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The structure-directing "key-to-lock" interaction of double σ-(I III )-hole donating iodonium cations with the O-flanked pseudo-lacune rims of [β-Mo 8 O 26 ] 4- gives halogen-bonded iodonium-beta-octamolybate supramolecular associates. In the occurrence of their tetragonal pyramidal motifs, deep and broad σ-(I III )-holes of a cation recognize the molybdate backbone, which provides an electronic pool localized around the two lacunae. The halogen-bonded I⋯O linkages in the structures were thoroughly studied computationally and classified as two-center, three-center bifurcated, and unconventional "orthogonal" I⋯O halogen bonds. In the latter, the O-atom approaches orthogonally the C-I III -C plane of an iodonium cation and this geometry diverge from the IUPAC criteria for the identification of the halogen bond., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

This work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)N x /SiN x refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiN x nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young's modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiN x nano-layer, k p values decrease significantly from 3.36 × 10 -8 g 2 cm -4 h -1 to 6.06 × 10 -9 g 2 cm -4 h -1 . The activation energy increases from 90.8 kJ·mol -1 for (AlTiZrHfTa)N x nitride coating to 126.52 kJ·mol -1 for the (AlTiZrHfTa)N x /SiN x nano-layered coating. The formation of a FCC (AlTiZrHfTa)-N x /a-SiN x nano-layered architecture results in the improvement of the resistance to oxidation at high temperature.

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but examples reported to date exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed cross-coupling reaction of an oxoverdazyl radical bearing three iodo-phenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼125 °C in an inert atmosphere; in a toluene solution upon prolonged heating at 90 °C in air, no decomposition was observed. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a range of experimental and theoretical techniques, such as SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry, and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

Various five-membered cyclic dibenzobromolium salts (dibenzo[ b , d ]bromol-5-ium chloride, nitrate, hydrogen sulfate, dihydrogen phosphate, trifluoroacetate, and tetrafluoroborate) were prepared by diazotization-cyclization of 2'-bromo-[1,1'-biphenyl]-2-amine in solution of appropriate acids. The chlorolium analogues (iodide, trifluoroacetate, and tetrafluoroborate) were obtained by a similar procedure. Additional dibenzohalolium derivatives (dibenzo[ b , d ]bromol-5-ium and dibenzo[ b , d ]chlorol-5-ium azides, bis(trifluoromethanesulfonyl)imidates, thiocyanates, and trifluoromethanesulfonates) were prepared by anion exchange. Structures of ten of these dibenzohalolium derivatives were established by X-ray analysis. Bond distances and angles for the halogen atoms in different dibenzohalolium derivatives were summarized and discussed., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

We designed 0D, 1D, and 2D supramolecular assemblies made of diaryliodonium salts (functioning as double σ-hole donors) and carboxylates (as σ-hole acceptors). The association was based on two charge-supported halogen bonds (XB), which occurred between I III sites of the iodonium cations and the carboxylate anions. The sequential introduction of the carboxylic groups in the aryl ring of the benzoic acid added a dimension to the 0D supramolecular organization of the benzoate, which furnished 1D-chained and 2D-layered structures when terephthalate and trimesate anions, correspondingly, were applied as XB acceptors. The structure-directing XB were studied using DFT calculations under periodic boundary conditions and were followed by the one-electron-potential analysis and the Bader atoms-in-molecules topological analysis of electron density. These theoretical methods confirmed the existence of the XB and verified the philicities of the interaction partners in the designed solid-state structures.

We developed an atom- and reaction mass efficient strategy for the preparation of diarylselenides using iodonium salts as reactants. The developed approach allows the obtaining of diarylselenides from the corresponding trimethoxyphenyl-substituted iodonium salts via a two-step one-pot reaction sequence. The proposed metal-free methodology is based on the involvement of both iodonium aryl groups for diarylation.

The development of novel photo-dynamic therapy (PDT) agents enabling to treat the oxygen-deficient tumors is the emerging tasks for the modern medicinal chemistry. Herein, we describe the design and preparation of water-soluble agents for PDT which generate active radical species upon light irradiation. Two conjugates of carbohydrates with 1,2,4,6-substituted-1,4-dihydro-1,2,4,5-tetrazin-3(2H)-ones (AlkVZs) demonstrated high oxygen-independent cytotoxicity on PC-3 and Jurkat cancer cells under light irradiation combining with low toxicity in the dark. The efficacy of prepared compounds was estimated using MTT and Alamar Blue tests as well as microscopic dead/live colored images and flow cytometry. The analysis of obtained results reveals the influence of sugar moiety on the activity of AlkVZs. We believe that obtained compounds have high potency as platform for design of new agents for photo-dynamic therapy., (© 2023 Wiley-VCH GmbH.)

