Design, synthesis, and biological evaluation of insect hormone agonists.

Agonists of insect hormones, namely molting hormone (MH) and juvenile hormone (JH), disrupt the normal growth of insects and can be employed as insecticides that are harmless to vertebrates. In this study, a series of experiments and computational analyses were conducted to rationally design novel insect hormone agonists. Syntheses and quantitative structure-activity relationship (QSAR) analyses of two MH agonist chemotypes, imidazothiadiazoles and tetrahydroquinolines, revealed that the structural factors important for the ligand-receptor interactions are significantly different between these chemotypes.

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C-F bond activation.

2-Fluorobenzofurans underwent efficient nickel-catalyzed coupling with arylboronic acids through the activation of aromatic C-F bonds. This method allowed us to successfully synthesize a range of 2-arylbenzofurans with various substituents. The reaction, which proceeded under mild conditions, involved β-fluorine elimination from nickelacyclopropanes formed by the interaction of 2-fluorobenzofurans with zero-valent nickel species.

Gold(I)-Catalyzed [2 + 2] and [3 + 2] Cycloadditions of 1,1-Difluoroallenes with Aldehydes: Switchable Syntheses of Fluorinated Oxetanes and Furans.

1,1-Difluoroallenes underwent regioselective [2 + 2] and [3 + 2] cycloadditions with aldehydes using Au(I) catalysts. An AuCl catalyst enabled an α,β-selective [2 + 2] cycloaddition of 1,1-difluoroallenes, yielding ()-3-alkylidene-2,2-difluorooxetanes. Conversely, an AuCl(IPr)-AgSbF catalyst facilitated an α,γ-selective [3 + 2] cycloaddition, followed by dehydrofluorination to produce aromatized 2-fluorofurans.

Amino acid-appended pyromellitic diimide liquid materials, their photoluminescence, and the thermal response that turns the photoluminescence off.

We report a liquid material based on an L-valine-appended pyromellitic diimide framework. This liquid adopts a room-temperature liquid with at -50 °C and can dissolve naphthalene derivatives to show various photoluminescent colors. Furthermore, the on/off photoluminescence of these solutions can be controlled by heating.

Impact of single-residue mutations on protein thermal stability: The case of threonine 83 of BC2L-CN lectin.

The thermal stability of trimeric lectin BC2L-CN was investigated and found to be considerably altered when mutating residue 83, originally a threonine, located at the fucose-binding loop. Mutants were analyzed using differential scanning calorimetry and isothermal microcalorimetry. Although most mutations decreased the affinity of the protein for oligosaccharide H type 1, six mutations increased the melting temperature (T) by >5 °C; one mutation, T83P, increased the T value by 18.

Facile Synthesis and Photoluminescent Properties of Asymmetric Perylene Diimides Capable of Tuning Emission Colors in Polymeric Matrices.

We report the facile synthesis of asymmetric perylene diimides (asym-PDIs) using readily available reagents, demonstrating their distinct photoluminescent properties. In CHCl, asym-PDIs exhibit higher solubility compared to traditional perylene dyes, of which solubilities can be varied by substituent selections. Among them, UV-vis absorption spectra of CPE in CHCl solution displayed no aggregate peaks in the ground state, maintaining high photoluminescent quantum yields.

A materials informatics driven fine-tuning of triazine-based electron-transport layer for organic light-emitting devices.

Materials informatics in the development of organic light-emitting diode (OLED) related materials have been performed and exhibited the effectiveness for finding promising compounds with a desired property. However, the molecular structure optimization of the promising compounds through the conventional approach, namely the fine-tuning of molecules, still involves a significant amount of trial and error. This is because it is challenging to endow a single molecule with all the properties required for practical applications.

Experimental modification in thermal stability of oligomers by alanine substitution and site saturation mutagenesis of interfacial residues.

For certain industrial applications, the stability of protein oligomers is important. In this study, we demonstrated an efficient method to improve the thermal stability of oligomers using the trimeric protein chloramphenicol acetyltransferase (CAT) as the model. We substituted all interfacial residues of CAT with alanine to detect residues critical for oligomer stability.

