Direct ligand exchange kinetics between hydrophilic molecules and quantum dots（QDs） was investigated. Meanwhile, pyrene was exploited as probe to detect the efficiency of the ligand exchange reaction between octade-...Direct ligand exchange kinetics between hydrophilic molecules and quantum dots（QDs） was investigated. Meanwhile, pyrene was exploited as probe to detect the efficiency of the ligand exchange reaction between octade- cylamine-coated QDs（ODA-QDs） and different ligands[ligand 1： NH2G3-OH, ligand 2： G4.5-PEG5-FA5, ligand 3： （COOH）2G3-OH or ligand 4： G4.5-PEG1-FAl]. It was indicated that water-soluble QDs exhibit the same fluores- cence and absorption spectra as ODA-QDs when they were dissolved in chloroform. Furthermore, the cellular expe- riments demonstrated that the folic acid（FA） targeting poly（amidoamine）（PAMAM） modified QD conjugates could be used as molecular targeting sensing systems for nanoparticle probes.展开更多
The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr...The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr,n-Bu),in chloroform solution have been determined in a temperature range of 20—50°C by means of high-performance liquid chromatography.It was found that both the forward and reverse reactions are of second order.All of the equilibrium constants K determined are 10.3±1.0,much greater than the value(K=4)calculated statistically which indicates that the ternary complexes are more stable than the binary complexes.The experimental results revealed that the reaction rate decreases with the increase in the size of R and R^1 groups and the latter are more remarkable,consistent with the deduction of steric effect.The activation parameters of the reactions have been calculated.In reaction series(11)and(12)(in the text)the isokinetic tempera- tures B=390±8K and β=346±15 K have been observed respectively.A plausiblemechanism in- volving an eight-membered ring intermediate has been proposed on the basis of experimental results.展开更多
基金Supported by the National Natural Science Foundation of China （No.21304084）, the Youth Foundation of Jilin Province, China（No.20080119） and the Graduate Innovation Program of Jilin University, China（No.20091010）.
文摘Direct ligand exchange kinetics between hydrophilic molecules and quantum dots（QDs） was investigated. Meanwhile, pyrene was exploited as probe to detect the efficiency of the ligand exchange reaction between octade- cylamine-coated QDs（ODA-QDs） and different ligands[ligand 1： NH2G3-OH, ligand 2： G4.5-PEG5-FA5, ligand 3： （COOH）2G3-OH or ligand 4： G4.5-PEG1-FAl]. It was indicated that water-soluble QDs exhibit the same fluores- cence and absorption spectra as ODA-QDs when they were dissolved in chloroform. Furthermore, the cellular expe- riments demonstrated that the folic acid（FA） targeting poly（amidoamine）（PAMAM） modified QD conjugates could be used as molecular targeting sensing systems for nanoparticle probes.
基金Project supported by the National Natural Science Foundation of China.
文摘The rate constants and equilibrium constants of ligand exchange reactions between his (alkylxanthato)palladium(Ⅱ),Pd(S_2COR)_2(R=Am,n-Hex,Bz),and bis(N,N-dialkyldithiocarbamato) palladium(Ⅱ),Pd(S_2CNR_2)_2(K=Et,n-Pr,n-Bu),in chloroform solution have been determined in a temperature range of 20—50°C by means of high-performance liquid chromatography.It was found that both the forward and reverse reactions are of second order.All of the equilibrium constants K determined are 10.3±1.0,much greater than the value(K=4)calculated statistically which indicates that the ternary complexes are more stable than the binary complexes.The experimental results revealed that the reaction rate decreases with the increase in the size of R and R^1 groups and the latter are more remarkable,consistent with the deduction of steric effect.The activation parameters of the reactions have been calculated.In reaction series(11)and(12)(in the text)the isokinetic tempera- tures B=390±8K and β=346±15 K have been observed respectively.A plausiblemechanism in- volving an eight-membered ring intermediate has been proposed on the basis of experimental results.
