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A Dianionic Dinickel(II) Complex and Its Oxidised Phenoxyl Radical States
Author(s) -
Benisvy Laurent,
Wanke Riccardo,
Guedes da Silva M. Fátima C.,
Pombeiro Armando J. L.
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100232
Subject(s) - chemistry , electron paramagnetic resonance , coordination sphere , crystallography , ion , nuclear magnetic resonance spectroscopy , benzamide , ligand (biochemistry) , mass spectrometry , radical , medicinal chemistry , stereochemistry , polymer chemistry , crystal structure , organic chemistry , nuclear magnetic resonance , chromatography , biochemistry , physics , receptor
The new dianionic dinickel(II) complex [NBu 4 ] 2 [Ni 2 (L) 2 ] {L 3– = trianionic form of 3,5‐di‐ tert ‐butyl‐2‐hydroxy‐ N ‐(2‐hydroxyethyl)benzamide} has been synthesised and characterised by 1 H, 13 C NMR and IR spectroscopy, mass spectrometry, elemental analysis and X‐ray crystallography. The X‐ray structure of [NBu 4 ] 2 [Ni 2 (L) 2 ] · EtOH · CH 3 CN reveals a quasiplanar dinickel(II) dianionic complex, each of the Ni II ions possessing a NO 3 planar coordination sphere that results from the ligation of L 3– in a NO 2 fashion through the N ‐amidate, O ‐phenolate and O‐bridging alcoholate donor atoms. The cyclic voltammogram of [Ni 2 (L) 2 ] 2– reveals two one‐electron reversible oxidation processes at relatively low potentials. The EPR and UV/Vis spectroscopic characterisations of the electrochemically generated one‐electron‐ and two‐electron‐oxidised products are consistent with two ligand‐based oxidation processes leading to the formation of relatively stable mono‐ and diphenoxyl radical complexes, [Ni 2 (L · )(L)] – and [Ni 2 (L · ) 2 ], respectively.