Singlet, Doublet, and Triplet Emissions of Diarylamine‐Modified Bismuth Pincer Complexes

Abstract We present six bismuth complexes ( NC R N )BiX 2 (X = Cl, I) with diarylamine‐modified pincer ligands ( NC R N = (4‐R‐C 6 H 4 ) 2 N‐C 6 H 2 ‐(CH 2 NMe 2 ) 2 ‐1,3; R = Me, O, NMe 2 ) and report on their optoelectronic, photophysical, and electrochemical properties. The complexes exhibit intriguing photophysical behavior, with the p ‐tolyl and p‐ anisyl derivatives showing phosphorescence at 77 K in frozen solvent matrices and at room temperature (r.t.) in the solid state. In THF solutions at r.t., only ligand‐based fluorescence is observed with strongly reduced quantum yields compared to free proligands NCH R N . Electrochemical studies reveal up to three reversible one‐electron oxidations. The NMe 2 ‐substituted complexes display the lowest oxidation potentials and the largest number of redox waves. Radical cations [ NCH NMe2 N ] + and [( NC NMe2 N )BiX 2 ] + are chemically stable and fluoresce weakly in the near‐infrared (NIR) at ca. 1200 nm.