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
The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were i...The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).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
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
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
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 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
A novel 2-indano[2,3b]-2-ferrocenyl- and 2-indano[2,3b]-2-(p-methoxy-phenyl)[1,5]benzo-2,5-dihydrothiazepine 5a,b (addition Michael/cyclization) (~30.32%), indano[2,3b]-2-ferrocenyl- and 2-(p-methoxyphenyl)[1,4] benzo...A novel 2-indano[2,3b]-2-ferrocenyl- and 2-indano[2,3b]-2-(p-methoxy-phenyl)[1,5]benzo-2,5-dihydrothiazepine 5a,b (addition Michael/cyclization) (~30.32%), indano[2,3b]-2-ferrocenyl- and 2-(p-methoxyphenyl)[1,4] benzothiazine 4a,b (addition “anti-Michael”/cyclization) (~45.43%), respectively, were obtained by the condensation of 2-ferrocenyl-and 2-(p-methoxy-phenyl)methyliden-1,3-indandiones 1a,b with o-aminothiophenol 2 in the presence of AcOH and HCl. A new “anti-Michael” addition reaction of 1,4-bis-heteronucleophile 2 into 2-arylmethyliden-1,3-indandiones was reported. As a result of this reaction the product 1a,b was obtained. The structures of the resultant compounds were elucidated by IR, 1H and 13C NMR spectroscopy, mass spectrometry, elemental and X-ray diffraction analysis. The in vitro antitumor activity of the obtained products was researched using the following human cancer cell lines: glioblastoma (CNS U-251), prostatic adenocarcinoma (PC-3), chronic myelogenous leukemia (K562), colorectal adenocarcinoma (HCT-15), mammary adenocarcinoma (MCF-7), and small cell lung cancer (SKLU) and the sulforhodamine B (SRB) method. Among these new compounds some thiazine and thiazepine derivatives showed compelling in vitro antitumor effects on cell lines K-562, HCT-15, SKLU-1 and MCF-7.展开更多
Whereas the proper choice of reaction solvent constitutes the cornerstone of the green solvent concept,solvent effects on chemical reactions are not mechanistically well understood due to the lack of feasible molecula...Whereas the proper choice of reaction solvent constitutes the cornerstone of the green solvent concept,solvent effects on chemical reactions are not mechanistically well understood due to the lack of feasible molecular models.Herein,by taking the case study of nucleophilic addition reaction in aqueous solution,we extend the proposed multiscale reaction density functional theory(RxDFT)method to investigate the intrinsic free energy profile and total free energy profile,and study the solvent effect on the activation and reaction free energy for the nucleophilic addition reactions of hydroxide anion with methanal and carbon dioxide in aqueous solution.The predictions of the free energy profile in aqueous solution for these two nucleophilic addition reactions from RxDFT have a satisfactory agreement with the results from the RISM and MD-FEP simulation.Meanwhile,the solvent effect is successfully addressed by examining the difference of the free energy profile between the gas phase and aqueous phase.In addition,we investigate the solvent effect on the reactions occurred near solid-liquid interfaces.It is shown that the activation free energy is significantly depressed when reaction takes place in the region within 10A distance to the substrate surface owing to the decrease of hydration free energy at the solid-liquid interface.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
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.
Six compounds including five proline derivatives have been prepared and tested as chiral organocatalysts for enantioselective aldol reactions and Michael additions. The enantiomeric excesses, which are highly dependen...Six compounds including five proline derivatives have been prepared and tested as chiral organocatalysts for enantioselective aldol reactions and Michael additions. The enantiomeric excesses, which are highly dependent on the molecular structure of catalysts as well as experimental conditions, have reached over 98%.展开更多
The Michael addition reactions of Z and E 4-methyl-benzaldoximes with propene were investigated theoretically by DFT method at B3LYP/6-31G* level.The calculation results show that both addition reactions are concerted...The Michael addition reactions of Z and E 4-methyl-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
Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study....Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.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.
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
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 National Natural Science Foundation of China(No.51876080)the Strategic International Scientific and Technological Innovation Cooperation Special Funds of National Key Research and Development Program of China(No.2016YFE0204000)+3 种基金the Program for Taishan Scholars of Shandong Province Governmentthe Recruitment Program of Global Experts(Thousand Youth Talents Plan)the Natural Science Foundation of Shandong Province(ZR2017BB002)the Key Research and Development Program of Shandong Province(2018GSF116014)。
文摘The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).
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.
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.
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.
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. 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A novel 2-indano[2,3b]-2-ferrocenyl- and 2-indano[2,3b]-2-(p-methoxy-phenyl)[1,5]benzo-2,5-dihydrothiazepine 5a,b (addition Michael/cyclization) (~30.32%), indano[2,3b]-2-ferrocenyl- and 2-(p-methoxyphenyl)[1,4] benzothiazine 4a,b (addition “anti-Michael”/cyclization) (~45.43%), respectively, were obtained by the condensation of 2-ferrocenyl-and 2-(p-methoxy-phenyl)methyliden-1,3-indandiones 1a,b with o-aminothiophenol 2 in the presence of AcOH and HCl. A new “anti-Michael” addition reaction of 1,4-bis-heteronucleophile 2 into 2-arylmethyliden-1,3-indandiones was reported. As a result of this reaction the product 1a,b was obtained. The structures of the resultant compounds were elucidated by IR, 1H and 13C NMR spectroscopy, mass spectrometry, elemental and X-ray diffraction analysis. The in vitro antitumor activity of the obtained products was researched using the following human cancer cell lines: glioblastoma (CNS U-251), prostatic adenocarcinoma (PC-3), chronic myelogenous leukemia (K562), colorectal adenocarcinoma (HCT-15), mammary adenocarcinoma (MCF-7), and small cell lung cancer (SKLU) and the sulforhodamine B (SRB) method. Among these new compounds some thiazine and thiazepine derivatives showed compelling in vitro antitumor effects on cell lines K-562, HCT-15, SKLU-1 and MCF-7.
基金supported by National Natural Science Foundation of China(Nos.91934302,21878078 and 21808056)。
文摘Whereas the proper choice of reaction solvent constitutes the cornerstone of the green solvent concept,solvent effects on chemical reactions are not mechanistically well understood due to the lack of feasible molecular models.Herein,by taking the case study of nucleophilic addition reaction in aqueous solution,we extend the proposed multiscale reaction density functional theory(RxDFT)method to investigate the intrinsic free energy profile and total free energy profile,and study the solvent effect on the activation and reaction free energy for the nucleophilic addition reactions of hydroxide anion with methanal and carbon dioxide in aqueous solution.The predictions of the free energy profile in aqueous solution for these two nucleophilic addition reactions from RxDFT have a satisfactory agreement with the results from the RISM and MD-FEP simulation.Meanwhile,the solvent effect is successfully addressed by examining the difference of the free energy profile between the gas phase and aqueous phase.In addition,we investigate the solvent effect on the reactions occurred near solid-liquid interfaces.It is shown that the activation free energy is significantly depressed when reaction takes place in the region within 10A distance to the substrate surface owing to the decrease of hydration free energy at the solid-liquid interface.
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.
文摘Six compounds including five proline derivatives have been prepared and tested as chiral organocatalysts for enantioselective aldol reactions and Michael additions. The enantiomeric excesses, which are highly dependent on the molecular structure of catalysts as well as experimental conditions, have reached over 98%.
文摘The Michael addition reactions of Z and E 4-methyl-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.
文摘Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.
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.