The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their...The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their distinct sensing mechanisms and experimental phenomena. The time-dependent density functional theory has been applied to investigate the ground states and the first singlet excited electronic states of the sensor as well as their possible Michael reaction products with cyanide, with a view to monitoring their geometries and photophysieal properties. The theoretical study indicates that the protic water solvent could lead to final Michael addition product of sensor a in the ground state, while the aprotic acetonitrile solvent could lead to carbanion as the final product of sensor b. Furthermore, the Michael reaction product of sensor a has been proved to have a torsion structure in its first singlet excited state. Correspondingly, sensor b also has a torsion structure around the nitrovinyl moiety in its first singlet excited state, while not in its carbanion structure. This could explain the observed strong fluorescence for sensor a and the quenching fluorescence for the sensor b upon the addition of the cyanide anions in the relevant sensing mechanisms.展开更多
A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A rang...A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A range of chalcones and nitroalkenes together with active methylene compounds have been converted smoothly to the corresponding products in high yields.展开更多
Photoinduoed reaction of chloranil (TCBQ) with 2-methylfuran la and 2,5-dimethylfuran 1b in benzene gave addition products 2a and 2b respecvely together with tetrachlorohydroquinone 3. A mechanism of sequential electr...Photoinduoed reaction of chloranil (TCBQ) with 2-methylfuran la and 2,5-dimethylfuran 1b in benzene gave addition products 2a and 2b respecvely together with tetrachlorohydroquinone 3. A mechanism of sequential electron and proton transfer from la or 1b to ~3TCBQ followed by coupling of the furfuryl and semiquinone radical pairs was proposed and is evidenced by the photo-CIDNP studies of the TCBQ-1a and TCBQ-1b systems.展开更多
A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitro...A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitromethane, and active methylene compounds were converted smoothly to the corresponding products in high yields. The simple procedure, very mild conditions, high yields, and reuse of the IL without any loss of catalytic activity make this protocol considerably attractive for academic researches and practical applications.展开更多
Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to ex...Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions.The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives bearing chiral quaternary carbon centers.展开更多
Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in...Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in excellent yields.展开更多
The Michael addition reactions of Z and E benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G^＊ level. The calculation results show that both addition reactions are concerted proce...The Michael addition reactions of Z and E benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G^＊ level. The calculation results show that both addition reactions are concerted processes accompanied by the migration of hydrogen from the atom oxygen to carbon. Both products Z and E nitrones have dipolar charge distributions and activities. Z isomer is more favorable in the reaction due to the barrier is lower.展开更多
The electronic structure and reactivities of Fe（CO）n （n = 3~5） addition to different fullerenes have been investigated through the first-principles calculations, and the results indicate that Fe（CO）3 and Fe（CO...The electronic structure and reactivities of Fe（CO）n （n = 3~5） addition to different fullerenes have been investigated through the first-principles calculations, and the results indicate that Fe（CO）3 and Fe（CO）4 can be adsorbed to the outside network of fullerene via hollow and bridge sites, respectively. Both of them have larger binding energy, but when Fe（CO）5 is adsorbed via the top site, the binding energy is relatively smaller. According to the directional curvature theory, the reactivities of Fe（CO）3 addition to the fullerenes are determined by KM of the ring center, and those of Fe（CO）4 addition by KD of the C–C bond curvature; while for Fe（CO）5, it presents weak reactivities in the addition reaction because of the larger volume effect. No matter whether the addition reaction takes place on the hollow or bridge site, the binding energies show a linear relationship with KD. This work further enriched the directional curvature theory and applied the isolobel analogy theory in the fullerene addition reactions.展开更多
The addition reaction of p chlorobenzaldoxime dehydrodimer and 1,3 dienes in refluxing chloroform gives linear 1,4 addition products. The reaction is probably a free radical process.
