• Schmitt, M.; Maylaender, M.; Heizmann, T.; Richert, S.; Buelow, C.; Hirsch, K.; Zamudio-Bayer, V.; Lau, J. T.; Krossing, I.: Isolation and Characterization of the Homoleptic Nickel(I) and Nickel(II) Bis-benzene Sandwich Cations. Angewandte Chemie - International Edition 61 (2022), p. e202211555/1-5

10.1002/anie.202211555
Open Access Version

Abstract:
A stable salt of the metalloradical [Ni(C6H6)2]+ hitherto unknown in the condensed phase was synthesized from [Ni(CO)4]+[WCA]− and benzene ([WCA]−=[F{Al(ORF)3}2]−; RF=C(CF3)3). Single crystal XRD reveals a remarkable asymmetrically η3,η6-slipped sandwich structure. The magnetic properties of the [Ni(C6H6)2]+ cation were determined in solution and in the gas phase. Oxidation with the synergistic Ag+/0.5 l2 system led to the salt [Ni(C6H6)2]2+([WCA]−)2. All products were fully characterized by means of IR, Raman, NMR/EPR, single crystal and powder XRD.