Five new copper(I) complexes─composed of the paired dibenzohalolium and [CuL 2 ] - (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) 4 ](BF 4 ), sodium 1,2,4-oxadiazolates, and dibenzohalolium triflates (or trifluoroacetates). This reaction is different from the previously reported Cu I -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. According to performed theoretical calculations, this noncovalent interaction (or noncovalent chelation) was recognized as the main force in the stabilization of the copper(I) complexes. An explanation for the different behavior of complexes, which provide either chelate or nonchelate binding, is based on the occurrence of additional -CH 3 ···π interactions, which were also quantified.

The arylation of azaheterocycles can be considered as one of the most important processes for the preparation of various biologically active compounds. In the present work, we describe a method for the copper-catalyzed N -arylation of hindered oxazolidinones using diaryliodonium salts. The method succeeds in good to excellent yields for the arylation of 4-alkyloxazolidinones, including sterically hindered isopropyl- and tert -butyl-substituted. The efficiency of the method was demonstrated for a wide range of diaryliodonium salts - symmetric and unsymmetric as well as ortho -substituted derivatives. The developed approach will provide an important contribution in the development and preparation of novel drugs and bioactive molecules containing oxazolidinone moieties.

A single-crystal X-ray diffraction (XRD) study of diaryliodonium tetrachloroaurates (or, in the recent terminology, tetrachloridoaurates), [( p -XC 6 H 4 ) 2 I][AuCl 4 ] (X = Cl, 1 ; Br, 2 ), was performed for 1 (the structure is denoted as 1a to show similarity with the isomorphic structure 2a ) and two polymorphs─ 2a (obtained from MeOH) and 2b (from 1,2-C 2 H 4 Cl 2 ). Examination of the XRD data for these three structures revealed 2-center C-X···Au III (X = Cl and Br) and 3-center bifurcated C-Br···( Cl - Au ) halogen bonding (abbreviated as XB) between the p -Cl or p -Br atoms of the diaryliodonium cations and the gold(III) atom of [AuCl 4 ] - . The noncovalent nature of Au III -involving interactions, the nucleophilicity of the gold(III) atoms, and the electrophilic role of p -X atoms of the diaryliodonium cations in the XBs were studied by a set of complementary computational methods. Combined experimental and theoretical studies allowed the recognition of the d-nucleophilicity of the [d 8 Au III ] atom which, regardless of its rather substantial formal 3+ charge, can function as a d-nucleophilic partner of XB. This conclusion was also supported by theoretical calculations performed for the structures' refcodes BINXOM and ICSD 62511; the obtained data verified the nucleophilicity of Au III toward a K + ions or a σ-(Cl)-hole, respectively. All our results, together with consideration of relevant literature, indicate that gold atoms in the three oxidation states (0, I, and even III) exhibit nucleophilicity in XBs.

The intramolecular oxidative cycloaddition reaction of alkyne- or alkene-tethered aldoximes was catalyzed efficiently by hypervalent iodine(III) species to afford the corresponding polycyclic isoxazole derivatives in up to a 94% yield. The structure of the prepared products was confirmed by various methods, including X-ray crystallography. Mechanistic study demonstrated the crucial role of hydroxy(aryl)iodonium tosylate as a precatalyst, which is generated from 2-iodobenzoic acid and m -chloroperoxybenzoic acid in the presence of a catalytic amount of p -toluenesulfonic acid.

