Table 1. Bimolecular Rate Constants, k^S Calculated from eq 2^a for Reactions of dpph^• with TEMPO^•, 4-OH-TEMPO^•, RSV, 3,5-DHA (See Figure 1E), and Equimolar Mixture of Tested Compounds (1:1, mol/mol) in Methanol (MeOH) and Ethyl Acetate (EtOAc).

RTA	EtOAcb	MeOHb	MeOH/H+
RSVc	1.01 ± 0.04	192 ± 7	2.4 ± 0.4
TEMPO•	0.03 ± 0.01	31 ± 4	132 ± 2
RSV + TEMPO•	0.97 ± 0.13	1360 ± 260
4-OH-TEMPO•	0.07 ± 0.03	12.6 ± 1.7	15.6 ± 3.8
RSV +4-OH-TEMPO•	1.21 ± 0.04	580 ± 16
3,5-DHAc		0.63 ± 0.06
3,5-DHA + TEMPO•		107 ± 1
TEMPO-H	7.7 ± 1.7	35 ± 1	44 ± 3
RSV+ TEMPO-H	9.0 ± 1.7	2100 ± 100

^aFull statistical and kinetic data, together with plots of eq 2 are given in the Supporting Information. When a 1:1 mixture was used, k^S was calculated from eq 2 with the assumption that [RTA] = [RSV] because for the initial rates RSV is a kinetically dominating RTA, see explanation in the text.

^bHB accepting ability expressed as β₂^H parameter is 0.41 for methanol and 0.45 for EtOAc. Methanol is also a donor for HB, its parameter of HB acidity, α₂^H = 0.367.¹⁷ The relative permittivities of methanol and ethyl acetate are 32.7 and 6.0, respectively.

^cpK_a values for RSV: 9.0 (for the 4’OH group), 9.8 and 11.3 (for the 3 and 5 OH group), see the discussion in ref (18); pK_a predicted for 3,5-DHA is 9.4.¹⁸