Β-diketonate Ligands Research Articles

A series of dinuclear lanthanide(iii) complexes constructed from Schiff base and β-diketonate ligands: synthesis, structure, luminescence and SMM behavior

A series of new isostructural lanthanide(III) complexes are reported which are constructed from Schiff base and β-diketonate ligands, namely, [Ln2(DBM)6(L)] (Ln = Sm (1), Eu (2), Gd (3), Dy (4), Yb (5); L = N,N′-bis(pyridin-2-ylmethylene)ethane-1,2-diamine, DBM = dibenzoylmethanide). The structures of the isomorphous complexes 1–5 were determined by single-crystal X-ray crystallography. The two Ln(III) ions in the molecules of 1–5 are bridged by a Schiff base ligand that displays a curved configuration. Complexes 1, 2 and 5 exhibit lanthanide ion-based luminescence not only in the solid state but also in methanol solution. The lifetimes and quantum yields of luminescence were also determined. The magnetic analysis reveals that complexes 4 and 5 exhibit field-induced single-molecule magnet behavior with energy barriers (Ueff/kB) of 46.8 and 23.0 K at direct current fields of 2000 Oe, respectively.

Seven phenoxido-bridged complexes encapsulated by 8-hydroxyquinoline Schiff base derivatives and β-diketone ligands: single-molecule magnet, magnetic refrigeration and luminescence properties

Seven dinuclear complexes based on 8-hydroxyquinoline Schiff base derivatives and β-diketone ligands, [RE2(hfac)4L2] (RE = Y (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6) and Lu (7); hfac(-) = hexafluoroacetylacetonate; HL = 2-[(4-chloro-phenylimino)-methyl]-8-hydroxyquinoline), have been synthesized, and structurally and magnetically characterized. Complexes 1-7 have similar dinuclear structures, in which each RE(III) ion is eight coordinated by two L(-) and two hfac(-) ligands in a distorted dodecahedron geometry. The luminescence spectra indicate that complex 3 exhibits characteristic Tb(III) ion luminescence, while 1 and 7 show HL ligand luminescence. The magnetic studies reveal that 2 features a magnetocaloric effect with the magnetic entropy change of -ΔSm = 16.83 J kg(-1) K(-1) at 2 K for ΔH = 8 T, and 4 displays slow magnetic relaxation behavior with the anisotropic barrier of 6.7 K and pre-exponential factor τ0 = 5.3 × 10(-6) s.

Dysprosium(III) complexes with a square-antiprism configuration featuring mononuclear single-molecule magnetic behaviours based on different β-diketonate ligands and auxiliary ligands.

Three mononuclear dysprosium(III) complexes derived from three β-diketonate ligands, 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb), 4,4,4-trifluoro-1-(4-fluorophenyl)-1,3-butanedione (tffb) and 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione (tfnb) as well as auxiliary ligands, 5-nitro-1,10-phenanthroline (5-NO2-Phen), DMF and 2,2'-bipyridine (bpy) have been synthesized and structurally characterized, namely [Dy(5-NO2-Phen)(tfmb)3] (1), [Dy(DMF)2(tffb)3] (2) and [Dy(bpy)2(tfnb)3]·0.5(1,4-dioxane) (3). The metal ions in 1-3 adopt an approximately square-antiprismatic (SAP) coordination environment with D4d axial symmetry. The magnetic properties of 1-3 have been investigated, displaying weak out-of-phase AC signals under a zero-DC field. With an applied DC field of 1200 Oe, the quantum tunnelling of the magnetization was suppressed in 1-3 with the pre-exponential factor τ0 = 5.3 × 10(-7) s and the effective barrier ΔE/kB = 83 K for 1 as well as the pre-exponential factor τ0 = 3.09 × 10(-7) s and the effective barrier ΔE/kB = 39 K for 3. Interestingly, for the frequency dependence of the out-of-phase (χ'') of the AC susceptibility of 2, two slow relaxation of the magnetization processes occurred under the applied magnetic field of 1200 Oe, corresponding to the fast relaxation (FR) phase and slow relaxation (SR) phase, respectively. Arrhenius analysis gave the effective energy barrier (ΔE/kB) of 55 K and the pre-exponential factor (τ0) of 8.23 × 10(-12) for the SR. It is thus very likely that the FR process in complex 2 results from QTM enhanced by dipolar interactions between the Dy ions or the presence of the applied field. The structure-property relationship of some Dy(III) based mononuclear SMMs with the SAP configuration was further discussed.

