Preparation of phosphorylated bis-pyrazolyl–pyridine nonadendate ligands and their terbium complexes. Part 2

A series of ligands has been constructed from a central bis-pyrazolyl–pyridine core and various deprotonable chelating pockets based on mixed carboxylate/phosphate or phosphate anionic functions and a central flexible pendent arm for subsequent grafting to biomaterials. For some of these ligands, the sequence of reactions incorporates an additional step introducing a substituted diethynylphenyl residue to increase significantly their solubility in polar organic solvents. The terbium(III) complexes of some of these ligands display outstanding spectroscopic properties with lifetimes ranging from 2.7 to 3.2 ms and quantum yields from 16% to 26% in water.