Lanthanide complexes with a biphosphonate ester ligand and their fluorescent properties

A bi-phosphonate ligand 4,4'-bis(diethylphosphonomethyl)biphenyl has been designed and synthesized. The ligand reacted with lanthanide nitrates forming three different types of coordination complexes: interwoven net polymer (type I), linear polymer (type II), and ladder polymer (type III). The photophysical properties of Sm3+, Eu3+, Tb3+ and Dy3+ complexes were investigated. The Sm3+, Eu3+ and Dy3+ complexes displayed the characteristic spectrum of the lanthanide ions. The Tb3+ complex exhibited a prominent strong fluorescence by excitation of 300 nm, which indicated that there may be a luminescence sensitization effect of the complex via excitation of the ligand. (C) 2015 Published by Elsevier B.V.