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Fe III and Fe II Phosphasalen Complexes: Synthesis, Characterization, and Catalytic Application for 2‐Naphthol Oxidative Coupling
Author(s) -
Oheix Emmanuel,
Herrero Christian,
Moutet Jules,
Rebilly JeanNoël,
Cordier Marie,
Guillot Régis,
Bourcier Sophie,
Banse Frédéric,
SénéchalDavid Katell,
Auffrant Audrey
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.202001662
Subject(s) - cyclic voltammetry , chemistry , trifluoromethanesulfonate , electron paramagnetic resonance , ligand (biochemistry) , crystallography , lability , inorganic chemistry , crystal structure , catalysis , medicinal chemistry , oxidative coupling of methane , counterion , solvent , ion , photochemistry , electrochemistry , organic chemistry , nuclear magnetic resonance , physics , receptor , electrode , biochemistry
We report on the synthesis and characterization of three iron(III) phosphasalen complexes, [Fe III (Psalen)(X)] differing in the nature of the counter‐anion/exogenous ligand (X − =Cl − , NO 3 − , OTf − ), as well as the neutral iron(II) analogue, [Fe II (Psalen)] . Phosphasalen (Psalen) differs from salen by the presence of iminophosphorane (P=N) functions in place of the imines. All the complexes were characterized by single‐crystal X‐ray diffraction, UV/Vis, EPR, and cyclic voltammetry. The [Fe II (Psalen)] complex was shown to remain tetracoordinated even in coordinating solvent but surprisingly exhibits a magnetic moment in line with a Fe II high‐spin ground state. For the Fe III complexes, the higher lability of triflate anion compared to nitrate was demonstrated. As they exhibit lower reduction potentials compared to their salen analogues, these complexes were tested for the coupling of 2‐naphthol using O 2 from air as oxidant. In order to shed light on this reaction, the interaction between 2‐naphthol and the Fe III (Psalen) complexes was studied by cyclic voltammetry as well as UV/Vis spectroscopy.