DFT rationalization of the mechanism and selectivity in a gold-catalyzed oxidative cyclization of diynones with alcohols.

The mechanism, regioselectivity, and chemoselectivity in a gold-catalyzed oxidative cyclization of diynones with alcohols to give furan-3-carboxylate derivatives were explored by density functional theory (DFT). The obtained results revealed that the first step of the global reaction involves a nucleophilic attack of a pyridine--oxide derivative on the catalyst-ligated diynone, forming a vinyl intermediate that can isomerize to an α,α'-dioxo gold carbene upon the cleavage of the N-O bond. In the second step, a nucleophilic addition is also completed pyridine--oxide instead of an alcohol proposed in the experiment.

Cu-Methylsilsesquioxane Cage Decorated with Cu(dppe) Moieties for Mild Oxidative Functionalization of Alkanes.

We report a high nuclear (Cu) complex synthesized via the self-assembly of copper-methylsilsesquioxane induced by the complexation with 1,2-bis(diphenylphosphino)ethane (dppe). The structure includes two cationic Cu(dppe) moieties and an anionic silsesquioxane cage of an unprecedented Cu structural type. The Cu cage fragment exhibits a unique () combination of Si-cyclic/Si-acyclic silsesquioxane ligands and () encapsulation of two different chloride and carbonate species.

Hidden in the frog: morphological and molecular characterization of Halipegus ovocaudatus (Platyhelminthes: Trematoda), type species of the genus Halipegus Looss, 1899.

The type species of the genus Halipegus Looss, 1899, Halipegus ovocaudatus (Vulpian, 1859) is a generalist parasite of different species of amphibians, mainly anurans. To date, the phylogenetic position of this species has not been established. Specimens of H.

The Morphological and Molecular Characterization of the Avian Trematodes and (Digenea: Cyclocoelidae) from the Middle Volga Region (European Russia).

The taxonomic status of many species of the family Cyclocoelidae is still unclear. Two species of cyclocoelids, and , were collected from the air sacs of birds ( and ) inhabiting the Middle Volga region (European Russia). Here, we provide the first detailed morphological description of these cyclocoelids and combine it with the first molecular phylogenetic analysis of Cyclocoelidae from birds in Russia based on partial sequences of their 28s rDNA and coI mtDNA genes.

Bimetallic NiCo Metal-Organic Frameworks with High Stability and Performance Toward Electrocatalytic Oxidation of Urea in Seawater.

The urea oxidation reaction (UOR) is an alternative anodic reaction for hydrogen generation via water splitting. The significance of UOR lies in both H production and the decontamination of urea-containing wastewater. Commercial electrocatalysts in this field are generally based on noble metals and show several limitations.

Multidimensional Hybrid Metal Phosphonate Coordination Networks as Synergistic Anticorrosion Coatings.

In the technologically important field of anticorrosion coatings, it is imperative to form well-defined and characterized films to protect the metal surface from corrosion. Phosphonate-based corrosion mitigation approaches are currently being exploited. Herein, the synergistic action of alkaline-earth metal ions and two carboxy-diphosphonates, PAIBA [-bis(phosphonomethyl)-2-aminoisobutyric acid] and BPMGLY [-(phosphonomethyl)glycine], is explored.

DFT Study on the Mechanisms and Selectivities in Rh (III)-Catalyzed [5 + 1] Annulation of 2-Alkenylanilides and 2-Alkylphenols with Allenyl Acetates.

The mechanisms and regio-, chemo-, and stereoselectivity were theoretically investigated in the Rh(III)-catalyzed [5 + 1] annulation of 2-alkenylanilides and 2-alkylphenols with allenyl acetates. Two different reactants, 2-alkenylanilides and 2-alkylphenols, were selected as model systems in the density functional theory calculations. The obtained theoretical results show that both these reactants exhibit similar steps, namely, (1) N-H/O-H deprotonation and C-H activation, (2) allenyl acetate migratory insertion, (3) β-oxygen elimination, (4) intramolecular nucleophilic addition of the nitrogen/oxygen-rhodium bond resulting in [5 + 1]-annulation, and (5) protonation with the formation of the desired product and regeneration of the Rh(III) catalyst.

