新型咪唑[2,1-b][1,3,4]噻二唑衍生物的合成及Cdc25B抑制活性

大量研究表明,细胞分裂周期25磷酸酯酶B(Cdc25B)在许多癌症中都是过度表达的,如乳腺癌、结肠癌、子宫颈癌、肺癌等.因此,抑制Cdc25B是治疗癌症的一种潜在方法.采用微波辐射法,合成出了20个新的2,6-二芳基-咪唑[2,1-b][1,3,4]噻二唑衍生物4,然后再经Vilsmeier-Haack反应,合成出了19个新的2,6-二芳基-咪唑[2,1-b][1,3,4]噻二唑-5-甲醛(5).利用IR,1H NMR和元素分析对新的中间体化合物3及目标产物4和5进行了结构表征.对所合成的目标化合物4和5进行了Cdc25B抑制活性筛选.实验结果表明,在浓度为5μg/mL时,目标化合物4c对Cdc25B的抑制活性最高,抑制率为87.68%,目标化合物4o和5m具有中等的抑制活性,其抑制率分别为55.76%和57.69%.它们是潜在的Cdc25B抑制剂.     

A simple and efficient copper oxide-catalyzed Barbier–Grignard reaction of unactivated aryl or alkyl bromides with ester

An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier–Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65 °C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving group of R²O^-group is discussed.     

Nucleation and Growth Synthesis of Siloxane Gels to Form Functional,Monodisperse, and Acoustically Programmable Particles

Nucleation and growth methods offer scalable means of synthesizing colloidal particles with precisely specified size for applications in chemical research, industry, and medicine. These methods have been used to prepare a class of silicone gel particles that display a range of programmable properties and narrow size distributions. The acoustic contrast factor of these particles in water is estimated and can be tuned such that the particles undergo acoustophoresis to either the pressure nodes or antinodes of acoustic standing waves. These particles can be synthesized to display surface functional groups that can be covalently modified for a range of bioanalytical and acoustophoretic sorting applications.     

Enzymetically Regulating the Self‐Healing of Protein Hydrogels with High Healing Efficiency

Enzyme‐mediated self‐healing of dynamic covalent bond‐driven protein hydrogels was realized by the synergy of two enzymes, glucose oxidase (GOX) and catalase (CAT). The reversible covalent attachment of glutaraldehyde to lysine residues of GOX, CAT, and bovine serum albumin (BSA) led to the formation and functionalization of the self‐healing protein hydrogel system. The enzyme‐mediated protein hydrogels exhibit excellent self‐healing properties with 100 % recovery. The self‐healing process was reversible and effective with an external glucose stimulus at room temperature.     

De Novo Design of an Endohedral Heteronuclear Dimetallofullerene (UGd)@C60 with Exceptional Structural and Electronic Properties

Ever since the first synthesis of La@C₈₂ and U@C₂₈, there has been a growing interest in the study of endohedral metallofullerenes (EMFs) because of their great potential in various applications. Here we design a novel heteronuclear EMF (U‐Gd)@C₆₀, by using density functional theory (DFT), which shows an encapsulation energy of about ?5.53 eV, comparable to that of U₂@C_60, La₂@C₈₀, and Lu₂@C₇₆. (U‐Gd)@C₆₀ is found to have a surprising twofold, single‐electron U?Gd bond that results from the strong nanoconfinement of the fullerene, dominated by uranium′s 5f and 6d and gadolinium′s 5d atomic orbitals. The ground state shows an 11‐et high spin state, and the net spins distributed on the U‐pole carbons are relatively scattered, while they are highly concentrated on the Gd‐pole carbons. The exceptional electronic characteristics of this novel EMF, containing both uranium and gadolinium atoms encapsulated, might prove useful for future applications in nuclear energy and biomedicine.     

Ultra‐performance liquid chromatography coupled with electrospray ionization/quadrupole time‐of‐flight mass spectrometry for the rapid analysis of constituents in the traditional Chinese medical formula Danggui San

In this work, ultra‐performance LC with ESI quadrupole TOF‐MS (UPLC–ESI‐Q‐TOF‐MS) and automated MetaboLynx analysis was used to rapidly separate and identify the chemical constituents of Danggui San, a traditional Chinese medical formula. The analysis was performed on a Waters UPLC BEH C₁₈ column using a gradient elution system. A hyphenated ESI and Q‐TOF analyzer was used for the determination of the accurate mass of the protonated or deprotonated molecule and fragment ions in both positive and negative modes. Based on retention times, accurate mass, and the mass spectrometric fragmentation characteristics, a total of 47 compounds distributed over the chemical groups of phthalides, flavonoids, monoterpene glycosides, sesquiterpenoids, phenolics, and alkaloids, were simultaneously separated within 18 min and identified or tentatively elucidated in Danggui San for the first time. UPLC–ESI‐Q‐TOF‐MS analysis revealed the complexity of the chemical composition of this formula. The method developed is rapid, accurate, reliable, and highly sensitive to characterize the chemical constituents of Danggui San.     

