Catalysis of Metallo-deuteroporphyrins for Cyclohexane Oxidation with Air

The efficient and selective oxidation of hydrocarbon catalyzed by metalloporphyrins has attracted much attention from the organic and industrial chemists. During the last decades of years, a huge amount of work has shown that substituted metalloporphyrins are efficient catalysts for the oxidation of hydrocarbons at unprecedented rates under very mild conditions. However, nearly all of the metalloporphyrins used as oxidation catalysts were based on the system of synthetic meso-tetraphenylporphyrin (TPP). The high accessibility of deuteroporphyrin together with its excellent stability and close relationship to the naturally occurring heme make it an ideal compound to mimic enzymatic systems based on heme. Therefore, to investigate the catalytic activity of the deuteroporphyrins complex and search more efficient biomimetic catalysts for hydrocarbon oxidation under mild conditions, the metallo-deuteroporphyrin dimethyl esters [M (DPDME)] were used as the catalysts for cyclohexane oxidation by air without any coreductant or solvent. The results indicated that the metallo-deuteroporphyrins could smoothly catalyze the oxidation of cyclohexane under the selected conditions; and they exhibited markedly higher catalytic activity than simple metallo-tetraphenylporphyrins. The effect of central metals was discussed.