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We demonstrate a strategy for designing high-performance, ambipolar, acene-based field-effect transistor (FET) materials, which is based on the replacement of C-H moieties by nitrogen atoms in oligoacenes. By using this strategy, two organic semiconductors, 6,13-bis(triisopropylsilylethynyl)anthradipyndine (1) and 8,9,10,11 -tetrafluoro-6, 13-bis(triisopropylsilylethynyl)-1-azapentacene (3), were synthesized and their FET characteristics studied. Both materials exhib high and balanced hole and electron mobilities, 1 having μh and μe of 0.11 and 0.15 cm²/V·s and 3 having μh and μe of 0.08 and 0.09 cm²/V·s, respectively. The successful demonstration of high and balanced ambipolar FET properties from nitrogen-containing oligoacenes opens up new opportunities for designing high-performance ambipolar organic semiconductors. [ABSTRACT FROM AUTHOR]

Two series of new oligothiophene-pentacene hybrid compounds were successfully synthesized and characterized, which consist of pentacene and anthradithiophene skeletons modified by different oligothienyl groups at 6,13 sites or 5,11 sites, respectively. Their optical, thermal, and electrochemical properties show regular variations with the length change of the side groups. These materials exhibit much higher solubility and significantly improved thermal and photooxidation stabilities compared with unmodified pentacene and anthradithiophene. [ABSTRACT FROM AUTHOR]

The tribe Oryzeae consists of 12 genera and 71 species with a world distribution. Zizania latifolia (Griseb.) Turcz. ex Stapf is included in this tribe and possesses numerous traits valuable for rice breeding, such as disease and insect resistance, cold and flood tolerance, and high grain quality. The genetics and breeding of Z. latifolia are still in their infancy. To facilitate genomic studies of Zizania, a genomic DNA library was constructed using a transformation-competent artificial chromosome (TAC) vector system. The TAC library contains 91, 584 TAC clones with an average insert size of approximately 45 kb, covering six haploid Zizania genome equivalents. Very low signals after hybridization with chloroplast and mitochondrial genes indicate that the TAC library is predominantly composed of nuclear DNA. The TAC clones were stable in E. coli for 100 generations. Clones containing the dihydrodipicolinate synthase (DHPS) gene were screened by pooled PCR. The positive clones can be used for Z. latifolia DHPS gene cloning and functional analysis. The library will be useful in studies of genome structure, gene cloning and evolution of rice. [ABSTRACT FROM AUTHOR]