A Caltech Library Service

Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence

Bailey, Gwendolyn A. and Buss, Joshua A. and Oyala, Paul H. and Agapie, Theodor (2021) Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence. Journal of the American Chemical Society, 143 (33). pp. 13091-13102. ISSN 0002-7863. doi:10.1021/jacs.1c03806.

[img] PDF (Detailed experimental procedures, full characterization, and spectroscopic data) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Open-shell compounds bearing metal–carbon triple bonds, such as carbides and carbynes, are of significant interest as plausible intermediates in the reductive catenation of C₁ oxygenates. Despite the abundance of closed-shell carbynes reported, open-shell variants are very limited, and an open-shell carbide has yet to be reported. Herein, we report the synthesis of the first terminal, open-shell carbide complexes, [K][1] and [1][BAr^F₄] (1 = P2Mo(≡C:)(CO), P2 = a terphenyl diphosphine ligand), which differ by two redox states, as well as a series of related open-shell carbyne complexes. The complexes are characterized by single-crystal X-ray diffraction and NMR, EPR, and IR spectroscopies, while the electronic structures are probed by EPR studies and DFT calculations to assess spin delocalization. In the d₁ complexes, the spin is primarily localized on the metal (∼55–77% Mo d_(xy)) with delocalization on the triply bonded carbon of ∼0.05–0.09 e⁻. In the reduced carbide [K][1], a direct metal–arene interaction enables ancillary ligand reduction, resulting in reduced radical character on the terminal carbide (⩽0.02 e⁻). Reactivity studies with [K][1] reveal the formation of mixed-valent C–C coupled products at −40 °C, illustrating how productive reactivity manifolds can be engendered through the manipulation of redox states. Combined, the results inform on the electronic structure and reactivity of a new and underrepresented class of compounds with potential significance to a wide array of reactions involving open-shell species.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bailey, Gwendolyn A.0000-0002-6636-4128
Buss, Joshua A.0000-0002-3347-8583
Oyala, Paul H.0000-0002-8761-4667
Agapie, Theodor0000-0002-9692-7614
Additional Information:© 2021 American Chemical Society. Received 11 April 2021. Published online 11 August 2021. Published in issue 25 August 2021. We thank Lawrence Henling, Michael Takase, and Manar Shoshani for invaluable crystallographic assistance. Lawrence Henling is also thanked for assistance with elemental analysis. G.A.B. is grateful to NSERC of Canada and the Resnick Sustainability Institute at Caltech for fellowship support. J.A.B. is grateful for an NSF graduate research fellowship. We thank the NSF (CHE-1800501), the Dow Next Generation Education Fund (instrumentation), and Caltech for funding. The authors declare no competing financial interest. Accession Codes. CCDC 2076055, 2076057–2076058, and 2076060 contain the supplementary crystallographic data for this paper.
Group:Resnick Sustainability Institute
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Resnick Sustainability InstituteUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Dow Next Generation Education FundUNSPECIFIED
Subject Keywords:Ligands, Delocalization, Inorganic carbon compounds, Quantum mechanics, Energy levels
Issue or Number:33
Record Number:CaltechAUTHORS:20210831-200226268
Persistent URL:
Official Citation:Terminal, Open-Shell Mo Carbide and Carbyne Complexes: Spin Delocalization and Ligand Noninnocence Gwendolyn A. Bailey, Joshua A. Buss, Paul H. Oyala, and Theodor Agapie Journal of the American Chemical Society 2021 143 (33), 13091-13102 DOI: 10.1021/jacs.1c03806
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110641
Deposited By: George Porter
Deposited On:31 Aug 2021 20:58
Last Modified:31 Aug 2021 20:58

Repository Staff Only: item control page