Specific effects of nucleophiles on the mercury(II)-assisted chloride aquation of the penta-amminechlorocobalt(III) cation and of the chloro[ethylenediaminetetra-acetato(3–)]cobaltate(III) anion

Abstract

Simple anions (X^–) such as CH₃CO₂^–, Cl^–, N₃^–, Br^– SCN^–, and CN^– influence the Hg²⁺-assisted chloride aquation of [CoCl(NH₃)₅]²⁺ and [Co(edta)Cl]^2–(H₄edta = ethylenediamine-NNN′N′-tetra-acetic acid) through the formation of HgX⁺. Observed rate changes reflect both the electrostatic and the inductive effects; the former predominates for CH₃CO₂^–, Cl^–, and N₃^–, while the latter does for CN^–. Aminopolycarboxylates, such as edta^4– and cdta^4–(H₄cdta = cyclopentane-1,2-diamine-NNN′N′-tetra-acetic acid) were specifically effective. A feature of the reactions with [CoCl(NH₃)₅]²⁺ is the production of [CoY(NH₃)₅]^–(Y = edta or cdta) alongside [Co(NH₃)₅(OH₂)]³⁺.