New versatile organyltellurium(IV) halides: Synthesis and X-ray structural features of the telluronium tellurolate salts [PhTe(CH3)2]2[TeX6] (X = Cl, Br) and [Ph3Te][PhTeX4] (X = Cl, Br, I)

TeX₄ (X = Cl, Br) react in HCl/HBr with [Ph(CH₃)₂Te]X (X = Cl, Br) to give [PhTe(CH₃)₂]₂[TeCl₆] (1) and [PhTe(CH₃)₂]₂[TeBr₆] (2). The reaction of PhTeX₃ (X = Cl, Br, I) in cooled methanol with [(Ph)₃Te]X (X = Cl, Br, I) leads to [Ph₃Te][PhTeCl₄] (3), [Ph₃Te][PhTeBr₄] (4) and [Ph₃Te][PhTeI₄] (5). In the lattices of the telluronium tellurolate salts 1 and 2, octahedral TeCl₆ and TeBr₆ dianions are linked by telluronium cations through Te?Cl and Te?Br secondary bonds, attaining bidimensional (1) and three-dimensional (2) assemblies. The complexes 3, 4 and 5 show two kinds of Te?halogen secondary interactions: the anion-anion interactions, which form centrosymmetric dimers, and two identical sets of three telluronium-tellurolate interactions, which accomplish the centrosymmetric fundamental moiety of the supramolecular arrays of the three compounds, with the tellurium atoms attaining distorted octahedral geometries. Also phenyl C-H?halogen secondary interactions are structure forming forces in the crystalline structures of compounds 3, 4 and 5.     

Potential use of bile salts in lipid self-assembled systems for the delivery of phytochemicals

Phytochemicals show many desirable functions such as anti-oxidant, anti-microbial, anti-inflammatory, anti-carcinogenic, anti-ageing, activities and so on.These biological functions can only be seen when the compounds are delivered at sufficient concentrations. However, the bioavailability of phytonutrients suffers from their limited absorption, transformation, and rapid clearance from the circulation. In this review, we survey recent studies on the use of bile salts in lipid self-assembled systems to enhance the bioavailability of phytochemicals and, consequently, their biological activity. The effect of bile salts on lipid self-assembled systems in terms of morphology, encapsulation efficiency, stability, bioavailability, and biological activities are discussed.     

Systematic Study of Quaternary Ammonium Cations for Bromine Sequestering Application in High Energy Density Electrolytes for Hydrogen Bromine Redox Flow Batteries

Bromine complexing agents (BCAs) are used to reduce the vapor pressure of bromine in the aqueous electrolytes of bromine flow batteries. BCAs bind hazardous, volatile bromine by forming a second, heavy liquid fused salt. The properties of BCAs in a strongly acidic bromine electrolyte are largely unexplored. A total of 38 different quaternary ammonium halides are investigated ex situ regarding their properties and applicability in bromine electrolytes as BCAs. The focus is on the development of safe and performant HBr/Br₂/H₂O electrolytes with a theoretical capacity of 180 Ah L⁻¹ for hydrogen bromine redox flow batteries (H₂/Br₂-RFB). Stable liquid fused salts, moderate bromine complexation, large conductivities and large redox potentials in the aqueous phase of the electrolytes are investigated in order to determine the most applicable BCA for this kind of electrolyte. A detailed study on the properties of BCA cations in these parameters is provided for the first time, as well as for electrolyte mixtures at different states of charge of the electrolyte. 1-ethylpyridin-1-ium bromide [C2Py]Br is selected from 38 BCAs based on its properties as a BCA that should be focused on for application in electrolytes for H₂/Br₂-RFB in the future.     

Cu-Catalyzed Arylation of Bromo-Difluoro-Acetamides by Aryl Boronic Acids,Aryl Trialkoxysilanes and Dimethyl-Aryl-Sulfonium Salts: New Entries to Aromatic Amides

We describe a mechanism-guided discovery of a synthetic methodology that enables the preparation of aromatic amides from 2-bromo-2,2-difluoroacetamides utilizing a copper-catalyzed direct arylation. Readily available and structurally simple aryl precursors such as aryl boronic acids, aryl trialkoxysilanes and dimethyl-aryl-sulfonium salts were used as the source for the aryl substituents. The scope of the reactions was tested, and the reactions were insensitive to the electronic nature of the aryl groups, as both electron-rich and electron-deficient aryls were successfully introduced. A wide range of 2-bromo-2,2-difluoroacetamides as either aliphatic or aromatic secondary or tertiary amides were also reactive under the developed conditions. The described synthetic protocols displayed excellent efficiency and were successfully utilized for the expeditious preparation of diverse aromatic amides in good-to-excellent yields. The reactions were scaled up to gram quantities.     

Efficient N-heterocyclic carbene nickel pincer complexes catalyzed cross coupling of benzylic ammonium salts with boronic acids

Pyridine-bridged bis-benzimidazolylidene nickel complexes exhibited very high catalytic activity toward cross coupling of inactive (hetero)aryl benzylic ammonium salts with (hetero)aryl and alkenyl boronic acids under mild reaction conditions. Even at 2 mol% catalyst loading, a wide range of substrates for both coupling partners with different steric and electronic properties were well tolerated.     

