic double bond is furnished efficiently with moderate to good E/Z selectivity and moderate atroposelectivity.In addition,moderate enantioselectivity can be realized by using a chiral ligand or with the assistant of a chiral quaternary ammonium salt.
基金financially supported by the National Natural Science Foundation of China(21273227,20903090)~~
文摘Rh/SiO2 catalysts with tethered-phosphines with different alkyl spacer lengths have been prepared,tested and characterized.Lengthening the alkyl spacer of the tethered-phosphine improved the flexibility of tethered-phospine,promoted the formation of active species and enhanced the activity of hydroformylation over other tethered-phosphine modified Rh/SiO2 catalysts.
基金supported by the National Natural Science Foundation of China(21473058,21273077)~~
文摘The neutral palladium（Ⅱ） complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-imidazolyl]dichloropalladium（Ⅱ）（1A） ligated by thiazolylimidazolyl-based phosphine（L1） in which thiazolylimidazolyl acted as an S- and N-donor provider with weak coordinating nature,and the ionic complex bis-[1-（5＇-diphenylphosphinothiazol-2＇-yl）-3-methylimidazolium]dichloropalladium（Ⅱ） trifluoromethanesulfonate（2A） ligated by thiazolylimidazolium-based phosphine（L2） after quaternization of L1 using methyl trifluoromethanesulphonate were synthesized.It was found that the introduced positive charges and strong electron-withdrawing effect in 2A not only led to changes in the configuration and structural stability of the complex,but also lowered its catalytic performance in carbonylative Sonogashira reactions.These effects reveal the important role of the N-donor in 1A.In addition,as an ionic palladium complex,2A combined with the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate could be recycled eight times as the catalyst in carbonylative Sonogashira reactions without detectable metal leaching.
文摘[Objective] This study aimed to investigate the killing effect of mixed fumi- gation of phosphine and carbon dioxide on eggs of Lasioderma serricorne F. [Method] The outside-storage phosphine generator was placed in a tabernacled smoke box, and the mortality rates of L. serricome F. eggs in the smoke box under conditions of different aluminium phosphide usage amount and different fumigation time were studied. In addition, the times needed by tabernacle and smoke box cen- ter to reach the phosphine concentration peak were recorded. [Result] The optimum conditions for killing the eggs of L. serricorne were as follows： temperature of （27± 2） ℃, relatively humidity of （45±5）%, aluminium phosphide usage amount of 1.5 g/m3 and effective exposure time of 96 h. The killing effect of mixed fumigation of phos- phine and carbon dioxide was increased with the extension of fumigation time. The increased usage amount of aluminium phosphide showed no significant effect on killing effect. The tabernacle space and smoke box center all required relatively short time to reach the phosphine concentration peak. If the tabernacle had a good airtightness, the overall fumigation time could be shortened. [Conclusion] The fumi- gation method is reliable, and it can be used for the control of L. serricorne F. in tobacco storage.
基金Supported by National Natural Science Foundation of China(41071305)~~
文摘[Objective] This study aimed to investigate the effects of phosphine on germination and physiological characteristics of rice seeds. [Method] Simulation envi- ronments were conducted to study the effects of high-level phosphine on germination status and physiological characteristics of rice seeds and explore the early environ- mental and ecological effects of phosphine on rice growth in phosphorus cycle of paddy field. [Result] Experimental results showed that the increase of phosphine con- centration in the environment resulted in the decrease of germination rate and ger- mination potential by 11.11% and 19.71%, respectively. In addition, the activities of catalase （CAT） and peroxidase （POD） were reduced to 94.35% and 92.61%, respec- tively; the content of malondialdehyde （MDA） was maximally increased by 29.11%, indicating that both germination potential and growth condition of rice seeds were in- hibited under conditions of high-level phosphine. [Conclusion] This study provided theoretical basis for investigating the effects of phosphine on germination of rice seeds under natural environment.
基金Funded by the National Natural Science Foundation of China(51566017)
文摘We prepared a kind of metal oxide-modified walnut-shell activated carbon(MWAC) by KOH chemical activation method and used for PH_3 adsorption removal. Meanwhile, the PH_3 adsorption equilibrium was investigated experimentally and fitted by the Toth equation, and the isosteric heat of PH_3 adsorption was calculated by the Clausius-Clapeyron Equation. The exhausted MWAC was regenerated by water washing and air drying. Moreover, the properties of five different samples were characterized by N_2 adsorption isotherm, SEM/EDS, XPS, and FTIR. The results showed that the maximum PH_3 equilibrium adsorption capacity was 595.56 mg/g. The MWAC had an energetically heterogeneous surface due to values of isosteric heat of adsorption ranging from 43 to 90 kJ/mol. The regeneration method provided an effective way for both adsorption species recycling and exhausted carbon regeneration. The high removal efficiency and big equilibrium adsorption capacity for PH_3 adsorption on the MWAC were related to its large surface area and high oxidation activity in PH_3 adsorption-oxidation to H_3 PO_4 and P_2 O_5. Furthermore, a possible PH_3 adsorption mechanism was proposed.
基金supported by the Tianjin Natural Science Foundation(No.043801311).
文摘A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800℃ to 400-500 ℃. The decomposition rate of phosphine achieved 100%.
