53537-59-0Relevant academic research and scientific papers
Anion radical oxidation of nickel(II) macrocyclic complexes. Pulse radiolysis of (2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene) nickel(II) in sodium bromide solution
Morliere,Patterson
, p. 1458 - 1465 (1981)
The oxidation of NiII(CR+4H) [CR+4H = 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene, α isomer] by Br2- and subsequent chemistry of Ni(III) intermediates have been studied by pulse radiolysis. The initial electron transfer is diffusion controlled and results in an initial product which exhibits characteristics of a Ni(III)-Br- adduct. The stability of this adduct, especially in acidic media, is dependent on bulk bromide concentration, demonstrating an equilibrium process of the form NiIII(CR+4H)(Br-)(H2O) + H2O ? NiIII(CR+4H)(H2O)2 + Br-, with Keq = 360 M-1. The pK of dissociation for the aquated species is 4.0 ± 0.8. At pH >5 displacement of the bound bromide is first order in [OH-] with a rate constant of 6 × 109 M-1 s-1. Disappearance of the NiIII(CR+4H)(OH-) intermediate is also pH dependent, suggesting amine dissociation in the ligand and formation of an unstable ligand radical leading to a final product with increased ligand unsaturation.
