Perdeuterated 2,2′-Bipyridine-6,6′-dicarboxylate: An Extremely Efficient Sensitizer for Thulium Luminescence in Solution

Structural Features of Eu3+ and Tb3+-Bipyridinedicarboxamide Complexes

Photoluminescent lanthanide complexes of Eu³⁺ and Tb³⁺ as central atoms and N⁶,N⁶'-diisopropyl-[2,2'-bipyridine]-6,6'-dicarboxamide as ligand were synthesized. The structure of these complexes was established by single-crystal X-ray diffraction, mass spectrometry, ¹H and ¹³C nuclear magnetic resonance, ultraviolet-visible, infrared spectroscopy, and thermogravimetry. Bipyridinic ligands provide formation of coordinatively saturated complexes of lanthanide ions and strong photoluminescence (PL). The Eu³⁺- and Tb³⁺-complexes exhibit PL emission in the red and green regions observed at a 340 nm excitation. The quantum yield for the complexes was revealed to be 36.5 and 12.6% for Tb³⁺- and Eu³⁺-complexes, respectively. These lanthanide compounds could be employed as photoluminescent solid-state compounds and as emitting fillers in polymer (for example, polyethylene glycol) photoluminescent materials.

Silicone Materials for Flexible Optoelectronic Devices

Polysiloxanes and materials based on them (silicone materials) are of great interest in optoelectronics due to their high flexibility, good film-forming ability, and optical transparency. According to the literature, polysiloxanes are suggested to be very promising in the field of optoelectronics and could be employed in the composition of liquid crystal devices, computer memory drives organic light emitting diodes (OLED), and organic photovoltaic devices, including dye synthesized solar cells (DSSC). Polysiloxanes are also a promising material for novel optoectronic devices, such as LEDs based on arrays of III-V nanowires (NWs). In this review, we analyze the currently existing types of silicone materials and their main properties, which are used in optoelectronic device development.

Rare Earth Complexes of Europium(II) and Substituted Bis(pyrazolyl)borates with High Photoluminescence Efficiency

Rare earth europium(II) complexes based on d-f transition luminescence have characteristics of broad emission spectra, tunable emission colors and short excited state lifetimes, showing great potential in display, lighting and other fields. In this work, four complexes of Eu(II) and bis(pyrazolyl)borate ligands, where pyrazolyl stands for pyrazolyl, 3-methylpyrazolyl, 3,5-dimethylpyrazolyl or 3-trifluoromethylpyrazole, were designed and synthesized. Due to the varied steric hindrance of the ligands, different numbers of solvent molecules (tetrahydrofuran) are participated to saturate the coordination structure. These complexes showed blue-green to yellow emissions with maximum wavelength in the range of 490-560 nm, and short excited state lifetimes of 30-540 ns. Among them, the highest photoluminescence quantum yield can reach 100%. In addition, when the complexes were heated under vacuum or nitrogen atmosphere, they finally transformed into the complexes of Eu(II) and corresponding tri(pyrazolyl)borate ligands and sublimated away.

Complexes of Ce(III) and Bis(pyrazolyl)borate Ligands: Synthesis, Structures, and Luminescence Properties

Luminescent cerium(III) complexes based on the d-f transition have characteristics of broad emission spectra, tunable emission colors, and short excited state lifetimes, showing potential applications in display, lighting, and other fields. Thus it is important to construct luminescent Ce(III) complexes with high photoluminescence efficiency and good stability. In this work, five Ce(III) complexes with dihydrobis(pyrazolyl)borate or diphenylbis(pyrazolyl)borate ligands, where pyrazolyl stands for pyrazolyl, 3-methylpyrazolyl, or 3,5-dimethylpyrazolyl, were designed and synthesized, showing emission colors from deep blue to yellow with a maximum wavelength in the range of 390-560 nm, short excited state lifetimes of 30-80 ns, and photoluminescence quantum yields exceeding 75% in solid powder. By comparing these complexes, it is found that higher photoluminescence efficiency and better thermal/air stability could be achieved in the complexes with dihydrobis(pyrazolyl)borate ligands.