石墨烯层数测量方法的研究进展

石墨烯具有高导电性、高韧度、高强度、超大比表面积等特点,在电子、航天工业、新能源、新材料等领域有广泛应用。对石墨烯层数测量方法的研究有助于深入理解石墨烯性能与微观结构之间的关系。本文着重阐述了包括光学显微镜、拉曼光谱、原子力显微镜和透射电镜等测量石墨烯层数的方法,同时比较了各种测量方法的优点及局限性,并指出石墨烯层数的测量方法还有待进一步完善。     

Low‐Background,Highly Sensitive DNA Biosensor by Using an Electrically Neutral Cobalt(II) Complex as the Redox Hybridization Indicator

An electrically neutral cobalt complex, [Co(GA)₂(phen)] (GA=glycollic acid, phen=1,10‐phenathroline), was synthesized and its interactions with double‐stranded DNA (dsDNA) were studied by using electrochemical methods on a glassy carbon electrode (GCE). We found that [Co(GA)₂(phen)] could intercalate into the DNA duplex through the planar phen ligand with a high binding constant of 6.2(±0.2)×10⁵ M ^?1. Surface studies showed that the cobalt complex could electrochemically accumulate within the modified dsDNA layer, rather than within the single‐stranded DNA (ssDNA) layer. Based on this feature, the complex was applied as a redox‐active hybridization indicator to detect 18‐base oligonucleotides from the CaMV35S promoter gene. This biosensor presented a very low background signal during hybridization detection and could realize the detection over a wide kinetic range from 1.0×10^?14 M to 1.0×10^?8 M , with a low detection limit of 2.0 fM towards the target sequences. The hybridization selectivity experiments further revealed that the complementary sequence, the one‐base‐mismatched sequence, and the non‐complementary sequence could be well‐distinguished by the cobalt‐complex‐based biosensor.     

Synthesis,Physical Properties,and Anion Recognition of Two Novel Larger Azaacenes: Benzannelated Hexazaheptacene and Benzannelated N,N′‐Dihydrohexazaheptacene

Two novel larger azaacenes with six or ten N atoms in their backbones, benzannelated 9,11,13,22,24,26‐hexazatetrabenzo[a,c,l,n]heptacene ( HATBH , 1 ) and benzannelated 9,26‐dihydro‐9,11,13,22,24,26‐hexaza‐tetrapyrido[3,2‐a: 2′,3′‐c: 3′′,2′′‐l: 2′′′,3′′′‐n]heptacene ( DHATPH, 2 ), have been successfully synthesized in two steps. The theoretical band gaps estimated through DFT calculations for HATBH ( 1 ) and DHATPH ( 2 ) are 1.949 eV and 2.278 eV, which are close to the experimentally obtained optical band gaps (2.14 eV and 2.39 eV). Interestingly, HATBH ( 1 ) can act as efficient anion sensor for F^? and H₂PO₄^?, while DHATPH ( 2 ) selectively responds to F^? among the ten different anions used (F^?, Cl^?, Br^?, I^?, PF₆^?, HSO₄^?, NO₃^?, BF₄^?, AcO^?, and H₂PO₄^?). Our synthetic strategy could offer a promising and easy way to obtain even larger azaacenes.     

Ultrasonic Preparation of Hierarchical Graphene‐Oxide/TiO2 Composite Microspheres for Efficient Photocatalytic Hydrogen Production

Hierarchical graphene oxide (GO)‐TiO₂ composite microspheres with different GO/TiO₂ mass ratios were successfully prepared by mixing GO and TiO₂ microspheres under ultrasonic conditions. Ultrasonication helped the GO and TiO₂ microsphere to uniformly mix on the microscale. The results showed that the GO‐TiO₂ composites that were prepared by ultrasonic mixing exhibited significantly higher hydrogen‐evolution rates than those that were synthesized by simple mechanical grinding, owing to synergetic effects, including enhanced light absorption and scattering, as well as improved interfacial charge transfer because of the excellent contact between the GO sheets and TiO₂ microspheres. In addition, GO‐TiO₂‐3 (3 wt. % GO) showed the highest hydrogen‐generation rate (305.6 μmol h^?), which was about 13 and 3.3‐times higher than those of TiO₂ microsphere and GO‐P25 (with 3 wt. % GO), respectively. Finally, a tentative mechanism for hydrogen production is proposed and supported by photoluminescence and transient photocurrent measurements. This work highlights the potential applications of GO‐TiO₂ composite microspheres in the field of clean‐energy production.