Fluorine-Activated and -Directed Allene Cycloadditions with Nitrile Oxides and Imine Oxides: Synthesis of Ring-Fluorinated Isoxazole Derivatives.

In this study, 1,1-difluoroallenes underwent a regioselective [2+3] cycloaddition with nitrile oxides and imine oxides in the presence of a AuCl catalyst. ()-4-Alkylidene-5,5-difluoroisoxazolines and -isoxazolidines were obtained in regioselective and diastereoselective manners by employing aurated difluoroallylic cation intermediates. The synthesized 5,5-difluoroisoxazolines were readily aromatized through dehydrofluorination or allylic fluorine substitution to provide 5-fluoroisoxazoles.

A rational design strategy of radical-type mechanophores with thermal tolerance.

Radical-type mechanophores (RMs) are attractive molecules that undergo homolytic scission of their central C-C bond to afford radical species upon exposure to heat or mechanical stimuli. However, the lack of a rational design concept limits the development of RMs with pre-determined properties. Herein, we report a rational design strategy of RMs with high thermal tolerance while maintaining mechanoresponsiveness.

Singlet Oxygen Generation Driven by Sulfide Ligand Exchange on Porphyrin-Gold Nanoparticle Conjugates.

Here, we report a switching method of singlet oxygen (O) generation based on the adsorption/desorption of porphyrins to gold nanoparticles driven by sulfide (thiol or disulfide) compounds. The generation of O by photosensitization is effectively suppressed by the gold nanoparticles and can be restored by a sulfide ligand exchange reaction. The on/off ratio of O quantum yield (Φ) reached 7.

Thienylene combined with pyridylene through planar triazine networks for applications as organic oxygen reduction reaction electrocatalysts.

Covalent triazine networks are interesting candidates for organic electrocatalytic materials due to their tunable, durable and sustainable nature. However, the limited availability of molecular designs that ensure both two-dimensionality and functional groups in the π-conjugated plane has hindered their development. In this work, a layered triazine network composed of thiophene and pyridine ring was synthesized by the novel mild liquid phase condition.

Assessment of electroencephalography modification by antipsychotic drugs in patients with schizophrenia spectrum disorders using frontier orbital theory: A preliminary study.

Aim: Schizophrenia is characterized by an abnormality in electroencephalography (EEG), which can be affected by antipsychotic drugs. Recently, the mechanism underlying these EEG alterations in schizophrenia patients was reframed from the perspective of redox abnormalities. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) can be calculated using a computational method and may be useful for evaluating the antioxidant/prooxidant effect of antipsychotic drugs.

Theoretical and Experimental Investigations of Stable Arylfluorene-Based Radical-Type Mechanophores.

Invited for the cover of this issue are the groups of Hideyuki Otsuka at the Tokyo Institute of Technology and Koichiro Mikami at the Sagami Chemical Research Institute. The image depicts theoretical and experimental investigations of stable arylfluorene-based radical-type mechanophores. Read the full text of the article at 10.

Theoretical and Experimental Investigations of Stable Arylfluorene-Based Radical-Type Mechanophores.

Radical-type mechanophores (RMs) can undergo homolytic cleavage of their central C-C bonds upon exposure to mechanical forces, which affords radical species. Understanding the characteristics of these radical species allows bespoke mechanoresponsive materials to be designed and developed. The thermal stability of the central C-C bonds and the oxygen tolerance of the generated radical species are crucial characteristics that determine the functions and applicability of such RM-containing mechanoresponsive materials.

Anion recognition by silanetriol in acetonitrile.

The anion recognition ability of 2,4,6-triisopropylphenylsilanetriol 5 has been evaluated by H NMR titrations in MeCN-. The anion recognition ability of silanetriol 5 was greater than those of the structurally related silanediols and silanemono-ol, although less effective than those of 1,3-disiloxane-1,3-diol and 1,3-disiloxane-1,1,3,3-tetraol. From the comparison of the association constants and DFT calculations, all three silanol groups of 5 cooperatively hydrogen bonded to anionic species.

