Au Acyclic (Amino)(N-Pyridinium)carbenoids: Synthesis via Addition of 2-PySeCl to Au-Bound Isonitriles, Structures, and Cytotoxicity.

In this study, we report the first example of acyclic (amino)(N-pyridinium)carbenoid gold(III) complexes synthesized via a coupling reaction between 2-pyridylselenyl chloride and Au(I)-bound isonitriles. The reaction involves an initial oxidative addition of the Se-Cl moiety to Au(I), followed by the nucleophilic addition of the pyridine fragment to the isonitrile's C≡N bond, furnishing a metallacycle. Importantly, this is the first example of the pyridine acting as a nucleophile towards metal-bound isonitriles.

Diverse Cyclization Pathways Between Nitriles with Active -Methylene Group and Ambiphilic 2-Pyridylselenyl Reagents Enabled by Reversible Covalent Bonding.

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is in contrast to what we observed before for other nitriles.

Coupling between 2-pyridyl-selenyl chloride and phenyl-seleno-cyanate: synthesis, crystal structure and non-covalent inter-actions.

A new pyridine-fused seleno-diazo-lium salt, 3-(phenyl-selan-yl)[1,2,4]selena-diazolo[4,5-]pyridin-4-ylium chloride di-chloro-methane 0.352-solvate, CHNSe ·Cl·0.352CHCl, was obtained from the reaction between 2-pyridyl-selenenyl chloride and phenyl-seleno-cyanate.

New Antibacterial and Antioxidant Chitin Derivatives: Ultrasonic Preparation and Biological Effects.

This work focuses on the first use of ultrasonic phenol-ene coupling as a polymer analogous transformation. The ultrasonic reaction was introduced into chitin chemistry, resulting in the fast and convenient preparation of new water-soluble cationic chitin derivatives. Since water-soluble derivatives of fully deacetylated chitin are poorly described in the literature, the synthesis of each new type of these derivatives is a significant event in polysaccharide chemistry.

Introducing Cationic Selenium-Containing Triazapentadiene Ligand Framework: Synthesis, Coordination Chemistry, and Antifungal Activity.

Positively charged ligands are scarce. Here, we report the synthesis of unprecedented cationic selenium-containing triazapentadiene ligand framework. The reaction between 2-pyridylselenyl reagents and NaN(CN) in a 2:1 ratio produces the sodium complexes featuring the cationic selenium-containing triazapentadiene (SeTAP) ligand.

Halogen Bond-Assisted Supramolecular Dimerization of Pyridinium-Fused 1,2,4-Selenadiazoles via Four-Center SeN Chalcogen Bonding.

The synthesis and structural characterization of α-haloalkyl-substituted pyridinium-fused 1,2,4-selenadiazoles with various counterions is reported herein, demonstrating a strategy for directed supramolecular dimerization in the solid state. The compounds were obtained through a recently discovered 1,3-dipolar cycloaddition reaction between nitriles and bifunctional 2-pyridylselenyl reagents, and their structures were confirmed by the X-ray crystallography. α-Haloalkyl-substituted pyridinium-fused 1,2,4-selenadiazoles exclusively formed supramolecular dimers via four-center Se···N chalcogen bonding, supported by additional halogen bonding involving α-haloalkyl substituents.

Synthesis and crystal structure of the adduct between 2-pyridyl-selenyl chloride and isobutyro-nitrile.

The reaction between 2-pyridyl-selenenyl chloride and isobutyro-nitrile results in the formation of the corresponding cationic pyridinium-fused 1,2,4-seleno-diazole, namely, 3-(propan-2-yl)-1,2,4-[1,2,4]selena-diazolo[4,5-a]pyridin-4-ylium chloride, CHNSe·Cl, in high yield (89%). The structure of the compound, established by means of single-crystal X-ray analysis at 100 K, has monoclinic (2/) symmetry and revealed the presence of bifurcated chalcogen-hydrogen bonding Se⋯Cl⋯H-Cl, and these non-covalent contacts were analysed by DFT calculations followed by a topological analysis of the electron-density distribution (ωB97XD/6-311++G** level of theory).

Chitosan and Its Derivatives: Preparation and Antibacterial Properties.

