Effect of single variable factor of electron‐acceptor on the luminescence quantum yield of terbium complex

Abstract Two series of terbium complexes of Tb 2 (4‐BMBA) 6 (phen) 2 (Tb−Br, 4‐BMBA=4‐Br‐3‐methylbenzoic acid, phen=1,10‐phenanthroline) and Tb 2 (4‐IMBA) 6 (phen) 2 (Tb−I, 4‐IMBA=4‐I‐3‐methylbenzoic acid) are synthesized by varying the single factor of electron‐acceptor property of substituent group Br and I at para ‐position of 3‐methylbenzoic acid. They crystalize in the same space group, ligand and metal ions are arranged in the same mode. Interestingly, the luminescence quantum yield (QY) of Tb−Br is greater than Tb−I, indicating that weaker electron‐acceptor group of I at para‐position of 3‐methylbenzoic acid leads to lower luminescence QY than Br in terbium complex. This is the first work to control the single variable factor to study the substituent group property on the luminescence QY of lanthanide complex. Further study reveals that Tb−I is a multiplex sensor for Fe 2+ , Co 2+ , and Ni 2+ .