一种检测肼的纳米粒子探针及其生物成像应用

肼是一种广泛使用的化工原料,但它也是一种有毒化学品,对人类健康和环境安全有着严重威胁.因此,开发一种方便、快速检测肼的方法具有重要的意义.本文制备了一种芘甲醛纳米粒子探针,其能和肼快速反应,从而使探针的荧光信号发生变化,实现对肼的荧光检测.该探针检测肼具有高选择性和灵敏度,并成功地应用于HeLa细胞和斑马鱼中肼的成像.     

A coumarin based chemodosimetric probe for ratiometric detection of hydrazine

A coumarin-based sensor containing trifluoroacetyl acetonate moiety was designed, synthesized, and applied for hydrazine detection. Hydrazinolysis of the chemodosimeter results in a prominent chromogenic and fluorescence ratiometric response toward hydrazine within 3 min. The probe is highly selective toward hydrazine over other important amines and other biologically and environmentally abundant analytes. The limit of detection (LOD) of the probe is in 10⁻⁶ M range. The sensing mechanism was supported by NMR and HRMS analysis. The experimentally observed change in structure and electronic properties of the sensor after reaction with hydrazine was modeled by Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT) computational calculations, respectively.     

Synthesis, characterization and photocrosslinking properties of polyacrylamides having bromo substituted pendant cinnamoyl moieties

New 3- and 4-bromocinnamoyl aniline were synthesized condensing 4-aminoacetophenone and the respective bromobenzaldehydes in the presence of sodium hydroxide. The monomers, 4-(3′-bromocinnamoyl) phenyl acrylamide (4,3′-BCPA) and 4-(4′-bromocinnamoyl) phenyl acrylamide (4,4′-BCPA) were prepared by reacting the respective chalcones and acryloyl chloride in the presence of triethylamine at 0-5 °C. Homopolymers of 4,3′-BCPA and 4,4′-BCPA was carried out in methyl ethyl ketone using benzoyl peroxide (BPO) under nitrogen atmosphere at 70 °C. The prepared polymers were characterized by UV, IR, ¹H-NMR and ¹³C-NMR techniques. The molecular weights (M_w and M_n) of the polymers were determined by gel permeation chromatography. The thermogravimetric analysis (TGA) of the polymers in nitrogen atmosphere reveals that they possess very good thermal stability required of a negative type photoresist. The glass transition temperature of poly(4,3′-BCPA) and poly (4,4′-BCPA) were found to be 55 and 64 °C respectively. The solubility of the polymers was tested in various polar and non-polar solvents. Photocrosslinking nature of the polymer samples was carried out in the presence and absence of various triplet photosensitizers in solution phase using chloroform solvent under medium frequency UV light. For using the polymers as negative photoresist materials the rate of photocrosslinking of the polymers was measured under the influence of different solvents, concentrations and position of the substituent.     

A ratiometric merocyanine-based fluorescent probe for detecting hydrazine in living cells and zebra fish

We developed a merocyanine-based fluorescent probe,NEPB,for tracing hydrazine(N_2 H_4) in a ratiometric manner with large Stokes shifts and long emission wavelength.The fluorescence color of probe NEPB changed from green to yellow upon addition of hydrazine.Probe NEPB displayed high selectivity and sensitivity to hydrazine in solution,and could ratiometrically monitor N_2 H_4 in living cells and zebrafish with low cytotoxicity.     

A Perylene diimide based fluorescent probe for caffeine in aqueous medium

Caffeine is a legal stimulant drug which has received considerable attention due to its widespread use as a beverage and in pharmaceutical formulations. However, reported chemosensors for caffeine are limited. In the present study use of a perylene diimide (PDI) derivative has been explored for the first time for detection and quantification of caffeine in an aqueous medium. Spectroscopic studies (UV-Vis, Fluorescence, FTIR and 1H-NMR) suggest that aspartic acid modified perylene diimide (PASP) may bind to caffeine through π-π interaction. This interaction results in immediate quenching of fluorescence and optical color change which can be perceived through naked eyes. This probe has been successfully used for bio-imaging of caffeine in living cells.     

