Folding-Induced Through-Space Magnetic Interaction of Poly(1,3-phenyleneethynylene)-Based Polyradicals

We synthesized poly­(1,3-phenyleneethynylene)­s bearing galvinoxyl moieties. The absorption ratio of the anion form in 1 M KOH methanol solution between 309 and 294 nm (<i>A</i>₃₀₉/<i>A</i>₂₉₄) decreased with increasing degree of polymerization. The wide-angle X-ray scattering of the powder, which was prepared by precipitation in dilute hydrochloric acid solution from the anion form in 1 M KOH methanol solution, showed a crystalline peak at 2θ = 28°. Polymers in which the chiral diethynyl-1,1′-binaphthyl moiety was inserted into the poly­(1,3-phenyleneethynylene) chain were synthesized, and clear Cotton effects were observed in the absorption region of the galvinoxyl anion chromophore in the CD spectra taken in 1 M KOH–MeOH solution, indicating an excess of one-handed folded helical conformation. A relatively strong antiferromagnetic interaction was observed for the polyradicals prepared by precipitating the anionic form from alkaline methanol solution accompanied with oxidation using aqueous K₃Fe­(CN)₆ solution. These observations suggest that the relatively strong antiferromagnetic interaction of the polyradicals was caused by the close packing between galvinoxyl radicals induced by the formation of the folded helical structure

Subnanoporous Highly Oxygen Permselective Membranes from Poly(conjugated hyperbranched macromonomer)s Synthesized by One-Pot Simultaneous Two-Mode Homopolymerization of 1,3-Bis(silyl)phenylacetylene Using a Single Rh Catalytic System: Control of Their Structures and Permselectivities

Novel well-defined complex polymers, polymers of acetylene-type macromonomers having silylene–vinylene–phenylene–ethynylene hyperbranches, investigated as a new class of subnanoporous oxygen permselective membrane materials, were synthesized very easily by one-pot simultaneous two-mode homopolymerization of a single monomer with a single catalyst. For this “simultaneous polymerization” we synthesized AB₂-type monomers (1,3-bis­(dimethylsilyl)­phenylacetylenes) containing one terminal triple bond and two Si–H groups. The resulting poly­(hyperbranched macromonomer)­s had high molecular weights, low densities, high solubility, and good self-membrane forming ability. They had higher oxygen permselectivities (α = <i>P</i>_O₂/<i>P</i>_N₂) than any other reported polymers having similar oxygen permeabilities (<i>P</i>_O₂). These excellent polymer membranes could be obtained only by the simultaneous polymerization. In the one-pot simultaneous polymerization, the two different modes of polymerizations, i.e., addition polymerization of the triple bond and polyaddition of the triple bond and two SiH groups in the single monomer, occurred simultaneously by using one catalytic system, i.e., [Rh­(norbornadiene)­Cl]₂/various amines. The ratio of the branches (<b>RB</b>), i.e., the addition polymerization and the polyaddition, could be controlled by changing the amine cocatalysts. Their oxygen permselectivities could be adjusted by controlling the polymer structures including <b>RB</b>

Synthesis of <i>Pure</i> Supramolecular Polymers from Poly(substituted Phenylacetylene)s by Highly Selective Photocyclic Aromatization and Their Characterization: Effect of the Structures and Properties of Precursor Covalent Polymers on those of the Resulting <i>Pure</i> Supramolecular Polymers

Several pure supramolecular polymers (SPs) were quantitatively synthesized by highly selective photocyclic aromatization (SCAT reaction) of poly(substituted phenylacetylene)s (CPs). The structures such as the degree of polymerization (DPn) and the one-handed helicities (chiralities) of the main chains of these precursor covalent polymers (CPs) were well-controlled by living or helix-sense-selective polymerizations. We found that the structures and properties of the resulting SPs were strongly influenced by those of the precursor CPs. In other words, some of the structures and properties of CPs were transferred to those of SPs. For example, the CPs with higher DPns yielded the corresponding SPs with higher DPns and strengths, and the CPs with one-handed helical chirality produced the corresponding SPs with enantioselective permeability in the membrane and supramolecular chirality in solution. In addition, since the shapes of solid materials from these CPs were transferred to the resulting SPs with some mechanical strength, they are promising for many practical applications such as membrane permeations

NLRP3-, ASC- and caspase-1-dependent secretion of IL-1β in mouse macrophages stimulated with unbaked calculus.

<p>Macrophages from wild-type (WT) (A, D, G, H), NLRP3-deficient (B, E), and ASC-deficient (C, F) mice were stimulated with indicated concentrations (A–C, H) or 500 μg/mL (D–G) of unbaked calculus for 8 h (A–C, G, H) or the indicated time (D–F). In G, the cells were pre-incubated with the caspase-1 inhibitor, z-YVAD-fmk. IL-1β concentrations in the culture supernatants were measured by ELISA (A–C, G). Total RNA was extracted and the relative quantity of IL-1β mRNA determined by RT-qPCR. The IL-1β mRNA levels were normalized to GAPDH and the expression levels at 0 h were adjusted to 1 (D–F). Cytotoxicity was quantified by measuring LDH release in the culture supernatants (H). The results are expressed as the mean ± standard error of triplicate assays. Representative results of three independent experiments are shown. ***p < 0.001 (<i>t</i>-tests).</p

IL-1β secretion induced by unbaked calculus was suppressed by phagocytosis inhibitor.

