title: Highly efficient luminescent hybrid materials covalently linking with europium(III) complexes via a novel fluorinated beta-diketonate ligand: synthesis, characterization and photophysical properties.
abstract: A novel highly fluorinated beta-diketonate ligand, 1-(3,5-bis(benzyloxy)phenyl)-4,4,5,5,5-pentafluoropentane-1,3-dione (HBBPPF) and its corresponding europium(III) ternary complex, Eu(BBPPF)(3)(DDXPO) [DDXPO = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide] were synthesized via a dexterously designed routine, characterized and its photophysical properties (PL) investigated. PL measurement results indicated that the europium(III) ternary complex exhibits intense red emission under UV light excitation with a solid-state quantum yield of 39%. An organic-inorganic mesoporous luminescent hybrid material was also constructed by linking the ternary europium(III) complex to the functionalized hexagonal mesoporous MCM-41 through the modified beta-diketonate ligand (SiBBPPF-Na). Beta-diketonate grafted to the coupling agent 3-(triethoxysilyl)propyl isocyanate was used as the precursor for the preparation of mesoporous materials. A modified MCM-41 mesoporous material containing ternary europium(iii) complex covalently bonded to the silica-based network, designated as Eu(BBPPF-Si)(3)(DDXPO)/MCM-41, was obtained by interacting SiBBPPF-Na with europium nitrate, DDXPO and MCM-41 via a ligand-exchange reaction. The new mesoporous hybrid material was characterized by powder X-ray diffraction, nitrogen adsorption-desorption, thermogravimetry, transmission electron microscopy, dynamic light scattering, FT-IR, (29)Si CP MAS NMR and (13)C NMR solid-state techniques, and photoluminescence spectroscopy. Eu(BBPPF-Si)(3)(DDXPO)/MCM-41 exhibits an efficient intramolecular energy transfer process from the silylated beta-diketonate to the central Eu(3+), namely, the "antenna effect", which favours a strong luminescent intensity (quantum yield = 43%). Thermogravimetric analysis on Eu(BBPPF-Si)(3)(DDXPO)/MCM-41 demonstrated that the thermal stability of the lanthanide complex was evidently improved as it was covalently bonded to the mesoporous MCM-41 matrix.
authors.affiliation: Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science & Technology (NIIST), CSIR, Thiruvananthapuram, 695 019, India.
authors.forename: Biju
authors.initials: B
authors.lastname: Francis
authors.forename: D B
authors.initials: DB
authors.lastname: Ambili Raj
authors.forename: M L P
authors.initials: ML
authors.lastname: Reddy
mesh_terms: D000327:Adsorption; D004735:Energy Transfer; D005063:Europium / Q000737:chemistry*; D054879:Halogenation; D007811:Lanthanum / Q000737:chemistry; D008024:Ligands; D049449:Luminescence; D009584:Nitrogen / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D008024:Ligands; C509968:MCM-41; D010087:Oxides; D005063:Europium; D007811:Lanthanum; D012822:Silicon Dioxide; D009584:Nitrogen