This comprehensive review illuminates the various methods of chitosan extraction, its antibacterial properties, and its multifarious applications in diverse sectors. We delve into chemical, physical, biological, hybrid, and green extraction techniques, each of which presents unique advantages and disadvantages. The choice of method is dictated by multiple variables, including the desired properties of chitosan, resource availability, cost, and environmental footprint.

Characteristic features of toxic metal content in hair samples of foreign students at RUDN University from different geographic regions.

Background: This study explores the regional variations in toxic metal accumulation among RUDN University students from various global regions.

Methods: This comparative analysis examined hair samples from students hailing from different regions, including Russia, Asia, the Middle East, Africa, and Latin America. The concentrations of Aluminium (Al), Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), and Tin (Sn) were measured in the hair samples.

Benzothiazole Derivatives of Chitosan and Their Derived Nanoparticles: Synthesis and In Vitro and In Vivo Antibacterial Effects.

In this work, we focused on synthesizing and assessing novel chitosan-based antibacterial polymers and their nanoparticles by incorporating benzothiazole substituents. The growing resistance to antibiotics has necessitated the search for alternative antimicrobial compounds. This study aimed to synthesize and evaluate chitosan-based polymers and nanoparticles with benzothiazole substituents for their antibacterial properties and toxicity.

Azo Coupling of Indoles Revisited: Synthesis of Biindolyl Photoswitches via the Azo-Coupling/C-H Functionalization Domino Approach.

When azo coupling of aryldiazonium salts with indoles was carried out in aprotic nonpolar solvent on air, a pseudo-three-component reaction has been discovered. Azo coupling is followed by a nucleophilic addition of a second indole unit to the indolium intermediate; aromatization and oxidation are achieved under air.

Novel Highly Efficient Antibacterial Chitosan-Based Films.

In this study, we elaborated new chitosan-based films reinforced by iron(III)-containing chitosan nanoparticles Fe(III)-CS-NPs at different concentrations. We found that the optimum concentration of Fe(III)-CS-NPs for the improvement of antibacterial and mechanical properties of the films was 10% (σ = ca. 8.

Chitosan-Based Antibacterial Films for Biomedical and Food Applications.

Antibacterial chitosan films, versatile and eco-friendly materials, have garnered significant attention in both the food industry and medicine due to their unique properties, including biodegradability, biocompatibility, and antimicrobial activity. This review delves into the various types of chitosan films and their distinct applications. The categories of films discussed span from pure chitosan films to those enhanced with additives such as metal nanoparticles, metal oxide nanoparticles, graphene, fullerene and its derivatives, and plant extracts.

Synthesis, crystal structure and Hirshfeld surface analysis of di-μ-iodido-bis-[(2,2'-bi-quinoline-κ ,')copper(I)].

The mol-ecular and crystal structures of the title compound, [CuI(CHN)], were examined by single-crystal X-ray diffraction and Hirshfeld surface analysis. The Cu atom is coordinated in a distorted tetra-hedral geometry by two N atoms from the 2,2'-bi-quinoline ligands and the two μ-bridging iodide ligands. The mol-ecules are in contact π-π-stacking inter-actions.

Biologically Active Supplements Affecting Producer Microorganisms in Food Biotechnology: A Review.

Microorganisms, fermentation processes, and the resultant metabolic products are a key driving force in biotechnology and, in particular, in food biotechnology. The quantity and/or quality of final manufactured food products are directly related to the efficiency of the metabolic processes of producer microorganisms. Food BioTech companies are naturally interested in increasing the productivity of their biotechnological production lines.

Chitosan-Based Ciprofloxacin Extended Release Systems: Combined Synthetic and Pharmacological (In Vitro and In Vivo) Studies.

Ciprofloxacin is one of the most effective antibiotics, but it is characterized by a range of side effects. Elaboration of drug-releasing systems which allow to diminish toxicity of ciprofloxacin is a challenging task in medicinal chemistry. The current study is focused on development of new ciprofloxacin releasing systems (CRS).

Robust Supramolecular Dimers Derived from Benzylic-Substituted 1,2,4-Selenodiazolium Salts Featuring Selenium⋯π Chalcogen Bonding.

