Oxygen Exchange and Cleavage of the Glycinate Chelate [Co(H₂NCH₂CH_2NH2)₂(H₂NCH₂CO₂)]²⁺ in Strongly Alkaline Solution

Abstract

Cleavage of the carboxylate chelate [Co(en)₂(glyO)]²⁺ has been studied in 0.75 mol dm^-3 NaOH . ¹⁸O-tracer results are interpreted as 16% C-O and 84% Co-O bond fission, the products ultimately being [Co(en)₂(OH)₂]⁺, Co^II, and glyO ^-. The major Co-O cleavage path is interpreted as an S_N1 (CB) process leading to both recapture of carboxylate oxygen (50%, k_ex = 4.8 × 10^-6 s^-1) and capture of solvent leading to [Co(en)₂(OH)( glyO )]⁺ (50%).