title: Isolation and detailed characterization of the trans-[(H2O)2FeCl4](-) anion: stabilization of novel iron(III) species by large organic cations.
abstract: 1,2-Diaminoethane (en) and FeCl3 give (enH2) [FeCl5(H2O)] (1) in concentrated HCl, extending the aquapentachloroferrate(III) series. For 1: C2H12N2Cl5OFe, orthorhombic, P2(1)2(1)2(1), a = 14.531(6) A, b = 10.772(4) A, c = 6.888(2) A, Z = 4. Diazabicyclo[2.2.2]octane dihydrochloride (DABCO-2HCl) and FeCl3 in concentrated HCl form a tetrachloroferrate(III) derivative whose subsequent ethanol treatment (restricted water access) results in the formation of a compound of composition (DABCOH2)2 [FeCl4(H2O)2]Cl3 (2). This contains the trans-[FeCl4(H2O)2](-) anion, in which the trans-Fe-O distances are 2.049(4) A. For 2: C12H32N4Cl7O2Fe, orthorhombic, Pnma, a = 16.378(3) A, b = 7.3323(6) A, c = 19.431(3) A, Z = 4. A combination of 57Fe Mössbauer spectroscopy and ac susceptibility data confirm uncanted 3D antiferromagnetic ground states with T(Néel) approximately 3.4 K for (enH2)[FeCl5(H2O)] and approximately 2.0 K for [DABCOH2]2[FeCl4(H2O)2]Cl3.
authors.affiliation: Faculty of Science, Technology and Engineering, La Trobe University, Victoria 3086, Australia. b.james@latrobe.edu.au
authors.forename: B D
authors.initials: BD
authors.lastname: James
authors.forename: M
authors.initials: M
authors.lastname: Bakalova
authors.forename: J
authors.initials: J
authors.lastname: Liesegang
authors.forename: W M
authors.initials: WM
authors.lastname: Reiff
authors.forename: B W
authors.initials: BW
authors.lastname: Skelton
authors.forename: A H
authors.initials: AH
authors.lastname: White