Highly efficient luminescent hybrid materials covalently linking with europium(iii) complexes via a novel fluorinated β-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.

Lanthanide mixed-ligand complexes of the [Ln(CAPh)3(Phen)] and [LaxEu1−x(CAPh)3(Phen)] (CAPh = carbacylamidophosphate) type. A comparative study of their spectral properties

“…1) can undoubtedly be assigned to ν(CO) stretching vibrations. As it was already mentioned, the structures of 1, 2 and 3 revealed different geometrical parameters of coordinated carbacylamidophosphate chelate rings 35 within one molecule. The asymmetric shape of the ν(CO) band ( Fig.…”

“…28 The intensity of these bands is mostly influenced among all the f-f transitions due to the changes in the immediate surrounding of the Nd(III) ion, making it 25 particularly suitable for probing the coordination environment around the ion. 19,30 The spectra were measured at 293 K in the 220-850 nm range in a solid state and in diluted 35 (C=1·10 -2 M) chloroform solution as well ( Fig.3A and 3B respectively). 29 The electronic absorption spectra of the neodymium complex 30 [Nd(Pip) 3 (Phen)] (Fig.3) show the absorption features similar to those reported previously for the analogous coordination compounds having coordination number of the central atoms 8 with different CAPh ligands.…”

“…13, 14 Int- 15 resting, that the substitution of the methylene group for the weak-acidic amide group allows to obtain the complexes both in molecular and acidic forms. All the 35 coordination compounds synthesized have fully been characterized by various spectroscopic techniques. 15 Effective sensitization of the lanthanide emission was expected for the coordination compounds with 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide (HPip), 15, 16 25 Cl 3 CC(O)N(H)P(O)[N(СН 2 ) 5 ] 2 which contain a chlorinated alkyl group and the additional "antenna ligand" 1,10phenantroline (Phen).…”

Synthesis, photoluminescent features and intramolecular energy transfer mechanism of europium (III) complexes with fluorinate β-diketone ligand and auxiliary ligands

“…6.9 nm, 6.5 nm, 5.6 nm, 3.9 nm and 3.6 nm corresponding to the complexes C1-C5, leading to intense pure red emission. The excellent intensity of 5 D 0 -7 F 2 transition as compared to 5 D 0 -7 F 1 transition points to the lack of an inversion symmetry in the coordination environment of europium ion [26][27][28]. The luminescent intensity ratio (I 1 /I 2 = 5 D 0 -7 F 2 / 5 D 0 -7 F 1 ) of electric to magnetic dipole transitions show the symmetry of the coordination sphere as well as monochromaticity properties of metal complexes, their values are found to be in the range 7.0-10.73, being the highest for complex C5.…”

Visible-emitting hybrid sol–gel materials comprising lanthanide ions: thin film behaviour and potential use as phosphors for solid-state lighting

“…Also, encapsulating a luminescent complex within a sol-gel matrix often resulted in an increase in the luminescence efficiency due to efficient shielding of the emissive ion by the inorganic matrix from non-radiative deactivation such as O-H oscillators. [22][23][24][25][26] The luminescence of these materials could be further improved by increasing the content of the emitter without self-quenching, thanks to a better dispersion of the coordinating sites within the matrix. [15][16][17] Lanthanide complexes can be inserted into an inorganic silica matrix in three ways, namely impregnation, doping and immobilization.…”