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 complexes: 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-pyrazolone (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-benzoyl-pyrazolone-5 (PMHP)] were synthesized and characterized by FT-IR spectra, UV-vis spectra and DTA-TG analysis. Room-temperature phosphorescence was observed from the Gd3+ complexes by excitation of the sample with the fourth harmonic frequency of a Nd:YAG laser beam (lambda = 266 nm) and the tripler energies of the pyrazolone ligands were evaluated. Both the fluorescence intensity and fluorescence lifetime of the Tb3+ complexes depend on the structure of the ligands and explanations are presented. The crystal structure [Tb(PMPP)(3) . 2H(2)O]. EtOH was 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 coordination polyhedron, six of which are from the three bidentate pyrazolone ligands and the other two are from the two coordination water molecules. Copyright (C) 1997 Elsevier Science Ltd.Chemistry, Inorganic & NuclearCrystallographySCI(E)47ARTICLE81381-13891