Insights into the photoinduced anion translocation of donor-π-acceptor (ion) molecules.

By strategic design and synthesis of a new series of phosphonium salts (compounds 1-7[OTf]), where [OTf] stands for the trifluoromethanesulfonate anion, we performed comprehensive spectroscopic and dynamic studies on the photoinduced anion migration in toluene. Our aim is to probe if the anion migration is associated with an intrinsic barrier or is barrier-free. After the occurrence of excited-state intramolecular charge transfer (ESICT) in 1-7, the charge redistribution of the cation triggers the translocation of the counter anion [OTf], resulting in emission spectral temporal evolution.

Triflic acid-promoted post-Ugi condensation for the assembly of 2,6-diarylmorpholin-3-ones.

We report a two-step one-pot synthesis of the 2,6-diarylmorpholin-3-one core based on the Ugi reaction of 2-oxoaldehyde with 2-hydroxycarboxylic acid, a primary amine and -butyl isocyanide followed by a triflic acid-promoted intramolecular condensation accompanied by the loss of the isocyanide-originated amide moiety. The overall transformation proceeds with complete retention of stereoconfiguration at the 2-hydroxycarboxylic acid-derived chiral center, allowing the target morpholin-3-ones to be obtained in an enantiopure form. Subsequent double bond hydrogenation and amide reduction allow the degree of unsaturation to be reduced, providing a convenient entry to the -2,6-diphenylmorpholine motif.

A [2.2]Isoindolinophanyl-Based Carbene (iPC) Ligand: Synthesis, Electronic and Photophysical Properties, and Application in Photocatalysis.

Cyclic amino(alkyl) and cyclic amino(aryl) carbenes (cAACs/cAArCs) have been established as very useful ligands for catalytic and photonic applications of transition metal complexes. Herein, we describe the synthesis of a structurally related sterically demanding, electrophilic [2.2]isoindolinophanyl-based carbene (iPC) that bears a [2.

Identification of a new HLA-B allele, HLA-B*35:594.

A novel HLA-B*35 allele, officially designated HLA-B*35:594, was identified by next-generation sequencing.

Synthesis, Structural Characterization, and Phosphorescence Properties of Trigonal Zn(II) Carbene Complexes.

The sterically demanding -heterocyclic carbene ITr (,'-bis(triphenylmethyl)imidazolylidene) was employed for the preparation of novel trigonal zinc(II) complexes of the type [ZnX(ITr)] [X = Cl (), Br (), and I ()], for which the low coordination mode was confirmed in both solution and solid state. Because of the atypical coordination geometry, the reactivity of was studied in detail using partial or exhaustive halide exchange and halide abstraction reactions to access [ZnLCl(ITr)] [L = carbazolate (), 3,6-di--butyl-carbazolate (), phenoxazine (), and phenothiazine ()], [Zn(bdt)(ITr)] (bdt = benzene-1,2-dithiolate) (), and cationic [Zn(μ-X)(ITr)][B(CF)] [X = Cl (), Br (), and I ()], all of which were isolated and structurally characterized. Importantly, for all complexes , the trigonal coordination environment of the Zn ion is maintained, demonstrating a highly stabilizing effect due to the steric demand of the ITr ligand, which protects the metal center from further ligand association.

Structural Control of Highly Efficient Thermally Activated Delayed Fluorescence in Carbene Zinc(II) Dithiolates.

Luminescent metal complexes based on earth abundant elements are a valuable target to substitute 4d/5d transition metal complexes as triplet emitters in advanced photonic applications. Whereas Cu complexes have been thoroughly investigated in the last two decades for this purpose, no structure-property-relationships for efficient luminescence involving triplet excited states from Zn complexes are established. Herein, we report on the design of monomeric carbene zinc(II) dithiolates (CZT) featuring a donor-acceptor-motif that leads to highly efficient thermally activated delayed fluorescence (TADF) with for Zn compounds unprecedented radiative rate constants k =1.

