Tri- and Tetravalent Titanium Alkyls Supported by Organic Amides
1996; American Chemical Society; Volume: 15; Issue: 4 Linguagem: Inglês
10.1021/om9508288
ISSN1520-6041
AutoresRavinder K. Minhas, L. Scoles, Shirley Wong, Sandro Gambarotta,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoThe reactions of both trivalent [(Cy2N)2Ti(μ-Cl)2Li(TMEDA)] (1) and tetravalent [(Cy2N)2TiCl2] (5) with R‘Li in THF or diethyl ether gave Ti(IV) complexes (Cy2N)2TiR‘2 [R‘ = CH2CMe3 (7), CH2CMe2Ph (8), CH2SiMe3 (9)]. Conversely, the reactions of 1, [{(i-Pr)2N}2TiCl2][Li(TMEDA)2] (2), and [{(Me3Si)2N}2TiCl2][Li(TMEDA)2] (3) with R‘Li [R‘ = Me, Ph, CH2Ph] gave the corresponding trivalent derivatives [(Cy2N)2Ti(μ-Bz)2Li(TMEDA)] (4a), [(Cy2N)2Ti(μ-Me)2Li(TMEDA)] (4b), [{(i-Pr)2N}2TiPh2][Li(TMEDA)2] (11), and [{(Me3Si)2N}2Ti(CH2Ph)2][Li(TMEDA)2] (12) via simple ligand replacement reactions. Oxidation of 12 with diphenylfulvene gave {(Me3Si)2N}2Ti(CH2Ph)2 (13). All these compounds are thermally labile and yielded intractable materials upon thermolysis. Only in the case of the neophyl derivative (Cy2N)2Ti(CH2CMe2C6H5)2 (8) a cyclometalated compound (Cy2N)2Ti(CH2CMe2C6H4) (10) was isolated and crystallized from the thermolyzed solution. The reaction of 1 with styrene oxide provided the Ti−oxo complex [(Cy2N)2TiCl]2O (14) which gave, upon alkylation with MeLi, the corresponding dinuclear alkyl derivatives [(Cy2N)2TiMe]2O (15). The molecular structures of 1 and 10−14 were demonstrated by X-ray diffraction analysis.
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