Pavlidis, S.; Teutloff, C.; Buzanich, A. G.; Krause, K. B.; Emmerling, F.; Bittl, R.; Abbenseth, J.: A Crystalline Bismuth(II) Radical Anion: Synthesis, Characterization, and Reactivity. Angewandte Chemie - International Edition 64 (2025), p. e202515545/1-6
10.1002/anie.202515545
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Abstract:
We report the synthesis of a planarized tris-amidobismuthane supported by a rigid, bulky NNN pincer ligand, which enforces a T-shaped geometry at the bismuth center. The Bi(NNN) complex features a low-lying LUMO with distinct Bi(6p) orbital character as shown by DFT calculations. Cyclic voltammetry reveals a fully reversible one-electron reduction at E1/2 = –1.85 V versus Fc0/+ in THF. Chemical reduction with KC8 in the presence of 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (222-crypt) enables the isolation of an unprecedented Bi(II) radical anion in high isolated yields. Multi-frequency EPR, X-ray absorption spectroscopy and SQUID magnetometry complemented by theoretical calculations confirm localization of the unpaired electron on the bismuth center. Preliminary reactivity studies display radical reactivity as shown by single-electron transfer chemistry and radical coupling reactions.