Toshihiro Okamoto 교수

[reaction: see text] A new intramolecular triple cyclization of bis(o-haloaryl)diacetylenes, via dilithiation followed by reaction with chalcogen elements, produces pi-conjugated compounds containing heterole-1,2-dichalcogenin-heterole fused tricyclic skeletons. The subsequent dechalcogenation with copper metal affords a series of thiophene- and selenophene-based heteroacenes.

Significant progress has been made in both molecular design and fundamental scientific understanding of organic semiconductors (OSCs) in recent years. Suitable charge-carrier mobilities (μ) have been obtained by many high-performance OSCs (μ > 10 cm² V^-1 s^-1), but drawbacks remain, including low solution processability and poor thermal durability. In addition, since aggregation of OSCs involves weak intermolecular interactions, the molecules are perpetually in th

5-Perfluorophenyl-11-phenyltetracene (FPPT) having both aryl (Ar) and perfluoroaryl (FAr) groups has been designed and synthesized to obtain well-defined n-n stacking structure of the tetracene core. Single-crystal X-ray analyses as well as photoconductivity and hole mobility measurements revealed that this strategy is promising for enhancement of the charge carrier properties.

The intramolecular double cyclization of bis(3-bromo-2-thienyl)acetylenes though a lithium-halogen exchange reaction with tBuLi followed by treatment with elemental sulfur produces two thiophene-fused thieno[3,2-c](1,2-dithiin)s. The subsequent dechalcogenation from the 1,2-dithiins with copper nanopowder affords tetrathienoacenes. On the basis of this two-step procedure, a series of trialkylsilyl-terminated, fused oligothiophenes, including hexathienoacene (a six thiophene-fused system) and oct

We have synthesized new-type of pentacene copolymers containing linear- and branched-dialkoxylphenyldiethynylene units via a modified Sonogashira coupling reaction at room temperature to prepare low-band gap polymers (<1.7 eV). The structures of polymers were confirmed by 1H NMR and the molecular weights were determined by size exclusion chromatography. The electrochemical and optical properties of the polymers were studied using cyclic voltammetry and UV−vis absorption to estimate the HOMO and

[structure: see text] A trimeric phenothiazine and its radical cation were prepared, and their structures were elucidated. In contrast to a largely twisted structure in the neutral species, the radical cation had a unique structure deformation that allowed charge-transfer-type conjugation from the outer phenothiazine rings to the central phenothiazine radical cation.

A series of functionalized pentacene derivatives based on symmetric and asymmetric substitutions of the terminal rings are synthesized (see figure). Field-effect mobilities as high as 0.23 cm2 V–1 s–1 are obtained with 2,3-dibrompentacene. These devices show improved stability compared to pentacene and exhibit no significant decrease in mobility or on/off ratio when stored in air, with and without light exposure, even after three months. Supporting information for this article is available on th

We have synthesized new types of pentacene− and anthradithiophene−dialkylfluorene conjugated copolymer via Suzuki cross-coupling polymerization. The polymer chemical structures and molecular weights were characterized by 1H NMR, 13C NMR, and gel permeation chromatography (GPC). Fundamental properties, such as electrochemical and optical behavior, were studied using cyclic voltammetry (CV) and UV−vis absorption (UV−vis) to estimate the highest occupied molecular orbital (HOMO) and lowest unoccupi

[structures: see text] An efficient method for the synthesis of 5,10-diaryldihydrophenazine was developed using a recently developed Pd(0)-mediated cross-coupling reaction. The products 1k and 3c showed excellent properties as hole injection materials in electroluminescent (EL) devices.

The on-surface Ullmann-type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9-diiododinaphtho[2,3-b:2',3'-d]thiophene (I-DNT-VW), which is

Abstract We have designed and synthesized a new donor/acceptor‐type tetracene derivative by the introduction of dicarboxylic imide and disulfide groups as electron‐withdrawing and ‐donating units, respectively. The prepared compounds, tetracene dicarboxylic imide (TI) and its disulfide (TIDS) have high chemical and electrochemical stability as well as long‐wavelength absorptions of up to 886 nm in the thin films. The crystal packing structure of TIDS molecules features face‐to‐face π‐stacking, d