Interaction of tin chlorides with iron, chromium and vanadium chlorides in tetrahydrofuran. Crystal structures of [Fe2(µ-Cl)3(thf)6][SnCl5(thf)], [Sn2(µ-OH)2Cl6(thf)2]·2thf and trans-[CrCl2(thf)4][SnCl5(thf)]

Abstract

The reaction of FeCl₃ with SnCl₂ in tetrahydrofuran (thf) yields the salt [Fe₂(µ-Cl)₃(thf)₆][SnCl₅(thf)]1. In the [Fe₂(µ-Cl)₃(thf)₆]⁺ cation, two six-co-ordinate Fe²⁺ ions separated by an Fe ⋯ Fe distance of 3.086(2)Å are bonded through three bridging Cl atoms. Compound 1 undergoes partial decomposition under reflux in thf to give [Fe₄(µ₃-Cl)₂(µ-Cl)₄Cl₂(thf)₆]2 and [SnCl₄(thf)₂]. The compound [Sn₂(µ-OH)₂Cl₆(thf)₂]·2thf 3 is formed under the influence of moisture during the crystallization of [SnCl₄(thf)₂]. It is a dimeric complex of Sn^IV in which each tin atom is surrounded octahedrally by three chlorine atom, one thf molecule and two bridging hydroxide groups. An additional two thf molecules are hydrogen-bonded to the oxygen atoms of the hydroxide groups. By contrast with FeCl₃, the reactions of [SnCl₄(thf)₂] with [MCl₃(thf)₃](M = V or Cr) in thf give tin(IV) salts of the type trans-[MCl₂(thf)₄][SnCl₅(thf)].