Hydrogen Atom Abstraction Thermodynamics of a mu-1,2-Superoxo Dicopper(II) Complex

作者：Kindermann Nicole; Guenes Can Jerome; Dechert Sebastian; Meyer Franc^*

来源：Journal of the American Chemical Society, 2017, 139(29): 9831-9834.

DOI：10.1021/jacs.7b05722

Pyrazolate-based mu-1,2-peroxo dicopper(II) complex 1 undergoes clean 1e(-) oxidation at low potential (-0.59 V vs Fc/Fc(+)) to yield the rather stable mu-1,2-superoxo dicopper(II) complex 3, which was characterized by spectroscopic methods ((nu) over tilde (O-O) = 1070 cm(-1), Delta(O-18-O-16) = -59 cm(-1)) and analyzed by DFT calculations. 3 is also formed via H-atom abstraction from the corresponding mu-1,1-hydroperoxo dicopper(II) complex 2, while 3 itself is able to abstract H-atoms from weaker X-H bonds such as TEMPO-H to re-form 2. Kinetic and thermodynamic analyses evidence a concerted proton-electron transfer pathway for these processes. The thermodynamic square scheme reveals a bond dissociation free energy of 71.7 +/- 1.1 kcal mol(-1) for the hydroperoxo OO-H bond of 2.

• 出版日期2017-7-26