Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced wit...Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced with NaBH4 to afford the corresponding aza-crown ethers. The liquid membrane transport or alkali cations using the five new macrocycles as the ion-carriers was also studied.展开更多
The design of artificial nucleases and nuclease mimics has attracted extensive attention and made great progress due to their significant scientific meanings and potential application in the field of gene medicine and...The design of artificial nucleases and nuclease mimics has attracted extensive attention and made great progress due to their significant scientific meanings and potential application in the field of gene medicine and molecular biology. This paper reviews recent progress in the investigation of artificial nuclease,including "bifunctional cooperative catalysis","dinuclear synergistic catalysis","metal-free catalysis" ,and especially,the studies of aza-crown ethers as artificial nucleases and their interaction with DNA.展开更多
Novel Co(Ⅱ) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants(ln K_(O2)) and thermodynamic parameters(△H°,△...Novel Co(Ⅱ) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants(ln K_(O2)) and thermodynamic parameters(△H°,△S°) were measured.And their catalytic performance in oxidation of p-xylene to p-toluic acid(PTA) was investigated.The enhancement of O_2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.展开更多
The unsymmetrical bis-Schiff base manganese(III) and cobalt(II) complexes with either benzo-10-aza-crown ether pendants (MnL1Cl, MnLZCl) or morpholino pendant (MnL3Cl, CoL3) have been employed as models for hy...The unsymmetrical bis-Schiff base manganese(III) and cobalt(II) complexes with either benzo-10-aza-crown ether pendants (MnL1Cl, MnLZCl) or morpholino pendant (MnL3Cl, CoL3) have been employed as models for hy- drolase by studying the kinetics of their hydrolysis reactions with p-nitrophenyl picolinate (PNPP). A kinetic model of PNPP cleavage catalyzed by these complexes is proposed. The effects of complex structures and reaction temperature on the rate of PNPP hydrolysis have been examined. All four complexes exhibit high catalytic activity and the rate increases with pH under 25℃. The complexes of ligands containing a crown ether group exhibit higher catalytic activities than the non-crown analogues. The catalytic activity of the complexes follows the order Mn(III) 〉 Co(II) under the same ligands.展开更多
基金We are gr ateful to the Natural Sc ience Foundation of Shandong Province for financial support ofthiswork (Q97B03123).
文摘Five new aza-crown ethers have been prepared by the condensation of 2,6-bis[(2-formylphenyl)oxymethyl] pyridine with different diamino compounds in hot methanol, the bis-Schiff bases without isolation were reduced with NaBH4 to afford the corresponding aza-crown ethers. The liquid membrane transport or alkali cations using the five new macrocycles as the ion-carriers was also studied.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20872061 & 20372032)the National Basic Research of China (Grant No. 2007CB925103)
文摘The design of artificial nucleases and nuclease mimics has attracted extensive attention and made great progress due to their significant scientific meanings and potential application in the field of gene medicine and molecular biology. This paper reviews recent progress in the investigation of artificial nuclease,including "bifunctional cooperative catalysis","dinuclear synergistic catalysis","metal-free catalysis" ,and especially,the studies of aza-crown ethers as artificial nucleases and their interaction with DNA.
基金supported by Chongqing Education Commission(No.KJ1400632)
文摘Novel Co(Ⅱ) complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants(ln K_(O2)) and thermodynamic parameters(△H°,△S°) were measured.And their catalytic performance in oxidation of p-xylene to p-toluic acid(PTA) was investigated.The enhancement of O_2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.
文摘The unsymmetrical bis-Schiff base manganese(III) and cobalt(II) complexes with either benzo-10-aza-crown ether pendants (MnL1Cl, MnLZCl) or morpholino pendant (MnL3Cl, CoL3) have been employed as models for hy- drolase by studying the kinetics of their hydrolysis reactions with p-nitrophenyl picolinate (PNPP). A kinetic model of PNPP cleavage catalyzed by these complexes is proposed. The effects of complex structures and reaction temperature on the rate of PNPP hydrolysis have been examined. All four complexes exhibit high catalytic activity and the rate increases with pH under 25℃. The complexes of ligands containing a crown ether group exhibit higher catalytic activities than the non-crown analogues. The catalytic activity of the complexes follows the order Mn(III) 〉 Co(II) under the same ligands.