Europium and Terbium Benzene-1,2,4,5-Tetracarboxylates: Synthesis Peculiarities, Crystal Structures, and Luminescent Thermometry up to 400 °C.

In this study, we successfully obtained for the first time a luminescent organic-based thermometer that exhibits high reproducibility, stability, and functionality up to 400 °C. Our approach involved the selection of novel highly emissive and thermally stable MOFs KEu(btec)(HO) and dehydrated KTb(btec), btec = benzene-1,2,4,5-tetracarboxylate, along with the highly thermally stable copolyimide P84 = 80% methylphenylene-diamine + 20% methylene as the matrix; luminescence lifetime was selected as a temperature-dependent parameter due to its versatility in diverse environmental conditions. Synthesis peculiarities were studied for various lanthanide benzene-1,2,4,5-tetracarboxylates, and the crystal structures of KEu(btec)(HO) and KTb(btec) were determined by Rietveld refinement from powder X-ray diffraction data.

Double Spin with a Twist: Synthesis and Characterization of a Neutral Mixed-Valence Organic Stable Diradical.

A convenient design strategy opens access to neutral open-shell mixed-valence species the redox transformation of charged stable precursors, , the spiro-fused borate anions. We have implemented this strategy for the synthesis of the first neutral mixed-valence diradical: two neutral mixed-valence radical fragments were assembled a twisted biphenyl bridge. The diradical is a crystalline solid obtained in almost quantitative yield by using a facile synthetic procedure.

Inductive detection of temperature-induced magnetization dynamics of molecular spin systems.

The development and technological applications of molecular spin systems require versatile experimental techniques to characterize and control their static and dynamic magnetic properties. In the latter case, bulk spectroscopic and magnetometric techniques, such as AC magnetometry and pulsed electron paramagnetic resonance, are usually employed, showing high sensitivity, wide dynamic range, and flexibility. They are based on creating a nonequilibrium state either by changing the magnetic field or by applying resonant microwave radiation.

The increase of europium-based OLED luminance through reducing the excited state lifetime by mixed-ligand complex formation.

An approach to the luminance increase of the europium-based OLED is proposed through the formation of the mixed-ligand complex. The introduction of two diverse anionic ligands around one europium ion forming a mixed-ligand complex is confirmed by powder X-ray diffraction, H and F NMR spectroscopy, MALDI MS spectroscopy, and luminescence spectroscopy. A decrease in the symmetry of the coordination environment leads to a 50% reduction of the lifetime of the excited state.

Structural Significance of Hydrophobic and Hydrogen Bonding Interaction for Nanoscale Hybridization of Antiseptic Miramistin Molecules with Molybdenum Disulfide Monolayers.

This paper reports an easy route to immobilize the antiseptic drug miramistin (MR) molecules between the sheets of molybdenum disulfide, known for excellent photothermal properties. Two hybrid layered compounds (LCs) with regularly alternating monolayers of MR and MoS, differing in thickness of organic layer are prepared and studied by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations and quantum theory of atoms in molecules (QTAIM) topological analysis. The obtained structural models elucidate the noncovalent interaction network of MR molecules confined in the two-dimensional spacing surrounded by sulfide sheets.

Solution-Processed OLED Based on a Mixed-Ligand Europium Complex.

An approach to increase the efficiency of europium-based OLEDs was proposed through the formation of a mixed-ligand complex. The design of a series of europium complexes, together with an optimization of the solution deposition, including the host selection, as well as the variation of the solvent and deposition parameters, resulted in a noticeable increase in OLED luminance. As a result, the maximum luminance of the Eu-based OLED reached up to 700 cd/m, which is one of the highest values for an Eu-based solution-processed OLED.

Change in the Electronic Structure of the Cobalt(II) Ion in a One-Dimensional Polymer with Flexible Linkers Induced by a Structural Phase Transition.

