Skip to main content
eScholarship
Open Access Publications from the University of California

Metal alkyls programmed to generate metal alkylidenes by α-H abstraction: prognosis from NMR chemical shift.

  • Author(s): Gordon, Christopher P
  • Yamamoto, Keishi
  • Searles, Keith
  • Shirase, Satoru
  • Andersen, Richard A
  • Eisenstein, Odile
  • Copéret, Christophe
  • et al.

Published Web Location

http://doi.org/10.1039/c7sc05039a
No data is associated with this publication.
Abstract

Metal alkylidenes, which are key organometallic intermediates in reactions such as olefination or alkene and alkane metathesis, are typically generated from metal dialkyl compounds [M](CH2R)2 that show distinctively deshielded chemical shifts for their α-carbons. Experimental solid-state NMR measurements combined with DFT/ZORA calculations and a chemical shift tensor analysis reveal that this remarkable deshielding originates from an empty metal d-orbital oriented in the M-Cα-Cα' plane, interacting with the Cα p-orbital lying in the same plane. This π-type interaction inscribes some alkylidene character into Cα that favors alkylidene generation via α-H abstraction. The extent of the deshielding and the anisotropy of the alkyl chemical shift tensors distinguishes [M](CH2R)2 compounds that form alkylidenes from those that do not, relating the reactivity to molecular orbitals of the respective molecules. The α-carbon chemical shifts and tensor orientations thus predict the reactivity of metal alkyl compounds towards alkylidene generation.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Item not freely available? Link broken?
Report a problem accessing this item