Redox data of ferrocenylcarboxylic acids in dichloromethane and acetonitrile

Redox data obtained from cyclic voltammetry experiments of the FeII/III oxidation of six ferrocenyl carboxylic acids is presented in this data in brief article. Data is obtained from the cyclic voltammograms at scan rates of two orders of magnitude (0.05 – 5.00 Vs−1) using (i) acetonitrile as solvent and tetrabutylammonium hexafluorophosphate as supporting electrolyte and (ii) dichloromethane as solvent and tetrabutylammonium tetrakispentafluorophenylborate, as the electrolyte. Data is reported versus the FeII/III redox couple of ferrocene. For more insight in the reported data, see the related research article “Solvent and substituent effect on Electrochemistry of ferrocenylcarboxylic acids”, published in Journal of Electroanalytical Chemistry [1].


Specifications
Chemistry Specific subject area Electrochemistry Type of data Table  Image Graph Figure  How

Data format
Raw Analysed

Parameters for data collection
Samples were used as synthesized. All the electrochemical experiments were performed in an M Bruan Lab Master SP glove box under a high purity argon atmosphere (H 2 O and O 2 < 10 ppm).

Description of data collection
All electrochemical experiments were done in a 2 ml electrochemical cell containing three-electrodes (a glassy carbon working electrode, a Pt auxiliary electrode and a Pt pseudo reference electrode), connected to a Princeton Applied Research PARSTAT 2273 electrochemical analyser. Data obtained were exported to excel for analysis and diagram preparation.

Data source location
University of the Free State Bloemfontein South Africa

Data accessibility
With the article

Value of the Data
• This data provides detailed electrochemical data for six ferrocenyl carboxylic acids in both DCM and ACN for scan rates over two orders of magnitude (0.05 -5.0 Vs −1 ). • This data illustrates the influence of the solvent used in cyclic voltammetry experiments, on the formal redox potential of Fe of the ferrocenyl group for ferrocenylcarboxylic acids. • This data illustrates the influence of the solvent on the peak current-voltage separations, E p , of the Fe oxidation peak of ferrocenyl carboxylic acids. • This data illustrates the electronic influence of electron-withdrawing carbonyl group on the iron's oxidation potential, depending on how close the carbonyl group is to the iron. • Accurate redox potential data of these ferrocenyl (Fc) carboxylic acids are important, since they are used as ligands in organometallic complexes.

Data
This article presents redox data of six ferrocene-containing carboxylic acids, 1 -6, reported versus the redox couple ferrocene (Fc) at 0, using decamethylferrocene (DmFc) as internal standard [2] , see Figure 1 for the series of complexes of this data study. Cyclic voltammograms obtained in dichloromethane (DCM) and acetonitrile (ACN) for compound 1 -6, with DmFc as internal standard, are shown in Figure 2 - Figure 9 . The cyclic voltammograms of DmFc and ferrocene in DCM and ACN are shown in Figure 10 and Figure 11 . Electrochemical data obtained from the cyclic voltammograms at scan rates 0.05 Vs −1 -5.00 Vs −1 are tabulated in Table 1 -Table 12 (0.10 Vs −1 data from reference [1] ). Presented data is related to the research article "Solvent and substituent effect on Electrochemistry of ferrocenylcarboxylic acids", published in Journal of Electroanalytical Chemistry [1] . The electronic influence of the different carboxylic acids  substituents on the redox potential of the ferrocenylgroup they are attached to, is illustrated in Figure 2 and Figure 3 . The electronic influence of the electron-withdrawing carbonyl group on the iron's oxidation potential, depends on how close the carbonyl group is to the iron. Redox data of ferrocene-containing compounds are important for application in asymmetric catalysis [3][4][5][6] , energy transfer processes [7] , biological applications [ 8 , 9 ], as additives in highburning rate composite rocket propellants [10] and non-linear optics [6] .

Experimental Design, Materials, and Methods
Electrochemical studies through cyclic voltammetry (CV) experiments were performed in an M Bruan Lab Master SP glove box under a high purity argon atmosphere (H 2 O and O 2 < 10 ppm), utilising a Princeton Applied Research PARSTAT 2273 potentiostat running Powersuite software (Version 2.58). The cyclic voltammetry experimental setup consists of a cell with three electrodes, namely (i) a glassy carbon electrode as working electrode, (ii) a platinum wire auxiliary and (ii) a platinum wire as pseudo reference electrode. The glassy carbon working electrode was polished and prepared before every experiment on a Buhler polishing mat first with 1micron and then with ¼-micron diamond paste, rinsed with H 2 O, acetone and DCM, and dried All scans initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and the indicated ferrocene-containing carboxylic acid (right) are indicated in V.

Fig. 5.
Cyclic voltammograms in DCM of FcCH 2 CO 2 H at scan rates 0.050 (smallest peak currents), 0.10 0, 0.20 0, 0.30 0, 0.40 0 and 0.500 (largest peak currents) Vs −1 . All scans initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and the indicated ferrocene-containing carboxylic acid (right) are indicated in V.  6. Cyclic voltammograms in DCM of Fc(CH) 2 CO 2 H at scan rates 0.050 (smallest peak currents), 0.100, 0.200, 0.300, 0.400 and 0.500 (largest peak currents) Vs −1 . All scans initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and the indicated ferrocene-containing carboxylic acid (right) are indicated in V.

Fig. 7.
Cyclic voltammograms in DCM of Fc(CH 2 ) 2 CO 2 H at scan rates 0.050 (smallest peak currents), 0.10 0, 0.20 0, 0.30 0, 0.40 0 and 0.500 (largest peak currents) Vs −1 . All scans initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and the indicated ferrocene-containing carboxylic acid (right) are indicated in V. Fig. 8. Cyclic voltammograms in DCM of Fc(CH 2 ) 3 CO 2 H at scan rates 0.050 (smallest peak currents), 0.100, 0.200, 0.300, 0.400 and 0.500 (largest peak currents) Vs −1 . All scans initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and the indicated ferrocene-containing carboxylic acid (right) are indicated in V.   10. Cyclic voltammograms in ACN of decamethylferrocene and ferrocene at scan rate 0.100 Vs −1 . The scan is initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and Fc (right) is indicated in V. Fig. 11. Cyclic voltammograms in DCM of decamethylferrocene and ferrocene at scan rate 0.100 Vs −1 . The scan is initiated in a positive direction. Data for the peak oxidation potential (E pa ), the formal reduction potential (E 0' ) and the peak current separation E p of the Fe II/III oxidation of DmFc (internal standard, left) and Fc (right) is indicated in V.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.