One-pot Synthesis and Photophysical Studies of Α-cycloamino-substituted 5-aryl-2,2'-bipyridines.

A series of α-cycloamine substituted 2,2'-bipyridines 3ae'-3ce' was obtained via the one-pot approach based on ipso-substitution of a cyano-group in 1,2,4-triazines, followed by aza-Diels-Alder reaction in good yields. Photophysical properties, including fluorosolvatochromism, were studied for 3ae'-3ce' and were compared with α-unsubstituted 2,2'-bipyridines. In addition, dipole moments differences in ground and excited states were calculated by both Lippert-Mataga equation and DFT studies and were compared to each other.

Triethylamine-Promoted Oxidative Cyclodimerization of 2-Azirine-2-carboxylates to Pyrimidine-4,6-dicarboxylates: Experimental and DFT Study.

An unprecedented oxidative cyclodimerization reaction of 2-azirine-2-carboxylates to pyrimidine-4,6-dicarboxylates under heating with triethylamine in air is described. In this reaction, one azirine molecule undergoes formal cleavage across the C-C bond and another across the C=N bond. According to the experimental study and DFT calculations, the key steps of the reaction mechanism include nucleophilic addition of ,-diethylhydroxylamine to an azirine to form an (aminooxy)aziridine, generation of an azomethine ylide, and its 1,3-dipolar cycloaddition to the second azirine molecule.

Investigating the Coating Effect on Charge Transfer Mechanisms in Composite Electrodes for Lithium-Ion Batteries.

The performance of lithium-ion batteries (LIBs) relies on the characteristics of the cathode material, including both intentionally applied coatings and naturally formed surface layers or binder adhesion. This study investigated the influence of the ion-permeable surface fraction, distribution, and characteristics of the coating on the performance of a lithium iron phosphate (LFP) electrode material. We developed an extended Newman-type half-cell model and examined the impact of coating parameters on the galvanostatic discharge curves of the LFP electrode material.

Insight into the Temperature-Dependent Canting of 4f Magnetic Moments from 4f Photoemission.

The orientation of the 4f moments offers an additional degree of freedom for engineering the spin-related properties in spintronic nanostructures of lanthanides. Yet, precise monitoring of the direction of magnetic moments remains a challenge. Here, on the example of the antiferromagnets HoRhSi and DyRhSi, we investigate the temperature-dependent canting of the 4f moments near the surface.

Modification Approaches of Polyphenylene Oxide Membranes to Enhance Nanofiltration Performance.

Presently, water pollution poses a serious threat to the environment; the removal of organic pollutants from resources, especially dyes, is very important. Nanofiltration (NF) is a promising membrane method to carry out this task. In the present work, advanced supported poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) membranes were developed for NF of anionic dyes using bulk (the introduction of graphene oxide (GO) into the polymer matrix) and surface (the deposition of polyelectrolyte (PEL) layers by layer-by-layer (LbL) technique) modifications.

Spray-Drying Hydrophobic Cellulose Nanocrystal Coatings with Degradable Biocide Release for Marine Antifouling.

With increasing awareness about the ecological environment, increased attention has been paid to the application of eco-friendly materials in the field of marine antifouling. In this work, a novel coating having good mechanical strength and static marine antifouling characteristics was fabricated using cellulose nanocrystals (CNCs) as the skeleton material, with in situ growth of SiO as the basic superhydrophobic material and introducing hexadecyl trimethyl ammonium bromide (CTAB) and 4-bromo2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (Econea) into the coating. Due to the high strength and rod structure of CNCs, the coating maintained super-hydrophobicity after 50 cycles of abrasion tests.

Green synthesis and characterization of iron oxide nanoparticles for the removal of heavy metals (Cd and Ni) from aqueous solutions with Antimicrobial Investigation.

Clove and green Coffee (g-Coffee) extracts were used to synthesize green iron oxide nanoparticles, which were then used to sorb Cd and Ni ions out of an aqueous solution. Investigations with x-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, nitrogen adsorption and desorption (BET), Zeta potential, and scanning electron microscopy were performed to know and understand more about the chemical structure and surface morphology of the produced iron oxide nanoparticles. The characterization revealed that the main component of iron nanoparticles was magnetite when the Clove extract was used as a reducing agent for Fe, but both magnetite and hematite were included when the g-Coffee extract was used.

Noble-Metal Nanoparticle-Embedded Silicon Nanogratings via Single-Step Laser-Induced Periodic Surface Structuring.

Here, we show that direct femtosecond laser nanostructuring of monocrystalline Si wafers in aqueous solutions containing noble-metal precursors (such as palladium dichloride, potassium hexachloroplatinate, and silver nitrate) allows for the creation of nanogratings decorated with mono- (Pd, Pt, and Ag) and bimetallic (Pd-Pt) nanoparticles (NPs). Multi-pulse femtosecond-laser exposure was found to drive periodically modulated ablation of the Si surface, while simultaneous thermal-induced reduction of the metal-containing acids and salts causes local surface morphology decoration with functional noble metal NPs. The orientation of the formed Si nanogratings with their nano-trenches decorated with noble-metal NPs can be controlled by the polarization direction of the incident laser beam, which was justified, for both linearly polarized Gaussian and radially (azimuthally) polarized vector beams.