The data presented in this article are related to the published research of "Effect of nitrogen content on structural and mechanical properties of AlTiZrTaHf(-N) high entropy films deposited by reactive magnetron sputtering". This database contains X-ray photoelectron spectroscopy (XPS) measurements, performed in order to determine the extents of nitrides formed in AlTiTaZrHf high entropy films. The latter were prepared by DC magnetron sputtering technique in reactive mode by adding the nitrogen to argon gas. The nitrogen flow rate is calculated by R N2  = N 2 /(N 2 +Ar). XPS measurements were done one month later. Oxides were detected on the top surface of the samples. 2p, 3d and 4f core level peaks were fitted in order to determine accurately the chemical composition of the nitride films. Al2p, Ti2p, Zr3d, Ta4f, and Hf4f reveal the formation of nitrides of all elements constituting the films. Atomic percentage of each element was calculated revealing an increase of nitrogen loading and decrease of the metallic fractions of the elements as R N2 grows from 5% to 50%. Nitridation behaviour of each element, as a function of the nitrogen flow rate, is investigated and presented., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Porous architectures characterized by parallel channels arranged in honeycomb or rectangular patterns are identified in two polymorphic crystals of a zwitterionic 4-(aryliodonio)-benzenesulfonate. The channels are filled with disordered water molecules which can be reversibly removed on heating. Consistent with the remarkable strength and directionality of the halogen bonds (XBs) driving the crystal packing formation, the porous structure is stable and fully preserved on almost quantitative removal and readsorption of water. The porous systems described here are the first reported cases of one-component 3D organic frameworks whose assembly is driven by XB only (XOFs). These systems are a proof of concept for the ability of zwitterionic aryliodonium tectons in affording robust one-component 3D XOFs. The high directionality and strength of the XBs formed by these zwitterions and the geometrical constraints resulting from the tendency of their hypervalent iodine atoms to act as bidentate XB donors might be key factors in determining this ability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Two alkylated verdazyl radicals (AlkVZs) were investigated as active compounds for photoinitiated controlled MCF-7 cell death. Observed results unambiguously showed that AlkVZ could be a potential structural moiety for the design of a novel family of photodynamic therapy agents. The main advantage of the proposed substances is an oxygen-independent generation of active radicals, which play a pivotal role in the treatment of oxygen-deficient tumors.

Hypervalent iodine heterocycles represent one of the important classes of hypervalent iodine reagents with many applications in organic synthesis. This paper reports a simple and convenient synthesis of benziodazolones by the reaction of readily available iodobenzamides with m -chloroperoxybenzoic acid in acetonitrile at room temperature. The structure of one of these new iodine heterocycles was confirmed by X-ray analysis. In combination with PPh 3 and pyridine, these benziodazolones can smoothly react with alcohols or amines to produce the corresponding esters or amides of 3-chlorobenzoic acid, respectively. It was found that the novel benziodazolone reagent reacts more efficiently than the analogous benziodoxolone reagent in this esterification.

Modified colloids and flat surfaces occupy an important place in materials science research due to their widespread applications. Interest in the development of modifiers that adhere strongly to surfaces relates to the need for stability under ambient conditions in many applications. Diazonium salts have evolved as the primary choice for the modification of surfaces. The term "diazonics" has been introduced in the literature to describe "the science and technology of aryldiazonium salt-derived materials". The facile reduction of diazonium salts via chemical or electrochemical processes, irradiation stimuli, or spontaneously results in the efficient modification of gold surfaces. Robust gold-aryl nanoparticles, where gold is connected to the aryl ring through bonding to carbon and films modified by using diazonium salts, are critical in electronics, sensors, medical implants, and materials for power sources. Experimental and theoretical studies suggest that gold-carbon interactions constructed via chemical reactions with diazonium salts are stronger than nondiazonium surface modifiers. This invited feature article summarizes the conceptual development of recent studies of diazonium salts in our laboratories and others with a focus on the surface modification of gold nanostructures, flat surfaces and gratings, and their applications in nanomedicine engineering, sensors, energy, forensic science, and catalysis.

Thermally resistant air-stable organic triradicals with a quartet ground state and a large energy gap between spin states are still unique compounds. In this work, we succeeded to design and prepare the first highly stable triradical, consisting of oxoverdazyl and nitronyl nitroxide radical fragments, with a quartet ground state. The triradical and its diradical precursor were synthesized via a palladium-catalyzed cross-coupling reaction of diiodoverdazyl with nitronyl nitroxide-2-ide gold(I) complex. Both paramagnetic compounds were fully characterized by single-crystal X-ray diffraction analysis, superconducting quantum interference device magnetometry, EPR spectroscopy in various matrices, and cyclic voltammetry. In the diradical, the verdazyl and nitronyl nitroxide centers demonstrated full reversibility of redox process, while for the triradical, the electrochemical reduction and oxidation proceed at practically the same redox potentials, but become quasi-reversible. A series of high-level CASSCF/NEVPT2 calculations was performed to predict inter- and intramolecular exchange interactions in crystals of di- and triradicals and to establish their magnetic motifs. Based on the predicted magnetic motifs, the temperature dependences of the magnetic susceptibility were analyzed, and the singlet-triplet (135 ± 10 cm -1 ) and doublet-quartet (17 ± 2 and 152 ± 19 cm -1 ) splitting was found to be moderate. Unique high stability of synthesized verdazyl-nitronylnitroxide triradical opens new perspectives for further functionalization and design of high-spin systems with four or more spins.

