Metal Hydroperoxides as Oxygen Atom Transfer Reagents

Abstract

The two-electron oxidation of I- by metal hydroperoxides (H2O)5CrO2H2+, (H2O)([14]aneN4)CoO2H2+ and (H2O)(Me6[14]aneN4)CoO2H2+ proceeds exclusively by an [H+]-catalyzed path. These reactions are 420−5700 times faster than the oxidation of I- by H2O2.

Generation of a Hydroperoxidochromium Complex from Nitratochromium(III) Ions and Hydrogen Peroxide

“…The kinetics of the initial jump were measured separately in stopped‐flowexperiments. The reaction obeyed a mixed third‐order rate law (rate = k [Cr aq OOH 2+ ][I – ][H + ]) and yielded k = (943 ± 25) M –2 s –1 , in good agreement with the known rate constant for the Cr aq OOH 2+ /I – /H + reaction (988 ± 16 M –2 s –1 ) 19…”

“…Because this complex, unlike Cr aq OO 2+ , does not exhibit unique spectral features that would unequivocally identify it, we resorted to kinetic identification. For that purpose, we used the characteristic reactions of Cr aq OOH 2+ with halide ions, shown in Equation (2) (X = I or Br) 16–18 …”

Direct Kinetic Studies of Atom Transfer and Electron Transfer Reactions of Hydroperoxo and High-Valent Oxo Complexes of Chromium

“…Interestingly, the rate constant for PPh 3 oxidation by L 1 (H 2 O)CrOOH 2+ is nearly identical to that for the oxidation by Cr aq OOH 2+ …”

Biomimetic Chemistry of Chromium. Intramolecular Conversion of Hydroperoxochromium(III) to Oxochromium(V)

“…Some synthetic hydroperoxometal complexes − persist in solution for several minutes or even hours in the absence of reducing substrates and decompose mainly by dissociation of H 2 O 2 from the metal. These complexes typically react as electrophiles and one-electron oxidants 5 and show no tendency to form oxenes, presumably because the nonparticipating ligands do not stabilize the metal in the 4+ or 5+ oxidation state.…”