Synthesis, Isolation and Characterization of Two Cationic Organo-bismuth(II) Pincer Complexes Relevant in Radical Redox Chemistry

Herein, we report the synthesis, isolation and characterization of two cationic organobismuth(II) compounds bearing N,C,N pincer frameworks, which are crucial intermediates in bismuth radical processes. X-ray crystallography uncovered a monomeric Bi(II) structure, while SQUID magnetometry in combination with NMR and EPR spectroscopy provide evidence for a para-magnetic S = 1/2 state. High resolution multifrequency EPR at X, Q, and W-band enable the precise assignment of the full g- and 209Bi A-tensors. Experimental data and DFT calculations reveal both complexes are metal-centered radicals with little delocalization onto the ligands.