Synthesis of 3-(Pyridin-2-yl)quinazolin-2,4(13)-diones via Annulation of Anthranilic Esters with -pyridyl Ureas.

A new route for the synthesis of quinazolin-2,4(13)-diones and thieno [2,3-]pyrimidine-2,4(1,3)-diones substituted by pyridyl/quinolinyl moiety in position 3 has been developed. The proposed method concluded in an annulation of substituted anthranilic esters or 2-aminothiophene-3-carboxylates with 1,1-dimethyl-3-(pyridin-2-yl) ureas. The process consists of the formation of -aryl-'-pyridyl ureas followed by their cyclocondensation into the corresponding fused heterocycles.

Effect of the Addition of Polyacrylic Acid of Different Molecular Weights to Coagulation Bath on the Structure and Performance of Polysulfone Ultrafiltration Membranes.

Membrane fouling is a serious issue in membrane technology which cannot be completely avoided but can be diminished. The perspective technique of membrane modification is the introduction of hydrophilic polymers or polyelectrolytes into the coagulation bath during membrane preparation via non-solvent-induced phase separation. The influence of polyacrylic acid (PAA) molecular weight (100,000, 250,000 and 450,000 g·mol) added to the aqueous coagulation bath (0.

Gold vs Light: Chemodivergent Reactivity of Diazoesters toward 2-Azirine-2-carboxylic Acids.

An orthogonal reactivity of diazo compounds toward azirine-2-carboxylic acids, switching with the reaction conditions, is demonstrated. A gold-catalyzed reaction is N-selective and produces 1,3-oxazin-6-ones, whereas a blue light activation leads to O-H insertion products, azirine-2-carboxylic esters. The observed chemodivergence is explained by the metal-bound and metal-free carbenes exhibiting different electronic properties in these reactions.

Noncovalent Chelation by Halogen Bonding in the Design of Metal-Containing Arrays: Assembly of Double σ-Hole Donating Halolium with Cu-Containing O,O-Donors.

Five new copper(I) complexes─composed of the paired dibenzohalolium and [CuL] (L = 1,2,4-oxadiazolate) counterions in which O,O-atoms of the anion are simultaneously linked to the halogen atom─were generated and isolated as the solid via the three-component reaction between [Cu(MeCN)](BF), sodium 1,2,4-oxadiazolates, and dibenzohalolium triflates (or trifluoroacetates). This reaction is different from the previously reported Cu-catalyzed arylation of 1,2,4-oxadiazolones by diaryliodonium salts. Inspection of the solid-state X-ray structures of the complexes revealed the strong three-center X···O,O (X = Br, I) halogen bonding occurred between the oxadiazolate moieties and dibenzohalolium cation.

Nanofiltration Mixed Matrix Membranes from Cellulose Modified with Zn-Based Metal-Organic Frameworks for the Enhanced Water Treatment from Heavy Metal Ions.

Nowadays, nanofiltration is actively used for water softening and disinfection, pre-treatment, nitrate, and color removal, in particular, for heavy metal ions removal from wastewater. In this regard, new, effective materials are required. In the present work, novel sustainable porous membranes from cellulose acetate (CA) and supported membranes consisting of CA porous substrate with a thin dense selective layer from carboxymethyl cellulose (CMC) modified with first-time synthesized Zn-based metal-organic frameworks (Zn(SEB), Zn(BDC)Si, Zn(BIM)) were developed to increase the efficiency of nanofiltration for the removal of heavy metal ions.

Water-Soluble Fullerene C Derivatives Are Effective Inhibitors of Influenza Virus Replication.

The influenza virus genome features a very high mutation rate leading to the rapid selection of drug-resistant strains. Due to the emergence of drug-resistant strains, there is a need for the further development of new potent antivirals against influenza with a broad activity spectrum. Thus, the search for a novel, effective broad-spectrum antiviral agent is a top priority of medical science and healthcare systems.

Room Temperature Synthesis of Bioactive 1,2,4-Oxadiazoles.

1,2,4-Oxadiazole is an essential motif in drug discovery represented in many experimental, investigational, and marketed drugs. This review covers synthetic methods that allow the conversion of different types of organic compounds into 1,2,4-oxadiazole at ambient temperature and the practical application of the latter approaches for the preparation of pharmaceutically important molecules. The discussed methods are divided into three groups.

Metal carbonyl mediated rearrangement of 5-(2-oxoalkyl)-1,2,4-oxadiazoles: synthesis of fully substituted pyrimidines.

Variously substituted ethyl 6-oxo-1,6-dihydropyrimidine-5-carboxylates can be easily prepared by a metal carbonyl mediated rearrangement of ethyl 3-oxo-2-(1,2,4-oxadiazol-5-yl)propanoates. The irradiation of a mixture of oxadiazoles and Fe(CO) in wet solvents with a 365 nm LED at room temperature for 2 h followed by heating at 80 °C for 2 h gives pyrimidines in up to 90% yield. This procedure enables the preparation of 6-oxo-1,6-dihydropyrimidine-5-carboxylates with various aryl substituents at the C2 and alkyl or aryl substituents at the C4 position.

