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.
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
