
%0 Journal Article
%A Lincoln, SF 
%A Stranks, DR 
%T Phosphato complexes of cobalt(III). II. Reversible chelation and ring-opening reactions
%J Australian Journal of Chemistry
%D 1968/01/01
%V 21
%N 1
%P 57-65
%K 
%R https://doi.org/10.1071/CH9680057
%U https://www.publish.csiro.au/paper/CH9680057 
%X The bidentate phosphato complex Co en2PO40; has been shown to exist in rapid reversible equilibrium with the monodentate complex Co en2OH.HPO40 A detailed kinetic analysis of the opposed ring-opening and ring-closing (or chelation) reactions has evaluated rate constants for each of the protonated forms in acid and basic media. The ring-opening reaction is subject to both acid and base catalysis. However, within the pH range 6-9, the bidentate form containing a four-member phosphate ring is thermodynamically more stable than the monodentate form. This is ascribed to a rapid chelation reaction arising from a favourable cis hydrogen-bonded transition state. 
