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Intermacrocyclic Interactions upon Stepwise Oxidations in a Monometallic Porphyrin Dimer: Ring versus Metal‐Center Oxidations and Effect of Counter Anions
Author(s) -
Singh Akhil Kumar,
Rath Sankar Prasad
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002188
Subject(s) - porphyrin , chemistry , dimer , crystallography , ring (chemistry) , oxidizing agent , metal , photochemistry , x ray photoelectron spectroscopy , radical ion , single crystal , ion , inorganic chemistry , organic chemistry , physics , nuclear magnetic resonance
The effect of intermacrocyclic interactions was studied by controlled and stepwise oxidations of a monometallic silver(II) porphyrin dimer that contains a highly flexible ethane bridge. Monometallic dimers are unique systems and behave differently from their dimetallic analogues on the basis of their available sites for storing oxidizing equivalents. UV‐visible spectrometry, 1 H NMR spectroscopy, XPS and single crystal X‐ray diffraction studies clearly suggest the removal of the first electron from the metal center. The removal of the second electron occurred from the ring center to form a π‐cation radical and, thereby, form a very unique mixed‐valent species. However, unlike in all other ethane‐bridged metalloporphyrin dimers reported earlier, the 2e‐oxidized species showed quite unusual structures depending on the nature of counter ions. Ions, such as SbF 6 , SbCl 6 and PF 6 , are engaged in strong interactions with the porphyrin π‐cation radical and causes substantial structural changes, including large deformation of the ring. The solid‐state structure remains intact in solution as well. The observations are further supported by DFT calculations.