Sulfate-induced large amplitude conformational change in a Solomon link.

A doubly-interlocked [2]catenane - or Solomon link - undergoes a complex conformational change upon addition of sulfate in methanol. This transformation generates a single pocket where two SO anions bind through multiple hydrogen bonds and electrostatic interactions. Despite the close proximity of the two anions, binding is highly cooperative.

Fast and Tunable Phosphorescence from Organic Ionic Crystals.

Crystalline diphosphonium iodides [MeR P-spacer-R Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λ values from 550 to 880 nm) and intensities (Φ reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions.

From Terminal to Spiro-Phosphonium Acceptors, Remarkable Moieties to Develop Polyaromatic NIR Dyes.

Phosphonium-based compounds gain attention as promising photofunctional materials. As a contribution to the emerging field, we present a series of donor-acceptor ionic dyes, which were constructed by tailoring phosphonium (A) and extended π-NR (D) fragments to an anthracene framework. The alteration of the π-spacer of electron-donating substituents in species with terminal - PPh Me groups exhibits a long absorption wavelength up to λ =527 nm in dichloromethane and shifted the emission to the near-infrared (NIR) region (λ=805 nm for thienyl aniline donor), although at low quantum yield (Φ<0.

An Air- and Moisture-stable Zinc(II) Carbene Dithiolate Dimer Showing Fast Thermally Activated Delayed Fluorescence and Dexter Energy Transfer Catalysis.

A dimeric Zn carbene complex featuring bridging and chelating benzene-1,2-dithiolate ligands is highly stable towards air and water. The donor-Zn-acceptor structure leads to visible light emission in the solid state, solution and polymer matrices with λ between 577-657 nm and, for zinc(II) complexes, unusually high radiative rate constants for triplet exciton decay of up to k =1.5×10  s at room temperature.

Identification of two novel HLA alleles, HLA-A*03:344:02 and -DQB1*04:02:24 in Russian individuals.

The novel HLA alleles HLA-A*03:344:02 and -DQB1*04:02:24 have synonymous mutations.

Kinetic Model and Experiment for Self-Ignition of Triethylaluminum and Triethylborane Droplets in Air.

Triethylaluminum Al(CH), TEA, and triethylborane, B(CH), TEB, are transparent, colorless, pyrophoric liquids with boiling points of approximately 190 °C and 95 °C, respectively. Upon contact with ambient air, TEA, TEB, as well as their mixtures and solutions, in hydrocarbon solvents, ignite. They can also violently react with water.

Two-Fold Intramolecular Phosphacyclization: From Fluorescent Diphosphapyrene Salts to Pentavalent Derivatives.

The synthesis of π-extended pyrene-based luminescent compounds containing two six-membered phosphacycles has been realized through a two-step synthesis. It involves a Cu(II)-mediated double cyclization of tertiary diphosphane derivatives to afford dicationic molecules with quaternized phosphorus centers. Subsequent transformation of diphosphonium species into the corresponding P-oxide derivatives has been successfully achieved through Pd(0)-assisted cleavage of the P-Ph bonds, which opens a promising way for the functionalization of polyaromatic P-systems.

Ultra-Long Lived Luminescent Triplet Excited States in Cyclic (Alkyl)(amino)carbene Complexes of Zn(II) Halides.

The high element abundance and d electron configuration make Zn -based compounds attractive candidates for the development of novel photoactive molecules. Although a large library of purely fluorescent compounds exists, emission involving triplet excited states is a rare phenomenon for zinc complexes. We have investigated the photophysical and -chemical properties of a series of dimeric and monomeric Zn halide complexes bearing a cyclic (alkyl)(amino)carbene (cAAC) as chromophore unit.

Multiple Emission of Phosphonium Fluorophores Harnessed by the Pathways of Photoinduced Counterion Migration.

