This letter presents ab initio calculation of Captodative effect on 2,2,2-trifluoroethylamine free radical on STO-3G level. The △Ecd is -50. 15 kJ/mol, which means that this radical is of extra stabilization energy.
The effects of N-2-hydroxyethyl-N-methyl-p-toluidine (HMT) on MMA polymerization using organic peroxide as an initiator and on AN photoinduced polymerization have been investigated respectively. The kinetics of polyme...The effects of N-2-hydroxyethyl-N-methyl-p-toluidine (HMT) on MMA polymerization using organic peroxide as an initiator and on AN photoinduced polymerization have been investigated respectively. The kinetics of polymerization and the overall activation energy of polymerization were determined. Based on kinetics study and the end group analysis of the polymer obtained by UV spectrum method, the initiation mechanism is proposed.展开更多
The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In com...The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE.展开更多
This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by ...This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.展开更多
Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. ...Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of cbitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide （O2^-）/hydroxyl （·OH） radicals scavenging, reducing power, iron ion chelating. The following results are obtained： first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O2 scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.展开更多
In this study,acetone extracts of thirteen different species distributed in Turkey Coasts including tunicates,sea anemones,sponges and corals were investigated for their superoxide(SO)radical scavenging and cytotoxic ...In this study,acetone extracts of thirteen different species distributed in Turkey Coasts including tunicates,sea anemones,sponges and corals were investigated for their superoxide(SO)radical scavenging and cytotoxic activities.VWhile SO radical scavenging activity was tested using alkaline DMSO method,cytotoxic activity was tested by MTT assay against Hep-2 cancer cell line.As a result of bioactivity studies,Paramuricea clavata extract showed展开更多
Pt(Ⅱ) and Pd(Ⅱ) complexes with 2′,3′,4′,5,7-pentahydroxy-flavone weresynthesized and characterized by elemental analysis, molar conductance, IR, ~1HNMR, TG-DTA, UV-Visspectroscopic techniques, and fluorescence an...Pt(Ⅱ) and Pd(Ⅱ) complexes with 2′,3′,4′,5,7-pentahydroxy-flavone weresynthesized and characterized by elemental analysis, molar conductance, IR, ~1HNMR, TG-DTA, UV-Visspectroscopic techniques, and fluorescence analysis. The scavenging effect on the superoxide radical(O_2^-) and the inhibitory effect on lipid peroxides were also investigated. Both the ligand andthe complexes exhibit scavenging effect on superoxide radicals, and the effect of the complexes isgreater than that of the ligand. The Pt(Ⅱ) complex exhibits the strongest scavenging efficiency.Both Pt(Ⅱ) and Pd(Ⅱ) complexes have the inhibitory effect on lipid peroxides, and the effect ofthe complexes is greater than that of the ligand, but the Pt(Ⅱ) complex has a high effect ofpromoting lipid peroxides.展开更多
文摘This letter presents ab initio calculation of Captodative effect on 2,2,2-trifluoroethylamine free radical on STO-3G level. The △Ecd is -50. 15 kJ/mol, which means that this radical is of extra stabilization energy.
基金The project supported by the National Natural Science Foundation of China
文摘The effects of N-2-hydroxyethyl-N-methyl-p-toluidine (HMT) on MMA polymerization using organic peroxide as an initiator and on AN photoinduced polymerization have been investigated respectively. The kinetics of polymerization and the overall activation energy of polymerization were determined. Based on kinetics study and the end group analysis of the polymer obtained by UV spectrum method, the initiation mechanism is proposed.
文摘The static O-H bond parameters including O-H bond length, O-H charge difference, O-H Mulliken population and O-H bond stretching force constant (k) for 17 phenols were calculated by ab initio method HF/6-31G**. In combination with the O-H bond dissociation enthalpies (BDE) of the phenols determined by experiment, it was found that there were poor correlationships between the static O-H bond parameters and O-H BDE. Considering the good correlationship bt tween O-H BDE and logarithm of free radical scavenging rate constant for phenolic antioxidant, it is reasonable to believe that the ineffectiveness of static O-H bond parameters in characterizing antioxidant activity arises from the fact that they cannot measure the O-H BDE.
基金Supported by National Natural Science Foundation of China
文摘This paper describes the synthesis and free radical ring-opening polymerization of 2-methyl-and 2-methyl-9-n-butyl (-7-methylene-1, 4, 6-trioxaspiro (4, 4) nonane). The structures of the two polymers were verified by IR, 'H and ^(13)C NMR spectra. The substituent on 9-position of 7-methylene-trioxaspiro (4, 4) nonane affects the structure of polymer and polymerization activity. The polymerization mechanism is discussed.
基金Supported by the Talent Program of Chinese Academy of Sciences (Dongbei Zhi Chun)Award Foundation of Scientific Research for Excellent Young and Middle-Age Scientist of Shandong Province (No. 2007BS07002)
文摘Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of cbitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide （O2^-）/hydroxyl （·OH） radicals scavenging, reducing power, iron ion chelating. The following results are obtained： first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O2 scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.
基金supported by the Turkish Academy of Science,Young Scientist Award(TUBA-GEBIP/2013)
文摘In this study,acetone extracts of thirteen different species distributed in Turkey Coasts including tunicates,sea anemones,sponges and corals were investigated for their superoxide(SO)radical scavenging and cytotoxic activities.VWhile SO radical scavenging activity was tested using alkaline DMSO method,cytotoxic activity was tested by MTT assay against Hep-2 cancer cell line.As a result of bioactivity studies,Paramuricea clavata extract showed
文摘Pt(Ⅱ) and Pd(Ⅱ) complexes with 2′,3′,4′,5,7-pentahydroxy-flavone weresynthesized and characterized by elemental analysis, molar conductance, IR, ~1HNMR, TG-DTA, UV-Visspectroscopic techniques, and fluorescence analysis. The scavenging effect on the superoxide radical(O_2^-) and the inhibitory effect on lipid peroxides were also investigated. Both the ligand andthe complexes exhibit scavenging effect on superoxide radicals, and the effect of the complexes isgreater than that of the ligand. The Pt(Ⅱ) complex exhibits the strongest scavenging efficiency.Both Pt(Ⅱ) and Pd(Ⅱ) complexes have the inhibitory effect on lipid peroxides, and the effect ofthe complexes is greater than that of the ligand, but the Pt(Ⅱ) complex has a high effect ofpromoting lipid peroxides.