Deep-blue emitting cerium(III) complexes with tris(pyrazolyl)borate and triflate ligand

Red, green and blue emitting materials, the three-primary colors, are very important in lighting and display. Red-emitting Eu(III) complexes and green-emitting Tb(III) complexes exhibit high color purity and photoluminescence (PL)...

Electron transfer pathways in photoexcited lanthanide(iii) complexes of picolinate ligands

A series of luminescent lanthanide(iii) complexes consisting of 1,4,7-triazacyclononane frameworks and three secondary amide-linked carbostyril antennae were synthesised. The metal binding sites were augmented with two pyridylcarboxylate donors yielding octadentate ligands. The antennae carried methyl, methoxymethyl or trifluoromethyl substituents in their 4-positions, allowing for a range of excited state energies and antenna electronic properties. The ¹H NMR spectra of the Eu(iii) complexes were found to be analogous to each other. Similar results were obtained in the solid-state by single-crystal X-ray crystallography, which showed the structures to have nine-coordinate metal ions with heavily distorted tricapped trigonal prismatic geometries. Steady-state and time-resolved luminescence spectroscopy showed that the antennae could sensitize both Tb(iii) and Eu(iii), however, quantum yields were lower than in other octadentate complexes lacking pyridylcarboxylate. Complexes with more electron-poor pyridines were less emissive even when equipped with the same antenna. The oxidation and reduction potentials of the antennae and the pyridinecarboxylates, respectively, were determined by cyclic voltammetry. The obtained values were consistent with electron transfer from the excited antenna to the pyridine providing a previously unexplored quenching pathway that could efficiently compete with energy transfer to the lanthanide. These results show the crucial impact that photophysically innocent ligand binding sites can have on lanthanide luminescence.

Some aspects of the formation and structural features of low nuclearity heterometallic carboxylates

Heterometallic carboxylate complexes are of paramount interest in pure and applied coordination chemistry. Despite that plurality of such type compounds have been published to date, synthetic aspects of their chemistry often remain in the shadow of intriguing physical properties manifesting by these species. Present review summarizes reliable data on direct synthesis of low nuclearity molecular compounds as well as coordination polymers on their base with carboxylate-bridged {M2Mg} (M = Co2+, Ni2+, Cd2+), {M2Li2} (M = Co2+, Ni2+, Zn2+, VO2+), {M2Ln2} and {M2Ln} (M = Cu2+, Zn2+, Co2+) metal cores. Structural features and stabilization factors are considered and principal outcomes are confirmed by quantum-chemical calculations. Particular attention is paid to consideration of ligand-exchange reactions that allow controllable modification of heterometallic metal core under mild conditions giving diverse molecular complexes with modified ligand environment or Metal-Organic Frameworks with permanent porosity.

Efficient Ytterbium Near-Infrared Luminophore Based on a Nondeuterated Ligand

A novel molecular ytterbium complex is reported with a new tetradentate ligand based on the 2,2'-bipyridine-6,6'-dicarboxylic acid scaffold. The photophysical properties are investigated, especially with respect to near-infrared luminescence. The ytterbium complex shows a rather high absolute luminescence quantum yield of Φ = 3.0% and a luminescence lifetime of τ_obs = 72 μs at room temperature in CD₃OD solution.

Lanthanide-based luminescence biolabelling

Multiplexing, time-resolution, FRET…lanthanide-based biolabels reveal exceptional spectroscopic properties for bioanalytical applications.

Selective pyridine recognition by an imidazole dicarboxylate-based 3D cadmium(ii) MOF

One newly prepared 3D polymer (1) composed of left- and right-handed helices containing [Cd₈(p-ClPhHIDC)₁₂(4,4′-bipy)₆] cages shows selective pyridine recognition, with a visual colour change from pearl to pink under ultraviolet irradiation.

Exploring supramolecular assembly and luminescent behavior in a series of RE-p-chlorobenzoic acid-1,10-phenanthroline complexes

Eleven new rare earth (RE)-p-chlorobenzoic acid-1,10-phenanthroline complexes have been synthesized and their structural, supramolecular and luminescent properties have been explored.