title: New efficient synthesis of [Ul4(meCN)4]. X-ray crystal structures of [Ul2(MeCN)7][Ul6], [Ul4(py)3], and [U(dmf)9]l4.
abstract: Reaction of UCl4 and excess Me3Sil in acetonitrile provides a convenient route to [Ul4(MeCN)4] (1), which was isolated in excellent yield and crystallized in acetonitrile as the ion pair complex [Ul2(MeCN)7][Ul6] (2). Compound 1 was transformed in pyridine (py) and dimethylformamide (dmf) into the Lewis base adducts [Ul4(py)3] (3) and [Ul4(dmf)6] (4). Crystals of 3 and [U(dmf)9]l4 (5) were obtained by slow diffusion of diethyl ether into pyridine or dmf solutions of 1; compound 5 is the first tetracationic {U4+} entity to have been crystallographically characterized.
authors.affiliation: Service de Chimie Moléculaire, DSM, DRECAM, CNRS URA 331, Laboratoire Claude Fréjacques, CEA/Saclay, 91191 Gif-sur-Yvette, France. berthet@drecam.cea.fr
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Berthet
authors.forename: Pierre
authors.initials: P
authors.lastname: Thuéry
authors.forename: Michel
authors.initials: M
authors.lastname: Ephritikhine