Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs
Ferrocene, Fc, and cobaltocenium hexafluorophosphate, CcPF6, have been recommended for use as internal reference redox couples in room-temperature ionic liquids (RTILs), as well as in more conventional aprotic solvents. In this study, the electrochemical behavior of Fc and CcPF6 is reported in eight...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
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American Chemical Society
2008
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| Online Access: | http://hdl.handle.net/20.500.11937/38389 |
| _version_ | 1848755307463835648 |
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| author | Rogers, E. Silvester, Debbie Poole, D. Aldous, L. Hardacre, C. Compton, R. |
| author_facet | Rogers, E. Silvester, Debbie Poole, D. Aldous, L. Hardacre, C. Compton, R. |
| author_sort | Rogers, E. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Ferrocene, Fc, and cobaltocenium hexafluorophosphate, CcPF6, have been recommended for use as internal reference redox couples in room-temperature ionic liquids (RTILs), as well as in more conventional aprotic solvents. In this study, the electrochemical behavior of Fc and CcPF6 is reported in eight commonly used RTILs; [C2mim][NTf2], [C4mim][NTf2], [C4mim][BF4], [C4mim][PF6], [C4mim][OTf], [C4mim][NO3], [C4mpyrr][NTf2], and [P14,6,6,6][FAP], where [Cnmim]+ = 1-butyl-3-methylimidazolium, [NTf2]- = bis(trifluoromethylsulfonyl)imide, [BF4]- = tetrafluoroborate, [PF6]- = hexafluorophosphate, [OTf]- = trifluoromethylsulfonate, [NO3]- = nitrate, [C4mpyrr]+ = N-butyl-N-methylpyrrolidinium, [P14,6,6,6 ]+ = tris(n-hexyl)-tetradecylphosphonium and [FAP]- = trifluorotris(pentafluoroethyl)phosphate, over a range of concentrations and temperatures. Solubilities and diffusion coefficients, D, of both the charged and neutral species were determined using double potential-step chronoamperometry, and CcPF6 (36.5−450.0 mM) was found to be much more soluble than Fc (27.5−101.8 mM). It was observed that classical Stokes−Einstein diffusional behavior applies for Fc and CcPF6 in all eight RTILs. Diffusion coefficients of Fc and CcPF6 were calculated at a range of temperatures, and activation energies calculated. It was also determined that D for Fc and CcPF6 does not change significantly with concentration. This supports the use of both Fc and CcPF6 to provide a well-characterized and model redox couple for use as a voltammetric internal potential reference in RTILs contrary to previous literature reports in the former case. |
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| format | Journal Article |
| id | curtin-20.500.11937-38389 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:54:13Z |
| publishDate | 2008 |
| publisher | American Chemical Society |
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| spelling | curtin-20.500.11937-383892017-09-13T14:15:05Z Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs Rogers, E. Silvester, Debbie Poole, D. Aldous, L. Hardacre, C. Compton, R. Ferrocene, Fc, and cobaltocenium hexafluorophosphate, CcPF6, have been recommended for use as internal reference redox couples in room-temperature ionic liquids (RTILs), as well as in more conventional aprotic solvents. In this study, the electrochemical behavior of Fc and CcPF6 is reported in eight commonly used RTILs; [C2mim][NTf2], [C4mim][NTf2], [C4mim][BF4], [C4mim][PF6], [C4mim][OTf], [C4mim][NO3], [C4mpyrr][NTf2], and [P14,6,6,6][FAP], where [Cnmim]+ = 1-butyl-3-methylimidazolium, [NTf2]- = bis(trifluoromethylsulfonyl)imide, [BF4]- = tetrafluoroborate, [PF6]- = hexafluorophosphate, [OTf]- = trifluoromethylsulfonate, [NO3]- = nitrate, [C4mpyrr]+ = N-butyl-N-methylpyrrolidinium, [P14,6,6,6 ]+ = tris(n-hexyl)-tetradecylphosphonium and [FAP]- = trifluorotris(pentafluoroethyl)phosphate, over a range of concentrations and temperatures. Solubilities and diffusion coefficients, D, of both the charged and neutral species were determined using double potential-step chronoamperometry, and CcPF6 (36.5−450.0 mM) was found to be much more soluble than Fc (27.5−101.8 mM). It was observed that classical Stokes−Einstein diffusional behavior applies for Fc and CcPF6 in all eight RTILs. Diffusion coefficients of Fc and CcPF6 were calculated at a range of temperatures, and activation energies calculated. It was also determined that D for Fc and CcPF6 does not change significantly with concentration. This supports the use of both Fc and CcPF6 to provide a well-characterized and model redox couple for use as a voltammetric internal potential reference in RTILs contrary to previous literature reports in the former case. 2008 Journal Article http://hdl.handle.net/20.500.11937/38389 10.1021/jp710134e American Chemical Society restricted |
| spellingShingle | Rogers, E. Silvester, Debbie Poole, D. Aldous, L. Hardacre, C. Compton, R. Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title | Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title_full | Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title_fullStr | Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title_full_unstemmed | Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title_short | Voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs |
| title_sort | voltammetric characterization of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in rtils |
| url | http://hdl.handle.net/20.500.11937/38389 |