Ceric Cyclopentadienides Bearing Alkoxy, Aryloxy, Chlorido, or Iodido Co-Ligands.
A series of heteroleptic tris(cyclopentadienyl) CeIVcomplexes has been isolated and crystallographically characterized, revealing the broad accessibility of such organocerium(IV) compounds. The oxidation of complexes CpMe3Ce(thf) and Cp'3Ce(thf) (CpMe=C5H4Me, Cp'=C5H4SiMe3), bearing monosubstituted electron-poor cyclopentadienyl ligands, with 0.5 equivalents of 1,4-benzoquinone or C2Cl6gave the cerium(IV) hydroquinolate complexes CpMe3Ce(OC6H4O)CeCpMe3and Cp'3Ce(OC6H4O)CeCp'3, or the chloride complexes CpMe3CeCl and Cp'3CeCl, respectively; the iodide complex Cp'3CeI was obtained from the reaction of Cp'3Ce(thf) with elemental iodine. The behavior of Cp'3CeCl in salt metathesis protocols employing alkali metal amides or alkyl, alkoxide, and aryloxide reagents was investigated, which gave rise to the robust and isolable cerium(IV) alkoxide Cp'3Ce(OtBu). Trivalent [Cp'2CeCl]2was synthesized by AlMe4→Cl exchange utilizing Cp'2Ce(AlMe4) and AlMe2Cl. The reactivity of [Cp'2CeCl]2towards the oxidants Ph3CCl, C2Cl6, 1,4-benzoquinone, and I2has been assessed, and has provided useful information on CeIII/CeIVredox deactivation pathways. In addition to X-ray structure analysis, all the complexes were characterized by NMR, DRIFT (diffuse reflectance IR Fourier transform), and UV/Vis spectroscopy as well as elemental analysis. The tetravalent compounds were further analyzed for their magnetic susceptibility by using Evans' method.
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
David
D
Schneider
Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
Nicole
N
Harmgarth
Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
Frank T
FT
Edelmann
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Reiner
http://orcid.org/0000-0002-1543-3787
R
Anwander
X-ray diffraction; cerium; oxidation; salt metathesis