Near-infrared luminescence of Nd3+and Yb3+complexes using a polyfluorinated pyrene-based β-diketonate ligand

Highly efficient near-infrared emitting Nd3+and Yb3+complexes have been developed based on a new polyfluorinated pyrene-appended β-diketonate ligand.

Pure White Light Emitting Tetrakis β-diketonate Dysprosium Complexes for OLED Applications

In this work, highly photoluminescent tetrakis β-diketonate of rare earth complexes M[Dy(acac)4] (M = Li+, Na+, K+) were synthesized to study the sensitization effect on Dy3+ ion by β-diketonate ligand. Emission spectra show intense peaks at 485 nm and 577 nm in blue and yellow region for the transition 4F9/2→6H15/2 and 4F9/2→6H13/2 of Dy3+ ion respectively. Blue to yellow intensity ratio was modified by introducing counter cation. The excitation spectra show an intense peak at 330 nm due to the absorption of π – π* band in ligand. Diffused reflectance (DR) spectra and excitation spectra show the similar peaks for the f-f transitions of Dy3+ which confirms that ligand to Dy3+ ion energy transfer occurred efficiently. The CIE chromaticity diagram shows that pure white light was achieved for sodium complex. It was found that excited state lifetime of sodium complex is very short (0.1378 ms and 0.042 ms) for the 4F9/2→6H15/2 and 4F9/2→6H13/2 transition of Dy3+ ion. It can be used for white organic light emitting diode (OLED) applications due to it's short life time and CCT value compatible with day light.

A family of tetranuclear quinolinolate Dy(iii)-based single-molecule magnets: effects of periphery ligand replacement on their magnetic relaxation.

Three complexes with formula {Dy(q)2(L)}2(μ3-OH)2{Dy(q)(L)}2(solvents) (where q = 8-quinolinolate; L = acetylacetone (acac) with (CH2Cl2)2 = solvent (1), 1,3-diphenyl-1,3-propanedione (DBM) and (CH2Cl2)2 = solvent (2), and hexafluoroacetylacetone (hfac) and CHCl3 = solvent (3)) were structurally and magnetically characterized. They have similar Dy4 structural cores bridged by N and O atoms from 8-quinolinolate, and only differ in the peripheral β-diketonate ligands. The variable-frequency and temperature alternating-current (ac) magnetic susceptibility measurements reveal that complexes 1 and 2 display significant zero-field single-molecule-magnet (SMM) behavior, while complex 3 exhibits the field-induced SMM behavior, albeit they possess the nearly same primary coordination sphere. The ac susceptibility measurement on the diluted samples verified that their relaxation was of purely molecular origin, and their distinct slow magnetic behaviors were related to the replacement of the peripheral β-diketonate ligand, which is responsible for their different individual Dy(iii) ions' magnetic anisotropy and intramolecular coupling, as confirmed by ab initio calculation.

Highly luminescent and stable lyotropic liquid crystals based on a europium β-diketonate complex bridged by an ethylammonium cation.

Soft lanthanide luminescent materials are impressive because of their tunable and self-assembling characteristics, which make them an attractive emerging materials field of research. In this report, novel luminescent lyotropic liquid crystals (LLCs) with four different mesophases have been fabricated by a protic ionic liquid (IL) based europium β-diketonate complex EA[Eu(TTA)4] (EA = ethylammonium, TTA = 2-thenoyltrifluoro-acetone) and an amphiphilic block copolymer (Pluronic P123). The protic IL, ethylammonium nitrate (EAN), was used as both the solvent and linkage to stabilize the doped complexes. Analyses by single-crystal X-ray diffraction for EA[Eu(TTA)4] and Fourier transform infrared spectroscopy for the LLC materials reveal convincingly that the ethylammonium cations establish an effective connection with both the carbonyl group of the β-diketonate ligand and the EO blocks of the amphiphilic block copolymer P123 via strong hydrogen bonding interactions. Due to this, an extremely long decay time of the excited state is obtained in EA[Eu(TTA)4] and excellent photostability of the luminescent LLCs could be achieved. The long-period ordered structures of the luminescent LLCs have been investigated by small-angle X-ray scattering measurements and the best luminescence performance was found in the most organized mesophase. Noteworthy, the LLCs could yield an effective confining effect on the europium complex accompanied by a sizeable elongation of the excited-state lifetime and an enhancement of the energy transfer efficiency, which reaches a remarkably high value of 52.6%. More importantly, the modulated luminescence properties observed in the four mesophase structures offer the potential and powerful possibility for these unique composite LLCs to be used in the fabrication of soft luminescent materials with tunable functions.

