Sulfone-Decorated Conjugated Organic Polymers Activate Oxygen for Photocatalytic Methane Conversion.

Oxidizing CH4 into liquid products with O2 under mild conditions still mainly relies on metal catalysis. We prepared a series of sulfone-modified conjugated organic polymers and found that the catalyst with proper SVI content (0.10) could drive O2 →H2 O2 →⋅OH to oxidize CH4 into CH3 OH and HCOOH directly and efficiently at room temperature under light irradiation. Experimental results showed that after 4 h reaction, decomposition rate and residual amounts of H2 O2 were 81.21 % and 4.83 mmol gcat -1 respectively, and CH4 conversion rate was 22.81 %. Mechanism studies revealed that illumination could induce the homolytic dissociation of S=O bonds on catalyst to produce oxygen and sulfur radicals, where the ⋅O could adsorb and activate CH4 , and the ⋅S could supply electrons for 1 O2 to generate H2 O2 and then for decomposing the H2 O2 into ⋅OH timely to oxidize CH4 . This research provided a novel organic catalysis approach for oxygen activation and utilization.

Anti-inflammatory activity of cecropin-A2 from Musca domestica.

This study aimed to investigate the anti-inflammatory activity of Musca domestica cecropin-A2 (Mdc-A2) toward Staphylococcus aureus (S. aureus) to learn more about their immunological functions. RAW264.7 cells were transfected with recombinant lentiviruses introduce pLEX-Mdc-A2into the RAW264.7 cell line (RAW-Mdc-A2). The RAW264.7 cell line with empty pLEX (RAW-pLEX) was produced in the same manner as a negative control. Real-time quantitative reverse transcription PCR (RT-PCR) was performed to analyze the mRNA expression of TNF-a, IL-1ß, NFκB-1 and NFκB-2 in S. aureus-stimulated RAW-Mdc-A2 cells and RAW-pLEX cells in untreated cells and cells treated for 3 h, 6 h, 12 h and 24 h. RT-PCR was performed to analyze the mRNA expression of TNF-a, NFκB-1 and NFκB-2 stimulated by Lipoteichoic acid (LTA). Production of TNF-a was detected by enzyme-linked immunosorbent assay (ELISA). Colony counts were used to calculate the number of CFU per mL of cell culture supernatants. The results showed that compared to RAW-pLEX cells, stable transfection of Mdc-A2 in RAW264.7 cells stimulated by S. aureus significantly down-regulated the mRNA expression of TNF-a transcript variant 1 (TNF-a-tv-1) at 6 h and 12 h and the mRNA expression of TNF-a transcript variant 2 (TNF-a-tv-2) at 3 h, 6 h and 12 h. Compared to RAW-pLEX cells, stable transfection of Mdc-A2 in RAW264.7 cells stimulated by S. aureus significantly down-regulated the mRNA expression of IL-1ß-T at 3 h, 6 h and 12 h as well as the mRNA expression of IL-1ß at 3 h and 6 h. The expression and production of TNF-a and bacterial burden of cell culture supernatants were significantly down-regulated in RAW-Mdc-A2 cells stimulated by S. aureus, and the expression and production of TNF-a were significantly down-regulated in RAW-Mdc-A2 cells stimulated by LTA. Compared to RAW-pLEX cells, stable transfection of Mdc-A2 in RAW264.7 cells stimulated by S. aureus significantly down-regulated the mRNA expression of NFκB-1 at 3 h, 6 h and 12 h as well as the mRNA expression of NFκB-2 at 6 h. Additionally, stable transfection of Mdc-A2 in RAW264.7 cells stimulated by LTA significantly down-regulated the mRNA expression of NFκB-1. In conclusion, Mdc-A2 possesses potent anti-inflammatory activity and potent antimicrobial activity. Additionally, Mdc-A2 may interact with LTA and execute strong anti-inflammatory activity by blocking the activation of NF-κB signaling pathways.

Tuning the absorption, charge transport properties, and solar cell efficiency with the number of thienyl rings in platinum-containing poly(aryleneethynylene)s.

The synthesis, characterization, and photophysics of a series of solution-processable and strongly visible-light absorbing platinum(II) polyynes containing bithiazole-oligo(thienyl) rings were presented. Tuning the polymer solar cell efficiency, as well as optical and charge transport properties, in soluble, low-band gap PtII-based conjugated poly(heteroaryleneethynylene)s using the number of oligothienyl rings is described. These materials are highly soluble in polar organic solvents due to the presence of solubilizing bithiazole moieties and show strong absorptions in the solar spectra, rendering them excellent candidates for bulk heterojunction polymer solar cells. Their photovoltaic responses and power conversion efficiencies (PCEs) depend to a large extent on the number of thienyl rings along the main chain, and some of them can be used to fabricate highly efficient solar cells with PCEs of up to 2.7% and a peak external quantum efficiency to 83% under AM1.5 simulated solar illumination, which is comparable to that of poly(3-hexylthiophene)-based devices fabricated without additional processing (annealing or TiO(x) layer). The influence of the number of thienyl rings and the metal group on the performance parameters and optimization of solar cell efficiency was evaluated and discussed in detail. At the same blend ratio of 1:4, the light-harvesting ability and PCE increase sharply as the thienyl chain length increases. The present work provides an attractive approach to developing conjugated metallopolymers offering broad solar absorptions and tunable solar cell efficiency and demonstrates the potential of metalated conjugated polymers for efficient power generation.