Iron(III), manganese(III), and cobalt(II) complexes of meso-tetrakis(p-chlorophenyl)porphyrin (Fe(TCl-PP)X, Mn(TClPP)X, and Co(TClPP)X, X = Cl or OAc) were immobilized onto 3-aminopropyl-functionalized silica (SF-3-APTS). SF-3-APTS acts as both axial base and support for immobilization of these metalloporphyrins. The obtained heterogeneous catalysts were characterized by Fourier transform infrared (FT-IR), UV-Vis, and inductively coupled plasma (ICP) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis (TGA) techniques. Their catalytic activity as biomimetic catalysts was investigated for the selective oxidation of primary and secondary benzylic alcohols to the corresponding carbonyl compounds with t-butylhydroperoxide as oxidant. SF-3-APTS-Fe(TClPP)Cl demonstrated higher catalytic activity than SF-3-APTS-Mn(TClPP)Cl and SF-3-APTS-Co(TClPP)OAc. The presence of electronwithdrawing substituents on benzylic alcohols enhances the rate of catalytic oxidation. SF-3-APTS-Fe(TClPP)Cl could be reused at least four times without significant loss of its catalytic activity.

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Fe(III), Mn(III) and Co(II) metalloporphyrins immobilized onto 3-aminopropyl-functionalized silica are synthesized and evaluated for their catalytic activity in the biomimetic oxidation of primary and secondary benzylic alcohols to corresponding carbonyl compounds (II). The immobilized Fe(III) porphyrin demonstrates the highest activity. This heterogeneous catalyst can be reused at least four times without any significant loss of activity. -(RAHIMI*, R.; GHOREISHI, S. Z.; DEKAMIN, M. G.; Monatsh. Chem. 143 (2012) 7, 1031-1038, http://dx.