Water soluble complexes derived from the interaction between Rh (CO) 2 (acac) and [Ir (COD) Cl] 2, respectively, with human serum albumin (HSA), were employed in the aqueous biphasic hydrogenation of α, β-unsaturated compounds as 2-cyclohexen-1-one (I), 2-butenal (V), 3-phenyl-2-propenal (IX) and 3-aryl-2-methyl-2-propenals (XIII and XVII). Both catalytic systems Rh/HSA and Ir/HSA showed to be very active in the hydrogenation of ketone I ...