A Silver Complex of 6,7-Dicyanodipyridoquinoxaline： π-Stacking Interactions and Luminescence

The reaction of 6,7-dicyanodipyridoquinoxaline （DICNQ） with AgNO3 in a 1：1 molar ratio by solution method gave a new complex [Ag（DICNQ）2]NO3 1. Single-crystal X-ray diffraction analysis reveals that the complex crystallizes in the space group Ibca of orthorhombic system with eight formula units in a cell. Crystal data for 1： a = 15.7055（17）, b = 18.411（2）, c = 20.680（2）A, V = 5979.7（11）A3, Z = 8, C32Hl2AgN13O3, Mr = 734.42, Dc = 1.632 g/cm3, μ= 0.734 mm-1, F（000） = 2928, S = 1.023 and T= 293（2） K. The final R = 0.0659 and wR = 0.1927 for 2118 observed reflections with I 〉 2σ（I）, and R = 0.0801 and wR = 0.2196 for all data. The complex builds up a packing structure by π-π stacking interactions and shows a luminescent feature.     

(4-Ferrocenylethyne) phenylamine on Graphene as the Signal Amplificator to Determinate Dopamine and Acetaminophen Simultaneously

A novel (4‐ferrocenylethyne) phenylamine functionalized graphene sheets (FEPA‐GR), coupling with chitosan (CS) were used as a signal amplification platform for simultaneous and sensitive determination of dopamine (DA) and acetaminophen (AC). In this work, FEPA used as electron transfer mediator can be immobilized on GR surface via strong π‐π stacking interaction between the conjugate chain of FEPA and GR, which effectively prevents FEPA electron mediator leaking from the electrode surface and amplified the signal. Transmission electron microscopy, FT‐IR spectroscopy, UV‐vis spectroscopy and electrochemical experiments results are all demonstrated the strong π‐π stacking interaction between FEPA and GR. The resulted biosensor exhibited a fast response, remarkable electrocatalytic activity, perfect anti‐interference ability and good stability for simultaneous detection of DA and AC. Under the optimum conditions, the oxidation peak currents of DA and AC were linearly correlated to their concentrations in the range of 2.0–135.0 µmol·L^?1 and 0.3–80.0 µmol·L^?1, respectively. The lower detection limits for DA and AC were 0.30 and 0.05 µmol·L^?1, respectively. The feasibility of the proposed method was validated by successfully applied to the simultaneous determination of DA and AC in serum samples with the standard addition method.     

A Novel Supramolecular Structure for a Lanthanum Picrate

A new complex of lanthanum picrate with N,N'-diethyl-N,N'-diphennyl-3-oxapentanediamide (L) was synthesized and its structure determined by X-ray diffraction measurements. It crystallizes as the ten-coordinate complex La(pic)₃L₂ in the triclinic space group P1 with a = 12.140(2), b = 14.250(2), c = 20.333(2) Å, α = 101.400(10), β = 99.390(10), γ = 102.400(10)°, U = 3289.1(8) ų, Z = 2, D_c = 1.519 g cm^-3. The complex possesses a novel ladder-like 2-D supramolecular structure directed by π-π interactions.     

Coumarinocoumarin-based fluorescent probe for the sensitive and selective detection of hydrazine in living cells and zebra fish

A coumarinocoumarin-based fluorescent probe,JCCA,was developed for the detection of N2 H4.JCCA exhibited a fast turn-on fluorescence enhancement in response to N2 H4 with good selectivity,sensitivity and a detection limit of 7.4 nmol/L.Significantly,JCCA displayed a good capability for visualizing N2 H4 in living cells and zebra fish.     

同时添加碳纳米管及石墨烯对热致液晶聚酯形状记忆行为及拉伸性能的影响

利用溶液共混的方法将碳纳米管(CNT)及石墨烯(G)同时加入到热致液晶聚酯中制备纳米复合材料.通过透射电镜(TEM)研究纳米粒子的分散及形貌.采用荧光光谱及拉曼光谱研究碳纳米填料与热致液晶聚酯基体之间存在π-π相互作用.利用电子万能试验机(EUTM)研究了材料的拉伸性能,由于CNT与G与基材之间作用力强,且CNT与G间的协效作用能有效地实现应力转移,同时加入CNT及G有助于提升复合材料的拉伸强度.动态热机械分析(DMA)数据表明,同时添加CNT与G对于复合材料的固定率影响不大,但会降低回复率;同时复合材料的回复应力也得到显著的提升.     

