Lanthanide Complexes with 4,4′-Bis(2-sulfonatostyryl)-biphenyl: Crystal Structures and Luminescence Properties

A series of new tris(pyrazolyl)borate (Tp(-)) and tris(2-pyridylpyrazolyl)borate (Tp(Py-)) Eu3+, Gd3+, Tb3+ and Dy3+ complexes with the dianionic ligand 4,4 '-bis(2-sulfonatostyryl)biphenyl (Ssp(2-), a widely used fluorescent whitener) were synthesized and their luminescence properties were studied. The Gd3+, Tb3+ and Dy3+ compounds possess only ligand-centered emission, arising from the Ssp(2-) ligand, with quantum yields of up to 60 %. While the emission centers in these complexes are similar, the positions of the luminescence maxima, the emission quantum yields, and the lifetimes change in the order [(Tp(2)Ln)(2)Ssp]<[(Tp(Py)LnSsp)(2)]<[Ln(2)Ssp(3)](n). Among the complexes studied, Eu3+-centered emission was observed for only [(Tp(2)Eu)(2)Ssp]. In this compound, Tp(-) plays the role of an antenna ligand for Eu3+-radiation, though the quantum yield is only 5 %.

Automated summary

A series of new tris(pyrazolyl)borate and tris(2-pyridylpyrazolyl)borate complexes with Eu3+, Gd3+, Tb3+, and Dy3+ were synthesized and their luminescent properties were studied. The Gd3+, Tb3+, and Dy3+ compounds exhibited ligand-centered emission, while the Eu3+ compound exhibited Eu3+-centered emission.