Figure 5.

Energy relationship between the activation barrier and the reaction energy of the CO₂ incorporation reaction. Plotted are the results for different nucleophiles L, attached to the Co^III–salen base structure as depicted in Figure 2; ^asalen ligand 1a: = -C₄H₈-, R^3–6 = H; ^bsalen ligand 1b: = -C₄H₈-, R^3–6 = t-Bu. The energies calculated for those ligands depicted with a red square do not follow the BEP relationship (for details, see text). The line represents the equation E_a = (1.9 ± 0.2)·ΔE + (99 ± 4) [kJ·mol⁻¹].