The base catalysed hydrolysis of trans-dichlorobis-(1,2-diaminoethane)-cobalt(III) and -(1,3-diaminopropane)cobalt(III) cations: rate-limiting proton transfer

Abstract

The base hydrolysis of trans-[Co(en)₂Cl₂]⁺(en = 1,2-diaminoethane) has been re-examined over the temperature range 5–45 °C. The plot of In (k_OH/T)vs. T^–1 is curved above 25 °C indicating a change towards rate-limiting deprotonation at higher temperatures. The rate constants for the base hydrolysis of trans-[Co(tn)₂Cl₂]⁺[tn = trimethylenediamine (1,3-diaminopropane)] are ca. 20 times greater than those for the (en)₂ complex in the range 5–10 °C but the temperature dependence suggests that deprotonation is rate-limiting even at the lowest temperatures studied.