A facile synthesis of octabromoperylene-3,4,9,10-tetracarboxylic dianhydride (Br8-PDA) (1), its diimides (Br8-PDIs) (2a-e), and bis-, tris-, and tetra-amino substituted diimides (5a-c) with six, five, and four remaining substitutable Br atoms, respectively, is reported. Octabromination results in facile chemical/electrochemical reduction, radical anion formation, and red-shifted optical properties. For the first time, diverse halogen-bonding interactions were identified in the PDA/PDI, which along with the attractive electronic features enhance the electron-transport characteristics compared to the di-/tetra-brominated PDIs (3/4).

The variations in physical parameters of an organic field-effect transistor having dioctylbenzothieno[2,3-b]benzothiophene (C8BTBT) as the channel semiconductor were investigated under different light irradiation conditions at wavelengths of 350 nm, 370 nm, 400 nm and by increasing exposure doses. The progress of the electro-optical history of the transistor was evaluated by repeating IeV scan cycles both in the dark and under light exposure. The information recorded upon different exposure times was used to detect the photoactivated charge-trapping effects. The device showed a stable IeV response in the dark bias (V-DS = -10 V, -10 V < V-GS < +10 V) conditions and a persistent threshold voltage (V-T) shift under illumination at all irradiation wavelengths. We suggested that the observed dose-dependent V-T drifts were due to charge retention in trap sites within the organic semiconductor. The threshold voltage was recognized as the main parameter affected by charge retention. V-T variations were modelled versus time through a single exponential revealing a maximum in charge relaxation times for irradiations at wavelengths of 370 nm, in proximity of the C8BTBT bandgap energy. Furthermore, bias-stress effects and persistent photoinduced V-T drifts were found to depend on comparable characteristic times. Therefore, a common nature for both the bias-stress decay and relaxation from photoexcitation mechanisms is likely. (C) 2015 Elsevier B.V. All rights reserved.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

ChemInformVolume 46, Issue 2 Heterocyclic Compounds ChemInform Abstract: A General Method for the Facile Synthesis of Optically Active 2-Substituted Piperazines via Functionalized 2,5-Diketopiperazines. Kate S. Ashton, Kate S. Ashton Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorMitchell Denti, Mitchell Denti Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorMark H. Norman, Mark H. Norman Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorDavid J. Jr. St. Jean, David J. Jr. St. Jean Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this author Kate S. Ashton, Kate S. Ashton Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorMitchell Denti, Mitchell Denti Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorMark H. Norman, Mark H. Norman Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this authorDavid J. Jr. St. Jean, David J. Jr. St. Jean Dep. Med. Chem., Amgen, Inc., Thousand Oaks, CA 91320, USASearch for more papers by this author First published: 19 December 2014 https://doi.org/10.1002/chin.201502165Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume46, Issue2January, 2015 RelatedInformation

Upon utilization of some common methods described in the literature for the synthesis of chiral, 2-substituted 2,5-diketopiperazines, extensive racemization was observed. Further investigation showed that heating in the presence of a mild base racemized the chiral center in the product diketopiperazines. A generalized, readily scalable route was sought and, after investigating the effect of base and temperature, conditions were identified that promoted cyclization without erosion of enantiomeric excess. An array of functionalization was tolerated and this procedure serves as a useful and reliable method for the facile synthesis of this important class of compounds.

Despite their favorable electronic and structural properties, the synthetic development and incorporation of thiazole-based building blocks into n-type semiconductors has lagged behind that of other pi-deficient building blocks. Since thiazole insertion into pi-conjugated systems is synthetically more demanding, continuous research efforts are essential to underscore their properties in electron-transporting devices. Here, we report the design, synthesis, and characterization of a new series of thiazolethiophene tetra- (1 and 2) and hexa-heteroaryl (3 and 4) co-oligomers, varied by core extension and regiochemistry, which are end-functionalized with electron-withdrawing perfluorohexyl substituents. These new semiconductors are found to exhibit excellent n-channel OFET transport with electron mobilities (mu(e)) as high as 1.30 cm(2)/(V center dot s) (I-on/I-off > 10(6)) for films of 2 deposited at room temperature. In contrary to previous studies, we show here that 2,2'-bithiazole can be a very practical building block for high-performance n-channel semiconductors. Additionally, upon 2,2'- and 5,5'-bithiazole insertion into a sexithiophene backbone of well-known DFH-6T, significant charge transport improvements (from 0.0010.021 cm(2)/(V center dot s) to 0.200.70 cm(2)/(V center dot s)) were observed for 3 and 4. Analysis of the thin-film morphological and microstructural characteristics, in combination with the physicochemical properties, explains the observed high mobilities for the present semiconductors. Finally, we demonstrate for the first time implementation of a thiazole semiconductor (2) into a trilayer light-emitting transistor (OLET) enabling green light emission. Our results show that thiazole is a promising building block for efficient electron transport in ?-conjugated semiconductor thin-films, and it should be studied more in future optoelectronic applications.

The synthesis and physicochemical properties of a new class of BODIPY-based donor-acceptor π-conjugated polymers are presented. Solution-processed top-gate/bottom-contact (TG-BC) thin-film transistors on flexible plastic substrates exhibit air-stable p-channel activities with charge carrier mobilities as high as 0.17 cm(2) /V·s and current on/off ratios of 10(5) -10(6) , the highest reported to date for a BODIPY-based semiconductor. The results shown here indicate a significant charge-transport improvement (>10000×) in BODIPY-based polymeric semiconductors, demonstrating its potential in future organic optoelectronic applications.