Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines
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...
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| Format: | Journal Article |
| Language: | English |
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AMER CHEMICAL SOC
2019
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| Online Access: | http://purl.org/au-research/grants/arc/FL170100041 http://hdl.handle.net/20.500.11937/80753 |
| _version_ | 1848764265898442752 |
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| author | Hammill, C.L. Noble, B.B. Norcott, P.L. Ciampi, Simone Coote, M.L. |
| author_facet | Hammill, C.L. Noble, B.B. Norcott, P.L. Ciampi, Simone Coote, M.L. |
| author_sort | Hammill, C.L. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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. |
| first_indexed | 2025-11-14T11:16:37Z |
| format | Journal Article |
| id | curtin-20.500.11937-80753 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:16:37Z |
| publishDate | 2019 |
| publisher | AMER CHEMICAL SOC |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-807532020-08-31T03:36:33Z Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines Hammill, C.L. Noble, B.B. Norcott, P.L. Ciampi, Simone Coote, M.L. Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science MOLECULAR-ORBITAL METHODS BASIS-SETS CARBOCATION POLYMERIZATION INSIGHTS 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. 2019 Journal Article http://hdl.handle.net/20.500.11937/80753 10.1021/acs.jpcc.8b12545 English http://purl.org/au-research/grants/arc/FL170100041 http://purl.org/au-research/grants/arc/DE160100732 http://purl.org/au-research/grants/arc/CE140100012 AMER CHEMICAL SOC fulltext |
| spellingShingle | Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science MOLECULAR-ORBITAL METHODS BASIS-SETS CARBOCATION POLYMERIZATION INSIGHTS Hammill, C.L. Noble, B.B. Norcott, P.L. Ciampi, Simone Coote, M.L. Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title | Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title_full | Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title_fullStr | Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title_full_unstemmed | Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title_short | Effect of Chemical Structure on the Electrochemical Cleavage of Alkoxyamines |
| title_sort | effect of chemical structure on the electrochemical cleavage of alkoxyamines |
| topic | Science & Technology Physical Sciences Technology Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science MOLECULAR-ORBITAL METHODS BASIS-SETS CARBOCATION POLYMERIZATION INSIGHTS |
| url | http://purl.org/au-research/grants/arc/FL170100041 http://purl.org/au-research/grants/arc/FL170100041 http://purl.org/au-research/grants/arc/FL170100041 http://hdl.handle.net/20.500.11937/80753 |