LUMINESCENCE PROPERTIES OF M-TERPHENYL-BASED EU3- VISIBLE AND NEAR-INFRARED EMISSION( AND ND3+ COMPLEXES )

Two novel m-terphenyl-based organic ligands (2 and 3) have been synthe sized. Photophysical studies show that the ligands form stable complex es with Eu3+, since typical Eu3+ luminescence is observed upon excitat ion of the ligand. The acyclic complex 2 . Eu3+ shows relatively long lifetimes in methanol (e.g. tau = 0.72 ms in CH3OH). The acylic ligand 2 allows the additional coordination of two solvent molecules and the ir high-energy vibrational modes form the main quenching pathway for t he Eu3+ luminescence. In comparison with 1 . Eu3+, the more rigid diox olane-containing complex 3 . Eu3+ provides an additional donor atom, w hich reduces the solvent coordination of 3 . Eu3+ (tau(3 . Eu1+) = 1.4 2 ms compared to tau(1 . Eu3+) 0.75 ms in CH3OH). The high-energy vibr ational modes of the organic ligand 3 are the most important quenchers . Typical near-infrared Nd3+ emission at 1060 and 1350 nm resulting fr om 3 . Nd3+ has been observed. Quenching by the solvent is still opera tive for 3 . Nd3+, because of the larger ionic radius of the Nd3+ ion.