36 / 2023-08-08 19:28:14

Modulating the Frontier Orbitals of L(X)Ga-substituted Diarsenes

diarsenes,radical cation,radical anion,π-bonding

New Technologies in Phosphorus Chemistry > 1) New reagents and methods in organophosphorus Chemistry

Dipnictenes are low-valent compounds containing a double bond between two group 15 elements. These compounds were deemed intrinsically unstable according to the “double bond rule” for elements other than nitrogen. Since the remarkable isolation of the first diphosphene by Yoshifuji et al. in 1981, all heavier homologues up to the dibismuthene were isolated.^[1] However, the reactivity of diarsenes, the heavier brothers of the diphosphenes, is still hardly explored today.^[2]

We herein present an improved synthesis of L(X)Ga-substituted diarsenes (L = [N(2,6-ⁱPr₂C₆H₃)C(Me)]₂CH)) giving access to these compounds in gram scale and their subsequent investigation in single electron transfer (SET) and salt elimination reactions. Utilizing our experience on diphosphene systems,^[3] we were able to isolate and fully characterize (EPR, IR, UV-vis, and NMR spectroscopy, sc-XRD) a diarsene butadiene dication, a diarsene radical anion as well as an N‑heterocyclic carbene (NHC) stabilized diarsene radical cation.

Reference

[1] a) N. Tokitoh, Y. Arai, T. Sasamori, R. Okazaki, S. Nagase, H. Uekusa, Y. Ohashi, J. Am. Chem. Soc. 1998, 120, 433–434; b) N. Tokitoh, Y. Arai, R. Okazaki, S. Nagase, Science 1997, 277, 78–80; c) A. H. Cowley, J. G. Lasch, N. C. Norman, M. Pakulski, J. Am. Chem. Soc. 1983, 105, 5506–5507; d) M. Yoshifuji, I. Shima, N. Inamoto, K. Hirotsu, T. Higuchi, J. Am. Chem. Soc. 1981, 103, 4587–4589.

[2] L. Weber, F. Ebeler, R. S. Ghadwal, Coord. Chem. Rev. 2022, 461, 214499.

[3] M. K. Sharma, S. Chabbra, C. Wölper, H. M. Weinert, E. J. Reijerse, A. Schnegg, S. Schulz, Chem. Sci. 2022, 13, 12643.