Double Metal Ions Competitively Control the Guest‐Sensing Process: A Facile Approach to Stimuli‐Responsive Supramolecular Gels

A facile approach to the design of stimuli‐responsive supramolecular gels (SRSGs) termed double‐metal‐ion competitive coordination control is reported. By this means, the fluorescence signals and guest‐selective responsiveness of the SRSGs are controlled by the competitive coordination of two different metal ions with the gelators and the target guest. To demonstrate this approach, a gelator G2 based on multiple self‐assembly driving forces was synthesized. G2 could form Ca²⁺‐coordinated metallogel CaG with strong aggregation‐induced emission (AIE). Doping of CaG with Cu²⁺ results in AIE quenching of CaG and formation of Ca²⁺‐ and Cu²⁺‐based metallogel CaCuG. CaCuG could fluorescently detect CN^? with specific selectivity through the competitive coordination of CN^? with the Cu²⁺ and the coordination of Ca²⁺ with G2 again. This approach may open up routes to novel stimuli‐responsive supramolecular materials.     

Improved conditions for periodate/Schiff's base‐based fluorescent staining of glycoproteins with dansylhydrazine in SDS‐PAGE

An improved periodate/Schiff's base based fluorescent stain with dansylhydrazine (DH) for glycoproteins in 1D and 2D SDS‐PAGE was described. Down to 4–8 ng of glycoproteins can be selectively detected within 2 h, which is approximately 16‐fold higher than that of original protocol, but similar to that of Pro‐Q Emerald 488 stain (Invitrogen, Carlsbad, USA). Furthermore, subsequent study of deglycosylation, glycoprotein affinity isolation, and LC‐MS/MS analysis were performed to confirm the specificity of the improved method. As a result, improved DH stain may provide a new choice for selective, economic, MS compatible, and convenient visualization of gel‐separated glycoproteins.     

The isolation and structural elucidation of three new biflavonoid glycosides from Lomatogonium carinthiacum

Three biflavonoid glycosides, named carinoside B, C and D (1, 2 and 3, respectively), were isolated from the n-BuOH crude extract of the aerial part of Lomatogonium carinthiacum (Wulfen) Rchb (L. carinthiacum). The structures of 1, 2 and 3 were elucidated by spectroscopic methods, including UV, IR, HR-ESI-MS and extensive 1D and 2D NMR techniques.     

Halogen Bonding to Amplify Luminescence: A Case Study Using a Platinum Cyclometalated Complex

The cocrystallization of a weakly luminescent platinum complex [Pt(btpy)(PPh₃)Cl] ( 1 ) (Hbtpy=2‐(2benzothienyl)pyridine; emission quantum yield Φ_em=0.03) with fluorinated bromo‐ and iodoarenes C₆F_6‐nX_n (X=Br, I; n=1, 2) results in the formation of efficient halogen‐bonding (XB) interactions Pt? Cl???X? R. An up to 22‐fold enhancement (Φ_em=0.65) in the luminescence intensity of the cocrystallized compound is detected, without a substantial change of the emission energy. Based on crystallographic, photophysical, and theoretical investigations, the contribution of the XB donors C₆F_6‐nX_n to the amplification of luminescence intensity is attributed to the enhancement of spin–orbit coupling through the heavy‐atom effect, and simultaneously to the suppression of the nonradiative relaxation pathways by increasing the rigidity of the chromophore center.     

铁电体中极化长程涨落的光子关联谱实验研究

从极化团簇的随机涨落出发, 利用维纳过程模型, 推导了铁电体中极化长程涨落的弛豫规律以及光强自相关函数所可能的表现形式. 阐述了微观极化团簇的弛豫过程与宏观测量弛豫规律之间的联系. 通过对原有氦氖激光光子关联谱实验装置进行改进, 观测了BaTiO₃和0.71Pb(Mg_1/3Nb_2/3)O₃-0.29PbTiO₃单晶中极化团簇长程涨落在居里点和立方到四方相变点附近的弛豫过程. 在BaTiO₃中发现极化团簇长程涨落在居里点之上4 K存在双弛豫现象, 此现象与其有序无序相变机理相联系. 在Pb(Mg_1/3Nb_2/3)O₃-0.29PbTiO₃中发现极化团簇长程涨落在相变点两侧都存在双弛豫现象. 利用推导的理论结果很好地拟合了实验结果并提取了极化团簇长程涨落的弛豫时间. 两种样品中极化团簇长程涨落的弛豫时间都在相变点出现突变, 并呈现临界慢化现象.     

A novel synthetic route for LiFePO_4/C cathode materials by addition of starch for lithium-ion batteries

LiFePO4/Carbon composite cathode material was prepared using starch as carbon source by spray-pelleting and subsequent pyrolysis in N2. The samples were characterized by XRD, SEM, Raman, and their electrochemical performance was investigated in terms of cycling behavior. There has a special micro-morphology via the process, which is favorable to electrochemical properties. The discharge capacity of the LiFePO4.C composite was 170 mAh g-1, equal to the theoretical specific capacity at 0.1 C rate. At 4 C current density, the specific capacity was about 80 mAh g-1, which can satisfy for transportation applications if having a more flat discharge flat.     

The effect of polymerization conditions on crystalline of polybutene-1 catalyzed by metallocene catalyst

Polybutene-1 was synthesized stereoselectively with the precursorη5-(pentamethyl-cyclopentadienyl) tribenzyloxide titanium (Cp*Ti(OBz)3) and methylaluminoxane (MAO). The effects of polymerization conditions, trimethyl alumina (TMA) content in MAO and temperature on the crystalline and molecular weight of the products, and catalytic activity were investigated. The structural properties of the polybutene-1 were characterized with 13C NMR and WAXD.     

Studies on the Neodymium-induced Pinacol Coupling of Aromatic Aldehydes and Ketones in Aqueous Media

1,2-Diols are very useful synthons for a variety of organic synthesis1, which have been used as intermediates for the construction of the skeletons of the biologically important natural products2. Within the last several years, various metals, such as Mg3…