Abstract
The hydrothermal synthesis, using tris-(2-ethylamino)amine (tren) as a template, and the crystal structures of three new hybrid iron fluorides, (H3O)(2)center dot[H(3)tren](2)center dot(FeF6)(2)center dot(FeF5(H2O))center dot 2H(2)O (1), [H(3)tren](2)center dot(FeF6)(2)center dot(FeF2(H2O)(4))center dot 8H(2)O (II) and [H(3)tren](2)center dot(FeF6)center dot(F)(3)center dot H2O (III), are reported. I, II, and III are triclinic (P-1), monoclinic (P2(1)/c) and orthorhombic (I222), respectively. The structure of I is built up from isolated FeF6 and FeF5(H2O) distorted octahedra separated by triprotonated [H(3)tren](3+) cations, disordered H3O+ cations and H2O molecules. In II, (FeF6)-F-III and neutral [(FeF2)-F-II(H2O)(4)] octahedra form, together with [H(3)tren](3+) cations, infinite (100) layers separated by extra water molecules. The structure of III consists of isolated and disordered FeF6 octahedra, fluoride anions F- connected to [H(3)tren](3+) cations and extra fluoride anions F- disordered with H2O molecules. All [H(3)tren](3+) cations have a "spider" type conformation. Fe-57 Mossbauer characterization shows that +III valence state can only be considered for iron cations in I and III and preliminary Mossbauer results are consistent with the presence of both +II and +III valences for iron cations in II, in agreement with the crystallographic results. (C) 2009 Elsevier Masson SAS. All rights reserved.