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The Journal of Physical Chemistry, Vol. 91, No. 18, 1987
B values allow to correct for the change of permittivity the experimental dissociation constants Kd of ionophores in solutions containing ligands. Conductance measurements were performed with a WayneKerr Universal Bridge B224 operating at a frequency of 1592 s-l, with a Philips DW 1902/01 cell. The cell was calibrated by determining the conductance of aqueous KC1 solutions in the concentration range 0.001-0.01 N, using the equation of Lind et a1.20 Viscosities were measured with the automatic Lauda viscosimeter. Dielectric constants were determined by means of a W.T.W. Dekameter operating at 2 MHz. All measurements were carried out at 25 f 0.01 "C. 2. Walden Products. The Walden products of the strongly dissociated ionophores Bu4N+Pi- and Hept4N+I- were determined by using some eight solutions with concentrations of the salts ranging from 0.6 to 14 X mol dm-3. The overall Walden products of these ionophores in absence of ligands in nitrobenzene in 25 O C are respectively 51.0 and 55.0 ohm-l cm2 CP mol-]. 3. Infrared Spectra. The spectra were taken with a Perkin Elmer 325 spectrophotometer with a slit of 1.07 cm-l at 3000 cm-'. 4. Solvent and Products. Nitrobenzene (Fluka purissimum) was distilled from activated alumina under reduced pressure. The (20) Lind, J. E.;Zwolenik, J. J.; Fuoss, R. M. J . Am. Chem. SOC.1959, 81, 1557.
Additions and Corrections residual conductivity K~ is lower than 3 X ohm-' cm-'. Tetramethylguanidine was a Merck product distilled under reduced pressure. Diphenylguanidinium, Fluka purissimum, was recrystallized from a methanol solution. Tetramethylguanidinium picrate and diphenylguanidinium picrate were prepared from picric acid and the bases, dissolved in benzene. The salts were purified by recrystallization respectively from methanol and benzene solutions. Tetrabutylammonium iodide (Eastman) was recrystallized from ethanol-ether solutions. Tetrabutylammonium picrate was prepared from picric acid and Merck tetrabutylammonium hydroxide. It was recrystallized from ethanol solutions. Triethylammonium chloride was a Fluka purissimum product recrystallized from benzene-methanol mixtures. Triethylammonium bromide, an Eastman Kodak product, was recrystallized from a methanol-butanol mixture. Diethylammonium bromide was obtained from diethylamine and HBr in aqueous solution. The solution was evaporated and the salt several times recrystallized from a dichloroethane-methanol mixture. 4-Nitrophenol, a Fluka purissimum product, was recrystallized from a water-methanol mixture. Acknowledgment. We thank Dr. Th. Zeegers-Huyskens who took and interpreted the infrared spectra. We thank the University of Leuven and the Belgian Instituut voor Wetenschappelijk Onderzoek in de Nijverheid en de Landbouw, for their financial support.
ADDITIONS AND CORRECTIONS 1986, Volume 90
David M. Wardlaw and R. A. Marcus*: Unimolecular Reaction Rate Theory for Transition States of Any Looseness. 3. Application to Methyl Radical Recombination.
+
Pages 5383-5393. The factor (23 1) should be deleted from eq 1.3. In eq IV.l, IV.3, and IV.4, the quantity g, should be in the numerator rather than in the denominator. In Table V, the heading for the fourth column should be NEJ(Rlt)uI/(2J+ l ) , with uI as defined in the text (p 5386). In Table IX, the headings for the second and third columns should be [ N Ef uMC]a//101* and [ N E Af (rAMC]u1/1018, respectively.
