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It is generally believed that cyano functionality is "toxic" to the classical MoCl 5-and WCl6based metathesis catalysts, but we here present such an example in which a group of cyano-containing acetylene monomers are polymerized by the "simple" metal halides. The WCl6(-Ph4Sn) catalysts in dioxane initiate the polymerizations of n-{ [(4′-cyano-4-biphenylyl)oxy]carbonyl}-1-alkynes (AnCN; n ) 2, 3, 8), yielding polymers (PAnCNs) with relatively narrow molecular weight distributions (Mw/Mn down to 1.3). The same metal-halide mixtures in toluene, however, are generally ineffective in polymerizing AnCNs, suggesting that the tungsten-oxo complexes are involved in the active center formation. The differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry analyses reveal that all the PAnCNs are mesomorphic, with the longer flexible spacer favoring the better ordering of the mesogenic groups. PA2CN shows monotropic nematicity, PA3CN exhibits enantiotropic nematicity, and PA8CN displays enantiotropic smecticity with an interdigitated molecular packing arrangement (s Ad) over a wide temperature range (ca. 110 °C). In-domain banded structures within the sAd layers of PA8CN are observed during the transit of the ba ˆtonnets to the focal-conic fan textures, and the formation of large scale band morphology is achieved by the application of shear force to PA8CN in its liquid crystalline state.

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Efficient light emission was obtained in a silole-based organic light-emitting diode. A high luminous current efficiency of 20 cd/A, corresponding to an external quantum efficiency of 8%, was achieved. The apparent violation of the upper theoretical limit of 5.5% for the external quantum efficiency of a singlet emitter is discussed. With a suitably designed cathode, a high power efficiency of ∼14 lm/W was obtained. A strong dependence of the power efficiency on the thickness of Alq3 layer is also observed and explained.

Organic ultraviolet (UV) filters are widely used in personal care products and occur ubiquitously in the aquatic environment. In this study, concentrations of seven commonly used organic UV filters were determined in seawater, sediment and five coral species collected from the eastern Pearl River Estuary of South China Sea. Five compounds, benzophenone-1, -3, and -8 (BP-1, -3, and -8), octocrylene (OC) and octyl dimethyl-p-aminobenzoic acid (ODPABA), were detected in the coral tissues with the highest detection frequencies (>65%) and concentrations (31.8 ± 8.6 and 24.7 ± 10.6 ng/g ww, respectively) found for BP-3 and BP-8. Significantly higher concentrations of BP-3 were observed in coral tissues in the wet season, indicating that higher inputs of sunscreen agents could be attributed to the increased coastal recreational activities. Accumulation of UV filters was only observed in soft coral tissues with bioaccumulation factors (log-values) ranging from 2.21 to 3.01. The results of a preliminary risk assessment indicated that over 20% of coral samples from the study sites contained BP-3 concentrations exceeding the threshold values for causing larval deformities and mortality in the worst-case scenario. Higher probabilities of negative impacts of BP-3 on coral communities are predicted to occur in wet season.

Parental exposure to polybrominated diphenyl ethers (PBDEs) in animals has been found to be transferred to the offspring. The environmental health risk and toxicity to the offspring are still unclear. The objective of the present study was to identify environmentally relevant concentrations of PBDEs for parental exposure that would cause developmental neurotoxicity in the offspring. Adult zebrafish were exposed to environmentally relevant concentrations of 0.8, 4.0 μg/L) via water. The results showed that PBDE exposure did not affect larvae hatching, malformation, or survival. The residue of PBDEs was detected in F1 eggs upon parental exposure. Acetylcholinesterase (AChE) activity was significantly inhibited in F1 larvae. Genes of central nervous system development (e.g., myelin basic protein, synapsin IIa, α1-tubulin) were significantly downregulated in larvae. Protein levels of α1-tubulin and synapsin IIa were also reduced. Decreased locomotion activity was observed in the larvae. This study provides the first evidence that parental exposure to environmentally relevant concentrations of PBDEs could cause adverse effects on neurodevelopment in zebrafish offspring.

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