Part I. Ionization equilibria of mono-p-methyl and mono-p-trideutriomethyl triphenylchloromethane in liquid sulfur dioxide. Part II. Spectrophotometric and conductance studies of some triphenyl-chloromethane derivatives in nitrobenzene at 25

Thesis (Ph.D.)--Boston UniversityThe work described here in this dissertation was undertaken to investigate the isotope effect on an equilibrium which is closely related to the assumed equilibria between reactants and transition states in solvolytic reactions and aromatic substitution. Earlier studies of the ion-forming equilibria of triphenylchloromethane and many of its o-, m-, and p-substituted derivatives together with data on the dissociation equilibria of many ionophores have provided a convenient means of evaluating substituent effects on the ionization equilibrium: Ar3CCl ↔ SO2 Ar3C+Cl- (1). The similarity of substituent effects in this system to those observed in solvolytic reactions (2,3) and electrophilic substitution reactions (4) has been elegantly demonstrated by Brown and Okamoto (5). Lewis and Boozer (6) suggest that β-deuterium isotope effects observed in the solvolysis of secondary alkyl halides and tosylates are dependent in part on the requirements of the developing carbonium ion for internal electron supply at the transition state. Studies of the ionization equilibrium above provide a measure of substituent effects where full carbonium character is unequivocally developed. [TRUNCATED