title: An investigation of the electron density of a Jahn-Teller-distorted Cr(II) cation: the crystal structure and charge density of hexakis(acetonitrile-κN)chromium(II) bis(tetraphenylborate) acetonitrile disolvate.
abstract: In the crystal structure of the title homoleptic Cr(II) complex, [Cr(CH3CN)6](C24H20B)2·CH3CN, the [Cr(CH3CN)6](2+) cation is a high-spin d(4) complex with strong static, rather than dynamic, Jahn-Teller distortion. The electron density of the cation was determined by single-crystal X-ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn-Teller distortion of the Cr(II) cation away from idealized octahedral symmetry. The topological analysis of the aspherical d-electron density about the Cr(II) cation showed that there are significant valence charge concentrations along the axial Cr-N axes. Likewise, there were significant valence charge depletions about the Cr(II) cation along the equatorial Cr-N bonds. These charge concentrations are in accordance with a Jahn-Teller-distorted six-coordinate complex.
authors.affiliation: Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
authors.forename: Arumugam
authors.initials: A
authors.lastname: Thangavel
authors.affiliation: Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
authors.forename: Marika
authors.initials: M
authors.lastname: Wieliczko
authors.affiliation: Department of Chemistry, Emory University, Atlanta, GA 30322, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Scarborough
authors.affiliation: Institut für Anorganische Chemie der Universität Göttingen, Tammannstrasse 4, Göttingen D-37077, Germany.
authors.forename: Birger
authors.initials: B
authors.lastname: Dittrich
authors.affiliation: X-ray Crystallography Center, Emory University, Atlanta, GA 30322, USA.
authors.forename: John
authors.initials: J
authors.lastname: Bacsa
keywords: aspherical-atom modeling; charge density; chromium(II) complexes; computational chemistry; crystal structure; electron density; multipole refinement; static Jahn–Teller distortion; tetraphenylborate