A Vanadium Methylidene

Senthil S, Fehn D, Gau MR, Bacon AM, Carroll PJ, Meyer K, Mindiola DJ (2024)


Publication Type: Journal article

Publication year: 2024

Journal

DOI: 10.1021/jacs.4c01906

Abstract

Examples of stable 3d transition metal methylidene complexes are extremely rare. Here we report an isolable and stable vanadium methylidene complex, [(PNP)V(=NAr)(=CH2)] (PNP = N[2-PiPr2-4-methylphenyl], Ar = 2,6-iPr2C6H3), via H atom transfer (HAT) from [(PNP)V(NHAr)(CH3)] or [(PNP)V(=NAr)(CH3)] using two or one equivalents of the TEMPO radical (TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl), respectively. Alternatively, the vanadium methylidene moiety can also be formed via the treatment of transient [(PNP)V=NAr] with the Wittig reagent, H2CPPh3. Structural and spectroscopic analysis, including 13C enriched labeling of the methylidene ligand, unequivocally confirmed the terminal nature of a rare 3d methylidene complex, featuring a V=CH2 bond distance of 1.908(2) Å and a highly downfield 13C NMR spectral shift at 298 ppm. In the absence of the ylide, intermediate [(PNP)V=NAr] activates dinitrogen to form an end-on bridging N2 complex, [(PNP)V(=NAr)]2211-N2), having a singlet ground state. Complex [(PNP)V(=NAr)(=CH2)] reacts with H3COTf to form [(PNP)V(=NAr)(OTf)], accompanied by the release of ethylene as evidenced by 1H NMR spectroscopy, and reactivity studies suggest a β-hydride elimination pathway.

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APA:

Senthil, S., Fehn, D., Gau, M.R., Bacon, A.M., Carroll, P.J., Meyer, K., & Mindiola, D.J. (2024). A Vanadium Methylidene. Journal of the American Chemical Society. https://doi.org/10.1021/jacs.4c01906

MLA:

Senthil, Shuruthi, et al. "A Vanadium Methylidene." Journal of the American Chemical Society (2024).

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