Silver Coordination Polymers Driven by Adamantoid Blocks for Advanced Antiviral and Antibacterial Biomaterials.

The development of sustainable biomaterials and surfaces to prevent the accumulation and proliferation of viruses and bacteria is highly demanded in healthcare areas. This study describes the assembly and full characterization of two new bioactive silver(I) coordination polymers (CPs) formulated as [Ag(aca)(μ-PTA)]·5HO () and [Ag(μ-ada)(μ-PTA)]·4HO (). These products were generated by exploiting a heteroleptic approach based on the use of two different adamantoid building blocks, namely 1,3,5-triaza-7-phosphaadamantane (PTA) and 1-adamantanecarboxylic (Haca) or 1,3-adamantanedicarboxylic (Hada) acids, resulting in the assembly of 1D () and 3D ().

The Diversity of Trematodes in Bats (Chiroptera, Vespertilionidae) from the Samarskaya Luka (European Russia).

Various bat species often occupy the same habitats. Cohabitation should induce different preferences in spatial or trophic components of the bat ecological niche to reduce their competition. This determines the differences in the trematode fauna of spp.

Theoretical Analysis of a Three-Component Reaction between Two Diazo Compounds and a Hydroxylamine Derivative: Mechanism, Enantioselectivity, and Effect of Cooperative Catalysis.

The mechanism, enantioselectivity, and effect of chiral phosphoric acid (CPA) cocatalyst were investigated by the density functional theory (DFT) for the three-component asymmetric aminohydroxylation between two diazo compounds and a hydroxylamine derivative. This type of cascade process is cooperatively catalyzed by Rh(OAc) and CPA. The obtained results clearly indicate that the first step of the global reaction involves a nucleophilic attack at the nitrogen center of -hydroxyaniline by rhodium-carbene intermediates producing imines.

Encapsulation of HSiWO into an Amide-Functionalized MOF: A Highly Efficient Nanocomposite Catalyst for Oxidative Desulfurization of Diesel Fuel.

Production of hydrocarbon fuels containing sulfur in ultralow levels is in high demand and requires the development of novel catalytic systems for oxidative desulfurization (ODS). Herein, a new nanocomposite SiW@ZSTU-10 catalyst containing HSiWO (SiW) encapsulated into a zinc(II) 3D metal-organic framework (MOF) (ZSTU-10) was assembled and characterized. The intricate structure and porosity of ZSTU-10 permit efficient encapsulation of the catalytically active SiW cages.

Coordination Polymers from an Amino-Functionalized Terphenyl-Tetracarboxylate Linker: Structural Multiplicity and Catalytic Properties.

An amino-functionalized terphenyl-tetracarboxylic acid, 2'-amino-[1,1':4',1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid (Htpta), was used as an adaptable linker to synthesize, under hydrothermal conditions, eight coordination polymers (CPs). The obtained products were formulated as [Co(μ-Htpta)] (), [Co(μ-Htpta)(2,2'-bipy)] (), [M(μ-Htpta)(2,2'-bipy)] (M = Mn (), Cd ()), [Ni(μ-tpta)(phen)(HO)] (), [Zn(μ-tpta)(phen)] (), {[Zn(μ-tpta)(μ-4,4'-bipy)]·HO} (), and [Zn(μ-tpta)(μ-Hbiim)(HO)] (), wherein 2,2'-bipyridine (2,2'-bipy), 4,4'-bipyridine (4,4'-bipy), 1,10-phenanthroline (phen), or 2,2'-biimidazole (Hbiim) are present as additional stabilizing ligands. The structural types of - vary from one-dimensional (1D) (, ) and two-dimensional (2D) (, , ) CPs to three-dimensional (3D) metal-organic frameworks (MOFs) (, , and ) with a diversity of topologies.

A Dual-Purpose Ce(III)-Organic Framework with Amine Groups and Open Metal Sites: Third-Order Nonlinear Optical Activity and Catalytic CO Fixation.

