Linear free energy relationships. VIII. Ionization potentials of aliphatic compounds

Ionization potentials (IP) of HX, CH3X, C2H5X, and i-C3H7X, where X is a substituent with non-bonded electrons, are directly proportional to ionization potentials of 4-substituted quinuclidines. This is taken as evidence that in general the energy required to remove an electron from a substituent X, as is the case in HX, CH3X, C2H5X, and i-C3H7X, is directly proportional to the energy required to remove an electron from a site remote from the substituent, as in the quinuclidines in which an electron is lost from the ring nitrogen. Furthermore, the IP's of the HX-i-C3H7X series are directly proportional to inductive substituent constants, σI, providing a valuable correlation between gas and solution phase behavior.