The kinetics and mechanism of the oxidation of 2-deoxy-D-glucose (dGlc) by Cr^VI which yields 2-deoxy-D-gluconic acid and Cr^III as final products when a ten-fold or higher excess of sugar over Cr^VI is used, have been studied. The redox reactions occur through Cr^VI→ Cr^IV→ Cr^III and Cr^VI→ Cr^V→ Cr^III paths. The experimental data were fitted with a multilinear regression program. The complete rate law for the chromium(VI) oxidation reaction is expressed by –d[Cr^VI]/dt={c[H⁺]+(d+e[H⁺]+f[H⁺]²)[dGlc]}[Cr^VI], where c=(5 ± 1)× 10^–4 dm³ mol^–1 s^–1, d=(3 ± 2)× 10^–4 dm³ mol^–1 s^–1, e=(115 ± 13)× 10^–4 dm⁶ mol^–2 s^–1 and f=(402 ± 17)× 10^–4 dm⁹ mol^–3 s^–1, at 50 °C. Chromium(V) is formed in a rapid step by reaction of the radical dGlc and Cr^VI and C^V reacts with dGlc faster than does Cr^VI. The chromium(V) oxidation of dGlc follows the rate low –dCr^V/dt=(k₁+k₂[H⁺])[dGlc][Cr^V], where k₁= 2.52 × 10^–4 dm³ mol^–1 s^–1 and k₂= 54.0 dm⁶ mol^–2 s^–1, at 25 °C. The EPR spectra show that three 1:1 Cr^V:dGlc intermediate complexes (g₁= 1.9781, g₂= 1.9752, g₃= 1.9758) are formed in rapid pre-equilibria before the redox steps.

The diMn^III complexes [Mn₂(5-Me-salpentO)(µ-MeO)(µ-AcO)(H₂O)Br] (1) and [Mn₂(3-Me-salpentO)(µ-MeO)(µ-AcO)(MeOH)₂]Br (2), where salpentOH = 1,5-bis(salicylidenamino)pentan-3-ol, were synthesised and structurally characterized. The two complexes include a bis(µ-alkoxo)(µ-acetato) triply-bridged diMn^III core with an Mn⋯Mn separation of 2.93–2.94 Å, the structure of which is retained upon dissolution. Complexes 1 and 2 show catalytic activity toward disproportionation of H₂O₂, with first-order dependence on the catalyst, and saturation kinetics on [H₂O₂], in methanol and DMF. In DMF, the two complexes are able to disproportionate at least 1500 eq. of H₂O₂ without significant decomposition, while in methanol, they rapidly lose activity with formation of a non-coupled Mn^II species. Electrospray ionisation mass spectrometry, EPR and UV/vis spectroscopy used to monitor the reaction suggest that the major active form of the catalyst occurs in the Mn₂ ^III oxidation state during cycling. The correlation between log(k_cat) and the redox potentials of 1, 2 and analogous complexes of other X-salpentOH derivatives indicates that, in this series, the oxidation of the catalyst is probably the rate-limiting step in the catalytic cycle. It is also noted that formation of the catalyst-peroxide adduct is more sensitive to steric effects in DMF than in methanol. Overall, kinetics and spectroscopic studies of H₂O₂ dismutation by these complexes converge at a catalytic cycle that involves the Mn₂ ^III and Mn₂ ^IV oxidation states.