Bis（diphenylphosphinyl）butadiyne reacted with methylcyclopentadiene at room temperature and four isomeric products were obtained. Crystal structures of isomers 1 and 3 have been determined. Crystal data for compound...Bis（diphenylphosphinyl）butadiyne reacted with methylcyclopentadiene at room temperature and four isomeric products were obtained. Crystal structures of isomers 1 and 3 have been determined. Crystal data for compound 1 C40H36O2P2·2CHCl3： monoclinic, space group C12/c1 with a = 17.983（2）, b = 11.8723（12）, c = 20.081（2） A, β = 111.218（3）°, V= 3996.5（8） A^3, Z = 4, Mr= 849.36, Dc = 1.412 g/cm^3, F（000） = 1752,μ = 0.546 mm^-1, the final R = 0.0351 and wR = 0.0951 for 3965 observed reflections （I 〉 2σ（I））; and those for compound 3 C40H36O2P2·H2O： triclinic, space group PI with a = 10.4144（15）, b = 13.0558（18）, c = 13.742（2） A, a = 70.453（8）, β = 75.382（8）, γ = 72.312（8）°, V = 1653.7（4） A^3, Z = 2, Mr= 628.64, Dc = 1.262 g/cm^3, F（000） = 664,μ = 0.169 mm^-1, the final R = 0.0593 and wR = 0.1296 for 4891 observed reflections （I 〉 2σ（I））. The structures of the other two isomers are identified via IR, ^1H NMR and MS spectra.展开更多
CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct...CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct' CCl_3(CH_2CF_2)_2Br. The result indicates that CCl_3SO_2Br can be used as an addendum in trichloromethyl-bromo-addition reactions to olefins.展开更多
Promoted by various reductants,the addition of 1-iodo-4-chloro- perfluorobutane to 1-hexene giving 1:1 adduct is reported.Based on these facts,several new redox systems are proposed.
Functionalized organozinc reagents can easily conduct 1,4-addition reaction with unsaturated esters in the presence of Cu(OAc)2 and LiCl under very Anld conditions to give the products in excellent yields.
Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite ...Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.展开更多
The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. Th...The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. The reactions were promoted by TMG, affording the desired adducts in acceptable to good yields.展开更多
Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridg...Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.展开更多
Chemical functionalization of graphene is a topic of paramount importance to broaden its applications in chemistry,physics,and biological science but remains a great challenge due to its low chemical activity and poor...Chemical functionalization of graphene is a topic of paramount importance to broaden its applications in chemistry,physics,and biological science but remains a great challenge due to its low chemical activity and poor dispersion.Here,we report a strategy for the photosynergetic electrochemical functionalization of graphene(EFG).By using chloride ion(Cl^(-))as the intercalation anions and co-reactants,the electrogenerated radicals confined in the expanded graphite layers enable efficient radical addition reaction,thus grasping crystallineperfect EFG.We found that the ultraviolet irradiation and applied voltage have increased the surface/interface concentration of Cl,thus boosting the functionalization of graphene.Theoretical calculation and experimental results verified the oxygen evolution reaction(OER)on EFG has been improved by regulating the doping of chlorine atoms.In addition,the reduced interlayer distance and enhanced electrostatic repulsion near the basal plane endow the fabricated EFG-based membrane with high salt retention.This work highlights a method for the in situ functionalization of graphene and the subsequent applications in OER and water desalination.展开更多
The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants,transition states,and products have been optimized,re...The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants,transition states,and products have been optimized,respectively at the B3LYP/6-311G（d,p） level.Vibrational frequencies,IR intensities and relative energies for various stationary points have been determined.The reaction pathways are identified by intrinsic reaction coordinate（IRC）calculations.Theoretical analysis provided conclusive evidence that the process is completed through five pathways of addition reaction of double bond,and the transition states are found to be four- membered ring compounds.Solvent effects are taken into account with the PCM model at the same level.This preliminary study shows that the complex formation is favored by the use of polar solvent.展开更多
基金This work was supported by the National Key Basic Research Special Foundation （No.2007CB815202 and No.2009CB220010） and the National Natural Science Foundation of China （No.20833008）.
文摘The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their distinct sensing mechanisms and experimental phenomena. The time-dependent density functional theory has been applied to investigate the ground states and the first singlet excited electronic states of the sensor as well as their possible Michael reaction products with cyanide, with a view to monitoring their geometries and photophysieal properties. The theoretical study indicates that the protic water solvent could lead to final Michael addition product of sensor a in the ground state, while the aprotic acetonitrile solvent could lead to carbanion as the final product of sensor b. Furthermore, the Michael reaction product of sensor a has been proved to have a torsion structure in its first singlet excited state. Correspondingly, sensor b also has a torsion structure around the nitrovinyl moiety in its first singlet excited state, while not in its carbanion structure. This could explain the observed strong fluorescence for sensor a and the quenching fluorescence for the sensor b upon the addition of the cyanide anions in the relevant sensing mechanisms.
