[N,N'-Bis(trimethylsilyl)-o-phenylenediamido](1,4-butanediyl)(phenylimido)tungsten(VI), a Deactivation Product from Olefin Metathesis Polymerization

The title compound (1), [o-(Me₃SiN)₂C₆H₄](PhN)W(CH₂CH₂CH₂CH₂) or [W(C₄H₈)(C₆H₅N)(C₁₂H₂₂N₂Si₂)], has been isolated as a deactivation product from olefin metathesis polymerization and its crystal structure determined. Compound (1) is a second polymorph of identical structure and stereochemistry to a published structure [Wang, VanderLende, Abboud & Boncella (1997), Organometallics. In the press], but with a different space group. The W atom has a square pyramidal coordination geometry with the phenylimido ligand occupying the apical position. A relatively short W-N(imido) bond, 1.736 (3) Å, is interpreted as arising from the interaction of the lone pair of N(imido) and the W metal center. W has bonds of 1.998 (3) and 2.013 (4) Å to the N atoms of the diamido ligand and 2.177 (4) and 2.185 (4) Å to the [alpha]-Carbon atoms of the metallacyclopentane ligand.

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