Luminescent and magnetic materials with a high content of Eu(3+)-EDTA complexes.

Bifunctional optical magnetic materials with a high europium content have been prepared. Chelating groups were introduced on the Fe3O4 surface with organosilanes containing ethylenediaminetetraacetic acid (EDTA) derivatives, which were previously prepared via a reaction between EDTA-dianhydride and aminoalkoxysilane agents: 3-(trimethoxysilyl)propylamine (1N), N-[3(trimethoxysilyl)propyl]ethylenediamine (2N) and N(1)-(3-trimethoxysilylpropyl)diethylenetriamine) (3N). The first coordination sphere of Ln-EDTA complexes present on the modified surfaces of Fe3O4 particles was completed by addition of β-diketonate ligands (tta: thenoyltrifluoroacetone, dbm: dibenzoylmethane, bzac: benzoylacetone and acac: acetylacetone) in order to improve their luminescence properties. The materials were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and wavelength dispersive X-ray fluorescence (WDXRF) and Fourier-transform infrared (FT-IR) spectroscopy as well as by zeta potential measurements and luminescence spectroscopy. The hybrid materials exhibited intense red emission, which can be assigned to the 4f-4f transitions of the Eu(3+) ion, indicating an efficient intramolecular ligand-to-metal energy transfer. The experimental intensity parameters (Ω2 and Ω4), lifetimes (τ), as well as radiative (Arad) and non-radiative (Anrad) decay rates of the Eu(3+) ion were determined and discussed. The strategies used to obtain these materials may contribute to the development of several bifunctional systems for practical applications.

Giant spin-phonon bottleneck effects in evaporable vanadyl-based molecules with long spin coherence.

Vanadium(iv) complexes have recently shown record quantum spin coherence times that in several circumstances are limited by spin-lattice relaxation. The role of the environment and vibronic properties in the low temperature dynamics is here investigated by a comparative study of the magnetization dynamics as a function of crystallite size and the steric hindrance of the β-diketonate ligands in VO(acac)2 (1), VO(dpm)2 (2) and VO(dbm)2 (3) evaporable complexes (acac- = acetylacetonate, dpm- = dipivaloylmethanate, and dbm- = dibenzoylmethanate). A pronounced crystallite size dependence of the relaxation time is observed at unusually high temperatures (up to 40 K), which is associated with a giant spin-phonon bottleneck effect. We model this behaviour by an ad hoc force field approach derived from density functional theory calculations, which evidences a correlation of the intensity of the phenomenon with ligand dimensions and the unit cell size.

Tungsten Oxide Film and Nanorods Grown by Aerosol-Assisted Chemical Vapor Deposition Using κ2-β-Diketonate and β-Ketoesterate Tungsten (VI) Oxo-Alkoxide Precursors

Deposition of continuous, dense WOx films and nanorods was accomplished by aerosol-assisted chemical vapor deposition (AACVD) using the recently synthesized precursors WO(OCH3)3(acac) (1), WO(OCH2C(CH3)3)3(tbac) (2), WO(OCH2C(CH3)3)3(dpm) (3), WO(OC(CH3)3)3(tbac) (4), and WO(OCH2C(CH3)3)3(tbpa) (5). This works seeks to define the deposition conditions and precursors that yield C-free tungsten oxide and the potential to control the stoichiometry and phase of deposited WOx. In addition, the systematic variation of the ligand chemistry provides insight into precursor design. Variation of the precursor and growth temperature during deposition revealed a window where C-free WOx was deposited using 3, 4, and 5. The surface morphology of the WOx varied from amorphous thin film to crystalline nanorods to dendrites as temperature was increased. Films grown between 150 and 350°C in pure N2 atmosphere are sub-stoichiometric, amorphous and contaminated with carbide species (3–9 at.%). As the deposition temperature increased (400–550°C), the tungsten became more oxidized, the sub-stoichiometric crystalline W18O49 monoclinic phase formed, and increased surface bound C was detected. Material was also deposited under oxidizing conditions (1–2% O2 in N2) as well as annealing in air at the deposition temperature. The material grown in N2/O2 carrier gas at low temperatures (200 and 300°C) is amorphous WOx, similar to that grown in N2. At higher temperature (350 and 550°C), however, GIXRD results reveal WOx corresponding to a sub-stoichiometric tetragonal phase transitioning to the monoclinic WO3 phase for samples grown at 550°C. This demonstrates that crystalline structure of WOx is affected by the growth temperature and introducing O2 in the carrier gas. Air annealing samples grown in pure N2 also produced structural and compositional changes, but not identical to those grown in a N2/O2 carrier gas. Notably, annealing samples grown at 250 and 350°C at the same temperature, produced C-free material with unchanged amorphous morphology. The measured stoichiometry and crystallinity showed a dependence on the precursor structure. The growth rate of deposited material was measured as a function of temperature and activation energies were estimated for growth of amorphous and nanostructured material. The systematic variation in activation energies is consistent with initial dissociation of the alkoxide C-O bonds and modifications of the steric bulk of the β-diketonate ligand.

