PHOTOPHYSICAL PROPERTIES OF EU3-HYDROXY-2,4,6-CYCLOHEPTATRIEN-1-ONE(,GD3+ AND TB3+ COMPLEXES WITH 2)

The spectroscopic properties (excitation and emission spectra at 4.2, 77 and 298 K, and temperature dependent lifetime measurements from 20 to 298 K) of the Gd(trop)(3) complex, (trop = C7H5O2-) are reported he re. This compound is used to elucidate the lack of luminescence in the isostructural complexes Eu(trop)(3) and Tb(trop)(3). The results show that the ligand triplet states are at lower energies than the Eu3+ an d Tb3+ emitting states (viz. the D-5(0) and D-5(4), respectively), thu s quenching the luminescence from these ions by non-radiative relaxati on to the ground state.