A novel approach to the preparation of imidazole-substituted cyclic iodonium salts has been developed via the oxidative cyclization of 1-phenyl-5-iodoimidazole using a cheap and available Oxone/H 2 SO 4 oxidative system. The structure of the new polycyclic heteroarenes has been confirmed by single-crystal X-ray diffractometry, revealing the characteristic structure features for cyclic iodonium salts. The newly produced imidazole-flanked cyclic iodonium compounds were found to readily engage in a heterocyclization reaction with elemental sulfur, affording benzo[5,1- b ]imidazothiazoles in good yields.

Thermally stable organic diradicals with a triplet ground state along with large singlet-triplet energy gap have significant potential for advanced technological applications. A series of phenylene-bridged diradicals with oxoverdazyl and nitronyl nitroxide units were synthesized via a palladium-catalyzed cross-coupling reaction of iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields. The diradicals exhibit high stability and do not decompose in an inert atmosphere up to 180 °C. For the diradicals, both substantial AF (ΔE ST ≈-64 cm -1 ) and FM (ΔE ST ≥25 and 100 cm -1 ) intramolecular exchange interactions were observed. The sign of the exchange interaction is determined both by the bridging moiety (para- or meta-phenylene) and by the type of oxoverdazyl block (C-linked or N-linked). Upon crystallization, diradicals with the triplet ground state form unique one-dimensional exchange-coupled chains with strong intra- and weak inter-diradical ferromagnetic coupling., (© 2020 Wiley-VCH GmbH.)

The on-demand generation of stable organic radicals from the precursors can be considered as an essential challenge for the plethora of applications in various fields of science. In this contribution, we prepared a range of N-(methyl)benzyl derivatives of 6-oxoverdazyl via atom transfer radical addition from moderate to high yields and studied their thermal- and photo-initiated homolysis. The kinetics of homolysis was measured, and the dissociating rate constant k d , activation energy E a and frequency factor A were estimated. Variation of the substituent at the C3-position of the verdazyl ring was successfully applied for fine-tuning the homolysis rate: the value of k d was higher for alkylverdazyls with electron-withdrawing groups, e.g., the para nitro group afforded a 6-fold increase in k d . In contrast to thermal homolysis, the rate of photoinduced decomposition depends on both the extinction coefficient and the value of activation energy. Thus, nitro-containing alkylated verdazyls show the highest homolysis rate in both types of initiations. The achieved results afford a novel opportunity in the controlled generation of verdazyls and further application of these compounds in medicine and chemical industry.

Plasmon-assisted transformations of organic compounds represent a novel opportunity for conversion of light to chemical energy at room temperature. However, the mechanistic insights of interaction between plasmon energy and organic molecules is still under debate. Herein, we proposed a comprehensive study of the plasmon-assisted reaction mechanism using unsymmetric iodonium salts (ISs) as an organic probe. The experimental and theoretical analysis allow us to exclude the possible thermal effect or hot electron transfer. We found that plasmon interaction with unsymmetrical ISs led to the intramolecular excitation of electron followed by the regioselective cleavage of C-I bond with the formation of electron-rich radical species, which cannot be explained by the hot electron excitation or thermal effects. The high regioselectivity is explained by the direct excitation of electron to LUMO with the formation of a dissociative excited state according to quantum-chemical modeling, which provides novel opportunities for the fine control of reactivity using plasmon energy.

