Crystal Structures and Thermal Behavior of Isostructural Bis(dibenzyldimethylammonium) Tetrachlorometallate [M = Mn(II), Co(II), Ni(II) and Zn(II)] Solvates Crystallized from Acetonitrile and/or Methanol Solutions

Autor: Sara Busi, Manu Lahtinen, Jussi Valkonen, Roland Fröhlich, Kari Rissanen
Rok vydání: 2007
Předmět:
Zdroj: Zeitschrift für Naturforschung B. 62:28-34
ISSN: 1865-7117
0932-0776
DOI: 10.1515/znb-2007-0105
Popis: Five isostructural bis(dibenzyldimethylammonium) tetrachlorometallate solvate complexes [M = Mn(II), Co(II), Ni(II) or Zn(II)] were crystallized from acetonitrile and/or methanol solutions. The crystal structures are compared to those of the analogous, isostructural copper compounds (X = Cl or Br) reported earlier. The complexes crystallize in the monoclinic space group P21/n with Z = 4, and unit cell dimensions of a ≈ 14.1, b ≈ 16.1, c ≈ 15.7 °A and β ≈ 108 - 109°. The asymmetric unit of these compounds contains one MCl4 2− anion, two Bz2Me2N+ cations in theW-conformation and one half of a disordered solvent molecule (acetonitrile or methanol). The geometry of the MCl4 2− anion is close to tetrahedral, whereas the analogous copper anions appeared in distorted tetrahedral geometries with trans angles of 124.4° for X = Cl and 123.6° for X = Br. In addition to the ionic interactions between the cations and the anions, the components are connected by weak C-H· · · Cl− bonds. As a distinction between the two crystallographically independent cations in the asymmetric unit, one type of independent cations form long chains via weak edge to face π-π interactions along the crystallographic b axis, whereas the other type of cations are not tied together by such weak π-π interactions. The coordination around the N atoms is also nearly tetrahedral, and neither static nor dynamic disorder of the Bz2Me2N+ cations can be observed. The complexes are thermally stable and melt close to the decomposition temperatures in the range 170 - 205 °C.
Databáze: OpenAIRE
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