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A convenient methodology for constructing 6,6‐difluorospiro[3.3]heptane scaffold – a conformationally restricted isoster of gem‐difluorocycloalkanes – is developed. A large array of novel 2‐mono‐ and 2,2‐bifunctionalized difluorospiro[3.3]heptane building blocks was obtained through the convergent synthesis strategy using a common synthetic precursor – 1,1‐bis(bromomethyl)‐3,3‐difluorocyclobutane. The target compounds and intermediates were prepared by short reaction sequences (6–10 steps) on a multigram scale (up to 0.47 kg). [ABSTRACT FROM AUTHOR]

The development of methodologies to control on demand and reversibly supramolecular transformations from self‐assembled metalla‐structures requires the rational design of architectures able to answer to an applied stimulus. While solvent or concentration changes, light exposure or addition of a chemical have been largely explored to provide these transformations, the case of pH sensitive materials is less described. Herein, we report the first example of a pH‐triggered dissociation of a coordination‐driven self‐assembled interlocked molecular link. It incorporates a pH sensitive benzobisimidazole‐based ligand that can be selectively protonated on its bisimidazole moieties. This generates intermolecular electrostatic repulsions that reduces drastically the stability of the interlocked structure, leading to its dissociation without any sign of protonation of the pyridine moieties involved in the coordination bonds. Importantly, the dissociation process is reversible through addition of a base. [ABSTRACT FROM AUTHOR]

Diversity-oriented approach to large artificial macrocycle libraries with a ring size of 13-18 atoms relying on the "build-couple-pair" strategy is disclosed. The "couple" phase included three one-pot steps including consequent amide coupling of N-Boc-monoprotected vicinal diamines with two alkenyl carboxylic acids, followed by ring-closing metathesis as the key "pair" step. The scope and limitations of the method were established for all three reagents. In particular, various acyclic, mono- and bicyclic aliphatic diamine derivatives with the N-C-C-N dihedral angle less than ca. 130° appeared to be suitable substrates. The proposed approach was used to construct a virtual library of 1.8·105 macrocycles derived from 12,283 different scaffolds. More than 40% of members of this library contained a protected amino function and hence can be suitable for the post-pairing modification, thus giving rise to at least a billionsize chemical space based on the REAL-type synthetic methodology. Validation of the approach under parallel synthesis conditions on a 383-member subset showed a 61% success rate over the whole 4-5-step reaction sequence. Finally, the synthetic approach also worked on a gram scale (up to 8.0 g). [ABSTRACT FROM AUTHOR]

Formyl MIDA boronate has been known to be an elusive type of acylboronate that has not been obtained to date. In this work, an approach to the one‐pot preparation and chemical transformations of formyl MIDA boronate were developed to provide new types of α‐functionalized organoboron compounds. Among them are acylboronate reagents which present boron‐substituted analogues of ynones and β‐dicarbonyl compounds. The developed synthetic procedures, utilizing formyl MIDA boronate, are tolerant to diverse functional groups, making this reagent an advantageous C1 building block for extending the scope of organoboron chemistry. [ABSTRACT FROM AUTHOR]

A protocol for the preparation of α‐boryl‐α‐bromoketones from alkenyl MIDA boronates was developed and applied to functionalized aliphatic derivatives. The reaction sequence included regioselective hydroxybromination of olefin moiety, followed by oxidation of alcohol group with Dess–Martin periodinane. The target trifunctional boronate‐containing derivatives were obtained in up to 94 % yield over two steps starting from alkenyl MIDA boronates. In some cases, functional groups present in the substrate participated in the bromohydroxylation step via intramolecular nucleophilic attack at the bromonium cation leading to cyclic products. Additionally, the reactivity of aliphatic α‐boryl‐α‐bromoketones was illustrated by nucleophilic substitution at the α‐C atom and heterocyclization reactions. [ABSTRACT FROM AUTHOR]

