TABLE 2

HSAB and ionization parameters for thiolate and enolate nucleophiles

Softness (σ) and nucleophilicity (ω; acrolein as the reacting electrophile) for the selected compounds were calculated as described in Materials and Methods.

Softness (σ × 103 ev−1)Nucleophilicity (ω × 103 ev)pKa% Anion (pH = 7.4)
2-ACP (enolate)4182047.828.5
GSH (thiolate)4272398.65.9
NAC (thiolate)3673169.50.8