Preparation and properties of the tungsten tris(imido) functional group
AuthorRodgers, Paula Marie, 1967-
AdvisorWigley, David E.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractThe first tris(imido) complex of a group 6 transition metal, [Li(THF)₄][W(=NAr)₃Cl] (8) (Ar = 2,6 iPr-C₆H₃) was prepared from W(=NAr)₂Cl₂(THF)₂ (2) and 2 equiv of the corresponding lithium amide, LiNHAr in THF. Complex (8) crystallizes in the monoclinic space group P2(1/n) with a = 13.787 (4) Å, b = 17.348 (5) Å, c = 22.781 (8) Å, and β = 90.43 (3)° with Z = 4. The crystal contains discrete C₃ᵥ [W(=NAr)₃Cl]⁻ anions with imido W-N-C(ipso) angles averaging 170.8 (15)° and imido W-N bonds averaging 1.782 (15) Å. The neutral imido species W(=NAr)₃(PMe₃) (15) was made by adding 10 equiv of PMe₃ to (8). "Coupling" of the imido ligand in (15) with CO₂ and O=C=NR (R = Ph, ᵗBu) gave W[NArC(O)O] (=NAr)₂ PMe₃ (20) and W[NArC(O)NR](=NAr)₂PMe₃ (19) respectively. 2,6 Diisopropylaniline was added to (8) to give the complex W(=NAr)₂(NHAr)₂ (9). The chloride ligand of complex (8) was replaced by Li alkyl reagents to yield alkylated product [Li(THF)₄][W(=NAr)₃R] (R = Me, ᵗBu and Np') (11-13). The cation of (8) was substituted by adding ⁿBu₄NBr to afford [ⁿBu₄N][W(=NAr)₃Br] (10). These and related synthetic and reactivity studies will be described.