Redox‐Controlled Olefin (Co)Polymerization Catalyzed by Ferrocene‐Bridged Phosphine‐Sulfonate Palladium Complexes

The facile and reversible interconversion between neutral and oxidized forms of palladium complexes containing ferrocene‐bridged phosphine sulfonate ligands was demonstrated. The activity of these palladium complexes could be controlled using redox reagents during ethylene homopolymerization, ethylene/methyl acrylate copolymerization, and norbornene oligomerization. Specifically in norbornene oligomerization, the neutral complexes were not active at all whereas the oxidized counterparts showed appreciable activity. In situ switching between the neutral and oxidized forms resulted in an interesting “off” and “on” behavior in norbornene oligomerization. This work provides a new strategy to control the olefin polymerization process.     

Gold‐Catalyzed Fluorination–Hydration: Synthesis of α‐Fluorobenzofuranones from 2‐Alkynylphenol Derivatives

The Au^I‐catalyzed fluorination–hydration of 2‐alkynylphenol derivatives in the presence of Selectfluor [1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo‐[2.2.2]octane bis(tetrafluoroborate)] has been developed. This method provides straightforward access to α‐fluorobenzofuranones with the construction of C?O, C=O, and C?F bonds in a single step on the basis of an Au^I/Au^III redox catalytic cycle. Several control experiments, including the asymmetric variant of this reaction, were also conducted to gain insight into the reaction mechanism.     

Thieno[3,4-c]pyrrole-4,6-dione based copolymers for high performance organic solar cells and organic field effect transistors

Donor-acceptor type copolymers have wide applications in organic field-effect transistors and organic photovoltaic devices. Thieno[3,4-c]pyrrole-4,6-dione (TPD), as an electron-withdrawing unit, has been widely used in D-A type copolymers recently. Till now, the highest power conversion efficiency and mobility of TPD-based copolymers are over 8% and 1.0 cm² V^-1 s^-1 respectively. In this review, the recent progress of TPD-based copolymers in organic solar cells and organic transistors is summarized.     

Solvent‐free Liquid Crystals and Liquids from DNA

As DNA exhibits persistent structures with dimensions that exceed the range of their intermolecular forces, solid‐state DNA undergoes thermal degradation at elevated temperatures. Therefore, the realization of solvent‐free DNA fluids, including liquid crystals and liquids, still remains a significant challenge. To address this intriguing issue, we demonstrate that combining DNA with suitable cationic surfactants, followed by dehydration, can be a simple generic scheme for producing these solvent‐free DNA fluid systems. In the anhydrous smectic liquid crystalline phase, DNA sublayers are intercalated between aliphatic hydrocarbon sublayers. The lengths of the DNA and surfactant are found to be extremely important in tuning the physical properties of the fluids. Stable liquid‐crystalline and liquid phases are obtained in the ?20 °C to 200 °C temperature range without thermal degradation of the DNA. Thus, a new type of DNA‐based soft biomaterial has been achieved, which will promote the study and application of DNA in a much broader context.