Dynamics for reaction of an ion pair in aqueous solution: reactivity of carboxylate anions in bimolecular carbocation-nucleophile addition and unimolecular ion pair collapse.
[reaction: see text]. The sum of the rate constants for solvolysis and 18O-scrambling of 4-MeC6H4(13)CH(Me)18OC(O)C6F5 in 50/50 (v/v) trifluoroethanol/water, k(solv) + k(iso) = 1.22 x 10(-5) s(-1), is larger than k(solv) = 1.06 x 10(-5) s(-1) for solvolysis of the unlabeled ester. This shows that the ion pair intermediate undergoes significant internal return. The data give k(-1) = 7 x 10(9) s(-1) for internal return by unimolecular collapse of the ion pair, which is significantly larger than k(Nu) = 5 x 10(8) M(-1) x s(-1) for bimolecular nucleophilic addition of carboxylate anions to 4-MeC6H4CH(Me)+.
Tsuji
Y
Y
Department of Biochemistry and Applied Chemistry, Kurume National College of Technology, Komorinomachi, Kurume 830-8555, Japan.
Mori
T
T
Richard
J P
JP
Amyes
T L
TL
Fujio
M
M
Tsuno
Y
Y
D000838:Anions; D002244:Carbon / Q000737:chemistry*; D002625:Chemistry, Organic / Q000379:methods*; D004952:Esters / Q000737:chemistry; D007477:Ions; D007700:Kinetics; D011138:Polytetrafluoroethylene / Q000737:chemistry
D000838:Anions; D004952:Esters; D007477:Ions; D002244:Carbon; D011138:Polytetrafluoroethylene