title: Auto-ionization in lutetium iodide complexes: effect of the Iioic radius on lanthanide-iodide binding.
abstract: Reaction of lutetium metal with 1.5 equiv of elemental iodine in 2-propanol leads to the isolation of LuI(3)(HO(i)Pr)(4) (1). An X-ray crystal structure reveals an ionic structure with well-separated [LuI(2)(HO(i)Pr)(4)] cations and [I] anions. Dissolution of 1 in pyridine generates the unusual alkoxide species [LuI(O(i)Pr)(py)(5)][I] (2) with the elimination of HI. An X-ray crystal structure of 2 confirmed the ionic nature of the compound, with the cationic portion of the complex exhibiting a seven-coordinated lutetium center with trans-disposed iodo and alkoxide ligands and five pyridine molecules equally displaced within the equatorial plane. Exposure of 2 to iodotrimethylsilane yields the expected triiodide species [LuI(2)(py)(5)][I] (3), which may also be prepared by refluxing commercially available LuI(3) in THF, followed by crystallization from a THF/pyridine mixture. The solid-state structure of 3 is similar to that of 2, with the alkoxide ligand having been replaced by an iodide. The formation of ionic structures 1-3 as opposed to the higher-coordinated neutral species may be traced to the small lutetium center and the presence of relatively strong Lewis bases within the coordination sphere of the metal.
authors.affiliation: Nuclear Materials Technology Division, Chemistry Division, and the Glenn T. Seaborg Institute for Transactinium Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Garth R
authors.initials: GR
authors.lastname: Giesbrecht
authors.forename: John C
authors.initials: JC
authors.lastname: Gordon
authors.forename: David L
authors.initials: DL
authors.lastname: Clark
authors.forename: Brian L
authors.initials: BL
authors.lastname: Scott