用于合成纯硅分子筛 AST 和 LTA 的动态有机结构导向剂(英文)

Pure-silica-zeolite(PSZ) AST and LTA are synthesized successfully by using the same structure-directing agent(SDA) molecule,but at different concentrations.A dynamic organic SDA is proposed to discuss the mechanism of phase discrimination between AST and LTA.Data suggest that the SDA molecules can self-assemble into dimer or trimer complexes at different concentrations by π-π interactions,and these differences can be taken advantage of to selectively synthesize either PSZ AST or LTA.These deviations from the Liebau's rules indicate that small changes in SDA chemistry,structure,and order in solution can have a great impact on the structure selectivity of the zeolite synthesis.     

苯并咪唑类离子液体及其铅(Ⅱ)配位聚合物的合成、晶体结构及电学性质研究

合成了新的离子液体金属配合物[Pb(m-HNA)(H2O)].NO3.3H2O(m-HNA为N,N′-二-羧甲基-2-丙基苯并咪唑盐),并通过元素分析,红外光谱,对其进行了表征,通过X射线单晶衍射测定了其晶体结构,在晶体结构中,标题物通过π-π相互作用、分子间氢键和配位键自组装成了三维网状结构。另外,电化学性质表明,该配合物的电解过程为准可逆过程。     

Syntheses and Crystal Structures of Two Coordination Compounds CuLCl（H2O） and Ni（L）2 （HL = 2-Carboxy-1,10-phenanthroline）

Two complexes CuLCl（H2O） 1 and Ni（L）2 2 （HL = 2-carboxy-1,10-phenanthroline） have been synthesized and characterized by single-crystal X-ray crystallography. The structure of 1 has a monoclinic space group P21/n with a = 7.985（2）, b = 16.067（3）, c = 9.694（2） A, β = 98.189（30）°, V= 1231.0（4） A^3, Z = 4, Dc = 1.836 g/cm^3,μ =1.998 mm^-1, F（000） = 684, the final R = 0.0301 and wR = 0.0810. The structure of 2 （C26H14N4NiO10） adopts an orthorhombic system, space group Pbea with a = 9.410（2）, b = 23.2410（5）, c = 23.8680（5） A, V = 5219.9（18） A^3, Z = 8, Mr = 601.12, Dc = 1,530 g/cm^3,μ = 0.809 mm^-1, F（000） = 2448, the final R = 0.0448 and wR = 0.1427. The Cu center of complex 1 exhibits a square pyramidal coordination environment with one oxygen and two nitrogen atoms from deprotonated 2-carboxy-1,10-phenanthroline, one oxygen atom from water and one chloride ion. The Ni center of complex 2 assumes a distorted octahedral coordination geometry consisting of two oxygen atoms and four nitrogen atoms of two deprotonated 2-carboxy-1,10-phenanthroline molecules. Supramolecular assembly has been found via noncovalent bonds, such as hydrogen bonds and π-π stacking interactions.     

交联聚苯撑乙炔的的合成及其荧光特性

利用Sonogashira偶联反应,首次合成了溶解性好且为乙烯基封端的聚苯撑乙炔化合物（PPE）,通过。HNMR谱、IR光谱对其结构进行了表征．将其热固化后,通过紫外可见吸收光谱和荧光发射光谱分析,证明了PPE的交联能够在一定程度上消除分子链间的相互作用和π-π堆积效应．     

CO_2响应石墨烯体系的制备及其性能研究

利用CO_2响应性的含芘聚合物(PNDV)作为分散剂,通过π-π共轭作用力成功附着在石墨烯表面,从而制得一种稳定的石墨烯分散体系。采用UV-Vis、IR、荧光光谱和透射电子显微镜对体系中石墨烯的分散性和CO_2响应性能进行表征。结果表明:PNDV可修饰在石墨烯表面,形成含芘聚合物和石墨烯的杂化体(PNDV-RGO),得到稳定均匀的石墨烯分散溶液。透射电镜显示石墨烯在体系中以单片层形式分布,最大宽度约1μm。在交替通入CO_2/N2后,PNDV-RGO杂化体表现出明显的分散/聚集现象。     