A new 1D-coordination polymer [Co(Piv)(NH(CH)NH)] (, Piv is MeCCO anion) was obtained, the mononuclear fragments {Co(OCR)} within which are linked by μ-bridged molecules of hexamethylenediamine (NH(CH)NH). For this compound, two different monoclinic 2/ (α-) and 2/ (β-) phases were found at room temperature by single-crystal X-ray diffraction analysis, with a similar structure of chains and their packages in unit cells. The low-temperature phase (γ-) of crystal at 150 K corresponds to the triclinic space group -1.

A 50% increase in the terbium-based OLED luminance through reducing the excited-state lifetime due to the introduction of gold nanoparticles.

An increase in the efficiency for a terbium-based OLED was achieved by introducing gold nanoparticles into the PEDOT:PSS hole injection layer and was mainly due to the improvement in carrier injection and the reduction of the excited-state lifetime. The introduction of plasmon-resonant gold nanoparticles resulted in a 50% increase in the Tb(czb)TDZP luminance, which reached 480 cd m and is the highest result for OLEDs based on aromatic carboxylates.

Field-Induced Slow Magnetic Relaxation in Co Cyclopropane-1,1-dicarboxylates.

New Co substituted malonate field-induced molecular magnets {[RbCo(cpdc)(HO)]∙6HO} () and [CsCo(cpdc)(HO)] () (where cpdc stands for cyclopropane-1,1-dicarboxylic acid dianions) were synthesized. Both compounds contain mononuclear bischelate fragments {Co(cpdc)(HO)} where the quasi-octahedral cobalt environment (CoO) is complemented by water molecules in apical positions. The alkali metal atoms play the role of connectors between the bischelate fragments to form 3D and 2D polymeric structures for and , respectively.

NIR luminescence thermometers based on Yb-Nd coordination compounds for the 83-393 K temperature range.

Multimetallic neodymium-ytterbium-gadolinium compounds with 9-anthracenate and 9-acridinate anions were tested in order to create the first luminescent thermometer for elevated temperatures. High luminescence intensity and high signal resolution were reached thanks to the concentration quenching elimination due to the partial substitution of the emitting ions with Gd. As a result, NIR emitting materials for luminescence thermometry in the wide temperature range (83-393 K) based on lanthanide coordination compounds (CCs) were obtained.

Record efficiency of 1000 nm electroluminescence from a solution-processable host-free OLED.

New ytterbium complexes K(Solv)[Yb(L)] (Solv = ethanol and/or water) with 2-tosylaminobenzylidene-aryloylhydrazones (HL, aryloyl = benzoyl; HL, aryloyl = 2-naphthoyl) demonstrated high solubility and hole mobility ( 2.6 × 10 cm V s), while their electron mobility and PLQY were different. The substitution of a benzoyl substituent with naphthoyl resulted in a significant increase of the electron mobility (6.

Europium complexes with dinitropyrazole: unusual luminescence thermal behavior and irreversible temperature sensing.

Europium 3,5-dinitropyrazole complexes demonstrate an unusual luminescence behavior upon heating, there is a noticeable increase of the luminescence intensity beyond a temperature of 200 °C. We propose and successfully demonstrate the possibility of using this phenomenon for sensing overheating above this temperature. An on/off ratio of 37 is reached.

Identifying lifetime as one of the key parameters responsible for the low brightness of lanthanide-based OLEDs.

OLEDs based on lanthanide complexes have decisive optical advantages but are hampered by low brightness. Despite the efforts to optimize several parameters such as quantum yield and charge carrier mobility, there seems to be another key parameter that hinders their performances. Experimental data are therefore collected for mixed-ligand europium complexes with bathophenanthroline and different classes of anionic ligands and screened to identify the key parameter responsible for this situation, which turns out to be the long lifetime of their excited states.

Eu(tta)DPPZ-based organic light-emitting diodes: spin-coating . vacuum-deposition.

