Fluorescence enhancement of Tb(III) complex with a new β-diketone ligand by 1,10-phenanthroline

Skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH

The pH of human sweat is highly related with a variety of diseases, whereas the monitoring of sweat pH still remains challenging for ordinary families. In this study, we developed a novel dual-emission Tb-MOF using DPA as the ligand and further designed and constructed a skin-attachable Tb-MOF ratio fluorescent sensor for real-time detection of human sweat pH. With the increased concentration of H+, the interaction of H+ with carbonyl organic ligand leads to the collapse of the Tb-MOF crystal structure, resulting in the interruption of antenna effect, and correspondingly increasing the emission of the ligand at 380 nm and decreasing the emission of the central ion Tb3+ at 544 nm. This Tb-MOF nanoprobe has a good linear response in the pH range of 4.12-7.05 (R2 = 0.9914) with excellent anti-interference ability. Based on the merits of fast pH response and high sensitivity, the nanoprobe was further used to prepare flexible wearable sensor. The wearable sensor can detect pH in the linear range of 3.50-6.70, which covers the pH range of normal human sweat (4.50-6.50). Subsequently, the storage stability and detection accuracy of the sensors were evaluated. Finally, the sensor has been successfully applied for the detection of pH in actual sweat samples from 21 volunteer and the real-time monitoring of pH variation during movement processing. This skin-attachable Tb-MOF sensor, with the advantages of low cost, visible color change and long shelf-life, is appealing for sweat pH monitoring especially for ordinary families.

Effects of Europium Complex on Thermal and Photoluminescence Properties of Polyurethane-Europium Materials

A europium complex with double bonds was synthesized with crotonic acid as the ligand and a europium ion as the center ion. Then, the obtained europium complex was added to synthesized poly(urethane-acrylate) macromonomers to prepare the bonded polyurethane-europium materials by the polymerization of the double bonds in the complex and the poly(urethane-acrylate) macromonomers. The prepared polyurethane-europium materials had high transparency, good thermal stability and good fluorescence. The storage moduli of polyurethane-europium materials are obviously higher than those of pure polyurethane. Polyurethane-europium materials exhibit bright red light with good monochromaticity. The light transmittance of the material decreases slightly with increases in the europium complex content, but the luminescence intensity gradually increases. In particular, polyurethane-europium materials possess a long luminescence lifetime, which has potential applications for optical display instruments.

Synthesis of green emissive terbium(III) complexes for displays: Optical, electrochemical and photoluminescent analysis

A series of heteroleptic terbium(III) complexes with fluorinated 2-thenoyltrifluoroacetone (TTFA) and other heteroaromatic units have been synthesized. The developed heteroleptic complexes were inspected via elemental study, cyclic voltammetry, thermal analysis and spectroscopic investigations. Optical band-gap data proposed the conducting property of prepared complexes. The photoluminescence emission profiles illustrated peaks based on terbium(III) cation (Tb³⁺ ) positioned at ~617, 586, 546 and 491 nm, imputed to ⁵ D₄ to ⁷ F_J (J = 3,4,5,6) transitions separately. Most intense peak at 546 nm corresponding to ⁵ D₄  → ⁷ F₅ transition is accountable for the green emissive character of developed complexes. The luminous character of complexes reveals the sensitization of Tb³⁺ by ligands. Color parameters further corroborates the green emanation of Tb³⁺ complexes. The photometric characteristics of complexes recommended their usages in designing display devices.

Mononuclear luminous β-diketonate Ln (III) complexes with heteroaromatic auxiliary ligands: Synthesis and luminescent characteristics

A series of lanthanide (samarium and terbium) β-diketonates with heteroaromatic auxiliary ligands have been synthesized. The prepared complexes were characterized through electrochemical, thermal and spectroscopic analyses. Infrared analysis reveals the binding of respective metal ion to oxygen and nitrogen atoms of diketone and ancillary ligands respectively. TG/DTG profiles provide thermal information and specify the high thermal stability of the prepared complexes. The complexes exhibit the sharp and structured Ln-based emission in visible region upon irradiation in UV range. Photophysical analysis demonstrated the green and orange-red emission due to the respective characteristic transitions of Tb³⁺ and Sm³⁺ ions. Photophysical properties affirm the luminous behavior of synthesized complexes. These luminous lanthanide complexes could be used as emitting material in designing OLEDs.