基金Supported by the Jilin University Innovation Fund(No.419070200033).
文摘A facile and efficient 1, 4-conjungate addition（Michael addition） reaction of active methylene compounds to aft-unsaturated compounds, catalyzed by guanidinium lactate ionic liquid（IL9）, has been developed. A range of chalcones and nitroalkenes together with active methylene compounds have been converted smoothly to the corresponding products in high yields.
文摘Photoinduoed reaction of chloranil (TCBQ) with 2-methylfuran la and 2,5-dimethylfuran 1b in benzene gave addition products 2a and 2b respecvely together with tetrachlorohydroquinone 3. A mechanism of sequential electron and proton transfer from la or 1b to ~3TCBQ followed by coupling of the furfuryl and semiquinone radical pairs was proposed and is evidenced by the photo-CIDNP studies of the TCBQ-1a and TCBQ-1b systems.
文摘A catalyst-free, facile and efficient Michael addition reaction of active methylene compounds as well as nitromethane with chalcones catalyzed by guanidinium lactate ionic liquid was done. A series of chalcones, nitromethane, and active methylene compounds were converted smoothly to the corresponding products in high yields. The simple procedure, very mild conditions, high yields, and reuse of the IL without any loss of catalytic activity make this protocol considerably attractive for academic researches and practical applications.
基金Financial support from Chinese Academy of Sciences (No.XDB 20020100)the National Natural Science Foundation of China (Nos.21572247,21871282) is gratefully acknowledged。
文摘Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions.The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives bearing chiral quaternary carbon centers.
文摘Functionalized organozinc reagents can easily under 1, 4-addition reaction withunsaturated esters in the presence of catalytic amount of Ni (acac)_2 and tertiary ammes under verymild conditions to give the products in excellent yields.
基金supported by the National Natural Science Foundation of China(No.20373033).
文摘The Michael addition reactions of Z and E benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G^＊ level. The calculation results show that both addition reactions are concerted processes accompanied by the migration of hydrogen from the atom oxygen to carbon. Both products Z and E nitrones have dipolar charge distributions and activities. Z isomer is more favorable in the reaction due to the barrier is lower.
基金Supported by the National Natural Science Foundation of China (No. 21073034)the State Key Laboratory of Structural Chemistry (No. 20090060)
文摘The electronic structure and reactivities of Fe（CO）n （n = 3~5） addition to different fullerenes have been investigated through the first-principles calculations, and the results indicate that Fe（CO）3 and Fe（CO）4 can be adsorbed to the outside network of fullerene via hollow and bridge sites, respectively. Both of them have larger binding energy, but when Fe（CO）5 is adsorbed via the top site, the binding energy is relatively smaller. According to the directional curvature theory, the reactivities of Fe（CO）3 addition to the fullerenes are determined by KM of the ring center, and those of Fe（CO）4 addition by KD of the C–C bond curvature; while for Fe（CO）5, it presents weak reactivities in the addition reaction because of the larger volume effect. No matter whether the addition reaction takes place on the hollow or bridge site, the binding energies show a linear relationship with KD. This work further enriched the directional curvature theory and applied the isolobel analogy theory in the fullerene addition reactions.
文摘The addition reaction of p chlorobenzaldoxime dehydrodimer and 1,3 dienes in refluxing chloroform gives linear 1,4 addition products. The reaction is probably a free radical process.
