Search results for "Valence isomer"
showing 3 items of 3 documents
Proton-Coupled Electron Transfer in Ferrocenium–Phenolate Radicals
2013
Electron and proton transfer (ET, PT) can be intimately coupled, provided suitable redox and acid/base sites are available. The amide-linked ferrocene–phenol H-1 is deprotonated to the phenolate [1]– by phosphazene bases and oxidized to the ferrocenium ion [H-1]+ by silver hexafluoroantimonate. Concomitant oxidation and deprotonation yields the radical [1]•, featuring a characteristic near-IR absorption band. The ground state of [1]• is best described as the ferrocenium–phenolate zwitterion [1b]• with a dynamic dissymmetric N···H···O hydrogen bond (PT). The ferrocenium–iminolate N···H–O tautomer [1b]•-NHO′ can undergo a thermal structural rearrangement to the high-energy OH···O tautomer [1b…
How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium‐Phenolate Radicals
2016
The ferrocenyl-phenol 2,4-di-tert-butyl-6-(ferrocenylcarbamoyl)phenol (H-1) forms intramolecular hydrogen bonds which are absent in its constitutional isomer 2,6-di-tert-butyl-4-(ferrocenylcarbamoyl)phenol (H-2). Their corresponding bases 1– and 2– show intra- and intermolecular NH···O hydrogen bonds, respectively. The phenolate 1– is reversibly oxidized to 1·, whereas 2– only undergoes a quasi-reversible oxidation to 2·, which suggests a higher reactivity. The radical pools of 1· and 2· formed by the oxidation/deprotonation of H-1 and H-2 have been probed by (rapid-freeze) electron paramagnetic resonance (EPR) spectroscopy and by spin-trapping techniques to elucidate the types of radicals …
Gold(iii) tetraarylporphyrin amino acid derivatives: ligand or metal centred redox chemistry?
2015
EPR spectroscopy and DFT calculations show that the site of reduction of porphyrinato gold(iii) complexes depends on the counterions X, the meso substituents R and the solvent.