A series of dinuclear Dy(iii) complexes bridged by 2-methyl-8-hydroxylquinoline: replacement on the periphery coordinated β-diketonate terminal leads to different single-molecule magnetic properties.

A series of HMq-bridged dinuclear dysprosium complexes, namely, [Dy(acac)2(CH3OH)]2(μ-HMq)2 (1), [Dy(DBM)2]2(μ-HMq)2(n-C6H14) (2), [Dy(hmac)2]2(μ-HMq)2 (3) and [Dy(hfac)3]2(μ-HMq)2 (4) (HMq = 2-methyl-8-hydroxyquinoline, acac = acetylacetone, DBM = dibenzoylmethane, hmac = hexamethylacetylacetonate and hfac = hexafluoroacetylacetonate), were structurally and magnetically characterized. X-ray crystallographic analyses of the structures reveal that HMq serves as the effective bridge to link two Dy(III) centers by means of the phenoxyl oxygen and nitrogen atoms and the periphery β-diketonate ligands complete the coordination sphere by bidentate oxygen atoms. The different substituents on the β-diketonate terminal lead to different coordination models mostly due to the steric hindrance of these substituents, and the electron-withdrawing or donating effects likely influence the strength of the ligand fields and the Dy(III) ion anisotropy. Measurements of alternating-current (ac) susceptibility on complexes 1-4 reveal that complexes 3 and 4 display significant zero-field single-molecule magnetic (SMM) behavior with barrier energy Ueff/kB = 14.8 K, τ0 = 1.8 × 10(-5) s and Ueff/kB = 9.2 K, τ0 = 1.7 × 10(-5) s, respectively, whereas 1 and 2 exhibit field-induced SMM behavior, and these differences are attributed to the alteration on the periphery β-diketonate ligands. Their distinct slow magnetic relaxation behaviors were related to their different individual Dy(III) ion magnetic anisotropy and intramolecular coupling, which were confirmed by ab initio calculations.

Faster Synthesis of Beta-Diketonate Ternary Europium Complexes: Elapsed Times & Reaction Yields.

β-diketonates are customary bidentate ligands in highly luminescent ternary europium complexes, such as Eu(β-diketonate)3(L)2, where L stands for a nonionic ligand. Usually, the syntheses of these complexes start by adding, to an europium salt such as EuCl3(H2O)6, three equivalents of β-diketonate ligands to form the complexes Eu(β-diketonate)3(H2O)2. The nonionic ligands are subsequently added to form the target complexes Eu(β-diketonate)3(L)2. However, the Eu(β-diketonate)3(H2O)2 intermediates are frequently both difficult and slow to purify by recrystallization, a step which usually takes a long time, varying from days to several weeks, depending on the chosen β-diketonate. In this article, we advance a novel synthetic technique which does not use Eu(β-diketonate)3(H2O)2 as an intermediate. Instead, we start by adding 4 equivalents of a monodentate nonionic ligand L straight to EuCl3(H2O)6 to form a new intermediate: EuCl3(L)4(H2O)n, with n being either 3 or 4. The advantage is that these intermediates can now be easily, quickly, and efficiently purified. The β-diketonates are then carefully added to this intermediate to form the target complexes Eu(β-diketonate)3(L)2. For the cases studied, the 20-day average elapsed time reduced to 10 days for the faster synthesis, together with an improvement in the overall yield from 42% to 69%.

