A Cation-Directed Enantioselective Sulfur-Mediated Michael/Mannich Three-Component Domino Reaction involving Chalcones as Michael Acceptors

A new approach has been developed for an asymmetric sulfur-mediated three-component intermolecular Michael/Mannich domino reaction using chalcones as Michael acceptors. This reaction is catalyzed by chiral quaternary ammonium salts derived from modified quinine and provides facile access to complex sulfur-containing compounds with three contiguous stereogenic centers in yields of up to 93%, with 95:5 <i>dr</i> and 95% <i>ee</i>. These compounds were further elaborated to give the equivalent of a chiral aza-Morita–Baylis–Hillman reaction involving chalcones and azetidines bearing four chiral centers

Highly Enantioselective and <i>Anti</i>-Diastereoselective Catalytic Intermolecular Glyoxylate–Ene Reactions: Effect of the Geometrical Isomers of Alkenes

An efficient method for the synthesis of homoallylic alcohols with high enantioselectivities and <i>anti</i>-diastereoselectivities via an In­(III)-catalyzed intermolecular glyoxylate–ene reaction has been developed. The geometrical isomers of alkenes were shown to have different reactivities. Only the isomers of the alkenes having a proton β-cis to the substituent reacted in this catalytic system

Structural Diversity for a Series of Novel Zn Metal–Organic Frameworks Based on Different Secondary Building Units

The secondary building unit (SBU) has been identified as a useful tool in the synthesis of metal–organic frameworks (MOFs). Herein, we synthesized six novel Zn complexes, namely, {[Zn₃(tci)₂(DMF)₂)]·2DMF·2CH₃OH}_<i>n</i> (<b>1</b>), {[Zn₃(tci)₂(DMSO)₂(H₂O)₂]·2DMSO·3H₂O}_<i>n</i> (<b>2</b>), {[ZnNa­(tci)­(H₂O)]·2H₂O}_<i>n</i> (<b>3</b>), {[Zn₅(tci)₂(OH)₄(H₂O)₂]·2H₂O}_<i>n</i> (<b>4</b>), {[Zn₃(tci)₂(phen)₂(H₂O)₂]·4H₂O}_<i>n</i> (<b>5</b>), and {[Zn₃(tci)₂(btb)₂(H₂O)₂]·6H₂O}_<i>n</i> (<b>6</b>) by utilizing different SBUs (tci = tris­(2-carboxyethyl) isocyanurate, phen = 1,10-phenanthroline, btb = 1,4-bis (1,2,4-triazole-1-ylmethyl) benzene). Complexes <b>1</b>–<b>4</b> were synthesized only by changing solvents, and complexes <b>5</b> and <b>6</b> were obtained by adding different auxiliary ligands on the same conditions. Structural analyses show that complexes <b>1</b> and <b>2</b> possess two-dimensional (2D) structures based on linear and triangular trinuclear Zn clusters. Complexes <b>3</b> and <b>4</b> exhibit 2D and three-dimensional (3D) frameworks built on rare infinite rod-shaped SBUs, while complex <b>5</b> belongs to a 3D framework with two kinds of left- and right-helical chains built from discrete dinuclear Zn clusters and mononuclear Zn atoms. Complex <b>6</b> exhibits high-connected 3D framework based on extended linear trinuclear Zn clusters

EdgeWorkflow: One click to test and deploy your workflow applications to the edge

EdgeWorkflow: One click to test and deploy your workflow applications to the edg

Melanin-Inspired Composite Materials: From Nanoarchitectonics to Applications

Synthetic melanin is a mimic of natural melanin analogue with intriguing properties such as metal–ion chelation, redox activity, adhesion, and broadband absorption. Melanin-inspired composite materials are formulated by assembly of melanin with other types of inorganic and organic components to target, combine, and build up the functionality, far beyond their natural capabilities. Developing efficient and universal methodologies to prepare melanin-based composite materials with unique functionality is vital for their further applications. In this review, we summarize three types of synthetic approaches, predoping, surface engineering, and physical blending, to access various melanin-inspired composite materials with distinctive structure and properties. The applications of melanin-inspired composite materials in free radical scavenging, bioimaging, antifouling, and catalytic applications are also reviewed. This review also concludes current challenges that must be addressed and research opportunities in future studies

Co(II)/Mn(II)/Cu(II) Coordination Polymers Based on Flexible 5,5′-(hexane-1,6-diyl)-bis(oxy)diisophthalic Acid: Crystal Structures, Magnetic Properties, and Catalytic Activity

