Abstract
Cyclopropenyl cation has been reversibly reduced electrochemically to the unsubstituted 3-cyclopropenyl radical, and with two electrons to the unsubstituted 3-cyclopropenyl anion. Reversible thermodynamic reduction potentials for both processes have been determined using second harmonic ac voltammetry. The same technique has been used to determine thermodynamic potentials for the one- and two-electron reduction of triphenylmethyl, cycloheptatrienyl, triphenylcyclopropenyl, trimethylcyclopropenyl, tri-tert-butylcyclopropenyl, and dipropylphenylcyclopropenyl cations. Adsorption effects were detected for two of these cations at a Pt, but not at an Au, electrode. The data were used in thermodynamic sequences to evaluate the basicity of various cyclopropenyl anions; a set of pKa's ranges from +50 to +74. Another thermodynamic sequence was used to evaluate the C-O bond dissociation energy of various cyclopropenols. Two unusual effects emerge: cyclopropenyl radicals are destabilized by alkyl groups, and they also appear to be destabilized relative to unconjugated radicals.
| Original language | English |
|---|---|
| Pages (from-to) | 4222-4229 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 98 |
| Issue number | 14 |
| Publication status | Published - 1976 |
Fingerprint
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Thermodynamic measurements on unsubstituted cyclopropenyl radical and anion, and derivatives, by second harmonic alternating current voltammetry of cyclopropenyl cations. / Wasielewski, Michael R; Breslow, Ronald.
In: Journal of the American Chemical Society, Vol. 98, No. 14, 1976, p. 4222-4229.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Thermodynamic measurements on unsubstituted cyclopropenyl radical and anion, and derivatives, by second harmonic alternating current voltammetry of cyclopropenyl cations
AU - Wasielewski, Michael R
AU - Breslow, Ronald
PY - 1976
Y1 - 1976
N2 - Cyclopropenyl cation has been reversibly reduced electrochemically to the unsubstituted 3-cyclopropenyl radical, and with two electrons to the unsubstituted 3-cyclopropenyl anion. Reversible thermodynamic reduction potentials for both processes have been determined using second harmonic ac voltammetry. The same technique has been used to determine thermodynamic potentials for the one- and two-electron reduction of triphenylmethyl, cycloheptatrienyl, triphenylcyclopropenyl, trimethylcyclopropenyl, tri-tert-butylcyclopropenyl, and dipropylphenylcyclopropenyl cations. Adsorption effects were detected for two of these cations at a Pt, but not at an Au, electrode. The data were used in thermodynamic sequences to evaluate the basicity of various cyclopropenyl anions; a set of pKa's ranges from +50 to +74. Another thermodynamic sequence was used to evaluate the C-O bond dissociation energy of various cyclopropenols. Two unusual effects emerge: cyclopropenyl radicals are destabilized by alkyl groups, and they also appear to be destabilized relative to unconjugated radicals.
AB - Cyclopropenyl cation has been reversibly reduced electrochemically to the unsubstituted 3-cyclopropenyl radical, and with two electrons to the unsubstituted 3-cyclopropenyl anion. Reversible thermodynamic reduction potentials for both processes have been determined using second harmonic ac voltammetry. The same technique has been used to determine thermodynamic potentials for the one- and two-electron reduction of triphenylmethyl, cycloheptatrienyl, triphenylcyclopropenyl, trimethylcyclopropenyl, tri-tert-butylcyclopropenyl, and dipropylphenylcyclopropenyl cations. Adsorption effects were detected for two of these cations at a Pt, but not at an Au, electrode. The data were used in thermodynamic sequences to evaluate the basicity of various cyclopropenyl anions; a set of pKa's ranges from +50 to +74. Another thermodynamic sequence was used to evaluate the C-O bond dissociation energy of various cyclopropenols. Two unusual effects emerge: cyclopropenyl radicals are destabilized by alkyl groups, and they also appear to be destabilized relative to unconjugated radicals.
UR - http://www.scopus.com/inward/record.url?scp=0001342787&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001342787&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0001342787
VL - 98
SP - 4222
EP - 4229
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 14
ER -