<p>Macrophages from wild-type mice were left untreated (A) or pre-incubated with the indicated concentrations of the phagocytosis inhibitor cytochalasin D (B). The cells were then stimulated with 500 μg/mL of unbaked calculus for 8 h. Low- (left) and high-magnification (right) electron microscope images are shown (A). The white arrow marks the location of the unbaked calculus inside the cells, and black arrows mark the location of the unbaked calculus outside the cells. Scale bars: 5 μm. IL-1β concentrations in the culture supernatants were measured by ELISA (B). The results are expressed as the mean ± standard error of triplicate assays. Representative results of three independent experiments are shown. *p < 0.05; ***p < 0.001 (<i>t</i>-tests).</p

Synthesis of One-Handed Helical Block Copoly(substituted acetylene)s Consisting of Dynamic <i>cis-transoidal</i> and Static <i>cis-cisoidal</i> Block: Chiral Teleinduction in Helix-Sense-Selective Polymerization Using a Chiral Living Polymer as an Initiator

By using a living one-handed helical <i>cis-transoidal</i> poly­(chiral substituted phenylacetylene) as a polymer initiator (poly­(<b>1</b>_n)), helix-sense-selective polymerization (<b>HSSP</b>) of an achiral phenylacetylene <b>2</b> having two hydroxy groups successfully afforded a diblock copoly­(phenylacetylene) (copoly­(<b>1</b>_n/<b>2</b>_m)) consisting of a dynamic one-handed helical <i>cis-transoidal</i> block and a static one-handed helical <i>cis-cisoidal</i> block. The formation of the diblock structure was confirmed by consumption of the chiral initiator, appearance of characteristic CD indicating the one-handed helical <i>cis-cisoidal</i> block, and occurrence of the selective photocylic aromatization reaction in the <i>cis-cisoidal</i> block. Therefore, <b>HSSP</b> has been achieved by using the chiral alkenyl groups in the initiator as a chiral source for the first time. In addition, since the <b>HSSP</b> was achieved in spite of the long distance between the chiral initiation site and the propagating site, chiral teleinduction through the rigid and static one-handed helical <i>cis</i>-cisoidal block based on domino effects was confirmed

Unbaked dental calculus induces IL-1β secretion via NLRP3-inflammasome in human PMNs and PBMCs.

<p>Freshly isolated human PMNs (A, G) and PBMCs (B, H) were stimulated with indicated concentrations of unbaked calculus. PMNs (C, E) and PBMCs (D, F) were also stimulated with 125 μg/mL of unbaked calculus in the presence or absence of the caspase-1 inhibitor, z-YVAD-fmk (10 or 20 μM) (C, D), MCC950 (10 μM) or glyburide (25 μM) (E, F). IL-1β concentrations in the culture supernatants were measured by ELISA (A–F). Cytotoxicity was quantified by measuring LDH release in the culture supernatants (G, H). The results are expressed as the mean ± standard error of triplicate assays. Representative results of three independent experiments using different donors are shown. *p < 0.05; **p < 0.01; ***p < 0.001 (<i>t</i>-tests).</p

Transformer of Achiral Amounts to Chirality: Double Reversal of Enantioselectivity Using a Single Cocatalyst in Asymmetric Polymerization

Chiral compounds play a vital role in our lives because we are made up of chiral polymers. A strict rule of chirality synthesis is “to obtain one enantiomer of a new chiral product, one enantiomer of a chiral source is needed”. If two enantiomers can be synthesized using a single chiral compound, we can both break the above rule and open up a more efficient route to useful chiral materials using a cheaper chiral source. Here we report the first example of double reversals of enantioselectivity in catalytic asymmetric polymerization of achiral monomers using a single isomer of simple chiral compounds as cocatalyst. Furthermore, we achieved this by changing only one achiral condition, that is, the amount of the chiral cocatalyst, without any other changes in the polymerization conditions. As a result, we easily and directly synthesized (+)- or (−)-polymer using a single chiral compound as a cocatalyst

Baked calculus induces IL-1β secretion via NLRP3-inflammasome in primed human PMNs and PBMCs.

<p>Freshly isolated human PMNs (A, E) and PBMCs (B, F) were primed with 1 ng/mL lipid A and stimulated with the indicated concentrations of baked calculus for 6 h. PMNs (C) and PBMCs (D) were also primed with 1 ng/mL lipid A and stimulated with 500 μg/mL of unbaked calculus in the presence or absence of MCC950 (10 μM), z-YVAD-fmk (10 μM) or glyburide (25 μM). IL-1β concentrations in the supernatants were measured by ELISA. Cytotoxicity was quantified by measuring LDH release in the culture supernatants (E, F). The results are expressed as mean ± standard error of triplicate assays. Representative results of three independent experiments using different donors are shown. *p < 0.05; **p < 0.01; ***p < 0.001 (<i>t</i>-tests).</p

Reversible Photogeneration of a Stable Chiral Radical-Pair from a Fast Photochromic Molecule

The photochromic naphthalene-bridged imidazole dimer containing a naphthyl moiety that tethers two triarylimidazole units shows instantaneous coloration upon exposure to UV light and rapid fading in the dark. In this work, we demonstrate the formation of a stable chiral radical-pair that exhibits no photoracemization even by repeated photochromic cycles. The photogenerated radical-pair from the imidazole dimer exhibits the Cotton effect in the visible light region, indicating the retention of the enantiomeric conformation of the radical-pair. This result suggests that the chirality resulting from the binaphthyl moiety induces exciton coupling between the two radical chromophores by through-space interaction