Bistable Optoelectronic Properties Originated from the Scissoring Motion of the TEMPO Skeleton in Supramolecular Radical Ferroelectrics.

Bistable materials with multiphysical channels, such as optical, electrical, and magnetic properties, have been paid dramatic attention due to their alternativity of the signal status in electronic devices. Herein, three stable supramolecular radicals ([(NH-TEMPO)(18-crown-6)][XF] (, X = P; , X = As; , X = Sb)) were synthesized and characterized. The former two molecules present ferroelectric phase transitions around 381.

Large-Area Flexible Memory Arrays of Oriented Molecular Ferroelectric Single Crystals with Nearly Saturated Polarization.

Molecular ferroelectrics (MFs) have been proven to demonstrate excellent properties even comparable to those of inorganic counterparts usually with heavy metals. However, the validation of their device applications is still at the infant stage. The polycrystalline feature of conventionally obtained MF films, the patterning challenges for microelectronics and the brittleness of crystalline films significantly hinder their development for organic integrated circuits, as well as emerging flexible electronics.

Fluorescent Organic π-Radicals Stabilized with Boron: Featuring a SOMO-LUMO Electronic Transition.

We report on the fluorescence properties of a new class of emissive and stable π-radicals that contain a boron atom at a position distant from the radical center. A fully planarized derivative exhibited an intense red fluorescence with high fluorescence quantum yields (Φ >0.67) even in polar solvents.

The First High-Temperature Supramolecular Radical Ferroics.

Organic radical ferroics such as TEMPO have attracted widespread interest. However, the relatively low Curie temperature of 287 K and melting point of 311 K severely hinder its application potential. Despite extensive interest, high-temperature radical ferroics have not yet been found.

Organic Ferroelectric Vortex-Antivortex Domain Structure.

Organic ferroelectrics are attracting tremendous interest because of their mechanical flexibility, ease of fabrication, and low acoustical impedance. Although great advances have been made in recent years, topological defects such as vortices remain relatively unexplored in the organic ferroelectric system. Here, from [quinuclidinium]ReO ([Q]ReO), we applied the molecular design strategy of H/F substitution to successfully synthesize the organic ferroelectric [4-fluoroquinuclidinium]ReO ([4-F-Q]ReO).

Record Enhancement of Phase Transition Temperature Realized by H/F Substitution.

A high transition temperature (T ) is essential for the practical application of ferroelectrics as electronic devices under extreme thermal conditions in the aerospace, automotive, and energy industries. In recent decades, the isotope effect and strain engineering are found to effectively modulate T ; however, these strategies are limited to certain systems. Developing simple, universal, and practical methods to improve T has become an imminent challenge for expanding the applications of ferroelectrics.

The Soft Molecular Polycrystalline Ferroelectric Realized by the Fluorination Effect.

For a century ferroelectricity has attracted widespread interest from science and industry. Inorganic ferroelectric ceramics have dominated multibillion dollar industries of electronic ceramics, ranging from nonvolatile memories to piezoelectric sonar or ultrasonic transducers, whose polarization can be reoriented in multiple directions so that they can be used in the ceramic and thin-film forms. However, the realization of macroscopic ferroelectricity in the polycrystalline form is challenging for molecular ferroelectrics.

DMSO/-BuONa/O-Mediated Aerobic Dehydrogenation of Saturated -Heterocycles.

Aromatic -heterocycles such as quinolines, isoquinolines, and indolines are synthesized via sodium -butoxide-promoted oxidative dehydrogenation of the saturated heterocycles in DMSO solution. This reaction proceeds under mild reaction conditions and has a good functional group tolerance. Mechanistic studies suggest a radical pathway involving hydrogen abstraction of dimsyl radicals from the N-H bond or α-C-H of the substrates and subsequent oxidation of the nitrogen or α-aminoalkyl radicals.

Directional Intermolecular Interactions for Precise Molecular Design of a High- T Multiaxial Molecular Ferroelectric.

Quasi-spherical molecules have recently been developed as promising building blocks for constructing high-performance molecular ferroelectrics. However, although the modification of spherical molecules into quasi-spherical ones can efficiently lower the crystal symmetry, it is still a challenge to precisely arouse a low-symmetric polar crystal structure. Here, by introducing directional hydrogen-bonding interactions in the molecular modification, we successfully reduced the cubic centrosymmetric Pm3̅ m space group of [quinuclidinium]ClO at room temperature to the orthorhombic polar Pna2 space group of [3-oxoquinuclidinium]ClO.

Thiadiazole dioxide-fused picene: acceptor ability, anion radical formation, and n-type charge transport characteristics.

Picene, which is an organic p-channel semiconductor and a component of superconductors, was derivatized with a thiadiazole-dioxide moiety to afford a novel acceptor molecule (PTDAO₂). PTDAO₂ can form stable anion radical species in solution and as a crystal, and its neutral crystalline thin film exhibits n-type transistor characteristics.

Ga(OTf)3-promoted sequential reactions via sulfur-assisted propargyl-allenyl isomerizations and intramolecular [4 + 2] cycloaddition for the synthesis of 1,3-dihydrobenzo[c]thiophenes.

A Ga(OTf)(3)-promoted sequential reactions via sulfur-assisted propargyl-allenyl isomerizations and intramolecular [4 + 2] cycloaddition for the synthesis of 1,3-dihydrobenzo[c]thiophenes. As a result of the ready availability of materials and the simple and convenient operation, the type of reaction presented here has potential utility in organic synthesis.

Sulfur-assisted five-cascade sequential reactions for the convenient and efficient synthesis of allyl thiophen-2-yl acetates, propionates, and ketones.

A sulfur-assisted five-cascade sequential reaction, wherein the in situ-generated allenyl allyl sulfides undergo thio-Claisen rearrangement, intramolecular Michael addition, and 1, 5-proton migration/aromatization to obtain allyl thiophen-2-yl acetates, propionates, and ketones as the final products, was reported. As a result of the ready availability of starting materials and the extremely simple and convenient operation, this type of reaction presented here has potential utility in organic synthesis. Application of this efficient method for the synthesis of potentially pharmaceutical compounds also might be useful for the pharmacists.