The modification of coordinated acetonitrile lability on cobalt(II) induced by the coordination of 2,2-Di(aminomethyl)propan-1-ol

Abstract

A single acetonitrile exchange process on Co(diap)(MeCN)₃²⁺ (where diap is 2,2-di(aminomethyl)-propan-1-ol) in acetonitrile solution is observed by ¹⁴N N.M.R. between 221 and 315.6 K. On the assumption that this process characterizes the two equivalent acetonitrile sites the following parameters are derived: k_ex(298 K) = (45 ± 3) x 10⁵ s^-1, ΔH? = 3l.0 ± 2.5 kJ mol^-1, ΔS? = -l4 ± 6 J Mol^-1 K^-1, where the exchange rate is given by 2k_ex[Co(diap)(MeCN)₃²⁺]. Alternative interpretations are also discussed.