New Heteroaromatic Complexing Agents and Luminescence of Their Europium(III) and Terbium(III) Chelates

Twelve heteroaromatic complexing agents 9a–I were synthesized with the purpose to develop suitable labels for time‐resolved luminescence‐based bioaffinity assays. The relative luminescence yields, excitation maxima, and emission decay constants of their europium(III) and terbium(III) chelates were determined. According to these results, 2,2′,2″,2‴‐[(2,2′‐bipyridine‐6,6′‐diyl)bis(methylenenitrilo)]tetrakis (acetic acid) (9e) and 2,2′,2″,2‴‐[(2,2′:6′,2″‐terpyridine‐6,6″‐diyl)bis(methylenenitrilo)] tetrakis(acetic acid) (91) are the most promising agents.