Fe(II) mononuclear complexes with a new aminopyridyl ligand bearing a pivaloylamido arm. Preparation and spectroscopic characterizations of a Fe(III)-hydroperoxo complex with oxygen and nitrogen donors.
Two new mononuclear FeII complexes, [(L52aH)FeII](PF6)2 (1-(PF6)2) and [(L52a)FeII]BPh4 (2-(BPh4)) have been synthesized with the new aminopyridyl ligand bearing a pivaloylamido arm L52aH (2,2-dimethyl-N-[6-({[2-(methyl-pyridin-2-ylmethyl-amino)-ethyl]-pyridin-2-ylmethyl-amino}-methyl)-pyridin-2-yl]-propionamide), or its deprotonated form L52a-. The structures of the ferrous complexes have been determined by X-ray analysis. The mononuclear FeII is in a pseudo-octahedral environment in both complexes, the six positions around the metal center being occupied by five nitrogen atoms and one oxygen atom from the ligand. Whatever the protonation state of the amide function, the structures are very similar, the FeII being 6-fold coordinated by the two amines, three pyridines, and the oxygen atom from the ligand. These two complexes exhibit an acid/base equilibrium in solution that has been studied by UV-vis spectroscopy and cyclic voltammetry in acetonitrile. The reactivity of 1-(PF6)2 with H2O2 in methanol affords the formation of a new low-spin FeIII(OOH) intermediate in which the oxygen atom is retained in the coordination sphere of the metal.
Martinho
Marlène
M
Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182, Laboratoire de Chimie Inorganique, Université Paris-XI, 91405 Orsay Cedex, France.
Banse
Frédéric
F
Sainton
Joëlle
J
Philouze
Christian
C
Guillot
Régis
R
Blain
Guillaume
G
Dorlet
Pierre
P
Lecomte
Sophie
S
Girerd
Jean-Jacques
JJ
D000577:Amides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry; D005296:Ferrous Compounds / Q000138:chemical synthesis / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism
D000577:Amides; D005290:Ferric Compounds; D005296:Ferrous Compounds; D008024:Ligands; D011725:Pyridines; D009584:Nitrogen; D010100:Oxygen