In the emerging field of intramolecular charge transfer induced counterion migration, we report the new insights into photophysical features of luminescent donor-acceptor phosphonium dyes (D-π-) A [X ] (π=-(C H ) -). The unique connectivity of the phosphorus atom affords multipolar molecules with a variable number of arms and the electronic properties of the acceptor group. In the ion-paired form, the transition from dipolar to quadrupolar configuration enhances the low energy migration-induced band by providing the additional pathways for anion motion.

Linear Carbene Pyridine Copper Complexes with Sterically Demanding ,'-Bis(trityl)imidazolylidene: Syntheses, Molecular Structures, and Photophysical Properties.

The sterically demanding carbene ITr ('-bis(triphenylmethyl)imidazolylidene) was used as a ligand for the preparation of luminescent copper(I) complexes of the type [(ITr)Cu(R-pyridine/R'-quinoline)]BF (R = H, 4-CN, 4-CHO, 2,6-NH, and R' = 8-Cl, 6-Me). The selective formation of linear, bis(coordinated) complexes was observed for a series of pyridine and quinoline derivatives. Only in the case of 4-cyanopyridine a one-dimensional coordination polymer was formed, in which the cyano group of the cyanopyridine ligand additionally binds to another Cu atom in a bridging manner, thus leading to a trigonal planar coordination environment.

Two new HLA alleles, HLA-B*18:200 and HLA-C*04:435 detected in Russian donors.

Two novel alleles, HLA-B*18:200 and HLA-C*04:435, are characterized.

The distinct O quenching mechanism between fluorescence and phosphorescence for dyes adsorbed on silica gel.

We herein aim to probe the emission quenched by O2 on silica gel. Our special focus is on the O2 quenching of the fluorescence of a series of organic D-π-A phosphonium compounds 1-3. The results show that the O2 quenching rate constants for the fluorescence of 1-3 are on the order of 1010 M-1 s-1, which are nearly on the same order as those measured for 1-3 and common organic compounds in solution.

Diffraction on periodic surface microrelief grating with positive or negative optical anisotropy.

Diffraction optical elements (DOE) are important elements of systems for images displaying and processing. The DOE materials with both positive and negative birefringence enhance performances and functionality of such systems. We have calculated the diffraction of rays passing through optically anisotropic grating with surface microrelief by using our original Exedeep software.

The novel HLA-B*57:135 allele was identified during high-resolution HLA typing.

HLA-B*57:135 differs from HLA-B*57:01:01:01 by one nucleotide exchange at position 692 (G->A).

Cationic Organophosphorus Chromophores: A Diamond in the Rough among Ionic Dyes.

Tunable electron-accepting properties of the cationic phosphorus center, its geometry and unique preparative chemistry that allows combining this unit with diversity of π-conjugated motifs, define the appealing photophysical and electrochemical characteristics of organophosphorus ionic chromophores. This Minireview summarizes the achievements in the synthesis of the π-extended molecules functionalized with P-cationic fragments, modulation of their properties by means of structural modification, and emphasizes the important effect of cation-anion interactions, which can drastically change physical behavior of these two-component systems.

Detection of an HLA-DQB1*06 variant, HLA-DQB1*06:364, in a Russian individual.

One nucleotide change in position 216 of HLA-DQB1*06:02 result in a novel allele, HLA-DQB1*06:364.

A Facile Molecular Machine: Optically Triggered Counterion Migration by Charge Transfer of Linear Donor-π-Acceptor Phosphonium Fluorophores.

The D-π-A type phosphonium salts in which electron acceptor (A=- PR ) and donor (D=-NPh ) groups are linked by polarizable π-conjugated spacers show intense fluorescence that is classically ascribed to excited-state intramolecular charge transfer (ICT). Unexpectedly, salts with π=-(C H ) - and -(C H C H )- exhibit an unusual dual emission (F and F bands) in weakly polar or nonpolar solvents. Time-resolved fluorescence studies show a successive temporal evolution from the F to F emission, which can be rationalized by an ICT-driven counterion migration.