KINETIC PREFERENCE WITHOUT THERMODYNAMIC STABILIZATION IN THE INTRA-VS INTERMOLECULAR FORMATION OF COPPER-DIOXYGEN COMPLEXES

We have previously detailed the chemistry of the reaction between dioxygen (02) and the mononuclear copper(1) species [(L)Cu(RCN)]+ (la) (L = tris[(2-pyridyl)methyl]amine; R = Me or Et), including a kineticdthermodynamics investigation. 1*2 In reactions with 02, l a initially forms a spectroscopically detectable (A= 410 nm, E = 4000 M-l cm-l) CdO2 = 1:l adduct [(L)Cu(O2)]+ (1b)lC (formally a superoxo-copper(I1) species), which further reacts rapidly with l a to give [{(L)-