The effect of the emission layer deposition method on the characteristics of OLEDs was studied on the example of the europium mixed-ligand complex Eu(tta)3DPPZ (tta: 2-thenoyltrifluoroacetone, DPPZ: dipyrido[3,2-a:2'c,3'c-c]phenazine). The maximum brightnesses of both OLEDs almost coincided, though OLED based on the spin-coated layer operated at lower voltages. The reason for that was the higher density and smoothness of the solution-processed layer.

Generation of a Hetero Spin Complex from Iron(II) Iodide with Redox Active Acenaphthene-1,2-Diimine.

The reaction of the redox active 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) and iron(II) iodide in acetonitrile led to a new complex [(dpp-BIAN)FeI] (). Molecular structure of was determined by the single crystal X-ray diffraction analysis. The spin state of the iron cation in complex at room temperature and the magnetic behavior of in the temperature range of 2-300 K were studied using Mossbauer spectroscopy and magnetic susceptibility measurements, respectively.

Highly NIR-emitting ytterbium complexes containing 2-(tosylaminobenzylidene)-N-benzoylhydrazone anions: structure in solution and use for bioimaging.

Solution behaviour in DMSO using 1D and 2D NMR spectroscopy was performed for lanthanide complexes Ln(L)(HL) and Ln(HL)Cl, containing non-macrocyclic 2-(tosylamino)-benzylidene-N-benzoylhydrazone (HL), and the structure of [Yb(L)] cation in solution was determined. Based on the NMR data, the possibility to obtain novel complexes containing [Ln(L)] was predicted, which was successfully synthesized, and the crystal structure of K(CHOH)[Yb(L)] was determined. Thanks to its high quantum yield of NIR luminescence (1.

Novel Polymorph of Favipiravir-An Antiviral Medication.

Various solid forms of pharmaceutically important compounds exhibit different physical properties and bioactivity; thus, knowledge of the structural landscape and prediction of spontaneous polymorph transformations for an active pharmaceutical ingredient is of practical value for the pharmaceutical industry. By recrystallization from ethyl acetate, a novel polymorph of 6-fluoro-3-hydroxypyrazine-2-carboxamide (trademark favipiravir, RNA polymerase inhibitor) was obtained and characterized using differential scanning calorimetry (DSC), infra-red spectroscopy and powder X-ray diffraction (XRD) analysis. The favipiravir molecule in two polymorphs realizes similar H-bonding motifs, but the overall H-bonded networks differ.

Complexes of Cobalt(II) Iodide with Pyridine and Redox Active 1,2-Bis(arylimino)acenaphthene: Synthesis, Structure, Electrochemical, and Single Ion Magnet Properties.

Complexes [(dpp-BIAN)CoI]·MeCN () and [(Py)CoI] () were synthesized by the reaction between cobalt(II) iodide and 1,2-bis(2,6-diisopropylphenylimino)acenaphthene (dpp-BIAN) or pyridine (Py), respectively. The molecular structures of the complexes were determined by X-ray diffraction. The Co(II) ions in both compounds are in a distorted tetrahedral environment (CoNI).

Probing Hydrogen-Bonding Properties of a Negatively Charged MoS Monolayer by Powder X-ray Diffraction and Density Functional Theory Calculations.

The contributions of various noncovalent interactions in stabilization of the assembled and delaminated MoS-hexamethylenetetramine (HMTA)-layered compound resulted from the assembly of protonated HMTA molecules and negatively charged 1T-MoS monolayers have been considered on the basis of powder X-ray diffraction pattern modeling, density functional theory calculations, and atoms in molecules quantum theory analysis. The structure with HMTA cations involved in NH···S bonding with MoS layers was concluded to be more advantageous than the alternative one with NH···N bonding between the cations. Delamination was demonstrated to essentially influence the hierarchy of interactions and leads to significant strengthening of the NH···S hydrogen bond established between HMTA and the MoS monolayer surface.

On the development of a new approach to the design of lanthanide-based materials for solution-processed OLEDs.

