Molecular Hybrids of Serum Albumin and Cobalt Phthalocyanine for Asymmetric Oxidation of C=C and C-H Bonds.

Molecular hybrids consisting of hydrophobic, water-insoluble cobalt phthalocyanine (CoPC) complex and noncatalytic protein bovine serum albumin (BSA) have been developed as a green catalyst for stereoselective oxidations, including C=C epoxidation and C-H hydroxylation. Effective encapsulation of CoPC into the BSA scaffold (CoPC-BSA) was achieved through agitation of BSA and CoPC in an aqueous solution, resulting in a structurally intact, stable protein-cofactor hybrid. Upon activation with H2O2, CoPC-BSA catalyzed epoxidations of styrene and cyclooctene with yields of 87-99%, achieving >99% enantioselectivity for R-styrene oxide. CoPC-BSA also enabled selective C-H oxidation of propanoic acid and methyl phenylacetate under mild conditions. For propanoic acid, L-lactic acid was the sole product of oxidation of propanoic acid, while methyl phenylacetate showed temperature-dependent enantioselectivity. When immobilized on silica beads, R-methyl mandelate with an enantioselectivity >92% at 80 °C was produced at a conversion of ∼99%. These results demonstrate the potential of molecular hybrids for enantioselective oxidations and highlight the critical role of protein flexibility and dynamics in tuning catalytic outcomes.