Synthesis and characterization of (η5-C5Me5) 2TaCl(THF), a useful synthetic precursor for the preparation of oxo, imido and methylidene derivatives of permethyltantalocene
1993; Elsevier BV; Volume: 462; Issue: 1-2 Linguagem: Inglês
10.1016/0022-328x(93)83360-8
ISSN1872-8561
AutoresDavid M. Antonelli, William P. Schaefer, Gerard Parkin, John E. Bercaw,
Tópico(s)Inorganic Chemistry and Materials
ResumoThe synthesis and characterization of Cp*2Ta(O)Cl (Cp* (η5-C5Me5)), Cp*2Ta(NPh)Cl, Cp*2Ta (O)H, Cp*2Ta(NR)H (R Ph, CMe3), Cp*2Ta(CH2)H, Cp*2Ta(CH2)Cl, Cp*2Ta(H2 CCH2)H, and the unusual cyclometallated product Cp*(η6-C5Me4CH2)TaH2 from Cp*2TaCI(THF) (THF tetrahydrofuran) is described. Cp*2TaCl(THF) is prepared by the Na / Hg reduction of Cp*2TaCl2 in THF and used in situ. These synthetic routes are more convenient than those previously described and in most cases give much higher yields and purer products. All attempts to isolate Cp*2TaCl(THF) as a pure crystalline solid have led instead to less reactive [Cp*2TaCl]n, whose structure is uncertain. Although Cp*2TaCl(THF) is only moderately stable in THF at room temperature, it has been characterized in solution by 1H NMR spectroscopy. Both [Cp*2TaCl]n and Cp*2TaCl(THF) react with CO to afford Cp*2TaCl(CO). An X-ray crystal structure determination for Cp*2Ta (NPh)Cl (triclinic space group P1 (number 2) with Z = 2; a = 8.627(2); b = 9.538(5), c = 16.890(5) Å, α = 74.81(3)°, β = 87.12(2)°, γ = 63.79(3)°, with V = 1200.0(8) Å3) reveals a linear TaNC group, as had been found previously for the closely related complex Cp*2Ta(NPh)H.
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