The series of benzylic-substituted 1,2,4-selenodiazolium salts were prepared via cyclization reaction between 2-pyridylselenyl chlorides and nitriles and fully characterized. Substitution of the Cl anion by weakly binding anions promoted the formation supramolecular dimers featuring four center SeN chalcogen bonding and two antiparallel selenium⋯π interactions. Chalcogen bonding interactions were studied using density functional theory calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of atoms-in-molecules (QTAIM), and the noncovalent interaction (NCI) plot.

Facile Access to 2-Selenoxo-1,2,3,4-tetrahydro-4-quinazolinone Scaffolds and Corresponding Diselenides via Cyclization between Methyl Anthranilate and Isoselenocyanates: Synthesis and Structural Features.

A practical method for the synthesis of 2-selenoxo-1,2,3,4-tetrahydro-4-quinazolinone was reported. The latter compounds were found to undergo facile oxidation with HO into corresponding diselenides. Novel organoselenium derivatives were characterized by the H, Se, and C NMR spectroscopies, high-resolution electrospray ionization mass spectrometry, IR, elemental analyses (C, H, N), and X-ray diffraction analysis for several of them.

Structural Organization of Dibromodiazadienes in the Crystal and Identification of Br···O Halogen Bonding Involving the Nitro Group.

Nitro functionalized dibromodiazadiene dyes were prepared and fully characterized including X-ray single crystal analysis. Electron deficient dibromodiazadienes were found to be able to act as donors of halogen bonding (XB), while the nitro group acted as an acceptor of the XB. Depending on the substituents, the Br···O XB competed with other weak interactions, and for some of the dyes, they even outcompeted the XB involving the nitro group.

[Minimally invasive esophagectomy for benign esophageal diseases: results of a two-center study].

Objective: To analyze the results of thoracoscopic esophagectomy for benign esophageal diseases.

Material And Methods: The study included 78 patients who underwent thoracoscopic esophagectomy between 2011 and 2019. Peptic and burn strictures of the esophagus were diagnosed in 53 patients, achalasia - in 24 patients.

Towards Anion Recognition and Precipitation with Water-Soluble 1,2,4-Selenodiazolium Salts: Combined Structural and Theoretical Study.

The synthesis and structural characterization of a series of supramolecular complexes of bicyclic cationic pyridine-fused 1,2,4-selenodiazoles with various anions is reported. The binding of trifluoroacetate, tetrachloroaurate, tetraphenylborate, perrhenate, and pertechnetate anions in the solid state is regarded. All the anions interact with selenodiazolium cations exclusively via a pair of "chelating" Se⋯O and H⋯O non-covalent interactions, which make them an attractive, novel, non-classical supramolecular recognition unit or a synthon.

The first selenium containing chitin and chitosan derivatives: Combined synthetic, catalytic and biological studies.

Ultrasonic approach to the synthesis of the first selenium-containing derivatives of chitin and chitosan has been developed. The synthetic procedure is simple, provides high yields, does not require harsh conditions, and uses water as the reaction medium. The elaborated chitin and chitosan derivatives and their based nanoparticles are non-toxic and possess high antibacterial and antifungal activity.

Nitrogen-Doped Carbon Nanodots Produced by Femtosecond Laser Synthesis for Effective Fluorophores.

Understanding the effect of heteroatom doping is crucial for the design of carbon nanodots (CNDs) with enhanced luminescent properties for fluorescence imaging and light-emitting devices. Here, we study the effect and mechanisms of luminescence enhancement through nitrogen doping in nanodots synthesized by the bottom-up route in an intense femtosecond laser field using the comparative analysis of CNDs obtained from benzene and pyridine. We demonstrate that laser irradiation of aromatic compounds produces hybrid nanoparticles consisting of a nanocrystalline core with a shell of surface-bonded aromatic rings.

Exploring Supramolecular Assembly Space of Cationic 1,2,4-Selenodiazoles: Effect of the Substituent at the Carbon Atom and Anions.

Chalcogenodiazoles have been intensively studied in recent years in the context of their supramolecular chemistry. In contrast, the newly discovered cationic 1,2,4-selenodiazole supramolecular building blocks, which can be obtained via coupling between 2-pyridylselenyl halides and nitriles, are virtually unexplored. A significant advantage of the latter is their facile structural tunability via the variation of nitriles, which could allow a fine tuning of their self-assembly in the solid state.