Developing methodologies for on‐demand control of the release of a molecular guest requires the rational design of stimuli‐responsive hosts with functional cavities. While a substantial number of responsive metallacages have already been described, the case of coordination‐tweezers has been less explored. Herein, we report the first example of a redox‐triggered guest release from a metalla‐assembled tweezer. This tweezer incorporates two redox‐active panels constructed from the electron‐rich 9‐(1,3‐dithiol‐2‐ylidene)fluorene unit that are facing each other. It dimerizes spontaneously in solution and the resulting interpenetrated supramolecular structure can dissociate in the presence of an electron‐poor planar unit, forming a 1:1 host–guest complex. This complex dissociates upon tweezer oxidation/dimerization, offering an original redox‐triggered molecular delivery pathway. [ABSTRACT FROM AUTHOR]

A novel fluorinated reagent for the synthesis of gem‐difluorostyrenes and their heterocyclic analogues – 2,2‐difluorovinyl pinacolborane (CF2=CHBPin) was developed. In particular, borylation of 1,1‐difluoroethylene with isopropoxy pinacolborane afforded the title compound on a multigram scale as stable, easy‐to‐handle liquid which can be stored at +4 °C for months. The Pd(dppf)Cl2‐catalyzed cross‐coupling of this reagent with (het)aryl and vinyl bromides works well with broad spectrum of substrates and is characterized by good yields, functional group tolerance, sufficient reproducibility, as well as scalability. [ABSTRACT FROM AUTHOR]

The paper reports experimental results on features of crystal structure and luminescent properties of the Eu1−xCayVO4 nanoparticles synthesized for the first time. The Eu1−xCaxVO4 compounds with x = 0, 0.05, 0.1, 0.15, and 0.20 are prepared by aqueous nitrate–citrate sol–gel synthesis. The obtained samples are characterized by XRD analysis. The Eu1−xCaxVO4 samples are crystallized in tetragonal structure. Phase composition of the sample depends on the x value. Increasing concentrations of the calcium ions leads to formation of the EuVO4 and CaV2O6 phases’ mixture. Luminescence properties of the synthesized Eu1−xCaxVO4 nanoparticles are considered in comparison with properties of the La1−x−yEuyCaxVO4 nanoparticles. Formation of two types of emission centers and arising of additional excitation band near 400 nm are observed for the both compositions. It is shown that second types of the emission centers have different structure and spectral characteristics for the Eu1−xCaxVO4 and La1−x−yEuyCaxVO4 nanoparticles, whereas the 400 nm excitation band has the same origin for the both compositions. [ABSTRACT FROM AUTHOR]

Abstract: Two M12L6 redox‐active self‐assembled cages constructed from an electron‐rich ligand based on the extended tetrathiafulvalene framework (exTTF) and metal complexes with a linear geometry (PdII and AgI) are depicted. Remarkably, based on a combination of specific structural and electronic features, the polycationic self‐assembled AgI coordination cage undergoes a supramolecular transformation upon oxidation into a three‐dimensional coordination polymer, that is characterized by X‐ray crystallography. This redox‐controlled change of the molecular organization results from the drastic conformational modifications accompanying oxidation of the exTTF moiety. [ABSTRACT FROM AUTHOR]

Eight alkyl triarylstannanecarbodithioates were synthesized starting from the corresponding triarylstannyl chlorides. They were fully characterized by IR and 1H, 13C, and 119Sn NMR spectroscopy and mass spectrometry. Their solid-state structures and geometric parameters were determined and compared to those of other classes of thiocarbonylthio compounds. These new organotin derivatives are efficient reversible chain-transfer agents for reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene (St) and n-butyl acrylate (BA), with controlled number-average molecular weights and narrow dispersities ( Ð<1.3). In some cases, loss of control of the polymerization was evidenced and supported by the observation of side products by 119Sn NMR spectroscopy. This phenomenon was attributed to the thermal instability of the Sn-RAFT terminal group. [ABSTRACT FROM AUTHOR]