An antiferromagnetically (AFM) coupled biradical based on oxoverdazyl and nitronylnitroxide was synthesized in 46 % yield using Sonogashira coupling. The obtained heterobiradical evidenced distinct properties of both radical entities in solution. Depending on the solvent, the prepared biradical crystallized in two different forms. SQUID magnetization measurements on Form II showed coupling constants J intraII /k B =-2.1 K and zJ interII /k B =-11.5 K. Consequently, total intermolecular exchange interactions are five times larger than the intramolecular ones. Further, DFT calculations explained this phenomenon and indicated the advantage of Form I for further in-depth investigations., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

The present research was undertaken to develop a chitosan-collagen film for controlled delivery of combinations of local anesthetics. The film has been prepared by casting which is a versatile, rapid and low-cost approach distinguished by high reproducibility. The mechanical, morphological, and physicochemical properties of the films and the impact of the drug loading were evaluated. We showed that the formulations have a good combination of strength and flexibility with high water permeability. Surface morphology investigation indicates a variation in roughness depending on the loaded compound. Release studies were performed in controlled environments and the data processed by the Higuchi model to assess the dynamics of the release. The local anesthetics, lidocaine, tetracaine, and benzocaine, were uniformly distributed within the matrix and released in a rate and magnitude specific for the drug concentration and combination tunable in a range time from 6 h to 24 h. The films dissolve completely in the physiological environment within 24 h without leaving any toxic metabolites as both of the components are recognized as safe. In vitro cytotoxicity and cell proliferation tests performed on human dermal fibroblast demonstrate the biocompatibility and lack of cytotoxicity of the prepared formulations., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The thermal stability of pseudocyclic and cyclic N -heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-λ 3 -iodanes (NHIs) through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is investigated. Peak decomposition temperatures ( T peak ) were observed within a wide range between 120 and 270 °C. Decomposition enthalpies (Δ H dec ) varied from -29.81 to 141.13 kJ/mol. A direct comparison between pseudocyclic and cyclic NHIs revealed high T peak but also higher Δ H dec values for the latter ones. NHIs bearing N -heterocycles with a high N/C-ratio such as triazoles show among the lowest T peak and the highest Δ H dec values. A comparison of NHIs with known (pseudo)cyclic benziodoxolones is made and we further correlated their thermal stability with reactivity in a model oxygenation., (Copyright © 2019, Boelke et al.; licensee Beilstein-Institut.)

A ditriflate derivative of 2-iodoxybenzoic acid (IBX) was prepared by the reaction of IBX with trifluoromethanesulfonic acid and characterized by single crystal X-ray crystallography. IBX-ditriflate is the most powerful oxidant in a series of structurally similar IBX derivatives which is best illustrated by its ability to readily oxidize hydrocarbons and the oxidation resistant polyfluoroalcohols.

The work is focused on the development of microspheres based on the combination of two polysaccharides; chitosan and alginic acid with the aim to allocate, hold, release and protect environmentally sensible molecules. The microspheres were prepared using a solvent-free, low cost and scalable approach and two enzymes; trypsin and protease from Aspergillus Oryzae have been used as a model to evaluate the microspheres peculiarities. The proteins were encapsulated during the microspheres preparation. The relationship between the polysaccharides weight ratio and the morphology, stability and ability of the carrier to allocate the enzymes has been evaluated. The enzymatic activity and the release kinetics were assessed in different conditions to assess the impact of the external environment. Obtained results demonstrate the efficacy of the prepared microspheres to preserve the activity of relevant bioactive compounds which are highly relevant in food, cosmetic and pharmaceutic, but the application is limited due to their high sensibility., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this contribution, we propose a novel functional surface-enhanced Raman spectroscopy (SERS) platform for the detection of one of the most hazardous heavy metal ions, Hg 2+ . The design of the proposed sensor is based on the combination of surface plasmon-polariton (SPP) supporting gold grating with the high homogeneity of the response and enhancement and mercaptosuccinic acid (MSA) based specific recognition layer. For the first time, diazonium grafted 4-ethynylphenyl groups have undergone the sunlight-induced thiol-yne reaction with MSA in the presence of Eosine Y. The developed SERS platform provides an extremely sensitive, selective, and convenient analytical procedure to detect mercury ions with limit of detection (LOD) as low as 10 -10 M (0.027 µg/L) with excellent selectivity over other metals. The developed SERS sensor is compatible with a portable SERS spectrophotometer and does not require the expensive equipment for statistical methods of analysis.

A new practical procedure of imination for sulfide has been developed. The treatment of ( N -tosylimino)-phenyl-λ³-iodane, PhINTs, with various sulfides in the presence of a catalytic amount of I₂ under metal-free conditions affords the corresponding N -tosylsulfilimine compounds with moderate to good yields. This facile transfer procedure of the sulfonylimino group can also be applied to triphenylphosphine to produce the respective iminotriphenylphosphoranes in high yields. According to the reaction mechanism studies, the process of imination from ( N -tosylimino)-phenyl-λ³-iodane to sulfide under the conditions may involve radical steps within the reaction mechanism.

