ROOM-TEMPERATURE FLUORESCENCE, PHOSPHORESCENCE AND CRYSTAL-STRUCTURE OF 4-ACYL PYRAZOLONE LANTHANIDE COMPLEXES - LN(L)(3)CENTER-DOT-2H(2)O

A series of ternary mixed ligand 4-acyl pyrazolone lanthanide complexe s: Ln(L)(3) . 2H(2)O [where Ln = Tb3+ or Gd3+, L = 1-phenyl-3-methyl-4 -acetyl-pyrazolone-5 (PMAP), 1-phenyl-3-methyl-4-propionyl-5-pyrazolon e (PMPP), 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone (PMIP), 1-phenyl -3-methyl-4-neovaleryl-pyrazolone-5 (PMNP) and 1-phenyl-3-methyl-4-ben zoyl-pyrazolone-5 (PMHP)] were synthesized and characterized by FT-IR spectra, UV-vis spectra and DTA-TG analysis. Room-temperature phosphor escence was observed from the Gd3+ complexes by excitation of the samp le with the fourth harmonic frequency of a Nd:YAG laser beam (lambda = 266 nm) and the tripler energies of the pyrazolone ligands were evalu ated. Both the fluorescence intensity and fluorescence lifetime of the Tb3+ complexes depend on the structure of the ligands and explanation s are presented. The crystal structure [Tb(PMPP)(3) . 2H(2)O]. EtOH wa s determined by X-ray diffraction. The structure was refined to R = 0. 064 (R(w) = 0.073). The complex is mononuclear and the central terbium ion is coordinated by eight oxygen atoms to form a square-antiprism c oordination polyhedron, six of which are from the three bidentate pyra zolone ligands and the other two are from the two coordination water m olecules. Copyright (C) 1997 Elsevier Science Ltd.