Nanoarchitectonics for conductive polymers using solid and vapor phases.

Conductive polymers have been extensively studied as functional organic materials due to their broad range of applications. Conductive polymers, such as polypyrrole, polythiophene, and their derivatives, are typically obtained as coatings and precipitates in the solution phase. Nanoarchitectonics for conductive polymers requires new methods including syntheses and morphology control.

Mechanochemical Reactions of Bis(9-methylphenyl-9-fluorenyl) Peroxides and Their Applications in Cross-Linked Polymers.

The exploration of mechanochemical reactions has brought new opportunities for the design of functional materials. We synthesized the novel organic peroxide mechanophore bis(9-methylphenyl-9-fluorenyl) peroxide (BMPF) and examined its mechanochromic properties. The mechanism behind its mechanofluorescence was clarified and harnessed in polymer networks that can release the small fluorescent molecule 9-fluorenone upon exposure to a mechanical stimulus.

Non-symmetric mechanophores prepared from radical-type symmetric mechanophores: bespoke mechanofunctional polymers.

A non-symmetric radical-type mechanophore (CF/ABF) was synthesized by molecular crossing between two radical-type mechanophores. The thermal stability and mechanoresponsiveness of CF/ABF were found to be tunable by altering the properties of the parent RMs. The CF/ABF-centred polymers showed mixed mechanochromism derived from the simultaneous generation of two radical species.

Segmented Polyurethane Elastomers with Mechanochromic and Self-Strengthening Functions.

Mechanochromic elastomers that exhibit force-induced cross-linking reactions in the bulk state are introduced. The synthesis of segmented polyurethanes (SPUs) that contain difluorenylsuccinonitrile (DFSN) moieties in the main chain and methacryloyl groups in the side chains was carried out. DFSN was selected as the mechanophore because it dissociates under mechanical stimuli to form pink cyanofluorene (CF) radicals, which can also initiate the radical polymerization of methacrylate monomers.

Contribution of Organofluorine Compounds to Pharmaceuticals.

Inspired by the success of fluorinated corticosteroids in the 1950s and fluoroquinolones in the 1980s, fluorine-containing pharmaceuticals, which are also known as fluoro-pharmaceuticals, have been attracting attention for more than half of a century. Presently, about 20% of the commercial pharmaceuticals are fluoro-pharmaceuticals. In this mini-review, we analyze the prevalence of fluoro-pharmaceuticals in the market and categorize them into several groups based on the chemotype of the fluoro-functional groups, their therapeutic purpose, and the presence of heterocycles and/or chirality to highlight the structural motifs, patterns, and promising trends in fluorine-based drug design.

Synthesis of a "Butterfly Cage" Based on a Double-Decker Silsesquioxane.

Novel polyhedral structures were prepared with a butterfly-shape composed of oligosiloxane wings and a double-decker silsesquioxane (DDSQ) body. The compounds were synthesized in two steps from commercially available alkoxysilanes, and their structures were confirmed using spectroscopic methods and X-ray crystallography. Not like other phenyl-substituted cage silsesquioxanes, these butterfly cages show very good solubility in common organic solvents.

Synthesis, Structures, and Thermal Properties of Symmetric and Janus "Lantern Cage" Siloxanes.

Symmetric and asymmetric (Janus-type) new "lantern cage" siloxanes (PhSiO ) (Me SiO) (RSiO ) (R=Ph or iBu) were synthesized through reaction of all-cis-[PhSi(OSiMe Br)O] with all-cis-[RSi(OH)O] (R=Ph or iBu). These precursors were obtained by facile two or three-step reactions from commercially available compounds. The spectroscopic properties of the resulting products were fully characterized and they showed high thermal stability and sublimation without decomposition.

Calcite formation induced by Ensifer adhaerens, Microbacterium testaceum, Paeniglutamicibacter kerguelensis, Pseudomonas protegens and Rheinheimera texasensis.

A wide range of bacterial species are able to induce calcium carbonate precipitation. Using our own laboratory-preserved strains, we have newly discovered that Ensifer sp. MY11e, Microbacterium sp.