Bright red luminescence and triboluminescence from PMMA-doped polymer film materials supported by Eu 3+ -triphenylphosphine based β-diketonate and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide

Herein, a new β-diketonate ligand, namely, 1-(4-(diphenylphosphino)phenyl)-4,4,5,5,5-pentafluoropentane-1,3-dione (DPPFH) has been synthesized and utilized for the construction of an antenna complex of Eu3+ [Eu(DPPF)3(DDXPO)] in the presence of a chelating ligand, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide (DDXPO). The developed Eu3+ compound has been well characterized and investigated the photophysical properties. The designed Eu3+ complex displays bright red luminescence upon irradiation at the ligand-centered band at 375 nm with a quantum yield of 39% in the solid-state. Interestingly, the ternary Eu3+ complex also exhibits brilliant triboluminescence in the daylight, which could be useful in the design of pressure and damage detection probes. In addition, the newly obtained Eu3+ complex was embedded into a PMMA matrix to form highly luminescent films having quantum yields as high as 45–50%. These plastic materials display enhanced thermal stability as compared to parent compound. The ground state coordination geometry of the typical Eu3+ complex was calculated using the Sparkle/RM1 model. The excellent agreement between the experimental and theoretically predicted photophysical data, attesting the efficacy of the theoretical approach implemented in the LUMPAC software (http://lumpac.pro.br).

Experimental Determination of Energy Transfer in Eu(III) Complexes Based on Pyrazole-Substituted 1,3-Diketones

We have successfully synthesized Eu-based luminophores promising for inkjet printing with almost 100% efficiency of energy transfer from ligands to the lanthanide ion. The luminophores with β-diketonate ligands are characterized by means of optical spectroscopy. We reveal the impact of different types of β-diketonates on the quantum yield of luminescence and determine a β-diketonate complex exhibiting the highest luminescence quantum yield and promising for organic light-emitting diode (OLED) applications. We discuss the reasons for decreasing quantum efficiencies of other types of investigated ligands.

Tris(β-diketonato)chromium(III) complexes: Effect of the β-diketonate ligand on the redox properties

A combined quantum chemistry and electrochemistry study of a series of tris(β-diketonato)-Cr(III) complexes showed that the different electron donating properties of the R and R' groups, substituted on the 1 and 3 positions of the β-diketonate ligand (RCOCHCOR')−, largely influence the redox properties of these complexes, due to the good communication between the R and R' groups and the metal via the β-diketonato-metal conjugated system. Linear relationships were obtained between the reduction potential of the tris(β-diketonato)-Cr(III) complexes and a variety of electronic parameters used to describe the electron-donating and -withdrawing power of the R and R' groups on the β-diketonate ligand.

Single-molecule magnet behavior of a dinuclear dysprosium compound constructed by 8-hydroxyquinoline Schiff base and β-diketonate ligands

A dinuclear dysprosium compound, [Dy2(dbm)4L2]2(1) (Hdbm=1,3-diphenyl-1,3-propanedione, HL=2-[[(4-fluorophenyl)imino]methyl]-8-hydroxyquinoline), have been synthesized, structurally and magnetically characterized. The X-ray structural analysis exhibits that the compound 1 is phenoxo-O bridged binuclear compound, in which two DyIII ions are bridged by two phenoxido oxygen atoms of two 8-hydroxyquinoline Schiff base ligands. Each DyIII centers exhibit an eight-coordinated environment. Magnetic measurements indicated that slow relaxation of the magnetization was clearly observed in 1, typical of SMM behavior.

Optimized single molecule magnet in double-decker hetero-metallic complexes

Two new hetero-metallic complexes [LnNa2(L)2(bta)(CH3OH)]∙nH2O∙mCH3OH (Ln=Dy (1), n=1, m=0; Er (2), n=0, m=1) supported by rigid hexadentate salen-type (H2L=N,N′-bis(2-oxy-3-methoxybenzylidene)-1,2-phenylenediamine) and β-diketonate (bta=benzoyltrifluoroacetone) ligands have been designed and synthesized. Structural analysis reveals that the Ln3+ ion has a typical double-decker sandwich structure with a distorted bicapped triangular prism. The magnetic analysis unveils that both complexes 1 and 2 are of single molecule magnet behavior, and both of them can be regarded as rare SMMs based on the salen-type ligand with a double-decker structure.

