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1

New oxadiazole derivatives as promising electron transport materials: synthesis and characterization of thermal, optical and electrochemical properties

100%

Liu C., Zhao P., Huang W.

Open Chemistry

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2007

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vol. 5

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issue 1

303-315

EN

2,5-bis-(4-biphenyl)-yl-1,3,4-oxadiazole (1a), 2,5-bis-(4-(6,8-difluoro)-biphenyl)-yl-1,3,4-oxadiazole (1b) and 2,5-bis-(4-(spiro-fluorenyl)-phenyl)-yl-1,3,4-oxadiazole (1c) were designed, synthesized and characterized. 1a–c were easily obtained from Suzuki reactions between 2,5-bis-(4-bromo-phynyl)-[1,3,4]oxadiazole (2) and aromatic boronic acids (3). They were characterized by 1H-NMR, DSC, TGA, UV-Vis, photoluminescence (PL) spectrometry and CV. The melting temperatures (T m) of 1a–c are 237, 208 and 370 °C, respectively, much higher than that of 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD, T m = 136 °C). The oxidation potentials of 1a–c are 1.86, 1.94 and 1.18 V, and their reduction potentials are −2.31, −2.22 and −2.27 V, respectively, indicating that the introduction of electronegative oxadiazole unit lowers the electron density in molecules and enhances their stabilities. The LUMO/HOMO energy levels of 1a–c are as low as −2.39/−6.56, −2.48/−6.69 and −2.43/−5.88 eV, respectively. The good thermal stabilities and low orbital levels of 1a–c make them promising electron-transporting or hole-blocking materials for organic optoelectronic devices.

2

Synthesis and electronic properties of pentacene derivatives as promising n-type semiconductor candidates

100%

Liu C., Tang Y., Nie S.

Open Chemistry

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2006

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vol. 4

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issue 4

723-731

EN

Two pentacene derivatives 1 and 2 were synthesized from the Diels-Alder reactions of furan derivatives with 1,4-benzoquinone. They were characterized by the methods of 1H - nuclear magnetic resonance spectroscopy (1H-NMR), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), ultraviolet and visible spectrophotometry (UV-VIS), photoluminescence (PL) spectrometry and cyclic voltammetry (CV). The energy gaps of 1 and 2, taken directly from spectroscopic measurements, are broad as 2.72 and 2.46 eV, leading to blue and greenish blue photoluminescence, respectively. The LUMO and HOMO energy levels are −2.77 and −5.49 eV for 1, and −2.91 and −5.37 eV for 2, respectively. The low energy levels make both 1 and 2 good air-stabilities and promising n-type semiconductor candidates for use in organic electronics.

3

Multifunctional PEG-grafted chitosan copolymer possessing amino and carboxyl (or formyl) groups

88%

Liu C., Wu Y., Wang X., Hu Z., Luo S.

Open Chemistry

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2010

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vol. 8

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issue 3

576-581

EN

New multifunctional PEG-grafted chitosan copolymers possessing both amino and carboxyl (4) or formyl (5) groups were synthesized by the grafting reaction method between chitosan and heterobifunctional PEG from anionic polymerization of ethylene oxide. Completion of the reactions and characterization of the resulting polymers were demonstrated by 1H NMR, FT-IR and GPC studies. The multifunctional polymers may have potential utility in gene/drug co-delivery or heterogeneous catalysis.

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1 Wu Y.

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New oxadiazole derivatives as promising electron transport materials: synthesis and characterization of thermal, optical and electrochemical properties

Synthesis and electronic properties of pentacene derivatives as promising n-type semiconductor candidates

Multifunctional PEG-grafted chitosan copolymer possessing amino and carboxyl (or formyl) groups