TY - JOUR
T1 - Reverse pulse voltammetry in ec2 reactions. Electrochemistry of 1-alkyl-4-t-butylpyridinium ions
AU - Talmor, Dov
AU - Hermolin, Joshua
AU - Kirowa-Eisner, Emilia
PY - 1982/10/8
Y1 - 1982/10/8
N2 - The applications of the reverse pulse method are extended in order to distinguish between different paths of electrodimerization. The method for determination of rate constants of the chemical reaction coupled with charge transfer (ec2) is further developed. Measurements of K′d vs. t p provide valuable information for the determination of rate constants. The reverse pulse method is applied in the study of the electrodimerization of 1-alkyl-4-t-butylpyridinium ions (1-alkyl=-CH3; -CH2CH3; -CH(CH 3)2) in acetonitrile. It is found that the electrodimerization mechanism is consistent with the sequence: Py+ + e = Py ⇋ 1 2 Py2. The formal potential Eo′ is measured directly for 1-CH(CH3)2, and indirectly for the other pyridium ions. All values are identical within experimental error (Eo′ = -1.835 V vs. Ag/Ag+). The values of kd and km are measured. With an increase in the size of the l-alkyl group, kd decreases and km increases. This is consistent with the expected "stabilization" of the radicals due to the increase of the l-alkyl group size which hinders the dimerization site (2- and 6-positions).
AB - The applications of the reverse pulse method are extended in order to distinguish between different paths of electrodimerization. The method for determination of rate constants of the chemical reaction coupled with charge transfer (ec2) is further developed. Measurements of K′d vs. t p provide valuable information for the determination of rate constants. The reverse pulse method is applied in the study of the electrodimerization of 1-alkyl-4-t-butylpyridinium ions (1-alkyl=-CH3; -CH2CH3; -CH(CH 3)2) in acetonitrile. It is found that the electrodimerization mechanism is consistent with the sequence: Py+ + e = Py ⇋ 1 2 Py2. The formal potential Eo′ is measured directly for 1-CH(CH3)2, and indirectly for the other pyridium ions. All values are identical within experimental error (Eo′ = -1.835 V vs. Ag/Ag+). The values of kd and km are measured. With an increase in the size of the l-alkyl group, kd decreases and km increases. This is consistent with the expected "stabilization" of the radicals due to the increase of the l-alkyl group size which hinders the dimerization site (2- and 6-positions).
UR - http://www.scopus.com/inward/record.url?scp=0039672437&partnerID=8YFLogxK
U2 - 10.1016/0022-0728(82)85105-X
DO - 10.1016/0022-0728(82)85105-X
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AN - SCOPUS:0039672437
SN - 0022-0728
VL - 139
SP - 81
EP - 95
JO - Journal of Electroanalytical Chemistry
JF - Journal of Electroanalytical Chemistry
IS - 1
ER -