Synthesis and photoluminescent behavior of Eu(III) complexes with 4,4,4-trifluoro-1-(6-methoxy-naphthalen-2-yl)-butane-1,3-dione

The fluorinated β-diketone ligand, 4,4,4-trifluoro-1-(6-methoxy- naphthalen-2-yl)-butane-1,3-dione (HL), and its ternary europium (III) complexes using water (H2O), 2,2-dipyridine (Bipy), 1,10-phenanthroline (Phen) and 4′-phenyl-terpyridine (Phterpy) as the secondary ligand were synthesized and characterized by elemental analysis, FT-IR, 1H NMR, UV–vis absorption, ESI–MS and fluorescence spectroscopic techniques. All these europium complexes exhibited the characteristic emission bands that arise from the 5D0→7FJ (J=0–4) transitions of the europium ion in solid state. Based on their emission spectra and lifetimes, the Judd–Ofelt intensity parameters (Ω2 and Ω4), the radiative decay rate Arad, the nonradiative rates Anrad, and the quantum efficiency (η) were determined and compared. The ternary complexes, EuL3·Bipy, EuL3·Phen and EuL3·Phterpy, exhibited much higher quantum efficiencies and lifetime values, which can be attributed to the displacement of water molecules from the coordination sphere by the heterocyclic nitrogen donors. Especially, the complex EuL3·Phen exhibited the longest lifetime τ (0.704ms) and the highest luminescence quantum efficiency η (47.9%) among these complexes. Meanwhile, complexes EuL3·Bipy, EuL3·Phen and EuL3·Phterpy also displayed higher Ω2 values than the complex EuL3·2H2O, indicating their hypersensitive character of the 5D0→7F2 transition and a highly polarizable chemical environment around the europium(III) ion.

Kinetic study of thermal decomposition of new Eu(III), Tb(III) and Gd(III) complexes with beta-diketone ligands and 4,4-diphenyl-2,2-dipyridyl, chloride of 1,10-phenantrolinium

Complexes of general formula [Eu(fod)3·L], [Tb(fod)3·L] and [Gd(fod)3·L] (where fod=6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadionate; L=4,4-diphenyl-2,2-dipyridyl or/and chloride of 1,10-phenantrolinium) were synthesized by reacting the corresponding salt of terbium and gadolinium with β-diketone(fod) and other ligands, and the precursor Eu(fod)3·2H2O with diphenylbipy and phenCl ligands. The thermal decomposition of these complexes along with description of some emitting materials is discussed in details. We focused on those complexes emitting in the visible region, which can be used in lighting industry (e.g., for the preparation of photo- and electro-luminescent devices) and for biological immunoassays. The thermal decompositions of Eu(fod)3·L, Tb(fod)3·L and Gd(fod)3·L are best described by R2 and R3 kinetic models. Some selected results of our work concerning the synthesis of highly luminescent complexes for application in lighting and light conversion technologies are reported. Such materials have been obtained by combining the peculiar luminescence properties of Eu3+ and Tb3+ antenna complexes with β-diketone (fod).

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

Abstract A series of novel luminescent europium (III) complexes based on fluorinated β-diketone ligand 4,4-difluoro-1-phenyl-1,3-butanedione (DPBD) and auxiliary ligands 2,2-biquinoline (biq) or 1,10-phenanthroline (phen) or neocuproine (neo) or 2,2-bipyridyl (bipy) have been synthesized. The ligand DPBD with their complexes Eu(DPBD)3·(H2O)2 (C1), Eu(DPBD)3·biq (C2), Eu(DPBD)3·phen (C3), Eu(DPBD)3·neo (C4) and Eu(DPBD)3·bipy (C5) were confirmed by elemental analysis, infrared (IR) and proton nuclear magnetic resonance (NMR) spectroscopy. The crystalline nature, photoluminescence and thermal behavior were investigated by powder X-ray diffraction (XRD), photoluminescence (PL) spectroscopy and TG/DTA-DSC respectively. The emission spectra of complexes showed the characteristics sharp bands in solid state corresponding to 5D0–7Fj (j = 0–3) transition of europium ion with 5D0–7F2 as the most intense transition. The emission spectra, energy transfer mechanism, luminescence decay time and relative quantum efficiency clearly reveals that these photophysical properties are greatly influenced by the π-conjugated system, stability of the complexes and the efficient energy transfer from DPBD ligand to emitting level of Eu3+ ion. The complex Eu(DPBD)3·bipy (C5) exhibited highest quantum efficiency, luminescence intensity bearing good CIE color coordinates (x = 0.64 and y = 0.34) matching the NTSC (National Television Standard Committee) standard values for the pure red color and longest lifetime which makes it a promising red-emitting component for display devices.