The present work focuses on the synthesis and properties of a novel multifunctional cerium(III) MOF, [Ce(data)(DMF)]·DMF (data: 2,5-diaminoterephthalate), abbreviated as NH-Ce-MUM-2. Its crystal structure reveals an intricate 3D 4,5-connected framework with a topology. This MOF features unique properties, such as open metal sites, presence of free amino groups, and high stability.

(Nematoda: Molineidae)-A Parasite of European Green Toad : Morphological and Molecular Data.

Nematodes of the genus are common parasites of the small intestine of amphibians and reptiles. Our recent molecular analysis of nematodes revealed that only , which possesses high morphological variability, parasitizes amphibians and reptiles in European Russia. Here we present the study of nematodes from the European green toad (Anura, Bufonidae) collected at different localities of the Middle Volga region in 2018-2022.

Fabrication of Cellulose Filters Incorporating Metal-Organic Frameworks for Efficient Nicotine Adsorption from Cigarette Smoke.

To prevent negative effects of smoking, there is constant research on the development of various types of sustainable filter materials, capable of removing toxic compounds present in cigarette smoke. Because of the extraordinary porosity and adsorption properties, metal-organic frameworks (MOFs) represent promising adsorbents for volatile toxic molecules such as nicotine. This study reports new hybrid materials wherein six types of common MOFs of different porosity and particle size are incorporated into sustainable cellulose fiber from bamboo pulp, resulting in a series of cellulose filter samples abbreviated as MOF@CF.

Pillared-MOF@NiV-LDH Composite as a Remarkable Electrocatalyst for Water Oxidation.

Oxygen evolution reaction (OER) represents a highly important electrochemical transformation in energy storage and conversion technologies. Considering the low rate of this four-electron half-reaction, there is a demand for efficient, stable, and noble-metal-free electrocatalysts to improve the kinetic and economical parameters. In this work, a new pillared-MOF@NiV-LDH nanocomposite based on a Co metal-organic framework (pillared-MOF) and heterometallic Ni/V-layered double hydroxide (NiV-LDH) was assembled via a simple protocol, characterized, and explored as an electrocatalyst in OER.

Cells with stochastically increased methyltransferase to restriction endonuclease ratio provide an entry for bacteriophage into protected cell population.

The action of Type II restriction-modification (RM) systems depends on restriction endonuclease (REase), which cleaves foreign DNA at specific sites, and methyltransferase (MTase), which protects host genome from restriction by methylating the same sites. We here show that protection from phage infection increases as the copy number of plasmids carrying the Type II RM Esp1396I system is increased. However, since increased plasmid copy number leads to both increased absolute intracellular RM enzyme levels and to a decreased MTase/REase ratio, it is impossible to determine which factor determines resistance/susceptibility to infection.

Postsynthetic Modification of NU-1000 for Designing a Polyoxometalate-Containing Nanocomposite with Enhanced Third-Order Nonlinear Optical Performance.

For the advancement of laser technologies and optical engineering, various types of new inorganic and organic materials are emerging. Metal-organic frameworks (MOFs) reveal a promising use in nonlinear optics, given the presence of organic linkers, metal cluster nodes, and possible delocalization of π-electron systems. These properties can be further enhanced by the inclusion of solely inorganic materials such as polyoxometalates as prospective low-cost electron-acceptor species.

Coordination Polymers Constructed from an Adaptable Pyridine-Dicarboxylic Acid Linker: Assembly, Diversity of Structures, and Catalysis.

4,4'-(Pyridine-3,5-diyl)dibenzoic acid (Hpdba) was explored as an adaptable linker for assembling a diversity of new manganese(II), cobalt(II/III), nickel(II), and copper(II) coordination polymers (CPs): [Mn(μ-pdba)(HO)] (), {[M(μ-pdba)(phen)]·2HO} (M = Co (), Ni ()), {[Cu(μ-pdba)(bipy)]·2HO} (), {[Co(μ-pdba)(bipy)]·2HO} (), [Co(μ-pdba)(μ-Hbiim)(Hbiim)] (), and [M(μ-pdba)(py)] (M = Co (), Ni ()). The CPs were hydrothermally synthesized using metal(II) chloride precursors, Hpdba, and different coligands functioning as crystallization mediators (phen: 1,10-phenanthroline; bipy: 2,2'-bipyridine, Hbiim: 2,2'-biimidazole; py: pyridine). Structural networks of - range from two-dimensional (2D) metal-organic layers (-, -) to three-dimensional (3D) metal-organic framework (MOF) () and disclose several types of topologies: (in ), (in , , ), (in ), 3,5L66 (in ), and SP 2-periodic net (6,3)Ia (in , ).

