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A simple treatment of the fundamentals of solution-phase voltammetry is followed by six examples of porphyrinoids highlighting how structural changes of the redox species influence formal reduction potentials. Electronic communication among different molecular groups is demonstrated, and it is shown how the correct solvent and supporting electrolyte choice may result in observing 17 of a possible 18 redox processes in a cadmium triple-decker phthalocyanine. The difference between outer- and inner-sphere electron transfer processes is used to introduce adsorption effects of redox species on electrodes. This forms the bases of electrocatalysis, and a short theoretical introduction to electrocatalysis is presented. The reader is then eased into electrocatalysis concepts through a discussion of electrocatalyzed alcohol oxidation and sulfite sensors with adsorbed porphyrin polymers. Covalent binding or adsorption to the electrode or solution-phase electrocatalysts are demonstrated. Electrocatalysis in fuel production or energy storage systems concludes this chapter. CO2 reduction by an Fe0 porphyrin, an octaalkoxylated Co phthalocyanine, which aggregates less, and covalent– and metal–organic framework complexes of Co porphyrinoids, are considered. Hydrogen evolution by Ni porphyrins, oxygen reduction to either H2O or H2O2, and H2O oxidation to O2 utilizing carefully chosen porphyrinoids are other reactions that are discussed.

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].

Four new ferrocenylsubphthalocyanines Y-BSubPc, with ferrocenylcarboxylic acid YH = Fc-CH2–CH2–COOH (1) or Fc-CH═CH–COOH (2) in the axial Y position, were synthesized with a 40% yield. The axial fe...

The data presented in this paper are related to the research article entitled "Electrochemical behaviour of chloro- and hydroxy-subphthalocyanines" [1]. This paper presents detailed oxidation and reduction potential data, obtained from cyclic voltammograms of three subphthalocyanines (SubPcs), in both dichloromethane (DCM) and dichloroethane (DCE) as solvent. The first SubPc is the unsubstituted boron-subphthalocyanine, (ClB)SubPc(H)12, as reference SubPc, the second SubPc is (ClB)SubPc(F)12, containing an electron-poor macro-cycle and (HOB)SubPc(C12H25)6(H)6, containing an electron-rich macro-cycle. The oxidation and reduction potential of (ClB)SubPc(F)12 in DCM is ca. 0.5 V more positive than that of the reference ClBSubPc(H)12, while oxidation and reduction potential of (HOB)SubPc(C12H25)6(H)6 in DCM is ca. 0.45 V more negative than that of the reference (ClB)SubPc(H)12.

The data presented in this paper is related to the research article entitled “Synthesis, Spectroscopy, Electrochemistry and DFT of Electron-Rich Ferrocenylsubphthalocyanines” [1] where electrochemical redox data and cyclic voltammograms at only a scan rate of 0.10 V s−1 of four ferrocenylsubphthalocyanine dyads Fc(CH2)nCO2BSubPc(H)12 (n = 0, 1 or 3) and FcCO(CH2)2CO2BSubPc(H)12, are presented. This data article provides extensive electrochemical redox data and cyclic voltammograms at various scan rates from 0.05 up to 5.00 V s−1 to illustrate the effect of the different scan rates on the electrochemical behaviour of the four ferrocenylsubphthalocyanine dyads.

A novel subphthalocyanine (HO)BSubPc(C12H25)6(H)6, 3, with a hydroxy group in the axial position and alkyl ligands (C12H25) on the non-peripheral positions as well as two other subphthalocyanines, ClBSubPc(H)12, 2, and ClBSubPc(F)12, 1, have been synthesized and characterized. The redox properties of subphthalocyanines 1–3 was investigated using cyclic voltammetry (CV), both in dichloromethane (at 25 °C) and dichloroethane (at 60 °C) as solvent and compared to previous studies. The electrochemical experimental conditions used made it possible for the first time to experimentally observe electrochemically quasi reversible oxidation for subphthalocyanines. It was found that the novel subphthalocyanine 3 exhibits the lowest macrocycle-based oxidation potential reported for SubPcs till date. The results obtained were further validated by DFT calculations on subphthalocyanines 1–3 as well as related subphthalocyanines from literature. Linear relationships between the redox potentials (oxidation and reduction vs Fc+/Fc) of these subphthalocyanines and various solvent phase B3LYP calculated energies were obtained.

