New luminescent polymers for leds and LECS

Statistical copolymers 5 containing poly(2-dimethyloctylsilyl-1,4-phenylenevinylene) (DMOS-PPV) and poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) have been synthesized using the dehydrohalogenation condensation route. The copolymers show a shift of photoluminescence maxima to longer wavelengths as the proportion of the MEH-PV unit increases. This trend is accompanied by reduced efficiencies and lower turn-on voltages in single layer electroluminescent devices. Light-emitting electrochemical cells (LECs) have been prepared using a blend of DMOS-PPV 1 with poly(ethylene oxide)/lithium triflate and the homopolymer poly[2-methoxy-5-(triethoxymethoxy)-1,4-phenylene vinylene] (MTEM-PPV) 9 with lithium triflate. In comparison with single-layer devices which were fabricated using the homopolymers 1 and poly[2,5-bis(triethoxymethoxy)-1,4-phenylene vinylene] (BTEM-PPV) 10 , the LEC devices showed lower turn-on voltages.     

Al-free Zr-zeolite beta as a regioselective catalyst in the Meerwein-Ponndorf-Verley reaction

Al-free Zr-zeolite beta catalyzes the transfer reduction of ketones to the corresponding alcohols in high yield and with exceptional stereocontrol. Notably, the catalyst is very robust and gives good results even with 10% water content in the reaction mixture.     

ACQ-to-AIE Transformation: Tuning Molecular Packing by Regioisomerization for Two-Photon NIR Bioimaging

The traditional design strategies for highly bright solid-state luminescent materials rely on weakening the intermolecular π–π interactions, which may limit diversity when developing new materials. Herein, we propose a strategy of tuning the molecular packing mode by regioisomerization to regulate the solid-state fluorescence. TBP-e-TPA with a molecular rotor in the end position of a planar core adopts a long-range cofacial packing mode, which in the solid state is almost non-emissive. By shifting molecular rotors to the bay position, the resultant TBP-b-TPA possesses a discrete cross packing mode, giving a quantum yield of 15.6±0.2 %. These results demonstrate the relationship between the solid-state fluorescence efficiency and the molecule's packing mode. Thanks to the good photophysical properties, TBP-b-TPA nanoparticles were used for two-photon deep brain imaging. This molecular design philosophy provides a new way of designing highly bright solid-state fluorophores.     

Silk‐Pectin Hydrogel with Superior Mechanical Properties,Biodegradability, and Biocompatibility

A new method is developed to prepare silk hydrogels and silk‐pectin hydrogels via dialysis against methanol to obtain hydrogels with high concentrations of silk fibroin. The relationship between the mechanical and biological properties and the structure of the silk‐pectin hydrogels is subsequently evaluated. The present results suggest that pectin associates with silk molecules when the silk concentration exceeds 15 wt%, suggesting that a silk concentration of over 15 wt% is critical to construct interacting silk‐pectin networks. The silk‐pectin hydrogel reported here is composed of a heterogeneous network, which is different from fiber‐reinforced, interpenetrated networks and double‐network hydrogels, as well as high‐stiffness hydrogels (elastic modulus of 4.7 ± 0.9 MPa, elastic stress limit of 3.9 ± 0.1 MPa, and elastic strain limit of 48.4 ± 0.5%) with regard to biocompatibility and biodegradability.     

Synergy between Brønsted acid sites and Lewis acid sites

Synergy between Br?nsted acid sites and Lewis acid sites in mesoporous Al-Zr-TUD-1 was demonstrated to exist in Br?nsted acid catalysed reactions, but not in Lewis acid catalysed reactions.     

Lignanoids and Diterpenoids from Callicarpa furfuraceae

The three new lignanoids 1 – 3 and the five new phyllocladane diterpenoids 7 – 11 were isolated from the leaves of Callicarpa furfuraceae, together with two known lignanoids, lariciresinol ( 4 ) and (+)‐sesamin ( 5 ), and five known diterpenoids, 17‐norphyllocladane‐3,16‐dion ( 6 ), calliterpenone ( 12 ), calliterpenone 17‐acetate ( 13 ), (3β,16α)‐phyllocladane‐3,16,17‐triol ( 14 ), and (3β,16α)‐phyllocladane‐3,16,17‐triol 17‐acetate ( 15 ). Their structures were established by spectral‐data interpretation.     

牛血清白蛋白与有机小分子偶氮磺Ⅲ、溴偶氮磺Ⅲ相互作用的研究

本文研究了在不同酸度下．偶氮磺、溴偶氮磺Ⅲ与牛血清白蛋白的作用情况，用光度法求出了不同条件下偶氮磺Ⅲ、溴偶氮磺Ⅲ与牛血清白蛋白的结合个数，并用三种不同的方法相互对照．证明偶氮磺Ⅲ、溴偶氮磺Ⅲ在牛血清白蛋白上有两类不同接合部位。利用Forster非幅射转移理论确定了有机小分子在牛血清白蛋白上的结合位置并对反应机理作了初步讨论。     

Generation of hyperchaos from the Chen–Lee system via sinusoidal perturbation

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen–Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, ε, and ω. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.