Pseudocyclic 2-benzimidazolyl-substituted diaryliodonium salts were obtained by the reaction of the corresponding [hydroxy(tosyloxy)iodo]arenes with arenes in the presence of trifluoromethanesulfonic acid. X-ray structural analysis of these iodonium salts confirmed their pseudocyclic structure with a short (2.57-2.58 Å) noncovalent I···N interaction. Treatment of 2-benzimidazolyl-substituted diaryliodonium triflates with a base afforded novel five-membered iodine-nitrogen heterocycles.

β-carotene is a natural compound with significant antioxidant activity. However, its poor solubility in water and low stability reduce its potential application. Innovative polyplexes based on the combination of amphiphilic chitosan assembled with DNA have been developed using a solvent-free, simple and low-cost method with the aim to load, retain and enhance the antioxidant capability of β-carotene. The polyplexes, with dimension about 100 nm, and excellent stability, were able to hold up to 400 μg of β-carotene per mg of the carrier, with minimal loss till two weeks. The antioxidant activity was significantly enhanced after loading, as demonstrated using two well known methods. Cytotoxicity assay confirmed the not toxicity of the system. The results suggest the polyplexes as an excellent candidate to develop formulation able to preserve and enhance the peculiarities of compounds which are used mainly in food, cosmetic and pharmaceutic but with still some limitations., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Phenol based aryliodonium salts were prepared by the reaction of [hydroxy(tosyloxy)iodo]arenes with aryl silyl ethers in the presence of trifluoromethanesulfonic acid. Structures of several aryliodonium salts with the hydroxy group in the para-position of the phenyl ring were established by single crystal X-ray crystallography. Under basic conditions, 4-hydroxyphenyl(phenyl)iodonium salts form a dimeric hypervalent iodine(iii) complex, oxyphenyl(phenyl)iodonium ylidic salt, the solid structure of which was confirmed by X-ray crystallography. Phenolic iodonium salts are potentially useful phenol transfer reagents in reactions with various anionic nucleophiles.

The selective preparation of 2-iodoxybenzenesulfonic acid (IBS, as potassium or sodium salts) by oxidation of sodium 2-iodobenzenesulfonate with Oxone or sodium periodate in water is reported. The single crystal X-ray diffraction analysis reveals a complex polymeric structure consisting of three units of IBS as potassium salt and one unit of 2-iodoxybenzenesulfonic acid linked together by relatively strong I=O···I intermolecular interactions. Furthermore, a new method for the preparation of the reduced form of IBS, 2-iodosylbenzenesulfonic acid, by using periodic acid as an oxidant, has been developed. It has been demonstrated that the oxidation of free 2-iodobenzenesulfonic acid under acidic conditions affords an iodine(III) heterocycle (2-iodosylbenzenesulfonic acid), while the oxidation of sodium 2-iodobenzenesulfonate in neutral aqueous solution gives the iodine(V) products.

An innovative microcarrier based on a carboxy-enriched and branched polylactic acid derivative was developed to enhance the in vitro phototoxicity of the photosensitizer and prodrug 5-aminolevulinic. Microparticles, prepared by double emulsion technique and loaded with the prodrug were carefully characterized and the effect of the polymer structure on the chemical, physical and biological properties of the final product was evaluated. Results showed that microparticles have a spherical shape and ability to allocate up to 30 μg of the photosensitizer per mg of carrier despite their difference in solubility. Release studies performed in various simulated physiological conditions demonstrate the influence of the branched structure and the presence of the additional carboxylic groups on the release rate and the possibility to modulate it. In vitro assays conducted on human epithelial adenocarcinoma cells proved the not cytotoxicity of the carriers in a wide range of concentrations. The hemocompatibility and surface proteins adsorption were evaluated at different microparticles concentrations to evaluate the safety and estimate the possible microparticles residential time in the bloodstream. The advantages, of loading 5-aminolevulinic acid in the prepared carrier has been deeply described in terms of enhanced phototoxicity, compared to the free 5-aminolevulinic acid formulation after irradiation with light at 635 nm. The obtained results demonstrate the advantages of the prepared derivative compared to the linear polylactide for future application in photodynamic therapy based on the photosensitizer 5-aminolevulinic acid., (Copyright © 2018 Elsevier B.V. All rights reserved.)

