Mechanistic information on the reaction of model palladium(II) complexes with purine nucleosides and 5′-nucleotides in reference to the antitumor activity of related platinum complexes
摘要:
The reaction of Pd(Me,en)Cl2 (Me4en=NNN',N'-tetramethylethylenediamine) with inosine and 5'-inosine monophosphate was studied as a function of chloride concentration and pH. Evidence for the formation of a 1:1 complex with these nucleophiles is presented, and the kinetic data indicate that Pd(Me4en)(Cl)H2O+ is the only reactive species under the selected experimental conditions. The results are compared to earlier data for the reactions of Pd(R4en)(H2O)22+ (R = H, Me, Et) with a series of nucleosides and 5'-nucleotides. The dependencies studied in this investigation allow some tentative extrapolations to conditions relevant for the antitumor activity of related Pt(II) complexes.
Effect of steric hindrance on kinetic and equilibrium data for substitution reactions of diaqua(N-substituted ethylenediamine)palladium(II) with chloride in aqueous solution
作者:H. Hohmann、B. Hellquist、R. van Eldik
DOI:10.1016/s0020-1693(00)80912-3
日期:1991.10
Abstract Kinetic and thermodynamic data are reported for the complex formation reactions: Pd(R4en)(H2O)22+Cl− Pd(R4en)(H2O)Cl++H2O and Pd(R4en)(H2O)Cl++Cl− Pd(R4en)Cl2+H2O, as a function of steric hindrance for RMe and Et. The reported rate constants for these reactions decrease drastically on increasing the steric hindrance. These findings along with strongly negative △S≠ values support the operation