Organic crystals constructed by pi-conjugated molecules have been paid great attention to in the field of organic optoelectronic materials. The superiorities of these organic crystal materials, such as high thermal stability, highly ordered structure, and high carrier mobility over the amorphous thin film ma-terials, make them attractive candidates for optoelectronic devices. Single crystal with definite struc-ture provides a model to investigate the basic interactions between the molecules (supramolecular interaction), and the relationship between molecular stacking modes and optoelectronic performance (luminescence and carrier mobility). Through modulating molecular arrangement in organic crystal, the luminescence efficiency of organic crystal has exceeded 80% and carrier mobility has been up to the level of 10 cm2·V?1·s?1. Amplified stimulated emission phenomena have been observed in many crys-tals. In this paper, we will emphatically introduce the progress in optoelectronic functional organic crystals and some correlative principle.
Organophosphorous compounds containing phosphorus as an integral part have been widely used in industry, organic synthesis and optoelectronics. o-Xylylene-α,α'-bis(triphenylphosphinebromide)(OXBTPPB) is a facile reagent to convert o-quinones(e.g., 9,10-phenanthrenequinone) into polycyclic aromatic hydrocarbons(PAHs). Herein lies an improved synthetic route to OXBTPPB. The resultant was carefully characterized with GC-EIMS, 1H NMR, 13C NMR, spectroscopic techniques. The EIMS shows characteristic peaks at m/z=262.4, 183.3, 108.2, 77.1 attributed to the [C18H15P]+·, [C12H8P]+, [C6H5P]+, [C6H5]+ ions, respectively. The 1H and 13C NMR spectrum shows well resolved peaks and all the hydrogens and carbons were well-assigned via a combined study of 1H-1H COSY, HMBC, and HMQC experiments. The mechanism for the formation of OXBTPPB was proposed based on literature and obtained experimental data. Meanwhile, the thermal stability of OXBTPPB was evaluated with TGA analysis, and an onset decomposition temperature(Td) was recorded at 323.6 °C.
A soluble poly(meta-phenylene)derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction.The polymer is soluble in common organic solvents,and the number-average molecular weight is about 6500.The UV-Vis and quantum chemical calculation indicate that the different conformation segments named "conformers" exist in the polymer backbones;it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound.The π-π transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm.Furthermore,the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 nm.The ultraviolet-emitting electroluminescence(EL)device with the single layer structure shows EL λmax of the derivative at 370 nm.
ZHENG Yan YANG Bing ZHANG Hai-quan LU Ping SHEN Fang-zhong LIU Lin-lin XU Hai YANG Guang-di MA Yu-guang
9,10-Phenanthrenequinone(PQ) and benzil are important α-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used 1H NMR, 13C NMR, 1H-1H COSY, HMBC, HMQC, UV-Vis absorption and emission, CV and TGA experiments to study PQ and benzil that provided the following novel results. (1) The 1H NMR(CDCl3) of PQ show δ 8.19(H1), 8.02(H4), 7.72(H3), 7.47(H2) instead of an earlier reported δ 8.25(H4), 8.08(H1), 7.80(H2), 7.55(H3); (2) in the 13C NMR(CDCl3), the C9/C10(C=O) signal of PQ appears upfield(δ 180.3) compared to C9/C10(C=O) signal of benzil(δ 194.5), which shows higher electrophilic character(more attractive for nucleophiles) of C9/C10(C=O) of benzil; (3) the first λmax for the UV-Vis absorption and emission of PQ are blue-shifted compared to benzil despite increased conjugation attributed to the different symmetries(C2v for PQ and C2h for Benzil) of the two molecules; (4) the emission spectrum of benzil is broader compared to that of PQ due to slower relaxation of the excited state; (5) The CV study shows that PQ and benzil are good electron acceptors and PQ shows a better reduction process than benzil due to an extra ring that provides stability for the reduced species(mono or diradical anions); (6) TGA shows the higher thermal stability of PQ than benzil attributed to the presence of phenanthrene unit in PQ.
Suzuki coupling reaction is widely used in the construction of conjugated polymers; however, there is still no report describing the mechanism and coupling of 9,10-phenanthrenequinone(PQ) building blocks via Suzuki reaction because PQ is sensitive to bases and light. Herein is reported the efficient Suzuki coupling of PQ with 9,10-dialkylfluorene with Na2CO3 as basic species and high molecular weight PQ-Alt-Dialkyl-Fluorene conjugated copolymer obtained in an yield of 42%. Based on the characterization data and well-accepted literature, we proposed a step-by-step mechanistic explanation for the formation of the PQ containing alternating conjugated copolymer.
Muddasir HanifLU PingZHENG YanLI MaoXIE Zeng-qiMA Yu-guangLI DiLI Jing-hong
