The Mechanism of the Magnetodielectric Response in a Molecule‐Based Trinuclear Iron Cluster Material

Magnetodielectric response mechanisms are critical for the rational design and synthesis of molecule‐based magnetodielectric materials. Herein, the magnetodielectric response was investigated in the molecule‐based material [Fe₃O(CH₃COO)₆(py)₃](py) ( 1 ). Its magnetodielectric coefficient (MD) is ?2.8 % for phase transition III and ?4.1 % for phase transition I. Study of the mechanism of the magnetodielectric response in 1 reveals that its magnetodielectric response at phase transition I is induced by the charge‐frustration of the trinuclear iron cluster, while that at phase transition III is attributed to the spin‐frustration of the trinuclear iron cluster, providing a new route for the design of magnetodielectric materials.     

Synthesis,structure and in vitro cytotoxicity testing of some 2‐aroylbenzofuran‐3‐ols

Five 2‐aroyl‐5‐bromobenzo[b]furan‐3‐ol compounds (two of which are new) and four new 2‐aroyl‐5‐iodobenzo[b]furan‐3‐ol compounds were synthesized starting from salicylic acid. The compounds were characterized by mass spectrometry and ¹H NMR and ¹³C NMR spectroscopy. Single‐crystal X‐ray diffraction studies of four compounds, namely, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐fluorophenyl)methanone, C₁₅H₈BrFO₃, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐chlorophenyl)methanone, C₁₅H₈BrClO₃, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐bromophenyl)methanone, C₁₅H₈Br₂O₃, and (4‐bromophenyl)(3‐hydroxy‐5‐iodobenzofuran‐2‐yl)methanone, C₁₅H₈BrIO₃, were also carried out. The compounds were tested for their in vitro cytotoxicity on the four human cancer cell lines KB, Hep‐G2, Lu‐1 and MCF7. Six compounds show good inhibiting abilities on Hep‐G2 cells, with IC₅₀ values of 1.39–8.03 µM.     

New alkaloids and isocoumarins from the marine gorgonian-derived fungus Aspergillus sp. SCSIO 41501

Abstract

Two new β-carboline alkaloids, aspergillspins A-B (1–2), three new quinolone alkaloids, aspergillspins C-E (3–5), and two new isocoumarins, aspergillspins F-G (6–7), together with four known alkaloids were isolated from the marine gorgonian-derived fungus Aspergillus sp. SCSIO 41501. Their structures were identified by spectroscopic analysis, and the absolute configurations of several chiral carbons in 2 and 3 were further established by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Their cytotoxic and antibacterial activities were also evaluated.     

3D Printing of Silk Protein Structures by Aqueous Solvent‐Directed Molecular Assembly

Hierarchical molecular assembly is a fundamental strategy for manufacturing protein structures in nature. However, to translate this natural strategy into advanced digital manufacturing like three‐dimensional (3D) printing remains a technical challenge. This work presents a 3D printing technique with silk fibroin to address this challenge, by rationally designing an aqueous salt bath capable of directing the hierarchical assembly of the protein molecules. This technique, conducted under aqueous and ambient conditions, results in 3D proteinaceous architectures characterized by intrinsic biocompatibility/biodegradability and robust mechanical features. The versatility of this method is shown in a diversity of 3D shapes and a range of functional components integrated into the 3D prints. The manufacturing capability is exemplified by the single‐step construction of perfusable microfluidic chips which eliminates the use of supporting or sacrificial materials. The 3D shaping capability of the protein material can benefit a multitude of biomedical devices, from drug delivery to surgical implants to tissue scaffolds. This work also provides insights into the recapitulation of solvent‐directed hierarchical molecular assembly for artificial manufacturing.     

Catalytic Asymmetric Synthesis of [2,3]‐Fused Indoline Heterocycles through Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction of Indoles with Azoalkenes

An unprecedented catalytic asymmetric inverse‐electron‐demand aza‐Diels–Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]‐fused indoline heterocycles were achieved in generally good yields (up to 97 %) with high regioselectivity and diastereoselectivity (>20:1 d.r.), and with excellent enantioselectivity (up to 99 % ee).     

Rhodium(III)‐ and Iridium(III)‐Catalyzed C7 Alkylation of Indolines with Diazo Compounds

A Rh^III‐catalyzed procedure for the C7‐selective C?H alkylation of various indolines with α‐diazo compounds at room temperature is reported. The advantages of this process are: 1) simple, mild, and pH‐neutral reaction conditions, 2) broad substrate scope, 3) complete regioselectivity, 4) no need for an external oxidant, and 5) N₂ as the sole byproduct. Furthermore, alkylation and bis‐alkylation of carbazoles at the C1 and C8 positions have also been developed. More significantly, for the first time, a successful Ir^III‐catalyzed intermolecular insertion of arene C?H bonds into α‐diazo compounds is reported.     

The Relationship between DNA Sequences and Oligonucleotide‐Templated Silver Nanoclusters and Their Fluorescence Properties

A novel approach was developed to study the relationship between DNA sequences and DNA‐templated silver nanoclusters (DNA‐Ag NCs) in detail by using an ordinary DNA strand as an example. Three kinds of Ag NCs are formed by using the DNA strand as a scaffold. By dividing the DNA template into several parts according to their different affinities to Ag⁺, it was found that the fluorescence properties of DNA‐Ag NCs are related to not only the sequences but also to the position of different parts in the template, which provides a more efficient approach to obtain DNA‐Ag NCs with required photoluminescence properties and may ultimately contribute to the targeted synthesis of DNA‐Ag NCs.     

Targeted Functionalization of Porous Materials for Separation of Alcohol/Water Mixtures by Modular Assembly

Three isoreticular hydrogen‐bonded frameworks with functionalized pore structures were constructed by a modular self‐assembly process in which a series of amino acids with various substituents serve as facile exchange subassemblies to decorate the pore wall. The ordered amino acid side‐chain groups in the pore channels play an important role in determining the adsorption behavior of the framework materials, and ensure exclusive adsorption of methanol/water over ethanol. Gas‐chromatographic separation experiments demonstrated that alcohols can be efficiently separated from ternary water/methanol/ethanol mixtures and revealed a key influence of the adsorbate–host framework interaction on the practical separation performance of mixtures.     

Water‐Promoted Ring‐Opening Reactions of N‐Substituted Saccharins and Phthalimides by Amines

The reactions of N‐substituted saccharins and phthalimides with amines were promoted by water. Various o‐sulfamoyl benzamides and N,N′‐disubstituted phthalamides were prepared in moderate to good yields. These reactions have prominent advantages, such as short reaction time, less by‐products and simple isolation of the products. Water can probably stabilize the reaction intermediates and facilitate precipitation of the ring‐opening products. When steric hindrance arose, hydrolytic compounds, either free acid or salts of the acids, were obtained. Possible reason for the formation of amine salts of o‐sulfamoyl benzoic acids was proposed.