New organohypervalent iodine compounds, arylbenziodoxaborole triflates, were prepared from 1-acetoxybenziodoxaboroles and arenes by treatment with trifluoromethanesulfonic acid under mild conditions. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.698 to 2.717 Å between oxygen and iodine in the benziodoxaborole ring. These new pseudocyclic aryliodonium salts readily generate aryne intermediates upon treatment with water at room temperature. The generated aryne intermediates react with various substrates to give the corresponding aryne adducts in moderate to good yields. Furthermore, the new benzyne precursors can also work as arylating reagents towards aromatic rings. The aryne intermediates generated from arylbenziodoxaborole triflates selectively react with tert-butyl phenol forming products of ortho arylation in moderate yields., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient cycloaddition of heterocyclic alkenes with nitrile oxides generated in situ from the corresponding aldoximes using organohypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (Koser's reagent), has been developed. The oxidative cyclization of various aldoximes with 1-propene-1,3-sultone affords the respective isoxazoline-ring-fused heterobicyclic products in moderate to good yields. Furthermore, the reaction of aldoxime with a cyclic phospholene-oxide under similar conditions produces the corresponding heterobicyclic phospholene oxides in moderate yields. The structures of bicyclic phospholene oxide and two sultones were established by single-crystal X-ray crystallography.

Polysaccharides based nanocomplexes have been developed for encapsulation, controlled delivery and to enhance the phototoxicity of the photosensitizer 5-aminolevulinic acid for application in photodynamic therapy. The nanocomplexes were prepared by coacervation in a solvent free environment using chitosan as polycation while alginic and polygalacturonic acid as polyanions. The complexes showed average dimension in the range 90-120nm, good stability in simulated physiological media and high drug encapsulation efficiency, up to 800μg per mg of carrier. Release studies demonstrate the possibility to tune the overall release rate and the intensity of the initial burst by changing the external pH. Cytotoxicity and photocytotoxicity tests confirmed the not toxicity of the used polysaccharides. Cell viability results confirmed the improvement of 5-aminolevulinic acid phototoxicity when loaded into the carrier compared to the free form. No effect of the irradiation on the nanocomplexes structure and on the release kinetics of the drug was observed. The results demonstrate that the prepared formulations have suitable properties for future application in photodynamic therapy and to ameliorate the therapeutic efficacy and overcome the side-effects related to the use of the photosensitizer 5-aminolevulinic acid., (Copyright © 2017. Published by Elsevier B.V.)

The use of organic-inorganic hybrid nanocarriers for controlled release of anticancer drugs has been gained a great interest, in particular, to improve the selectivity and efficacy of the drugs. In this study, iron oxide nanoparticles were prepared then surface modified via diazonium chemistry and coated with chitosan, and its derivative chitosan-grafted polylactic acid. The purpose was to increase the stability of the nanoparticles in physiological solution, heighten drug-loading capacity, prolong the release, reduce the initial burst effect and improve in vitro cytotoxicity of the model drug doxorubicin. The materials were characterized by DLS, ζ-potential, SEM, TGA, magnetization curves and release kinetics studies. Results confirmed the spherical shape, the presence of the coat and the advantages of using chitosan, particularly its amphiphilic derivative, as a coating agent, thereby surpassing the qualities of simple iron oxide nanoparticles. The coated nanoparticles exhibited great stability and high encapsulation efficiency for doxorubicin, at over 500μg per mg of carrier. Moreover, the intensity of the initial burst was clearly diminished after coating, hence represents an advantage of using the hybrid system over simple iron oxide nanoparticles. Cytotoxicity studies demonstrate the increase in cytotoxicity of doxorubicin when loaded in nanoparticles, indirectly proving the role played by the carrier and its surface properties in cell uptake., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Surface-modified gold multibranched nanoparticles (AuMs) were prepared by simple chemical reduction of gold chloride aqueous solution followed by in situ modification by using water-soluble arenediazonium tosylates with different functional organic groups. Chemical and morphological structures of the prepared nanoparticles were examined by using transmission electron and scanning electron microscopies. The covalent grafting of organic compounds was confirmed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and Raman spectroscopy techniques. Covalent functionalization of nanoparticles significantly expands the range of their potential uses under physiological conditions, compared with traditional non-covalent or thiol-based approaches. The antibacterial effect of the surface-modified AuMs was evaluated by using Escherichia coli and Staphylococcus epidermidis bacteria under IR light illumination and without external triggering. Strong plasmon resonance on the AuMs cups leads to significant reduction of the light power needed kill bacteria under the mild conditions of continuous illumination. The effect of the surface-modified AuMs on the light-induced antibacterial activities was founded to be dependent on the grafted organic functional groups.

