Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines (2024)

Hammill, C. L., Noble, B. B., Norcott, P. L., Ciampi, S., & Coote, M. L. (2019). Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines. Journal of Physical Chemistry C, 123(9), 5273-5281. https://doi.org/10.1021/acs.jpcc.8b12545

Hammill, Chelsey L. ; Noble, Benjamin B. ; Norcott, Philip L. et al. / Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines. In: Journal of Physical Chemistry C. 2019 ; Vol. 123, No. 9. pp. 5273-5281.

@article{864f77f8f8104261bf199e69ffd7ed0b,

title = "Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines",

abstract = "A test set of 14 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-based alkoxyamines was studied via a combination of cyclic voltammetry and accurate quantum chemistry to assess the effect of substituents on electrochemical cleavage. The experimental oxidation potentials of alkoxyamines falling into the range of 1.1-1.6 V versus Ag/AgCl in acetonitrile, were well reproduced by theory (MAD 0.04 V), with values showing good correlation with the σR Hammett parameters of both the R-group and the OR-group in TEMPO-R. Importantly, most of the studied alkoxyamines underwent oxidative cleavage to form either TEMPO· and R+ or TEMPO+ and R·, with the former favored by electron-donating substituents on R (e.g., 2-oxolane, Ac, CH(CH3)Ph, i-Pr, t-Bu) and the latter by electron withdrawing substituents (Bn, allyl, CH(CH3)C(O)OCH3, C(CH3)2C(O)OCH3, CH(CH3)CN). Where R is not stabilized (e.g., R = CH2C(O)OCH3, Me, Et), fully or almost fully reversible oxidation - without cleavage - was observed, making these species promising candidates for battery applications. Finally, in the case of R = Ph, where N-O cleavage occurred, a phenoxy cation and an aminyl radical were generated. On the basis of these results, TEMPO-based alkoxyamines can provide a variety of electrochemically generated carbon-centered radicals and carbocations for use in synthesis, polymerization, and surface modification.",

author = "Hammill, {Chelsey L.} and Noble, {Benjamin B.} and Norcott, {Philip L.} and Simone Ciampi and Coote, {Michelle L.}",

note = "Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",

year = "2019",

month = mar,

day = "7",

doi = "10.1021/acs.jpcc.8b12545",

language = "English",

volume = "123",

pages = "5273--5281",

journal = "Journal of Physical Chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

number = "9",

}

Hammill, CL, Noble, BB, Norcott, PL, Ciampi, S & Coote, ML 2019, 'Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines', Journal of Physical Chemistry C, vol. 123, no. 9, pp. 5273-5281. https://doi.org/10.1021/acs.jpcc.8b12545

Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines. / Hammill, Chelsey L.; Noble, Benjamin B.; Norcott, Philip L. et al.
In: Journal of Physical Chemistry C, Vol. 123, No. 9, 07.03.2019, p. 5273-5281.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines

AU - Hammill, Chelsey L.

AU - Noble, Benjamin B.

AU - Norcott, Philip L.

AU - Ciampi, Simone

AU - Coote, Michelle L.

N1 - Publisher Copyright:© 2019 American Chemical Society.

PY - 2019/3/7

Y1 - 2019/3/7

N2 - A test set of 14 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-based alkoxyamines was studied via a combination of cyclic voltammetry and accurate quantum chemistry to assess the effect of substituents on electrochemical cleavage. The experimental oxidation potentials of alkoxyamines falling into the range of 1.1-1.6 V versus Ag/AgCl in acetonitrile, were well reproduced by theory (MAD 0.04 V), with values showing good correlation with the σR Hammett parameters of both the R-group and the OR-group in TEMPO-R. Importantly, most of the studied alkoxyamines underwent oxidative cleavage to form either TEMPO· and R+ or TEMPO+ and R·, with the former favored by electron-donating substituents on R (e.g., 2-oxolane, Ac, CH(CH3)Ph, i-Pr, t-Bu) and the latter by electron withdrawing substituents (Bn, allyl, CH(CH3)C(O)OCH3, C(CH3)2C(O)OCH3, CH(CH3)CN). Where R is not stabilized (e.g., R = CH2C(O)OCH3, Me, Et), fully or almost fully reversible oxidation - without cleavage - was observed, making these species promising candidates for battery applications. Finally, in the case of R = Ph, where N-O cleavage occurred, a phenoxy cation and an aminyl radical were generated. On the basis of these results, TEMPO-based alkoxyamines can provide a variety of electrochemically generated carbon-centered radicals and carbocations for use in synthesis, polymerization, and surface modification.

AB - A test set of 14 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-based alkoxyamines was studied via a combination of cyclic voltammetry and accurate quantum chemistry to assess the effect of substituents on electrochemical cleavage. The experimental oxidation potentials of alkoxyamines falling into the range of 1.1-1.6 V versus Ag/AgCl in acetonitrile, were well reproduced by theory (MAD 0.04 V), with values showing good correlation with the σR Hammett parameters of both the R-group and the OR-group in TEMPO-R. Importantly, most of the studied alkoxyamines underwent oxidative cleavage to form either TEMPO· and R+ or TEMPO+ and R·, with the former favored by electron-donating substituents on R (e.g., 2-oxolane, Ac, CH(CH3)Ph, i-Pr, t-Bu) and the latter by electron withdrawing substituents (Bn, allyl, CH(CH3)C(O)OCH3, C(CH3)2C(O)OCH3, CH(CH3)CN). Where R is not stabilized (e.g., R = CH2C(O)OCH3, Me, Et), fully or almost fully reversible oxidation - without cleavage - was observed, making these species promising candidates for battery applications. Finally, in the case of R = Ph, where N-O cleavage occurred, a phenoxy cation and an aminyl radical were generated. On the basis of these results, TEMPO-based alkoxyamines can provide a variety of electrochemically generated carbon-centered radicals and carbocations for use in synthesis, polymerization, and surface modification.

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U2 - 10.1021/acs.jpcc.8b12545

DO - 10.1021/acs.jpcc.8b12545

M3 - Article

SN - 1932-7447

VL - 123

SP - 5273

EP - 5281

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 9

ER -

Hammill CL, Noble BB, Norcott PL, Ciampi S, Coote ML. Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines. Journal of Physical Chemistry C. 2019 Mar 7;123(9):5273-5281. doi: 10.1021/acs.jpcc.8b12545