Spectroscopic and magnetic studies of mixed lanthanide complexes:: LnL3α,α′Dipy in solution and in solid

New monomeric complexes LnL(3)bip(1/2bip) were synthesized (Ln=Eu3+, Tb3+); L-phosphoro-azo derivative of beta-diketone: CCl3C(O)NP(O)(OCH3)(2) and bip-alpha,alpha'dipyridyl and single crystals were grown. X-Ray diffraction studies were done. The complexes crystallize in the triclinic system, space group P (1) over bar. Magnetic susceptibility and magnetization of the crystals were investigated. High resolution absorption, luminescence and excitation spectra were measured for crystals at 293, 77 and 4 K in order to characterize their physical properties. Radiative and nonradiative processes were analyzed. The role of the ligand singlet and triplet states in energy-transfer as well as the charge-transfer states in emission quenching were studied. (C) 2002 Elsevier Science B.V. All rights reserved.