Hybrid composites of lanthanide metal-organic frameworks with epoxy silanes for highly sensitive thermometry.

Post-synthetic modification of metal-organic frameworks (MOFs) and fabrication of hybrid composites are currently hot topics in the development of new functional materials. In this study, a facile and direct approach for coupling of lanthanide MOFs with epoxy silanes was developed, providing an access to a new series of functional composites. Two types of commercially available epoxy silane, namely 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (ECTMS) and (3-glycidoxypropyl)methyl diethoxysilane (KH563), were used to modify Ln-BTB MOFs ([Ln(BTB)(HO)]·2(CHO); Ln = Tb or EuTb; HBTB = 1,3,5-benzenetrisbenzoic acid) covalent grafting involving mechanical grinding, epoxide coupling and curing reactions.

Acetone Factor in the Design of Cu-, Cu-, and Cu-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes.

The present study describes a new feature in the self-assembly of cagelike copperphenylsilsesquioxanes: the strong influence of acetone solvates on cage structure formation. By this simple approach, a series of novel tetra-, hexa-, or nonacoppersilsesquioxanes were isolated and characterized. In addition, several new complexes of Cu or Cu nuclearity bearing additional nitrogen-based ligands (ethylenediamine, 2,2'-bipyridine, phenanthroline, bathophenanthroline, or neocuproine) were produced.

Therapeutic Potential of a Water-Soluble Silver-Diclofenac Coordination Polymer on 3D Pancreatic Cancer Spheroids.

This work describes the traditional wet and green synthetic approaches, structural features, and extensive bioactivity study for a new coordination polymer [Ag(-PTA)(Df)(HO)]·3HO () that bears a silver(I) center, a 1,3,5-triaza-phosphaadamantane (PTA) linker, and a nonsteroidal anti-inflammatory drug, diclofenac (Df). Compared to cisplatin, compound exhibits both anti-inflammatory properties and very remarkable cytotoxicity toward various cancer cell lines with a high value of selectivity index. Additionally, the 3D model representing human pancreas/duct carcinoma (PANC-1) and human lung adenocarcinoma (A549) was designed and applied as a clear proof of the remarkable therapeutic potential of .

Coordination Polymers from Biphenyl-Dicarboxylate Linkers: Synthesis, Structural Diversity, Interpenetration, and Catalytic Properties.

The present work explores two biphenyl-dicarboxylate linkers, 3,3'-dihydroxy-(1,1'-biphenyl)-4,4'-dicarboxylic (HL) and 4,4'-dihydroxy-(1,1'-biphenyl)-3,3'-dicarboxylic (HL) acids, in hydrothermal generation of nine new compounds formulated as [Co(μ-HL)(phen)(HO)] (), [Mn(μ-HL)(phen)]·4HO (), [Zn(μ-HL)(2,2'-bipy)(HO)] (), [Cd(μ-HL) (2,2'-bipy)(HO)] (), [Mn(μ-HL)(μ-HL)(μ-4,4'-bipy)]·4HO (), [Zn(μ-HL)(μ-4,4'-bipy)] (), [Zn(μ-HL)(phen)] (), [Cd(μ-HL)(phen)] (), and [Cu(μ-HL) (μ-4,4'-bipy)(HO)] (). These coordination polymers (CPs) were generated by reacting a metal(II) chloride, a HL or HL linker, and a crystallization mediator such as 2,2'-bipy (2,2'-bipyridine), 4,4'-bipy (4,4'-bipyridine), or phen (1,10-phenanthroline). The structural types of - range from molecular dimers () to one-dimensional (, , ) and two-dimensional (, ) CPs as well as three-dimensional metal-organic frameworks (, , ).