Equilibria and kinetics for 𝑝H-dependent axial ligation of alkyl(aquo) cobaloximes with aromatic and aliphatic N-donor ligands

Journal of Chemical Sciences

V Sridhar¹  D Sudarshan Reddy¹  N Ravikumar Reddy¹  S Satyanarayana1¹ 

[1] Department of Chemistry, Osmania University, Hyderabad 500 007, India$$

关键词: Alkylcobaloximes;    histamine;    histidine;    imidazoles;    equilibrium constants.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Equilibria and kinetics of the reaction of bromomethyl(aquo) cobaloxime with histamine, histidine, glycine and ethyl glycine ester and iodomethyl(aquo) cobaloxime with cyanide, imidazole and substituted imidazoles were studied as a function of 𝑝H at 25°C, 1.0 M ionic strength (KCl) by spectrophotometry technique. The rate of substitution of H2O varies with the 𝑝𝐾𝑎 of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. Dissociation kinetic reactions were also studied as a function of 𝑝H. Binding and kinetic data were interpreted based on the basicity, steric crowd of the entering ligand and HSAB principle. To compare the rate constants of the entering ligands 𝑝H independent second-order rate constants were calculated.

【 授权许可】

Unknown