[RuII(FT)(bipy)(NO)][PF6]3 [FT is the electron-rich 4'-(2-fluorenyl)-2,2':6',2"-terpyridine ligand and bipy is 2,2'-bipyridine] is synthesized and characterized. It crystallizes in the triclinic P1 space group [a = 9.5362(2) Å, b = 10.3946(4) Å, c = 22.5701(8) Å, α = 94.7400(10)°, β = 94.9400(10)°, γ = 101.0680(10)]. A photochemical study is presented in comparison with that of the parents cis(Cl,Cl)-[RuII(FT)Cl2(NO)][PF6] and trans(Cl,Cl)-[RuII(FT)Cl2(NO)][PF6]. The three derivatives release nitric oxide (·NO) under irradiation at λ = 405 nm with respective quantum yields of 0.06, 0.31, and 0.10. Their two-photon absorption (TPA) cross-sections (sTPA) were investigated by the Z-scan technique on related derivatives in which two hexyl chains were introduced to improve their solubility while their spectroscopic properties remained almost unaffected. The resulting σTPA values of 100 GM at λ = 800 nm are in the window of transparency for human tissues, and the bipyridine-based complex exhibits a slight tendency for higher efficiency. The replacement of the [RuII(Cl)2(NO)] core by [RuII(bipy)(NO)] provides a much simpler synthesis, and the TPA-induced ·NO-release capabilities are in the same range of magnitude. Therefore, it is envisioned that ·NO donors of greater complexity with several metal centers could be investigated in future. [ABSTRACT FROM AUTHOR]

The Mitsunobu alkylation of 4- tert-butylcalix[4]arene with ( S)-(2-diphenylthiophosphinoferrocenyl)methanol followed by desulfuration of the thiophosphine unit using tris(dimethylamino)phosphine afforded enantiomerically pure calixarene mono- and di(ferrocenylphosphine) ligands in high yields. The calixarene mono(ferrocenylphosphine) ligands exhibited good catalytic activity but low atropoenantioselectivity when used in the asymmetric Suzuki-Miyaura coupling reaction of 1-naphthaleneboronic acid and 1-bromo-2-methylnaphthalene. However, the di(ferrocenylphosphine) ligand displayed both good catalytic activity and enantioselectivity ( ee values up to 86 %) when employed in the asymmetric Tsuji-Trost allylic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. [ABSTRACT FROM AUTHOR]

The investigated La1-xRExVO4 (RE = Eu, Sm) solid solutions are characterized by intensive emission of the RE ions that is excited from the wide spectral range including UV region of intrinsic transitions in the vanadate host. We have carried out comparable analysis of characteristics of the La1-xRExVO4 compounds synthesized by three different methods: solid state reaction, co-precipitation and sol-gel synthesis. The investigation revealed differences in luminescence and excitation spectra of samples obtained by different methods. Spectra of the samples with lower activator concentrations have a more complicated character. They contain exceed number of lines that is caused by formation of two types of RE3+ emission centers. Spectral exhibitions of the second ('at surface') type of centers are observed up to x = 0.05, 0.1 and 0.3 for samples synthesized by solid state, co-precipitation and sol-gel methods, respectively. The presence of the 'at surface' type of centers leads to essential increasing of total intensity of emission. Differences in excitation spectra give us a possibility to suppose that enhancement of luminescence intensity is also due to expanded excitation range caused by 'at surface' centers in UV region. Therefore, 'at surface' centers satisfy better absorption of UV light. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We report the use of fluorescent La1-xEuxVO4 (0.1 ≤ x ≤ 0.3) nanoparticles as near-field optical sensors. A single particle was glued at the end of a sharp atomic force microscope tip and scanned on the surface of a test sample made of sub-micron sized holes in a thin silver film. Illumination of the sample was performed at λ = 532 nm in a transmission configuration. The light transmitted through the apertures induced the fluorescence of europium ions. The collection of the fluorescence light as a function of the tip position above the surface allowed to map the near-field distribution in the vicinity of the holes, at different heights above the surface showing the beam divergence in free space above the sample. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The tandem reduction/oxidation of fluorenyl compounds was performed with LiAlH4 under air to afford the corresponding 9-hydroxyfluorenyl derivatives in good yields. This methodology with LiAlH4 is unprecedented and most likely proceeds by an organoaluminium intermediate, and in the proposed mechanism. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis of cationic surfactants based on 1-aminoisoindole. The physico-chemical properties were studied by conductometry, tensiometry, dynamic light scattering and transmission electron microscopy in water and in formamide. The reactivity of these novel surfactants has been studied at concentrations below and above critical aggregation concentrations (CAC) and it was found that reactions can proceed in structured media without the addition of other catalysts. [ABSTRACT FROM AUTHOR]

