Tweaking the bridge in metallocene Zr(IV)/W(IV) bimetallic hydrides.
Dalton Trans
; 52(2): 394-408, 2023 Jan 03.
Article
em En
| MEDLINE
| ID: mdl-36519954
ABSTRACT
Zirconocene cations react with Cp2WH2 affording the bimetallic [Cp2Zr(µ-H)(µ-η1η5-C5H4)WHCp]+ bridging hydride 1 (Cp = cyclopentadienyl anion, C5H5-) via σ-bond metathesis. Complex 1 features an atypical out of plane Zr(µ-H)W moiety, where no intermetallic interaction is involved, and a fluxional core. Coordination geometry and bond distances of the bridging hydride interaction can be modulated upon reaction with Lewis bases and unsaturated substrates. PMe3, P(p-tol)3, 3,5-dimethylpyridine and THF bind to 1 and shift the hydride bridge on the coordination plane of Zr. Insertion of olefins and alkynes into the Zr-C bond of 1 leads instead to alkyl and vinyl species where the Zr and W coordination planes are perpendicular to each other. Such alterations of the Zr(µ-H)W arrangement are reflected in the average 1H NMR chemical shift values of the hydride, which correlate linearly with computed Zr-H distances. Reactivity experiments with H2 showed that the bridging hydride interaction prevents bimetallic cooperativity and that σ-bond metathesis between Zr-C and H-H bonds is the preferred pathway for all the investigated complexes.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article