Herein we describe the synthesis of a new series of copolymers (PSeBx) containing selenopheno [3,4-b]selenophene and benzodiselenophene, which exhibited a high power conversion efficiency (PCE) of 6.87% in a bulk heterojunction (BHJ) solar cell device (PSeB2/ PC 71 BM). In comparison with its thiophene analogue, PTB9, the new polyselenopheno[3,4-b]selenophene-co-benzodiselenophene (PSeB2) showed a lower band gap and improved charge carrier mobility as high as 1.35 × 10 −3 cm 2 V −1 s −1 .

A new polyphenylene-co-furan (PPF) and a polyhenylene-co-thiophene (PPT) have been synthesized utilizing the Stille coupling reaction and their luminescence properties characterized. The UV−vis, electroluminescence (EL), photoluminescence (PL), and current−field (I−F) characteristics, as well as the stability of the emission of light, were studied in detail for both polymer LED devices. Comparisons of the EL and PL characteristics between PPT and PPF suggest that the quantum efficiency of PPF is higher than that of PPT. However, it was also found that PPF is photochemically unstable and its electroluminescent intensity decays faster than that of PPT.

A combined experimental and theoretical approach has been used to disentangle the fundamental mechanisms of the fragmentation of the three isomers of nitroimidazole induced by vacuum ultra-violet (VUV) radiation, namely, 4-, 5-, and 2-nitroimidazole. The results of mass spectrometry as well as photoelectron–photoion coincidence spectroscopy display striking differences in the radiation-induced decomposition of the different nitroimidazole radical cations. Based on density functional theory (DFT) calculations, a model is proposed which fully explains such differences, and reveals the subtle fragmentation mechanisms leading to the release of neutral species like NO, CO, and HCN. Such species have a profound impact in biological media and may play a fundamental role in radiosensitising mechanisms during radiotherapy.

The valence and core-level photoelectron spectra of gaseous indole, 2,3-dihydro-7-azaindole, and 3-formylindole have been investigated using VUV and soft X-ray radiation supported by both an ab initio electron propagator and density functional theory calculations. Three methods were used to calculate the outer valence band photoemission spectra: outer valence Green function, partial third order, and renormalized partial third order. While all gave an acceptable description of the valence spectra, the last method yielded very accurate agreement, especially for indole and 3-formylindole. The carbon, nitrogen, and oxygen 1s core-level spectra of these heterocycles were measured and assigned. The double ionization appearance potential for indole has been determined to be 21.8 ± 0.2 eV by C 1s and N 1s Auger photoelectron spectroscopy. Theoretical analysis identifies the doubly ionized states as a band consisting of two overlapping singlet states and one triplet state with dominant configurations corresponding to holes in the two uppermost molecular orbitals. One of the singlet states and the triplet state can be described as consisting largely of a single configuration, but other doubly ionized states are heavily mixed by configuration interactions. This work provides full assignment of the relative binding energies of the core level features and an analysis of the electronic structure of substituted indoles in comparison with the parent indole.

To synthesize nonlinear optical polyimides exhibiting high nonlinearity and high thermal stablity, a new monomer bearing phenylenediamine and a diazo benzene-type nonlinear optical chromophore (compound 1) was synthesized and polymerized with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride. This diazo chromophore possesses a microscopic optical nonlinearity larger than either the Disperse Red 1 or DANS chromophores. Copolymerization of compound 1 and 1,4diaminophenylene with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride yielded copolyimides with higher glass transition temperatures. These polyimides exhibit large electrooptic coefficients, r33 ∼ 14-35 pm/V. The second harmonic measurements indicate long-term stability of the dipole orientation (>800 h at 100 °C) for these polyimides.

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Three novel new compounds derived from antiparasitic precursors have been synthesized and tested for their antiamoebic and antigiardial activities. The condensation of 2-(2-methyl-5-1H-nitroimidazolyl)ethylamine (6) with 5-nitro-2-furylacrylic acid (7) gave 3-(5-nitrofuran-2-yl)-N-[2-(5-nitroimidazol-1-yl)ethyl]acrylamide (8). Condensation of 7 with 7-chloro-4-(piperazin-1-yl)quinoline (9) afforded 1-[4-(7-chloroquinolin-4-yl)piperazin-1-yl)-3-(5-nitrofuran-2-yl)propenone as a mixture of two isomers; 10-a (the E-isomer) and 10-b (the Z-isomer). In addition, the reaction of 9 with 1-(2-bromoethyl)-2-methyl-5-nitroimidazole (11) in the presence of K2CO3 and NaI yielded 7-chloro-4-(4-[2-(5-nitroimidazol-1-yl)ethyl]-piprazin-1-yl)quinoline (12). On the basis of preliminary screening data for these new compounds, compound 12 exhibited potent lethal activities against Entamoeba histolytica and Giardia intestinalis; its IC50 ( about 1 µM) was lower, at least by a factor of five, compared to the standard drug, metronidazole. In addition, the IC50 of compound 12 against the tested parasites is 600 times below that against Hep-2 and Vero cells. Compounds 8 and 10-a also exhibited potent or moderate antiamoebic and antigiardial activities with IC50 values of about 5.5 µM, and 140 µM, respectively, against the tested parasites. These two hybrid molecules, 8, 10-a, were also non-cytotoxic at the lethal concentrations against the parasites.

The Stille coupling reaction was explored to synthesize novel polymers with a pending NLO chromophore exhibiting a large μβ value but high chemical sensitivity. This approach enabled the synthesis of aromatic polyimides through the careful design of dibromo monomers bearing NLO chromophores. The resulting polyimide was shown to possess a glass transition temperature of 170 °C and a large electrooptic coefficient.