Photochemical Tungsten–Carbon Bond Cleavage in Bicyclic Tungstacyclopentanes
W(NCPh<sub>3</sub>)(OSiPh<sub>3</sub>)<sub>2</sub>(C<sub>7</sub>H<sub>12</sub>) (<b>1</b>) and W(NAd)(OSiPh<sub>3</sub>)<sub>2</sub>(C<sub>7</sub>H<sub>12</sub>) (<b>2</b>) undergo photochemical α-hydrogen abstraction to form alkylidenes. Transient absorption studies suggest that fast W-C homolysis precedes thermal α-hydrogen abstraction. Radical trapping experiments in the presence of 5,5-dimethyl-1-pyrroline-<i>N</i>-oxide (DMPO) support formation of an alkyl radical in these reactions. DFT calculations of models of <b>1</b> and <b>2</b> are also consistent with formation of W(V)-alkyl-radical intermediates that ultimately abstract an α-hydrogen to form the alkylidene. This study provides evidence for W-C bond cleavage in reactions that convert catalytically inactive d<sup>0</sup> tungstacyclopentanes into metathesis-active alkylidenes.
Authors
- Matthew P. Conley (ORCID: https://orcid.org/0000-0001-8593-5814)
- Vivek Vasudev
- Veronica Carta (ORCID: https://orcid.org/0000-0001-8089-8436)
- René Riedel (ORCID: https://orcid.org/0000-0003-1501-0538)
- Logan Trowbridge
- Richard R. Schrock (ORCID: https://orcid.org/0000-0001-5827-3552)
- Marielle Sewell
- Xavier Solans‐Monfort (ORCID: https://orcid.org/0000-0002-2172-3895)
- Christopher J. Bardeen
- Shankar Ramaswamy
- Mariona Sodupe
- Robert J. Dillon
Institutions
- Universitat Autònoma de Barcelona (ES)
- United States Army Combat Capabilities Development Command (US)
- University of California System (US)
Publication Details
- Journal
- Journal of the American Chemical Society
- Published
- 2026-01-06
- DOI
- https://doi.org/10.1021/jacs.5c19313
- Primary Topic
- Radical Photochemical Reactions
- Type
- article
- Field-Weighted Citation Impact
- 0.00