Synthesis of Fused-Ring Derivatives Containing Bifluorenylidene Units via Pd-Catalyzed Tandem Multistep Suzuki Coupling/Heck Cyclization Reaction

A series of bifluorenylidene derivatives has been facilely synthesized via a palladium-catalyzed tandem multistep Suzuki cross-coupling and Heck cyclization in one pot. The tandem reaction involves two sequential Suzuki couplings and a subsequent Heck cyclization. The target products are obtained in good yields up to 94%. Even in an extended conjugated substrate, the anticipated products can be prepared.

Zwitterionic liquid crystalline polythiophene as an antibiofouling biomaterial

To address a key challenge of conjugated polymers in biomedical applications having poor antifouling properties that eventually leads to the failure and reduced lifetime of bioelectronics in the body, herein we describe the design, synthesis, and evaluation of our newly designed multifunctional zwitterionic liquid crystalline polymer PCBTh-C8C10, which is facilely synthesized using oxidative polymerization. A conjugated polythiophene backbone, a multifunctional zwitterionic side chain, and a mesogenic unit are integrated into one segment. By DSC and POM characterization, we verify that the introduction of 3,5-bis(2-octyl-1-dodecyloxy)benzene as a mesogenic unit into the polythiophene backbone allows the formation of the liquid crystalline mesophase of the resulting polymer. We also demonstrate that the PCBTh-C8C10 coated surface exhibits good conductivity, stability, hydrophilicity, and remarkable antibiofouling properties against protein adsorption, cell growth, and bacteria attachment. This new zwitterionic liquid crystalline polymer having good antibiofouling features will be widely recognized as a promising biomaterial that is applicable in implantable organic bioelectronics via inhibiting the foreign body response. A deep understanding of structure-property relationships of zwitterionic conjugated polymers has also been provided in this study.

Chiroptical Properties in Thin Films of π-Conjugated Systems

Chiral π-conjugated molecules provide new materials with outstanding features for current and perspective applications, especially in the field of optoelectronic devices. In thin films, processes such as charge conduction, light absorption, and emission are governed not only by the structure of the individual molecules but also by their supramolecular structures and intermolecular interactions to a large extent. Electronic circular dichroism, ECD, and its emission counterpart, circularly polarized luminescence, CPL, provide tools for studying aggregated states and the key properties to be sought for designing innovative devices. In this review, we shall present a comprehensive coverage of chiroptical properties measured on thin films of organic π-conjugated molecules. In the first part, we shall discuss some general concepts of ECD, CPL, and other chiroptical spectroscopies, with a focus on their applications to thin film samples. In the following, we will overview the existing literature on chiral π-conjugated systems whose thin films have been characterized by ECD and/or CPL, as well other chiroptical spectroscopies. Special emphasis will be put on systems with large dissymmetry factors (g_abs and g_lum) and on the application of ECD and CPL to derive structural information on aggregated states.

Zwitterionic Porous Conjugated Polymers as a Versatile Platform for Antibiofouling Implantable Bioelectronics

Here, we describe the design, synthesis, and evaluation of two kinds of multifunctional zwitterionic linear poly(carboxybetaine thiophene) (PCBTh) and porous poly(carboxybetaine thiophene-co-9,9'-bifluoreneylidene) (PCBTh-coBF) polymers, which can be facilely synthesized using Yamamoto and Suzuki polycondensation, respectively. The integrations of zwitterionic polymer-based biomaterials that consist of conjugated polymer backbones, multifunctional zwitterionic side chains, and distorted units are designed and studied to address a key challenge of conjugated polymers in biomedical applications: biofouling phenomena that eventually lead to the failure and reduced lifetime of bioelectronics in the body. The introduction of a twisting unit into the polymer backbone allows us to tune the porosity, morphology, optical properties, and efficiency of antibiofouling features of resulting polymers. The PCBTh-coBF coated surface exhibits good conductivity, stability, hydrophilicity, and antibiofouling properties against protein adsorption, cell growth, and bacteria attachment, which may be useful for chronic in vivo bioelectronics applications by minimizing the foreign body response.

Ring-expansion approach towards extended asymmetric benzopentafulvalenes: overcrowded olefinic structure and chain length-dependent properties

A strain energy-induced ring-expansion is described to construct novel asymmetric benzopentafulvalenes precisely, which show chain length-dependent physical properties and air-stable ambipolar carrier transport.

The synthesis and property investigation of π-bridged 9,9′-bifluorenylidene ladder as an electron acceptor

We synthesized a ladder-type 9,9′-bifluorenylidene dimer with good electron acceptability and demonstrated the π-bridged insertion exhibited significant effects on photophysical and electrochemical properties compared with its macrocyclic counterpart.