Fig. 3.

Structure–activity relationship between $log{k}_{\text{cat}}({\text{O}}_2^{•-})$ and E_1/2 (Mn^IIIP/Mn^IIP) in mV versus NHE for cationic Mn(III) porphyrins. Compounds at the plateau of the bell-shaped curve are those that bear both meso and beta substituents and have highest k_cat. Yet, they are stabilized in Mn +2 oxidation state, lose readily Mn and are thus are only important for mechanistic purposes. The falling limb of the bell-shaped curve is more obvious in SARs of anionic and neutral porphyrins (Batinic-Haberle et al. 2010). Compounds are: 1 MnT(TFTMA)P^5+, 2 MnBM-2-PyP⁵⁺, 3 MnTM-4-PyP⁵⁺, 4 MnTM-3-PyP⁵⁺, 5 MnTrM-2-PyP⁵⁺, 6 MnTnBu-2-PyP⁵⁺, 7 MnTnPr-2-PyP⁵⁺, 8 MnTnHex-2-PyP⁵⁺, 9 MnTDMOE-2-ImP⁵⁺, 10 MnTnOct-2-PyP⁵⁺, 11 MnClTE-2-PyP⁵⁺, 12 MnTE-2-PyP⁵⁺, 13 MnTM-2-PyP⁵⁺, 14 MnTDE-2-ImP⁵⁺, 15 MnTM,MOE-2-ImP⁵⁺, 16 MnTMOE-2-PyP⁵⁺, 17 MnTDM-2-ImP⁵⁺, 18 MnCl₂TE-2-PyP⁵⁺, 19 MnCl₃TE-2-PyP⁵⁺, 20 MnCl₅TE-2-PyP⁵⁺, 21 MnCl₄TE-2-PyP⁵⁺, 22 MnBr₈TM-4-PyP⁴⁺, and 23 MnBr₈TM-3-PyP⁴⁺. Data are taken from Batinic-Haberle et al. (2010) and Kachadourian et al. (1998). The names of porphyrins are listed in the list of abbreviations