Fig. 7. Relationship between the association constants for formation of 1 : 1 complexes with tri-n-butyl phosphine oxide in n-octane at 298 K (log K) and the Hammett parameter σm for substituent X. Compounds 1–5 are shown in blue (Y = OH), and the equation of the line is y = 2.35x + 2.97. Compounds 6–10 are shown in orange (Y = H), and the equation of the line is y = 1.89x + 2.21.