High-throughput sensor microtiter plate of new terbium complexes for the determination of anthracene in seawater

A new fluorescent sensing microtiter plate (MTP) was developed for high sensitivity monitoring of anthracene in seawater samples. For this purpose, two ternary complexes of Tb(III) ions with dibenzoylmethane and neocuproine [Tb(DBM)₂(MePhen)] or with dibenzoylmethane and bathocuproine [Tb(DBM)₂(PhMePhen)] were synthesized. Elemental analysis, energy dispersive X-ray analysis, X-ray diffraction, infrared and ultraviolet-visible emission, and thermal analysis were conducted on the Tb(III) complexes. The limits of detection (D_L) were 0.14 and 1.05 μmol L^-1 for [Tb(DBM)₂(MePhen)] and [Tb(DBM)₂(PhMePhen)], respectively. [Tb(DBM)₂(PhMePhen)] MTP is embedded in a membrane made of cellulose acetate. The first high-throughput anthracene sensor MTP, based on [Tb(DBM)₂(PhMePhen)] sensor showed a linear range, from 0.2 to 20 μmol L^-1. [Tb(DBM)₂(PhMePhen)] MTP was validated for accurate and precise monitoring of anthracene using gas chromatography. The selectivity of the [Tb(DBM)₂(PhMePhen)] MTP toward anthracene was examined. The data indicated that [Tb(DBM)₂(PhMePhen)] MTP is suitable for rapid and direct detection of anthracene.

Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate

Ten mononuclear rare earth complexes of formula [La(btfa)3(H2O)2] (1), [La(btfa)3(4,4′-Mt2bipy)] (2), [La(btfa)3(4,4′-Me2bipy)2] (3), [La(btfa)3(5,5′-Me2bipy)2] (4), [La(btfa)3(terpy)] (5), [La(btfa)3(phen)(EtOH)] (6), [La(btfa)3(4,4′-Me2bipy)(EtOH)] (7), [La(btfa)3(2-benzpy)(MeOH)] (8), [Tb(btfa)3(4,4′-Me2bipy)] (9) and (Hpy)[Eu(btfa)4] (10), where btfa = 4,4,4-trifuoro-1-phenylbutane-1,3-dionato anion, 4,4′-Mt2bipy = 4,4′-dimethoxy-2,2′-bipyridine, 4,4′-Me2bipy = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-bipyridine, terpy = 2,2′:6′,2′-terpyridine, phen = 1,10-phenathroline, 2-benzpy = 2-(2-pyridyl)benzimidazole, Hpy = pyridiniumH+ cation) have been synthesized and structurally characterized. The complexes display coordination numbers (CN) eight for 1, 2, 9, 10, nine for 5, 6, 7, 8 and ten for 3 and 4. The solid-state luminescence spectra of Tb-9 and Eu-10 complexes showed the same characteristic bands predicted from the Tb(III) and Eu(III) ions. The Overall Quantum Yield measured (ϕTOT) at the excitation wavelength of 371 nm for both compounds yielded 1.04% for 9 and up to 34.56% for 10.

Photoluminescence performance of green light emitting terbium (III) complexes with β-hydroxy ketone and nitrogen donor ancillary ligands

An efficient and cost-effective technique, solution precipitation approach is adopted to synthesize five bright green luminescent terbium (III) complexes by employing the main β-hydroxy ketone ligand, 2-hydroxy-4-ethoxyacetophenone, and ancillary ligands like bathophenanthroline, 5,6-dimethyl-1,10-phenanthroline, 1,10-phenanthroline, and 2,2-bipyridyl. The elemental compositions and binding mode of ligand to terbium (III) ion can be validated by using energy dispersive X-ray analysis, elemental analysis, Fourier transform infrared, and proton nuclear magnetic resonance spectroscopy. The complexes are thermally stable up to 158°C and possess the cubic shaped particles as confirmed by thermogravimetric analysis and scanning electron microscopic study, respectively. The band-gap energy (3.02-2.92 eV) of complexes is reckoned through diffuse reflectance spectra, which tailors them as potential candidates in the field of military radars. The photoluminescence studies unveil that the complexes exhibit the bright green luminescence corresponding to ⁵ D₄ → ⁷ F₅ transition of Tb³⁺ ion (548 nm) under the excitation wavelength of 395 or 397 nm. The Commission International de I'Eclairage chromaticity coordinates (x, y) and color purity substantiates the green emission of complexes. The energy transfer mechanism elucidates that the main ligand and ancillary ligands sensitize Tb³⁺ ion, which in turn enhances the luminescence efficiency of the emissive layer of white organic light emitting diodes. The results reveal that the complexes are considered as good contenders in the field of display devices and laser technology. Lastly, in vitro antimicrobial and antioxidant activity proclaim the potent antimicrobial and antioxidant actions of complexes via tube dilution and 2, 2-diphenyl-1-picrylhydrazyl assays, respectively.

