The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by ' cage ' vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate ofpolymerization isThe relationship...The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by ' cage ' vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate ofpolymerization isThe relationship between the induction period (τ) and the temperature of polymerization as well as the concentrations of reactants can be expressed as follows :The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreases with increasing temperature of polymerization and concentrations of vanadyl polycarboxylate and thioureaThe polymerization mechanism was proposed and discussed.展开更多
The new vanadyl complex [VO（o-van）2（H2O）]（o-van=o-vanillin）was synthesized and characterized by IR,elemental analysis,and X-ray diffraction analysis.In the complex,the vanadium atom was coordinated to six oxygen...The new vanadyl complex [VO（o-van）2（H2O）]（o-van=o-vanillin）was synthesized and characterized by IR,elemental analysis,and X-ray diffraction analysis.In the complex,the vanadium atom was coordinated to six oxygen atoms and formed a distorted octahedral structure.The crystal belongs to monoclinic system with space group P21/n,a=0.9414（4）nm,b=1.6103（6） nm,c=1.1710（4）nm,β=111.493（6）°,V=1.6518（10）nm3,Z=4,DC=1.557 g·cm-3,F（000）=796,R1=0.0424,wR2=0.0842.展开更多
Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are sim...Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are similar in chemical structures but different in glucose-lowering effects. Our experimental results show that they are both transported via passive diffusion with apparent permeabilty coefficients (apical→basolateral) of (82.0 ± 6.7)× 10-7 and (14.6 ± 0.7)× 10-7 cm· s-1, respec-tively. This suggests that absorptivity of VO(acac)2 is much higher than that of VO(ma)2. This difference may be related to the metabolism of either compound, or its ligand, or both in the course of the transport. However, This difference in absorption will cause the great difference in bioavailability,which might account for better efficacy of VO(acac)2 than VO(ma)2 as the insulin-mimic agent.展开更多
基金This project is supported by the National Natural Science Foundation of China.
文摘The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by ' cage ' vanadyl polycarboxylate (P=VO)-thiourea (TU) complex was investigated. The overall rate ofpolymerization isThe relationship between the induction period (τ) and the temperature of polymerization as well as the concentrations of reactants can be expressed as follows :The molecular weight of polyacrylonitrile increases with increasing monomer concentration and decreases with increasing temperature of polymerization and concentrations of vanadyl polycarboxylate and thioureaThe polymerization mechanism was proposed and discussed.
文摘The new vanadyl complex [VO（o-van）2（H2O）]（o-van=o-vanillin）was synthesized and characterized by IR,elemental analysis,and X-ray diffraction analysis.In the complex,the vanadium atom was coordinated to six oxygen atoms and formed a distorted octahedral structure.The crystal belongs to monoclinic system with space group P21/n,a=0.9414（4）nm,b=1.6103（6） nm,c=1.1710（4）nm,β=111.493（6）°,V=1.6518（10）nm3,Z=4,DC=1.557 g·cm-3,F（000）=796,R1=0.0424,wR2=0.0842.
基金supported by the National Natural Science Foundation of China(Grant No.20101001)
文摘Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are similar in chemical structures but different in glucose-lowering effects. Our experimental results show that they are both transported via passive diffusion with apparent permeabilty coefficients (apical→basolateral) of (82.0 ± 6.7)× 10-7 and (14.6 ± 0.7)× 10-7 cm· s-1, respec-tively. This suggests that absorptivity of VO(acac)2 is much higher than that of VO(ma)2. This difference may be related to the metabolism of either compound, or its ligand, or both in the course of the transport. However, This difference in absorption will cause the great difference in bioavailability,which might account for better efficacy of VO(acac)2 than VO(ma)2 as the insulin-mimic agent.