Monoamine oxidase inhibition properties of 2,1-benzisoxazole derivatives.

Monoamine oxidase (MAO) are flavoenzymes that metabolize neurotransmitter, dietary and xenobiotic amines to their corresponding aldehydes with the production of hydrogen peroxide. Two isoforms, MAO-A and MAO-B, are expressed in humans and mammals, and display different substrate and inhibitor specificities as well as different physiological roles. MAO inhibitors are of much therapeutic value and are used for the treatment of neuropsychiatric and neurodegenerative disorders such as depression, anxiety disorders, and Parkinson's disease.

Cyclometalated platinum(II) complexes with acyclic diaminocarbene ligands for OLED application.

A novel series of cyclometalated platinum(II) complexes bearing acyclic diaminocarbene (ADC) ancillary ligands were designed and prepared. Their photophysical properties were systematically studied through experimental and theoretical investigations. All complexes exhibit green phosphorescence with a quantum efficiency of up to 45% in 2 wt% doped PMMA film at room temperature.

Mass and Charge Transfer in a Polymeric NiSalen Complex at Subzero Temperatures.

Electrochemical energy storage systems have a wide range of commercial applications. They keep energy and power even at temperatures up to +60 °C. However, the capacity and power of such energy storage systems reduce sharply at negative temperatures due to the difficulty of counterion injection into the electrode material.

Novel Mixed Matrix Membranes Based on Poly(vinylidene fluoride): Development, Characterization, Modeling.

Membrane technology is an actively developing area of modern societies; with the help of high-performance membranes, it is possible to separate various mixtures for many industrial tasks. The objective of this study was to develop novel effective membranes based on poly(vinylidene fluoride) (PVDF) by its modification with various nanoparticles (TiO, Ag-TiO, GO-TiO, and MWCNT/TiO). Two types of membranes have been developed: dense membranes for pervaporation and porous membranes for ultrafiltration.

A family of CuI-based 1D polymers showing colorful short-lived TADF and phosphorescence induced by photo- and X-ray irradiation.

Exploiting 2-(alkylsulfonyl)pyridines as 1,3-N,S-ligands, herein we have constructed 1D CuI-based coordination polymers (CPs) bearing unprecedented (CuI) chains and possessing remarkable photophysical properties. At room temperature, these CPs show efficient TADF, phosphorescence or dual emission in the deep-blue to red range with outstandingly short decay times of 0.4-2.

Influence of the Chemical Structure on the Mechanical Relaxation of Dendrimers.

The rheological properties of macromolecules represent one of the fundamental features of polymer systems which expand the possibilities of using and developing new materials based on them. In this work, we studied the shear-stress relaxation of the second generation PAMAM and PPI dendrimer melts by atomistic molecular dynamics simulation. The time dependences of relaxation modulus () and the frequency dependences of the storage and loss moduli were obtained.

Halogen Bond-Involving Supramolecular Assembly Utilizing Carbon as a Nucleophilic Partner of I⋅⋅⋅C Non-covalent Interaction.

Co-crystallization of 180°-orienting σ-hole-accepting tectons, namely, 1,4-diisocyanobenzene (1) and 1,4-diisocyanotetramethylbenzene (2), with such homoditopic halogen bond donors as 1,4-diiodotetrafluorobenzene (1,4-FIB) and 4,4'-diiodoperfluorobiphenyl (4,4'-FIBP) afforded co-crystals 1 ⋅ 1,4-FIB, 1 ⋅ 4,4'-FIBP, and 2 ⋅ 1,4-FIB. Their solid-state structures exhibit 1D-supramolecular arrangements, which are based on poorly explored I⋅⋅⋅C halogen bonding; this study is the first in which the supramolecular assembly utilizing halogen bonding with a terminal C atom was performed. The use of the potentially tetrafunctional σ-hole accepting tetraiodoethylene (TIE) leads to supramolecular architecture of a higher dimension, 3D-framework, observed in the structure of 1 ⋅ TIE.

Intrinsically Conducting Polymer Composites as Active Masses in Supercapacitors.

Intrinsically conducting polymers ICPs can be combined with further electrochemically active materials into composites for use as active masses in supercapacitor electrodes. Typical examples are inspected with particular attention to the various roles played by the constituents of the composites and to conceivable synergistic effects. Stability of composite electrode materials, as an essential property for practical application, is addressed, taking into account the observed causes and effects of materials degradation.

Creation of a Composite Bioactive Coating with Antibacterial Effect Promising for Bone Implantation.

When creating titanium-containing bone implants, the bioactive coatings that promote their rapid engraftment are important. The engraftment rate of titanium implants with bone tissue depends significantly on the modification of the implant surface. It is achieved by changing either the relief or the chemical composition of the surface layer, as well as a combination of these two factors.