To systematically explore the impact of coordination complexes on the synthesis of 2-imidazoline and 1,4,5,6-tetrahydropyrimidine derivatives, five Co­(II)/Mn­(II)/Cu­(II) architectures, formulated as {[Co­(L)_0.5­(H₂O)₂]·​CH₃OH·​H₂O}_<i>n</i> (<b>1</b>), {[Co­(L)_0.5­(pbib)]·​4H₂O}_<i>n</i> (<b>2</b>), [Mn­(L)_0.5­(Hatz)_0.5­(H₂O)]_<i>n</i> (<b>3</b>), {[Cu­(L)_0.5(phen)₂]­[Cu­(L)_0.5­(phen)₂]·0.5L·5H₂O}_<i>n</i> (<b>4</b>), and {[Cu­(L)_0.5(2,2′-bpy)­(H₂O)]·H₂O}_<i>n</i> (<b>5</b>) (H₄L = 5,5′-(hexane-1,6-diyl)-bis­(oxy)­diisophthalic acid, pbib = 1,4-bis­(imidazol-1-ylmethyl)­benzene, Hatz = 1<i>H</i>-1,2,4-triazol-3-amine, phen = 1,10-phenanthroline, 2,2′-bipy = 2,2′-bipyridine), have been designed and synthesized. <b>1</b> presents a (4,4)-connected 2D <i>sql</i> net with its point (Schläfli) symbol of (4⁴·6²)₂, which is finally extended to a 3D supramolecular framework by π···π stacking interactions. <b>2</b> has a 3D (4,4)-connected new topology net with a point symbol of (8⁶)₂. <b>3</b> features a (4,4)-connected 3-fold interpenetrating 3D <i>pts</i> topology network with the Schläfli symbol (4²·8⁴)₂. <b>4</b> possesses two binuclear molecules, and these adjacent binuclear units are further stretched to a 2D infinite packing structure through two distinct types of π···π stacking interactions. <b>5</b> is a 2D layer structure with the (8)­(8⁴·12²) topology. The magnetic studies of <b>1</b> and <b>3</b> elucidate that both of them signify antiferromagnetic interactions. <b>4</b> and <b>5</b> have been justified to be available heterogeneous catalysts for the synthesis of 2-imidazoline and 1,4,5,6-tetrahydropyrimidine derivatives

YCP possesses a lower binding affinity and mediates a hyporesponsiveness in TLR2 or TLR4 KO B cells.

<p><b>A:</b> Splenic B cells from WT (BALB/c), TLR2 KO (B6.129-Tlr2^tm1Kir/J and TLR4 KO (C57BL/10ScNJ) mice were incubated with fl-YCP for 1 h, and then harvested for measurement of mean fluorescence intensity (MFI) by flow cytometry. The experiments were performed in triplicate, and the combined results are presented. <b>B–D:</b> WT, TLR2 and TLR4 KO B cells were stimulated with YCP, Pam₃CSK₄ or LPS for 48 h, and then subjected to proliferation assay (B) and total IgM quantification (C). The supernatants obtained from each untreated or YCP-treated group were assayed for the content of anti-YCP IgM by indirect ELISA (D) (n = 6, ^*<i>p</i>≤0.05, ^**<i>p</i>≤0.01 vs. WT by Mann–Whitney U test).</p

YCP promotes B cell proliferation and induces IgM response.

<p><b>A:</b> Effect of YCP on B cell proliferation. Splenic B cells were treated with YCP or LPS at the indicated concentrations, and cell proliferation was measured by MTT assay at 48 h (n = 6, ^**<i>p</i>≤0.01 vs. medium by Kruskal–Wallis test followed by Dunn's post-hoc test, ^##<i>p</i>≤0.01 vs. medium by Mann–Whitney U test). <b>B:</b> The production of IgM, IgG, IgA, IgD and IgE in response to YCP stimulation. Splenic B cells were incubated with 80 nM of YCP for 48 h or 96 h, and supernatants were then collected for quantification of each Ig isotype using sandwich ELISA (n = 5, ^**<i>p</i>≤0.01 vs. medium by Mann–Whitney U test). <b>C:</b> A dose-dependent induction of IgM antibodies by YCP at 48 h (n = 6, ^*<i>p</i>≤0.05, ^**<i>p</i>≤0.01 vs. medium by Kruskal–Wallis test followed by Dunn's post-hoc test, ^##<i>p</i>≤0.01 vs. medium by Mann–Whitney U test). <b>D:</b> IgM reactivity to YCP in supernatants from naïve and YCP-treated B cells. Splenic B cells were left untreated or treated with YCP for 48 h, and the supernatants collected from each group were subjected to measurement of YCP-bound IgM using indirect ELISA (n = 6, ^**<i>p</i>≤0.01 vs. medium by Mann–Whitney U test). <b>E:</b> Titration of IgM antibodies to YCP in supernatants from naïve and YCP-stimulated B cells (n = 6, ^**<i>p</i>≤0.01 vs. medium by Mann–Whitney U test).</p

Antibodies to TLR2 and TLR4 attenuate YCP functions in B cells.

<p>Splenic B cells were pretreated with anti-TLR2, anti-TLR4 or respective isotype controls (20 µg/ml) for 2 h before the addition of YCP. After 48 h incubation, cell proliferation (A) and total IgM concentration in supernatants (B) were measured using MTT assay or ELISA, respectively (n = 6, ^*<i>p</i>≤0.05, ^**<i>p</i>≤0.01 by Mann–Whitney U test).</p

Fluoresceinamine-labeled YCP binds to B cells positively.

<p>Splenic B cells were incubated with media alone, fl-YCP, or FLA at the indicated concentrations for 1 h at 4°C, and then spotted on a slide and subjected to confocal laser scanning. Experiments were performed in triplicate. The representative of cells with fluorescence and normal light observation and a merged image for each group are presented.</p