Phenanthroline-A Versatile Ligand for Advanced Functional Polymeric Materials

The controlled incorporation of phenanthroline moieties into polymers is introduced, demonstrating their application as metal-ion complexing ligands for the construction of advanced macromolecular structures. Specifically, two phenanthroline-containing monomers based on acrylate and styrene functionalities, were synthesized. Each monomer was readily copolymerized with either N,N-dimethylacrylamide or styrene via nitroxide-mediated polymerization, resulting in narrowly distributed polar or non-polar copolymers. To demonstrate the versatility of the established polymer systems, the polar polymer was employed for transition metal induced single-chain nanoparticle formation, verified by diffusion-ordered NMR and UV/Vis spectroscopy. Furthermore, the non-polar polymer allows facile incorporation of lanthanide ions, creating luminescent metallo-polymers, in-depth characterized by advanced photophysical experiments and 2D NMR measurements.

Synthesis, Photoluminescence Behavior of Green Light Emitting Tb(III) Complexes and Mechanistic Investigation of Energy Transfer Process

A series of five new terbium(III) ion complexes with 4,4-difluoro-1-phenylbutane-1,3-dione (HDPBD) and anciliary ligands was synthesized. The composition and properties of complexes were analyzed by elemental analysis, IR, NMR, powder X-ray diffaraction, TG-DTG and photoluminescence spectroscopy. These complexes exhibited ligand sensitized green emission at 546 nm associated with ⁵D₄ → ⁷F₅ transitions of terbium ion in the emission spectra. The photoluminescence study manifested that the organic ligands act as antenna and facilitate the absorbed energy to emitting levels of Tb(III) ion efficiently. The enhanced luminescence intensity and decay time of ternary C2-C5 complexes observed due to synergistic effect of anciliary ligands. The CIE color coordinates of complexes came under the green region of chromaticity diagram. The mechanistic investigation of intramolecular energy transfer in the complexes was discussed in detail. These terbium(III) complexes can be thrivingly used as one of the green component in light emitting material and in display devices. Graphical Abstract Illustrate the sensitization process of the Tb ion and intramolecular energy transfer process in the Tb³⁺ complex.

Synthesis, photoluminescence and biological properties of terbium(III) complexes with hydroxyketone and nitrogen containing heterocyclic ligands

The ternary terbium(III) complexes [Tb(HDAP)3⋅biq], [Tb(HDAP)3⋅dmph] and [Tb(HDAP)3⋅bathophen] were prepared by using methoxy substituted hydroxyketone ligand HDAP (2-hydroxy-4,6-dimethoxyacetophenone) and an ancillary ligand 2,2-biquinoline or 5,6-dimethyl-1,10-phenanthroline or bathophenanthroline respectively. The ligand and synthesized complexes were characterised based on elemental analysis, FT-IR and (1)H NMR. Thermal behaviour of the synthesized complexes illustrates the general decomposition patterns of the complexes by thermogravimetric analysis. Photophysical properties such as excitation spectra, emission spectra and luminescence decay curves of the complexes were investigated in detail. The main green emitting peak at 548nm can be attributed to (5)D4→(7)F5 of Tb(3+) ion. Thus, these complexes might be used to make a bright green light-emitting diode for display purpose. In addition the in vitro antibacterial activities of HDAP and its Tb(III) complexes against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and antifungal activities against Candida albicans and Aspergillus niger are reported. The Tb(3+) complexes were found to be more potent antimicrobial agent as compared to the ligand. Among all these complexes, [Tb(HDAP)3⋅bathophen] exhibited excellent antimicrobial activity which proves its potential usefulness as an antimicrobial agent. Furthermore, in vitro antioxidant activity tests were carried out by using DPPH method which indicates that the complexes have considerable antioxidant activity when compared with the standard ascorbic acid.

Nucleotide/Tb3+ coordination polymer as a luminescent nanosensor: synthesis and sensing of iron(ii) in human serum

Lanthanide ions and nucleotides were used to design and prepare a kind of responsive luminescent nanosensor for iron ions through a self-assembly process.