P2X3 purinoreceptors expressed in mammalian sensory neurons play a key role in several processes, including pain perception. From the venom of the Central Asian spider Geolycosa sp., we have isolated a novel peptide, named purotoxin-1 (PT1), which is to our knowledge the first natural molecule exerting powerful and selective inhibitory action on P2X3 receptors. PT1 dramatically slows down the removal of desensitization of these receptors. The peptide demonstrates potent antinociceptive properties in animal models of inflammatory pain. ANN NEUROL 2010;67:680-683 [ABSTRACT FROM AUTHOR]

The study aimed to determine whether occupational contact urticaria and symptoms of mucous membranes, reported by five workers in a cactus nursery; were due to IgE-mediated allergy to Schlumbergera cacti. The five persons had positive skin prick tests to the plants as is and positive histamine-release tests, and in three of them specific IgE to the cacti could be demonstrated by Maxisorp RAST and immunoblotting. Four of the patients were atopic, and the fifth had a positive skin prick test to cat dander, indicating latent atopy. Skin prick tests with cacti were negative in most atopic volunteers, and all had negative histamine-release tests. The results suggest a true IgE-mediated allergy to the cacti, and both genetic predisposition and close contact with the plants at work - seem to be important factors in the emergence of this new occupational allergy. [ABSTRACT FROM AUTHOR]

Our investigation aimed to produce and characterize a kiwi extract and to use this extract to investigate a possible cross-reactivity with birch pollen. Kiwi was extracted in two buffers: phosphate-buffered saline (PBS) and borate-buffered saline (BBS). Extraction in BBS produced a double amount of protein, and a more stabile extract. Tandem crossed-immunoelectrophoresis showed that the BBS and PBS extracts had several common, but also a few individual, proteins. The mixture of both extracts was assumed to represent the most complete allergen extract. The allergenic properties of the kiwi extract were investigated by immunoblotting (IB), RAST, and histamine-release (HR) test in 15 birch-pollen-allergic patients (eight of them with clinical kiwi allergy) and one with clinical monoallergy to kiwi. All eight birch-pollen-allergic patients with kiwi allergy and the kiwi-monoallergic patient were positive in kiwi IB binding most frequently to proteins of 10-12 and 20-25 kDa. With our extract, RAST was positive in four kiwi-allergic and one non-kiwi-allergic patient, whereas the HR test was positive in five kiwi-allergic patients and negative in all non-kiwi-allergic patients. RAST and IB inhibition demonstrated cross-reactivity between birch-pollen and kiwi allergens due to a 10-12 kDa protein. In conclusion, a kiwi extract with allergenic properties was produced, and, by the methods used, cross-reactivity was demonstrated between birch-pollen and kiwi allergens. [ABSTRACT FROM AUTHOR]

The authors thank Mr. Vitalii Boklashchuk for the artwork, and Mr. Bohdan Vashchenko for its final editing. More information can be found in the Full Paper by O. O. Grygorenko et al. GLO:5AG/23jun20:ejoc202000797-toc-0001.jpg PHOTO (COLOR): . gl B The Front Cover b shows aliphatic -boryl- -bromoketones - versatile trifunctional templates for synthesis of organoboronates. The authors thank Mr. Vitalii Boklashchuk for the artwork, and Mr. Bohdan Vashchenko for its final editing. [Extracted from the article]

The article discusses the intermolecular structure of Bis{1-methyl-5-[3-(1-methyl-1H-tetrazolo[5,1-a]-isoindol-5-yI)allylidene]-5H-tetrazolo[5,1 -a]iso-indol-1 -ium} tetracyanonickelate(II). The molecular structure consists of two organic cations, C21H17N8+ or [MTIT]+, and a centrosymmetric inorganic dianion, [Ni(CN)4]2-. The ions stack along the b axis and are connected by a number of C-H...N hydrogen bonds. These cations are positioned axial to the Ni atoms. One more pair of N...H contacts is formed with two dye cations that are almost perpendicular to the plane of the [Ni(CN)4]2-.