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Synthesis of Crystallographically Characterizable Bis(cyclopentadienyl) Sc(II) Complexes: (C5H2tBu3)2Sc and {[C5H3(SiMe3)2]2ScI}1.
Queen, Joshua D; Anderson-Sanchez, Lauren M; Stennett, Cary R; Rajabi, Ahmadreza; Ziller, Joseph W; Furche, Filipp; Evans, William J.
Afiliação
  • Queen JD; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Anderson-Sanchez LM; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Stennett CR; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Rajabi A; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Ziller JW; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Furche F; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
  • Evans WJ; Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
J Am Chem Soc ; 146(5): 3279-3292, 2024 Feb 07.
Article em En | MEDLINE | ID: mdl-38264991
ABSTRACT
The synthesis of previously unknown bis(cyclopentadienyl) complexes of the first transition metal, i.e., Sc(II) scandocene complexes, has been investigated using C5H2(tBu)3 (Cpttt), C5Me5 (Cp*), and C5H3(SiMe3)2 (Cp″) ligands. Cpttt2ScI, 1, formed from ScI3 and KCpttt, can be reduced with potassium graphite (KC8) in hexanes to generate dark-red crystals of the first crystallographically characterizable bis(cyclopentadienyl) scandium(II) complex, Cpttt2Sc, 2. Complex 2 has a 170.6° (ring centroid)-Sc-(ring centroid) angle and exhibits an eight-line EPR spectrum characteristic of Sc(II) with Aiso = 82.6 MHz (29.6 G). It sublimes at 200 °C at 10-4 Torr and has a melting point of 268-271 °C. Reductions of Cp*2ScI and Cp″2ScI under analogous conditions in hexanes did not provide new Sc(II) complexes, and reduction of Cp*2ScI in benzene formed the Sc(III) phenyl complex, Cp*2Sc(C6H5), 3, by C-H bond activation. However, in Et2O and toluene, reduction of Cp*2ScI at -78 °C gives a dark-red solution, 4, which displays an eight-line EPR pattern like that of 1, but it did not provide thermally stable crystals. Reduction of Cp″2ScI, in THF or Et2O at -35 °C in the presence of 2.2.2-cryptand, yields the green Sc(II) metallocene iodide complex, [K(crypt)][Cp″2ScI], 5, which was identified by X-ray crystallography and EPR spectroscopy and is thermally unstable. The analogous reaction of Cp*2ScI with KC8 and 18-crown-6 in Et2O gave the ligand redistribution product, [Cp*2Sc(18-crown-6-κ2O,O')][Cp*2ScI2], 6, as the only crystalline product. Density functional theory calculations on the electronic structure of these compounds are reported in addition to a steric analysis using the Guzei method.

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Revista: J Am Chem Soc Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Estados Unidos País de publicação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Revista: J Am Chem Soc Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Estados Unidos País de publicação: Estados Unidos