Fig. 4: Secondary isotope effects of the Fe-catalyzed ODA reaction.

a Computed secondary kH/kD KIE and EIE results for the formation of A in the quartet (Q) and sextet (S) states by the B3LYP-D3 method. b Experimental kH/kD KIE result for the formation of A. c Schematic of the isotope effects and the computed zero-point energy differences (EH−D, in kcal mol−1) of the key structures by the B3LYP-D3 method.