Electrochemical properties of ‘figure-eight’-cyclooctapyrroles (octaphyrins) and their metal complexes

Gisselbrecht, Jean Paul; Bley-Escrich, Jordi; Gross, Maurice; Zander, Lars; Michels, Martin; Vogel, Emanuel

doi:10.1016/s0022-0728(99)00214-4

Cited by 20 publications

(18 citation statements)

References 19 publications

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“…[113] Similar redox patterns were observed for the two free bases 114 and 115: Both undergo five distinct redox steps, two reductions and three oxidations. As confirmed by cyclic voltammetry, the two reduction as well as the first two oxidation waves represent reversible one-electron steps.…”

Section: Figure-eight Octaphyrins and Their Metal Complexesmentioning

confidence: 53%

Synthetic Expanded Porphyrin Chemistry

2003

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Expanded porphyrins are synthetic analogues of the porphyrins, and differ from these and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core with a minimum of 17 atoms, while retaining the extended conjugation features that are a hallmark of these quintessential biological pigments. The result of core expansion is to produce systems with novel spectral and electronic features, interesting and, often unprecedented, cation-coordination properties, and, in many cases, an ability to bind anions in certain protonation states. Also adding to the appeal of expanded porphyrins is their central role in addressing issues of aromaticity. In many cases, they also display structural features, such as decidedly nonplanar "figure-eight" motifs, that have no antecedents in the chemistry of porphyrins or related macrocyclic compounds. In this Review, the various synthetic approaches now being employed to produce expanded porphyrins as well as their various applications-related aspects are discussed.

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Section: Figure-eight Octaphyrins and Their Metal Complexesmentioning

confidence: 53%

Synthetic Expanded Porphyrin Chemistry

2003

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“…[21] Until now, electrochemical investigations of macrocyclic polypyrroles containing more than four pyrrole units remain rather scarce, [17] and studies on octapyrrolic macrocycles are restricted to preliminary studies on the free bases and some complexes of 1 and 3 in CH 2 Cl 2 . [22] In the present paper the electrochemical behaviour of a new series of cyclooctaphyrins, namely 2, has been investigated in dry benzonitrile. Its behaviour will be compared with previously Figure 1.…”

Section: Introductionmentioning

confidence: 99%

“…Its behaviour will be compared with previously Figure 1. Free bases and complexes, studied in the three hexadecaethylcyclooctaphyrin series; the ethyl groups are omitted for clarity published data [22] involving 1 and 3. However, to obtain a better insight into the redox behaviour of the three series of COP and to allow consistent comparison, the previously studied COP (1, 3Ϫ10, 16Ϫ18) have been reinvestigated here in dry benzonitrile by hydrodynamic voltammetry, by cyclic voltammetry, and by UV/Vis spectroelectrochemistry.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and Spectroelectrochemical Investigations of “Figure-Eight” Octapyrrolic Macrocycles, Free Bases, and Their Mononuclear, Homo- and Heterodinuclear Complexes with Divalent Transition Metals

Bley-Escrich

Gisselbrecht

Vogel

et al. 2002

Eur. J. Inorg. Chem.

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This work reports on electrochemical investigations of ''figure-eight''-shaped cyclooctapyrrolic macrocycles (octaphyrins) 1−3 and of some of their mono-and dinuclear transition metal complexes. The octaphyrins 1−3 differ mainly in the size of the main conjugation pathway, which involves either 4n π-electrons for 1 and 3, or (4n + 2) π-electrons for 2. All species studied undergo six redox steps, namely two reductions and four oxidations. The two reductions and the first three oxidations are reversible one-electron transfers. The fourth oxidation is either reversible, or irreversible due to a subsequent chemical reaction. Depending on the complex studied, the third and fourth oxidations occur either at similar potentials, so that a global two-electron step is observed, or at distinct potentials, leading to two well-separated signals.

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“…The two reduction and first two oxidation steps of the other two cobalt complexes, CoH 2 L 2 and CoCuL 2 , are similar to those of the free base H 4 L 2 . [26,27] After the second oxidation step, the complexes have a distinct behavior. When using RDV and CV, CoH 2 L 2 presents a third oneelectron oxidation that occurs at 0.73 V/Fc, which is 280 mV less positive than the third oxidation of the free base (Table 2).…”

Section: Electrochemical Studiesmentioning

confidence: 99%

Electrochemical and Spectroelectrochemical Investigations of Mono‐ and Binuclear Cobalt(II) Complexes of “Figure‐Eight” Octapyrrolic Macrocycles

Bley-Escrich¹,

Gisselbrecht²,

Michels

et al. 2004

Eur J Inorg Chem

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In this paper, electrochemical investigations of a set of three cyclooctaphyrin complexes containing divalent cobalt are reported. These complexes are the homodinuclear cobalt-cobalt complex Co 2 L 1 with the ligand H 4 L 1 , the mononuclear cobalt complex CoH 2 L 2 and the heterodinuclear copper(II)-cobalt complex CoCuL 2 with the ligand H 4 L 2 . All of these species undergo two reduction and three oxidation processes, all of which are reversible one-electron transfers. The two reduction and first two oxidation steps are ligand-centered, as confirmed by spectroelectrochemical investigations. In contrast, the third oxidation corresponds to a metal-cent-

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Electrochemical properties of ‘figure-eight’-cyclooctapyrroles (octaphyrins) and their metal complexes

Cited by 20 publications

References 19 publications

Synthetic Expanded Porphyrin Chemistry

Synthetic Expanded Porphyrin Chemistry

Electrochemical and Spectroelectrochemical Investigations of “Figure-Eight” Octapyrrolic Macrocycles, Free Bases, and Their Mononuclear, Homo- and Heterodinuclear Complexes with Divalent Transition Metals

Electrochemical and Spectroelectrochemical Investigations of Mono‐ and Binuclear Cobalt(II) Complexes of “Figure‐Eight” Octapyrrolic Macrocycles

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