Design,synthesis, and biological evaluation of novel substituted imidazo[2,1-a]isoindole derivatives as antibacterial agents

An efficient protocol has been developed for the synthesis of fused imidazo[2,1-a]isoindol-5-ones (2a–d) from 2-iodo benzoic acids and N,N-carbonyldiimidazole (CDI) using one-pot Pd-catalyzed C?C bond coupling. The reaction of imidazo[2,1-a]isoindol-5-one (2a–d) with substituted α-bromo ketones in toluene afforded corresponding imidazo[2,1-a]isoindolium derivatives (3a–i) in good yields. The structures of the title compounds were well established on the basis of infrared (IR), ¹H NMR, carbon-13 nuclear magnetic resonance (¹³C NMR), mass spectral data, and elemental analysis (C, H, and N). In vitro antibacterial results revealed that, the compounds 3b and 3i were found to possess an excellent broad spectrum of inhibiting potency against all the tested bacterial strains with minimum inhibitory concentration values ranging from 3.125 to 25?µg mL^?1.     

4-(Azulen-1-yl) six-membered heteroaromatics substituted in 2- and 6- positions with 2-(2-furyl)vinyl, 2-(2-thienyl)vinyl or 2-(3-thienyl)vinyl moieties

The synthesis of pyrylium and pyridinium salts and pyridines with azulene-1-yl moieties in position 4 and two 2-heteroarylvinyl groups in positions 2 and 6 was accomplished. The pyrylium salts were obtained starting from pyranones and pyridines could be prepared from these salts by treating them with ammonium acetate. The general procedures for the synthesis of pyridinium salts, which occur with good results in less delocalized electronic systems, do not take place when applied to the above obtained pyrylium salts. Therefore, as starting material 4-(azulen-1-yl)-1-(n-butyl)-2,6-dimethylpyridinium perchlorate was used, which was condensed with heteroarylcarboxaldehydes. These compounds were completely characterized and some of their spectra were discussed. Their interaction with some metal ions was revealed, observing an affinity better than in the case of simple azulenepyridines. In the last part of the paper are presented redox potentials for several pyrylium salts and pyridines in comparison with those of the nonvinylogated derivatives.     

Mild,rapid and efficient metal-free synthesis of 2-aryl-4-aryloxyquinolines via direct Csp2O bond formation by using diaryliodonium salts

An efficient ligand- and transition metal-free procedure for the direct C_sp²O bond formation for the arylation of 2-aryl-4-quinolones was developed. The synthesis of the starting quinolones was carried out under our optimized Cu-catalyzed CN bond formation conditions between 2′-bromoacetophenone and benzamide derivatives followed by cyclization. Easily prepared diaryliodonium salts were used as aryl source. Highly functionalized 4-aryloxyquinolines were obtained in a mild and operationally simple protocol, which involves conventional heating and short periods of time. The method shows good to excellent yields and broad toleration of functional groups like fluorine or trifluoromethyl, which are important in medicinal chemistry. The C_sp²O bond formation process herein described for the quinolone functionalization offers an excellent non-toxic alternative to the transition metal-catalyzed reactions that not only can potentially contaminate the final compounds but also can be environmental pollutants.     

Two Energetic Salts based on 5,5′‐Bitetrazole‐1,1′‐diolate: Syntheses,Characterization, and Properties

Two salts based on 1H,1′H‐5,5′‐bitetrazole‐1,1′‐diolate (BTO) anion with pyrazole ( 1 ) and imidazole ( 2 ) cations were synthesized with metathesis reactions. Structural characterization was accomplished for them by using the element analysis, Fourier transform infrared spectroscopy (FT‐IR), NMR and mass spectrum, and X‐ray single crystal diffraction. Thermal analysis for the title salts were determined by means of differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) as well as the calculation of non‐isothermal kinetic parameters. Consequently, both salts shown acceptable thermal stabilities as the decomposition temperatures were over 200 °C. The enthalpies of formation were calculated for these salts using the measured combustion energies with a result of 70.6 kJ · mol^–1 for 1 and –47.8 kJ · mol^–1 for 2 , respectively. Impact and friction sensitivities were also tested and the results indicated that these salts both have low sensitivities (>40 J, 120 N). The title energetic salts possess acceptable performance, they can therefore be applied in the field of energetic materials.     

Synthesis,characterization and antimicrobial activity of β-aminovinylphosphonium salts derived from aromatic amino acids

This study presents the synthesis, characterization and antimicrobial activity evaluation of β-aminovinyl-phosphonium salts derived from aromatic amino acids. The compounds were prepared in the reaction of (formylmethyl)triphenylphosphonium chloride with various aromatic amino acids and their structures were determined by elemental analysis, IR and NMR spectroscopy. All synthesized compounds were tested for their antibacterial and antifungal activity.