Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins

K. Araki, H. Winnischofer, H. E. Toma, H. Maeda, A. Osuka, Hiroyuki Furuta

Research output: Contribution to journalArticle

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Abstract

The cis-doubly N-confused porphyrin, H2N2CP, containing two adjacent confused pyrrole rings has been investigated from the point of view of its acid-base and electrochemical behavior in dichloromethane. This novel porphyrin isomer can form two metal-carbon bonds in the central core, stabilizing metal ions in unusually high oxidation states. Furthermore, the two outside N-pyrrole atoms remain available for acid-base and specific solvent interactions. Protonation of the pyrrole N atoms proceeds according to two successive steps, while only a single deprotonation step has been observed in the presence of bases. Similarly, in the case of the silver and copper complexes the protonation and deprotonation of the outer pyrrole rings have been detected, confirming the structure of the metalated species as MIII-HN2CP. The electrochemical reduction of the metal ions (III/II redox process) and oxidation of the macrocycle ring have been detected respectively at -0.9 and 1.4 V based on spectroelectrochemical measurements in conjunction with the acid/base equilibrium studies. Additional waves observed around -0.5 and 1.3 V have been assigned to redox processes involving water molecules associated with the doubly N-confused porphyrins.

Original languageEnglish
Pages (from-to)2020-2025
Number of pages6
JournalInorganic Chemistry
Volume40
Issue number9
DOIs
Publication statusPublished - Apr 23 2001
Externally publishedYes

Fingerprint

Pyrroles
Porphyrins
pyrroles
porphyrins
Deprotonation
acids
Acids
Protonation
Metal ions
rings
metal ions
acid base equilibrium
Atoms
Oxidation
oxidation
Methylene Chloride
Silver
Isomers
atoms
Copper

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins. / Araki, K.; Winnischofer, H.; Toma, H. E.; Maeda, H.; Osuka, A.; Furuta, Hiroyuki.

In: Inorganic Chemistry, Vol. 40, No. 9, 23.04.2001, p. 2020-2025.

Research output: Contribution to journalArticle

Araki, K, Winnischofer, H, Toma, HE, Maeda, H, Osuka, A & Furuta, H 2001, 'Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins', Inorganic Chemistry, vol. 40, no. 9, pp. 2020-2025. https://doi.org/10.1021/ic000441j
Araki, K. ; Winnischofer, H. ; Toma, H. E. ; Maeda, H. ; Osuka, A. ; Furuta, Hiroyuki. / Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins. In: Inorganic Chemistry. 2001 ; Vol. 40, No. 9. pp. 2020-2025.
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