ABSTRACT
High-mobility organic thin film transistors based on a benzobisthiadiazole-containing polymer are presented together with their morphological and optical properties. A very tight packing pattern of "edge-on" orientated polymer chains is observed in their thin films after annealing, and the hole mobility of this polymer is up to 2.5 cm(2) V(-1) s(-1) .
Subject(s)
Thiadiazoles/chemistry , Thiophenes/chemistry , Transistors, Electronic , Microscopy, Atomic Force , Polymers/chemical synthesis , Polymers/chemistry , SpectrophotometryABSTRACT
Concentration matters: the self-assembly of title compound 1 evolves from well-defined ribbons to vesicles to baskets, upon simply decreasing the concentration of 1 in tetrahydrofuran. Electron microscopy revealed a unique self-assembled structure: baskets are formed by curved and self-wrapped nanometer-thin ribbons. The self-assembly of π-conjugated molecule 1 enables to construct nano/micro structures with desired optoelectronic properties.
ABSTRACT
High mobility ambipolor organic thin-film transistors based on an ultralow bandgap polymer are presented together with their morphological and optical properties. Hole and electron mobilities of this polymer are of 1.0 cm(2) V(-1) s(-1) and 0.7 cm(2) V(-1) s(-1), respectively. The inverter based on two identical ambipolar transistors exhibits a gain around 35.
Subject(s)
Polymers/chemistry , Thiadiazoles/chemistry , Thiophenes/chemistry , Transistors, Electronic , ElectronsABSTRACT
A successful synthesis of novel diimides, namely anthracene diimide containing six-membered imide rings, with potential application in organic electronics is reported. The single crystal of 5a exhibits a close interplanar spacing of 3.45 Å between molecules in a stack.
ABSTRACT
By understanding the role of DMF as a hydride source via a Pd-catalyzed reaction and switching to CH(3)CN solvent, an efficient route for the synthesis of emeraldicene and some new substituted derivatives is reported with potential application in organic electronics. Additionally, the nucleophilic alkylation of emeraldicene 4 a with alkyllithium reagents provides monosubstituted compounds 7 a and 7 b, the latter crystallizing in columnar stacks, with π-π overlap between adjacent molecules in the stack.
ABSTRACT
A cyclophane with a [36]annulene periphery, including four anthrylene and two phenylene units, was synthesized in a four-step sequence using a McMurry cyclization. Upon crystallization from different solvents, four different conformations were determined by X-ray structure analysis. Two conformations exhibit a double twist (Hückel topology) and two structures include a single twist (Möbius topology). By using DFT calculations a conformation with a triple twist (Möbius) was located. However, our calculations and the NMR spectroscopy data do not provide evidence for aromaticity (for Möbius structures) or antiaromaticity (for Hückel structures).
ABSTRACT
Neuroendocrine carcinoma is a type of neuroendocrine system neoplasm that occurs in organisms in which amine precursor uptake and decarboxylation (APUD) cells are uncommon. In the human body, the most common sites of neuroendocrine carcinoma are the gastrointestinal tract and the lungs. From a histologic standpoint, these tumors are identified by their positive reaction to silver stains and specific markers for neuroendocrine tissues, such as chromogranin A, synaptophysin, and neuron-specific enolase. In addition to local symptoms, these tumors may cause flushing, wheezing, and episodic diarrhea secondary to the release of vasoactive substances. Our medline search encompassing the 20-year period prior to 2003 found few cases of this type of tumor in the paranasal sinuses and nasal cavities and only 1 case of an isolated neuroendocrine carcinoma in the nasopharynx. We describe another case of an isolated nasopharyngeal neuroendocrine carcinoma, which we observed in a 74-year-old woman. We review the clinical presentation and the surgical and systemic treatment.