The targeted design of lanthanide-based emitters for solution-processed organic light-emitting diodes (OLEDs) resulted in obtaining an NIR OLED with one of the highest efficiencies among ytterbium-based solution-processed OLEDs (30 μW W-1). The design was aimed at the combination of high luminescence efficiency with solubility and charge carrier mobility. The latter was achieved thanks to the introduction of the purposefully selected neutral ligands, which combine electron mobility and the ability to sensitize lanthanide luminescence.

One-pot five-component high diastereoselective synthesis of polysubstituted 2-piperidinones from aromatic aldehydes, nitriles, dialkyl malonates and ammonium acetate.

A novel five-component diastereoselective synthesis of polysubstituted 2-piperidinones is reported. The Knoevenagel condensation-Michael addition-Mannich cascade of two equivalents of aromatic aldehydes, nitriles, dialkyl malonates and ammonium acetate or aqueous ammonia in alcohols provides convenient access to alkyl (3SR,4RS,6SR)-5,5-dicyano-2-oxo-4,6-diarylpiperidine-3-carboxylates with three stereocenters in 52-90% or dialkyl (2SR,3RS,4RS,5SR)-2,4-diaryl-3-cyano-6-oxopiperidine-3,5-dicarboxylates with four stereocenters in 38-88%. The formation of products was highly stereoselective, with only one diastereomer formed.

Pot, atom and step economic (PASE) assembly of salicylaldehydes, malononitrile dimer and 4-hydroxypyridine-2(1H)-ones into medicinally relevant 5H-chromeno[2,3-b]pyridine scaffold.

The new multicomponent reaction (MCR) has been found: one-pot selective and efficient formation of the new 5-(4-hydroxy-2-oxo-1,2-dihydropyridin-3-yl)-substituted 5H-chromeno[2,3-b]pyridines in 61-97% yields directly from simple and easily available salicylaldehydes, malononitrile dimer and 4-hydroxypyridine-2(1H)-ones in small amount of pyridine-ethanol catalyst/solvent system. This complex "domino" transformation includes Knoevenagel condensation of salicylaldehyde with malononitrile dimer, Michael addition of 4-hydroxypyridine-2(1H)-one, double Pinner-type reaction cyclization and isomerization with following protonation. This facile multicomponent process opens a new way to 5-(4-hydroxy-2-oxo-1,2-dihydropyridin-3-yl)-substituted 5H-chromeno[2,3-b]pyridine systems, which are promising compounds for the treatment for human inflammatory TNFα-mediated diseases and different biomedical applications.

Interplay of noncovalent interactions in antiseptic quaternary ammonium surfactant Miramistin.

The molecular and crystal structure of the widely used antiseptic benzyldimethyl{3-[(1-oxotetradecyl)amino]propyl}ammonium chloride monohydrate (Miramistin, MR), CHNO·Cl·HO, was determined by a single-crystal X-ray diffraction study and analyzed in the framework of the QTAIM (quantum theory of atoms in molecules) approach using both periodic and molecular DFT (density functional theory) calculations. The various noncovalent intermolecular interactions of different strengths were found to be realized in the hydrophilic parts of the crystal packing (i.e.

Remarkable high efficiency of red emitters using Eu(iii) ternary complexes.

We have synthesized Eu(iii) ternary complexes possessing record photoluminescence yields up to 90%. This high luminescence performance resulted from the absence of quenching moieties in the Eu coordination environment and an efficient energy transfer between ligands, combined with a particular symmetry of the coordination environment.

High diastereoselective amine-catalyzed Knoevenagel-Michael-cyclization-ring-opening cascade between aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones.

A highly diastereoselective three-component cascade reaction among aromatic aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones takes place under the catalysis of triethylamine, providing (3SR,4SR)-4-aryl-3-[(E)-(hydroxyimino)(aryl)methyl]-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-diones in 45-85% yields. The transformation presumably proceeds through a sequential cascade of Knoevenagel/Michael-addition/cyclization/ring-opening reactions. This process was carried out in green media (EtOH/water, 1:1-1:3) at reflux.