The series [(CO)5W═C(XR)Fc] (1, XR = OEt; 3, XR = NHBu) as well as [(CO)5W═C(XR)–Fc′–(XR)C═W(CO)5] (2, XR = OEt; 4, XR = NHBu) of mono- and biscarbene tungsten(0) complexes with Fc = FeII(C5H5)(C5H4) for monosubstituted derivatives and Fc′ = FeII(C5H4)2 for disubstituted derivatives were synthesized and characterized spectroscopically. The oxidized ferrocenium complex [1+]·PF6 was also synthesized and characterized. Electrochemical and computational studies were mutually consistent in confirming the sequence of redox events for the carbene derivatives 1–4 as first a carbene double-bond reduction to a radical anion, –W–C•, at peak cathodic potentials less than −2 V, then a ferrocenyl group oxidation in the range 0.206 0.540 V vs FcH/FcH+ in CH2Cl2/[(nBu4)N][PF6]. This is in contrast with the sequence of oxidation events in ferrocenylcarbene complexes of chromium, where Cr(0) is first oxidized in a one-elec...

A series of Group 7 Fischer carbene complexes, [Cp(CO)2 Mn(I) =C(OEt)Ar] (Cp=cyclopentadienyl, Ar=Th=thienyl (1 a), Ar=Fu=furyl (2 a), Ar=Fc=ferrocenyl (3 a)) and biscarbene complexes, [Cp(CO)2 MnC(OEt)Ar'(OEt)CMn(CO)2 Cp] (Ar'=Th'=2,5-thienylene (1 b), Ar'=Fu'=2,5-furylene (2 b), Ar'=Fc'=1,1'-ferrocendiyl (3 b)) was synthesized and characterized. Chemical oxidation of [Cp(CO)2 MnC(OEt)Fc] (3 a) and isolation of the oxidised species [3 a][PF6 ] possessing a Mn(II) centre proved possible below -30 °C in dichloromethane solution. The ESR spectrum of the transiently stable radical cation, [3 a][PF6 ], confirmed the presence of a low-spin Mn(II) centre characterized by a rhombic g tensor (gx =1.975, gy =2.007 and gz =2.130) in frozen dichloromethane at 77 K with (55) Mn hyperfine coupling constants A1 , A2 and A3 of 115, 33 and 43 G, respectively. Electrochemical studies demonstrated the influence of the Ar substituent on the oxidation potential. All complexes showed that the redox potentials of carbene double bond reduction and Mn(I) oxidation were dependent on the type of Ar group, but only 3 b showed resolved oxidations for the two Mn(I) centres. Surprisingly, Mn(I) oxidation occurs at lower potentials than ferrocenyl oxidation. Density functional theory (DFT) calculations were carried out to delineate the nature of the species involved in the oxidation and reduction processes and clearly confirm that oxidation of Mn(I) is favoured over that of ferrocene.

A series of ferrocenyl and thienyl mono- and biscarbene chromium(0) complexes 1-6 were synthesised. The complexes were characterised both spectroscopically and electrochemically, and the single crystal X-ray structure of 3 was determined. Electrochemical measurements in CH2Cl2 revealed that the carbene double bond of 1-6 is reduced to an anion radical, (-)Cr-C˙ at formal reduction potentials-1.7 V vs. FcH/FcH(+). A computational study on 1, 3 and 4 (B3LYP/def2-SVP level) is consistent with electrochemical results in showing that electrochemically generated chromium(I) species may be further electrochemically irreversibly oxidised to chromium(II) at Epa0.95 V. The reactivity towards follow-up chemical reactions of the anodically produced Cr(II) species is much higher than the reactivity of the cathodically produced radical anions as the latter was still observably reoxidised to the parent Cr=C species at fast scan rates. The ferrocenyl group is oxidised electrochemically reversibly to ferrocenium at larger potentials than the electrochemically reversible oxidation of the Cr(0) centre to Cr(I). That all redox centres in 1-6 are involved in one-electron transfer steps was confirmed by comparing the ferrocenyl voltammetric wave with those of the other redox centres in linear sweep voltammetric experiments. The ferrocenyl group was electrochemically shown to stabilise the Cr=C centre almost as much as the NHBu, and much more than the ethoxy and thienyl groups.