Homogeneous oxidation of alkanes: Role of rhodium–alkyl complexes

The effects of metals and ligands on the oxidation of n-octane using iridium and rhodium “PNP” aminodiphosphine complexes

“…86 It is important to note that in the majority of cases, the latter two mechanisms dominate. However, generally, and considering the selectivity for different products observed over the Rh-based catalysts (except for 2c ), the data support the slight involvement of mechanism A during oxidation using these catalysts, which is in agreement with the findings of Chepaikin et al 85 In contrast, Ir-based catalysts very dominantly follow mechanisms B and C.…”

“…Outer-sphere (A) and inner-sphere (B) and free-radical (C) mechanisms of C-H bond activation in alkanes. 85,86 involvement of mechanism A during oxidation using these catalysts, which is in agreement with the findings of Chepaikin et al 85 In contrast, Ir-based catalysts very dominantly follow mechanisms B and C.…”

“…According to the recent work by Chepaikin et al, 85 oxidative homogeneous catalysis of alkanes can follow two mechanisms. Mechanism A is referred to as an outer-sphere mechanism (A), where the reaction takes place using the in situ generated oxo and peroxo metal complexes.…”

“…Outer-sphere (A) and inner-sphere (B) and free-radical (C) mechanisms of C–H bond activation in alkanes. 85,86 …”

“…It is known that catalysts following mechanism A are highly sensitive toward the metals and ligands that are used to synthesize the catalysts. 85 Therefore, we focused on the recyclability of catalysts 1c and 2c , that were recovered and re-used over two more cycles (Figure 7), since we were interested in examining whether the structure of the catalyst was important during the radical pathways (mechanisms B and C) or not. The amounts of catalyst recovered were low due to mechanical loss during sampling and the small amounts of catalysts used.…”