Synthesis and characterization of multiple and metallacyclic imido compounds of the early transition metals
AuthorAllen, Kevin Dale, 1968-
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 bis(imido) complex Nb(=NAr)₂Cl(py)₂(Ar=2,6-diisopropylphenyl) reacts with two equivalents of LiNHAr in THF to form [Li(THF)₄)][Nb(=NAr)₂(NHAr)₂] (2). Likewise [Nb(NEt₂)₂Cl₃]₂ reacts with excess LiNHAr in THF to form 2. A similar neutral bis(imide) bis(amide) compound (9) of molybdenum has been made. Experiments are presented that suggest the (tris)imido functional group (Nb(=NAr)₃) - arises via an intermolecular deprotonation of [Nb(=NR)₂(NHR)₂]⁻. Complex 2 reacts with 1 equivalent of ᵗBuLi to form the tris(imide) amide [Li₂(THF)₄][Nb(=NAr)₃(NAr)] (6). Ta(OR)₂Cl₃(OEt₂) (OR=2,6-diisopropylphenoxide) reacts with excess 6-methylquinoline (6MQ) to form (η¹-(N)-6MQ)Ta(OR)₂Cl₃ (10). Compound 10 cannot be reduced to the η²-(N,C) product; however, (η₆-C₆Me₆)Ta(OR)₂Cl reacts with excess 6MQ to form (η²-(N,C)-6MQ)Ta(OR)₂Cl(Et₂O) (11), a precursor to metallacyclic imides and a proposed HDN intermediate. Compound 10 can be reduced to afford an unusual Ta(IV) complex (ηˣ-6MQ)Ta(OR)₂Cl₂ (12).