terbiumdipicolinate

Terbium dipicolinate refers to a coordination complex formed between terbium(III) ions and dipicolinic acid (pyridine-2,6-dicarboxylic acid, DPA). In typical coordination, three DPA ligands bind to a Tb3+ center, often with one or more water molecules completing the coordination sphere, giving formulations such as Tb(DPA)3(H2O)n. Dipicolinic acid acts as a tridentate ligand, coordinating through its two carboxylate groups and the pyridine nitrogen.

The complex is notable for its luminescent properties. Dipicolinic acid sensitizes the terbium ion by absorbing ultraviolet light and transferring energy to Tb3+, a phenomenon known as the antenna effect. This yields sharp, characteristic Tb3+ emission lines, with the most intense transition near 545 nm (green). The luminescence lifetime is typically in the millisecond range, enabling time-resolved spectroscopic measurements and reduction of background fluorescence.

Applications of terbium dipicolinate center on its use as a luminescent probe and analytical reagent. It is employed in studies of lanthanide coordination chemistry and in sensors for dipicolinic acid, a biomarker associated with bacterial endospores. The strong, narrow Tb3+ emissions facilitate detection in aqueous samples and in solid-state materials. The Tb(DPA)3 motif is one example within the broader family of lanthanide–DPA complexes, which also includes europium and other lanthanides.

See also: dipicolinic acid; terbium(III) complexes; lanthanide luminescence.