Oxidation and reduction data of four subphthalocyanines with axially coordinated ferrocenylcarboxylic acids

Redox data obtained from cyclic voltammetry experiments of the FeII/III and ring-based oxidation and reductions of subphthalocyanines containing a ferrocenylcarboxylic acid as axial ligand, is presented in this data in brief article. The FeII/III oxidation of ferrocenylsubphthalocyanines which containing the electron-withdrawing fluorine atoms at the peripheral and non-peripheral positions, are ca. 0.100 V more positive than FeII/III oxidation of ferrocenylsubphthalocyanines containing hydrogens at the peripheral and non-peripheral positions. For more insight into the reported data, see the related research article “Redox and photophysical properties of four subphthalocyanines containing ferrocenylcarboxylic acid as axial ligands” [1].


Specifications
Chemistry Specific subject area Electrochemistry Type of data With the article Related research article P.J. Swarts, J. Conradie, Redox and photophysical properties of four subphthalocyanines containing ferrocenylcarboxylic acid as axial ligands [1] .
Value of the Data • The electrochemistry of subphthalocyanines provides insight and understanding into the macrocyclic ring-based oxidation and reduction processes. Introducing a ferrocenyl unit at the axial position of a subphthalocyanine, has a strong influence on the optical and redox properties of the ferrocenylsubphthalocyanines. Several ferrocenylsubphthalocyanines showed photo-induced electron-transfer properties that are important for solar devices which convert sunlight into electricity. Different axial ligands and ring substituents can finetune the redox properties of subphthalocyanines for use in different applications. This data provides detailed redox data of four ferrocenylsubphthalocyanines containing different axial ligands and different ring substituents. • The data reported here provides insight for electrochemists into the effect of both electronrich or electron-poor macrocycles of ferrocenylsubphthalocyanines Y-BSubPc(H) 12 and Y-BSubPc(F) 12 respectively, on the iron(II/III) oxidation potential of the ferrocenylcarboxylic acid ligand Y in the axial position. Axial ligand Y = either a non π -communicating (Fc -CH 2 -CH 2 -COO-) or a π -communicating (Fc -CH = CH-COO-) ferrocenyl moiety.
• Availability of electrochemical data of both the iron(II/III) and ring-based oxidation and reduction processes, assisting in future research in designing ferrocenylsubphthalocyanines with specific redox properties.

Data Description
The electrochemical data of ferrocenylsubphthalocyanines 1 -4 shown in Figure 1 is summarized in Tables 1-4 , with the cyclic voltammograms (CVs) shown in Figures 2-7 . Raw cyclic voltammetric data is available in excel format as supplementary data files. Comparative CVs, comparing the shift in the CV data of these ferrocenylsubphthalocyanines relative to the known chloro-subphthalocyanines ( 5 and 6 ) [2] , are shown in Figure 2 . The ferrocenylcarboxylic acid axial ligand causes the reduction peaks of the ferrocenylsubphthalocyanines to shift more negative relative to the chlorosubphthalocyanines. Cyclic voltammograms of the fluorinated subphthalocyanines 3 and 4 , showed one iron-based and one ring-based oxidation as well as three ringbased reductions. Cyclic voltammograms of the non-fluorinated subphthalocyanines 1 and 2 , also
40 a E p is the peak anodic potential for oxidation ( E ox ) and peak cathodic potential for reduction ( E red ). b i p is the peak anodic current for oxidation ( i pa ) and peak cathodic current for reduction ( i pc ). c peak current ratio = i pc /i pa for oxidation and i pa /i pc for reduction.
showed one iron-based and one ring-based oxidation, but only two ring-based reductions. Previous studies showed that the first oxidation in related ferrocenylsubphthalocyanines is iron based [ 1 , 3-5 ]. The iron-based first oxidation in compounds 1 -4 occurs at a lower potential than the first ring-based oxidation in 1 -6 . Porphyrins [6] , phthalocyanines [7] and subphthalocyanines (SubPcs) [ 8 , 9 ] can show up to three ring-based oxidations and three ring-based reductions. In most cases the first ring-based oxidation of the SubPcs exhibits irreversible behaviour [9] ; however, in this case chemically reversible first ring-based oxidation, with peak current ratios of 1 and peak current separations of E = 0.074 -0.084 V, were obtained.

Experimental Design, Materials and Methods
Electrochemical studies by means of cyclic voltammetric (CV) experiments were performed in an MBraun Lab Master SP glove box under a high purity argon atmosphere (H 2 O and O 2 < 10 ppm), utilizing 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 electrode 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 1-micron and then with ¼-micron diamond paste, rinsed with H 2 O, acetone and DCM, and dried before each experiment. Table 2 Electrochemical data (potential in V vs. Fc/Fc + ) in DCM for ca . 5 × 10 −4 mol dm −3 of Fc(CH) 2 CO 2 -BSubPc(H) 12 (compound 1 ), at indicated scan rates ( ν in V/s). See Figure 5 for assigment of peaks. 57 a E p is the peak anodic potential for oxidation ( E ox ) and peak cathodic potential for reduction ( E red ). b i p is the peak anodic current for oxidation ( i pa ) and peak cathodic current for reduction ( i pc ). c peak current ratio = i pc /i pa for oxidation and i pa /i pc for reduction.  Table 3 Electrochemical data (potential in V vs Fc/Fc + ) in DCM for ca . 5 × 10 −4 mol dm −3 of Fc(CH 2 ) 2 CO 2 -BSubPc(F) 12 (compound 4 ), at indicated scan rates ( ν in V/s). See Figure 6 for assigment of peaks. 69 a E p is the peak anodic potential for oxidation ( E ox ) and peak cathodic potential for reduction ( E red ). b i p is the peak anodic current for oxidation ( i pa ) and peak cathodic current for reduction ( i pc ). c peak current ratio = i pc /i pa for oxidation and i pa /i pc for reduction.

Table 4
Electrochemical data (potential in V vs. Fc/Fc + ) in DCM for ca . 5 × 10 −4 mol dm −3 of Fc(CH) 2 CO 2 -BSubPc(H) 12 (compound 3 ), at indicated scan rates ( ν in V/s). See Figure 7 for assigment of peaks. 27 a E p is the peak anodic potential for oxidation ( E ox ) and peak cathodic potential for reduction ( E red ). b i p is the peak anodic current for oxidation ( i pa ) and peak cathodic current for reduction ( i pc ). c peak current ratio = i pc /i pa for oxidation and i pa /i pc for reduction.

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.

Ethics Statement
This work does not require any ethical statement.