Highly enhanced visible-light photocatalytic hydrogen evolution on g-C3N4 decorated with vopc through π-π interaction

Photocatalytic H₂ evolution reactions on pristine graphitic carbon nitrides (g-C₃N₄), as a promising approach for converting solar energy to fuel, are attractive for tackling global energy concerns but still suffer from low efficiencies. In this article, we report a tractable approach to modifying g-C₃N₄ with vanadyl phthalocyanine (VOPc/CN) for efficient visible-light-driven hydrogen production. A non-covalent VOPc/CN hybrid photocatalyst formed via π-π stacking interactions between the two components, as confirmed by analysis of UV-vis absorption spectra. The VOPc/CN hybrid photocatalyst shows excellent visible-light-driven photocatalytic performance and good stability. Under optimal conditions, the corresponding H₂ evolution rate is nearly 6 times higher than that of pure g-C₃N₄. The role of VOPc in promoting hydrogen evolution activity was to extend the visible light absorption range and prevent the recombination of photoexcited electron-hole pairs effectively. It is expected that this facile modification method could be a new inspiration for the rational design and exploration of g-C₃N₄-based hybrid systems with strong light absorption and high-efficiency carrier separation.     

二（2-吡啶基）甲二醇·亚氨基二乙酸根合镍（Ⅱ）配合物的合成与表征

合成了一个单核镍配合物Ni（H2bpd）[NH（CH2COO）2]（H2O）2（H2bpd=bis（2-pyridyl）methanediol,二（2-吡啶基）甲二醇）,并用IR和X射线单晶衍射进行结构测定.该化合物属单斜晶系,P2（1）/c空间群,晶胞参数：a=1.031 05（3）,b=1.003 52（3）,c=1.747 270（10）nm,β=106.232（2）°,Z=4,Dc=1.638 g/cm3,μ=1.169 mm-1,F（000）=888,R=0.087 4,wR2=0.172 8.此化合物中金属镍原子与两个配体中的三个氮原子和三个氧原子螯合,形成扭曲的八面体构型.在氢键,π-π堆积和CH-π作用下,化合物形成了3D结构.     

α/β类蛋白折叠中π-π相互作用的特异性

以α/β类蛋白的2种典型折叠类型为研究对象,对205个低相似度蛋白样本中的π-π相互作用进行统计分析.计算结果表明,(α/β)8-barrel折叠中π-π相互作用的分布密度高于经典Rossmann折叠,且在关键的局部区域的差异更加显著;芳香族氨基酸在(α/β)8-barrel结构中更容易形成π-π相互作用;色氨酸对应的3种π-π相互作用组合在(α/β)8-barrel折叠中出现的几率显著高于经典Rossmann折叠;(α/β)8-barrel折叠中π-π相互作用形成复杂π网络的能力强于经典Rossmann折叠.上述结果表明,π-π相互作用在α/β类蛋白的不同折叠类型中存在特异性,其在稳定(α/β)8-barrel结构中的作用强于经典Rossmann折叠.     

Iron-doping Accelerating NADH Oxidation over Carbon Nitride

As a state-of-the-art conjugated polymer photocatalyst, graphitic carbon nitride(abbreviated as g-C₃N₄)has shown great potential in photocatalytic cofactor(reduced form of nicotinamide adenine dinucleotide, NADH) regene-ration. Herein, Fe-doped g-C₃N₄ was engineered for photocatalytic NADH oxidation. The π-π interaction between the NADH molecule and the conjugated heptazine building block facilitates the adsorption of NADH onto the framework, as revealed by density functional theory(DFT) calculations. Furthermore, iron doping promoted the oxidation kinetics of NADH under blue LED illumination. The conversion ratio of NADH to its oxidized form could be up to 85.7% in 20 min, comparing with 59.4% for metal-free counterpart. Enzyme assay employing formate dehydrogenase(FDH) further verified the selectivity of the products, with 67.5%±2.6% of enzymatically active 1,4-NADH being regenerated following the oxidation process. Scavenger experiments suggest the dominant role of photo-induced electrons in the oxidation of NADH. This work could shed light on developing a novel cofactor regeneration route through the synergistic effect between the metal doping and noncovalent interaction based on the conjugated polymer.