title: Structural, magnetic and optical properties of an Fe(III) dimer bridged by the meridional planar divergent N,N'-bis(salicyl)hydrazide and its photo- and electro-chemistry in solution.
abstract: {Fe(III)Cl(DMF)(2)}(2)(L) where L is N,N'-bis(salicyl)hydrazide has been synthesized as red crystals and characterized using single-crystal diffraction, infrared and UV-vis spectroscopies, and its magnetic properties studied. The dimeric unit in the structure is formed through the two meridional sets of divergent O, N, O coordinating atoms of the hexacoordinated and quadruply charged ligand. With the presence of the inversion symmetry the Fe atoms are strictly planar with the ligand. The magnetic exchange interaction is found to be antiferromagnetic with a J = -5.98(3) cm(-1) through the rare Fe-N-N-Fe pathway. Irradiation of the FeCl(3)/H(4)L red DMF solution in the visible region of the spectrum resulted in its complete discoloration and from which the unknown colorless salt [Fe(II)(DMF)(6)][Fe(II)Cl(4)] and the neutral ligand have been identified by single crystal diffraction. The UV-visible spectra of FeCl(3), H(4)L and their mixture in DMF solution indicate that the iron complex is the absorbing species and the presence of the free ligand in the irradiated solution suggests that the ligand is potentially acting as a catalyst to the photoreduction of Fe(III) to Fe(II), while electrochemistry points to a mixed-valent (Fe(II)-Fe(III)) intermediate in the process.
authors.affiliation: Laboratoire DECOMET, Institut de Chimie de Strasbourg, CNRS-UMR 7177, Université de Strasbourg, 4, rue Blaise Pascal, 67070 Strasbourg Cedex 1, France.
authors.forename: Khaled
authors.initials: K
authors.lastname: Cheaib
authors.forename: David
authors.initials: D
authors.lastname: Martel
authors.forename: Nicolas
authors.initials: N
authors.lastname: Clément
authors.forename: Fabrice
authors.initials: F
authors.lastname: Eckes
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Kouaho
authors.forename: Guillaume
authors.initials: G
authors.lastname: Rogez
authors.forename: Samuel
authors.initials: S
authors.lastname: Dagorne
authors.forename: Mohamedally
authors.initials: M
authors.lastname: Kurmoo
authors.forename: Sylvie
authors.initials: S
authors.lastname: Choua
authors.forename: Richard
authors.initials: R
authors.lastname: Welter