Stable Open-Shell Phosphorane Based on a Redox-Active Amidodiphenoxide Scaffold.
Inorg Chem
; 56(15): 8661-8668, 2017 Aug 07.
Article
em En
| MEDLINE
| ID: mdl-28661124
ABSTRACT
The synthesis and redox reactivity of pentacoordinate phosphorus compounds incorporating a redox-active ONO amidodiphenoxide scaffold [ONO = N,N-bis(3,5-di-tert-butyl-2-phenoxide)amide] are described. Dichloro- and diphenylphosphoranes, 2·Cl2 and 2·Ph2, respectively, are synthesized and crystallographically characterized. Cyclic voltammograms of 2·Cl2 show only a single irreversible oxidation (Epa = +0.83 V vs Cp2Fe0/+), while the diphenyl analogue 2·Ph2 is reversibly oxidized at lower applied potential (E1/2 = +0.47 V vs Cp2Fe0/+). Chemical oxidation of 2·Ph2 with AgBF4 produces the corresponding radical cation [2·Ph2]â¢+, where electron paramagnetic resonance spectroscopy and density functional theory calculations reveal that the unpaired spin density is largely ligand-based and is highly delocalized throughout the ONO framework of the paramagnetic species. The solid-state structures indicate only minor geometrical changes between the neutral 2·Ph2 and oxidized [2·Ph2]â¢+ species, consistent with fast self-exchange electron transfer, as observed by NMR line-broadening experiments.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2017
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Article