Transition Metal Chemistry

, Volume 17, Issue 5, pp 443–445 | Cite as

Base hydrolysis ofcis-(methyl/ethylamine)bis(ethylenediamine) (salicylato)cobalt(III) complexes

  • Guru C. Pradhan
Full Papers


The kinetics of the base hydrolysis ofcis-[Co(en)2(RNH2)-(SalH)]2+ (R=Me or Et; SalH=HOC6H4CO 2 ) were investigated in aqueous ClO 4 in the 0.004–0.450 mol dm−3 [OH] range, I=0.50 mol dm−3 at 30–40°C. The phenoxide species is hydrolysed via [OH]-independent and [OH]-dependent paths, the latter being first order in [OH]. The high rate of alkali-independent hydrolysis of the phenoxide species is associated with high ΔH and ΔS values, in keeping with the SNICB mechanism involving an amido conjugate base generated by the phenoxide-assisted NH-deprotonation of the coordinated amine. The [OH]-dependent path also involves the conventional SN1 CB mechanism. The rate constant, k1, for the SNICB path exhibits a steric acceleration with the increasing size of the non-labile alkylamine, whereas the rate constant, k2, for the SN1CB path shows a reverse trend.


Dependent Path Transition Meet Base Hydrolysis Phenoxide Conjugate Base 


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Copyright information

© Chapman & Hall 1992

Authors and Affiliations

  • Guru C. Pradhan
    • 1
  1. 1.Department of ChemistryUtkal UniversityBhubaneswarIndia

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