基金Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars and the State Education Ministry
文摘Bis（diphenylphosphinyl）butadiyne reacted with methylcyclopentadiene at room temperature and four isomeric products were obtained. Crystal structures of isomers 1 and 3 have been determined. Crystal data for compound 1 C40H36O2P2·2CHCl3： monoclinic, space group C12/c1 with a = 17.983（2）, b = 11.8723（12）, c = 20.081（2） A, β = 111.218（3）°, V= 3996.5（8） A^3, Z = 4, Mr= 849.36, Dc = 1.412 g/cm^3, F（000） = 1752,μ = 0.546 mm^-1, the final R = 0.0351 and wR = 0.0951 for 3965 observed reflections （I 〉 2σ（I））; and those for compound 3 C40H36O2P2·H2O： triclinic, space group PI with a = 10.4144（15）, b = 13.0558（18）, c = 13.742（2） A, a = 70.453（8）, β = 75.382（8）, γ = 72.312（8）°, V = 1653.7（4） A^3, Z = 2, Mr= 628.64, Dc = 1.262 g/cm^3, F（000） = 664,μ = 0.169 mm^-1, the final R = 0.0593 and wR = 0.1296 for 4891 observed reflections （I 〉 2σ（I））. The structures of the other two isomers are identified via IR, ^1H NMR and MS spectra.
文摘CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct' CCl_3(CH_2CF_2)_2Br. The result indicates that CCl_3SO_2Br can be used as an addendum in trichloromethyl-bromo-addition reactions to olefins.
文摘Promoted by various reductants,the addition of 1-iodo-4-chloro- perfluorobutane to 1-hexene giving 1:1 adduct is reported.Based on these facts,several new redox systems are proposed.
文摘Functionalized organozinc reagents can easily conduct 1,4-addition reaction with unsaturated esters in the presence of Cu(OAc)2 and LiCl under very Anld conditions to give the products in excellent yields.
基金supported by the National Natural Science Foundation of China (51872321, 11874402, 52172260, 52072402,52102332 and 52102267)Ministry of Sciecnce and Technology of the People’s Republic of China (2021YFB3800103)the Fundamental Research Fund for the Central University,Nankai University (023/63213101)。
文摘Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.
文摘The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. The reactions were promoted by TMG, affording the desired adducts in acceptable to good yields.
基金National Natural Science Foundation of China(NSFC,Nos.21772032,21877206,and 22101074)the 111 Project(No.D17007)+3 种基金Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)China Postdoctoral Science Foundation(No.2019M660173)the Natural Science Foundation of Henan Province(No.202300410233)Henan Key Laboratory of Organic Functional Molecules and Drug Innovation for financial support。
文摘Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.
基金Project supported by the National Natural Science Foundation of Chinathe Foundation of National Key Laboratory of Bioorganic Natural Product Chemistry of China.
文摘Linalyl alkyl or aryl carbinols were regioselectively synthesized by the reaction of geranyl bromide and powdered tin with aldehydes and ketones.
基金supported by the Natural Science Foundation of Guangxi Province(2021GXNSFBA220077,GUIKE AD23026050)National Natural Science Foundation of China(22102035 and 22162006)Innovation Project of Guangxi Graduate Education(XYCBZ2024021).
文摘Chemical functionalization of graphene is a topic of paramount importance to broaden its applications in chemistry,physics,and biological science but remains a great challenge due to its low chemical activity and poor dispersion.Here,we report a strategy for the photosynergetic electrochemical functionalization of graphene(EFG).By using chloride ion(Cl^(-))as the intercalation anions and co-reactants,the electrogenerated radicals confined in the expanded graphite layers enable efficient radical addition reaction,thus grasping crystallineperfect EFG.We found that the ultraviolet irradiation and applied voltage have increased the surface/interface concentration of Cl,thus boosting the functionalization of graphene.Theoretical calculation and experimental results verified the oxygen evolution reaction(OER)on EFG has been improved by regulating the doping of chlorine atoms.In addition,the reduced interlayer distance and enhanced electrostatic repulsion near the basal plane endow the fabricated EFG-based membrane with high salt retention.This work highlights a method for the in situ functionalization of graphene and the subsequent applications in OER and water desalination.
基金supported by the Natural Science Foundation of Shandong Province(No.Y2003B03,Y2006B42).
文摘The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants,transition states,and products have been optimized,respectively at the B3LYP/6-311G（d,p） level.Vibrational frequencies,IR intensities and relative energies for various stationary points have been determined.The reaction pathways are identified by intrinsic reaction coordinate（IRC）calculations.Theoretical analysis provided conclusive evidence that the process is completed through five pathways of addition reaction of double bond,and the transition states are found to be four- membered ring compounds.Solvent effects are taken into account with the PCM model at the same level.This preliminary study shows that the complex formation is favored by the use of polar solvent.