New pseudocyclic benziodoxole tosylates were prepared by the treatment of 1-hydroxybenziodoxolones with p-toluenesulfonic acid or via ligand transfer reaction between PhI(OH)OTs (Koser's reagent) and substituted 2-iodobenzoic acids under mild condition. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.362 Å between oxygen and iodine in the iodoxole ring. Pseudocyclic benziodoxole tosylates readily react with various organic substrates as electrophiles or oxidants to afford the corresponding iodonium salts or the products of oxidation. Furthermore, these compounds can be used as efficient recyclable hypervalent iodine reagents. The reduced form of a pseudocyclic benziodoxole tosylate, 2-iodobenzoic acid, can be efficiently recovered from the reaction mixture by a simple acid-base liquid-liquid biphasic procedure., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Gastric ulceration properties (gastrointestinal toxicity) of the sodium salt of 4-(0-β-D-glucopyranosyloxy) benzoic acid, a new nonsteroidal anti-inflammatory drug (NSAID) intended for the treatment of chronic inflammatory diseases of the kidney and urinary tract, have been tested on laboratory animals. Acute NSAID-induced gastropathy was induced in rats by oral administration of indomethacin, nimesulide, diclofenac, acetylsalicylic acid and the new drug. Test animals were killed by instantaneous decapitation 4 h after treatment and their gastrointestinal tracts were studied by pathomorphological methods on micropreparations and histological sections of gastric mucosa. It was established that the new drug, in contrast to reference NSAIDS, did not exhibit gastropathic action on the gastric mucosa.

We have evaluated the anti-inflammatory activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid in comparison to well-known nonsteroidal anti-inflammatory drugs (NSAIDs). Carrageenan suspension (1%, 0.1 mL) was injected into subplantar region of the right hindpaw of rats (n = 12) pretreated (7 days and 60 min before carrageenan injection) intragastrically with methyl ester of 4(β-D-glucopyranosyloxy)benzoic acid (20 mg/kg), acetylsalicylic acid (20 mg/kg), 4-hydroxybenzoic acid (20 mg/kg), or vehicle (2 mL of purified water). Paw edema volume was measured plethysmographically at 1, 2 and 4 h after carrageenan injection. The results showed that intragastric administration of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid in a dose of 20 mg/kg for 7 days decreased the intensity of experimental inflammation.

It was compared the diuretic activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid for enteral (intragastric) and parenteral ways of administration. The test substance was administered enterally and parenterally (subcutaneously in the region of the withers) in a daily dose of 18 µmol/kg for the first seven days and in a dose of 54 mmol/kg for the next seven days. Diuretic activity of the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid was evaluated in terms of urine volume. Urine was analyzed for creatinine and the concentration of sodium, potassium and chloride ions. Experiments showed that the sodium salt of 4-(O-β-D-glucopyranosyloxy)benzoic acid produced a diuretic effect only for the enteral administration route.

New experimental procedures for the preparation of dibenziodolium salts by oxidative cyclization of 2-iodobiphenyl in the presence of appropriate strong acids are described. Particularly useful is a convenient one-pot synthesis of dibenziodolium hydrogen sulfate from 2-iodobiphenyl using Oxone as an inexpensive and environmentally safe oxidant. Dibenziodolium hydrogen sulfate, bis(triflyl)imidate, or triflate can be readily converted to various other dibenziodolium derivatives (chloride, bromide, thiocyanate, azide, cyanide, phenylsulfinate) by anion exchange. Structures of key products have been established by single-crystal X-ray diffraction analysis. Particularly interesting is the X-ray structure of dibenziodolium thiocyanate, which represents the first example of a structurally characterized hypervalent iodine compound with a relatively short iodine-sulfur secondary bond distance.

A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs) based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs) were prepared by simple chemical reduction of iron(III) chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material.

An environmentally friendly Matsuda-Heck reaction with arenediazonium tosylates has been developed for the first time. A range of alkenes was arylated in good to quantitative yields in water. The reaction is significantly accelerated when carried out under microwave heating. The arylation of haloalkylacrylates with diazonium salts has been implemented for the first time.