The synthesis of multiblock copolymer brush based on DSPAAC and CuAAC click reaction

Multiblock copolymer brushes have broad application in thermoplastic elastomers, drug delivery, porous materials, and nanolithography due to their unique structure and properties. In this research, a novel multiblock copolymer brush (PHEA-g-PEG)_x-co- (PEG₂₃)_y was synthesized by combining the efficient double strain-promoted azide-alkyne cycloaddition (DSPAAC) and copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reactions. The gel permeation chromatography (GPC), proton nuclear magnetic resonance spectrometer (¹H NMR), Fourier transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM) were used to characterize the prepared polymers. The results demonstrated that the novel multiblock copolymer brush was successfully prepared. The mole ratio was 1/0.84 between block PHEA-g-PEG and block PEG₂₃, and the grafting density was 100%. The AFM image showed the morphologies of cylinder, sphere, and beads on a string owning to the random distribution of PHEA-g-PEG and PEG.     

Gallium “Shears” for C=N and C=O Bonds of Isocyanates

Digallane [L¹Ga−GaL¹] ( 1 , L¹=dpp-bian=1,2-[(2,6-iPr₂C₆H₃)NC]₂C₁₂H₆) reacts with RN=C=O (R=Ph or Tos) by [2+4] cycloaddition of the isocyanate C=N bonds across both of its C=C−N−Ga fragments to afford [L¹(O=C−NR)Ga−Ga(RN−C=O)L¹] (R=Ph, 3 ; R=Tos, 4 ). The reactions with both isocyanates result in new C−C and N−Ga single bonds. In the case of allyl isocyanate, the [2+4] cycloaddition across one C=C−N−Ga fragment of 1 is accompanied by insertion of a second allyl isocyanate molecule into the Ga−N bond of the same fragment to afford compound [L¹Ga−Ga(AllN− C=O)₂L¹] ( 5 ) (All=allyl). In the presence of Na metal, the related digallane [L²Ga−GaL²] ( 2 ; L²=dpp-dad=[(2,6-iPr₂C₆H₃)NC(CH₃)]₂) is converted into the gallium(I) carbene analogue [L²Ga:]⁻ ( 2 A ), which undergoes a variety of reactions with isocyanate substrates. These include the cycloaddition of ethyl isocyanate to 2 A affording [Na₂(THF)₅]{L²Ga[EtN−C(O)]₂GaL²} ( 6 ), cleavage of the N=C bond with release of 1 equiv. of CO to give [Na(THF)₂]₂[L²Ga(p-MeC₆H₄)(N−C(O))₂−N(p-MeC₆H₄)]₂ ( 7 ), cleavage of the C=O bond to yield the di-O-bridged digallium compound [Na(THF)₃]₂[L²Ga-(μ-O)₂-GaL²] ( 8 ), and generation of the further addition product [Na₂(THF)₅][L²Ga(CyNCO₂)]₂ ( 9 ). Complexes 3 – 9 have been characterized by NMR (¹H, ¹³C), IR spectroscopy, elemental analysis, and X-ray diffraction analysis. Their electronic structures have been examined by DFT calculations.     

Glucose biosensor based on glucose oxidase immobilized on a nanofilm composed of mesoporous hydroxyapatite, titanium dioxide, and modified with multi-walled carbon nanotubes

We report on a highly sensitive glucose biosensor that was fabricated from a composite made from mesoporous hydroxyapatite and mesoporous titanium dioxide which then were ultrasonically mixed with multi-walled carbon nanotubes to form a rough nanocomposite film. This film served as a platform to immobilize glucose oxidase onto a glassy carbon electrode. The morphological and electrochemical properties of the film were examined by scanning electron microscopy and electrochemical impedance spectroscopy. Cyclic voltammetry and chronoamperometry were used to characterize the electrochemical performances of the biosensor which exhibited excellent electrocatalytic activity to the oxidation of glucose. At an operating potential of 0.3?V and pH 6.8, the sensor displays a sensitivity of 57.0?μA?mM^?1?cm^?2, a response time of <5?s, a linear dynamic range from 0.01 to 15.2?mM, a correlation coefficient of 0.9985, and a detection limit of 2?μM at an SNR of 3. No interferences are found for uric acid, ascorbic acid, dopamine and most carbohydrates. The sensor is stable and was successfully applied to the determination of glucose in real samples.

Synthesis, structure and properties of a two-dimensional iron(II) metal-organic framework

Reaction of FeSO₄·7H₂O with 5-(isonicotinamido)isophthalic acid (H₂INAIP) in the presence of NaOH results in the formation of a two-dimensional network [Fe(INAIP)(H₂O)]_n·2nH₂O. In the complex, each INAIP^2? ligand links three Fe(II) atoms to give a double-chain structure using its two carboxylate groups in ?? ₁?C?? ¹:?? ¹ and ?? ₂?C?? ¹:?? ¹ coordination modes. The chains are interlinked to form a layer structure through Fe?CN interactions, which it is extended to a three-dimensional supramolecular structure by H-bonding interactions. The thermal and magnetic properties of the complex were investigated, and antiferromagnetic interactions were observed. Moreover, the adsorption behavior shows that the title complex has obviously selective adsorption of CO₂ over N₂ after the removal of the solvent molecules within the pores.     

两个三环己基锡吡啶羧酸酯化合物的合成、结构及量子化学研究

以2-氯烟酸(ClPyCOOH)、吡啶-3-甲酸(PyCOOH)分别与三环己基氢氧化锡反应,合成了两个三环己基锡杂环羧酸酯[Cy3Sn(ClPyCOO)(H2O)](1),[Cy3Sn(PyCOO)(H2O)](2)(Cy为环己基)。经IR、1H NMR、元素分析和X射线衍射表征结构。配合物均属单斜晶系,空间群C2/c。晶体学参数:化合物1,a=2.018 97(5)nm,b=1.361 16(4)nm,c=1.957 58(5)nm,β=104.815 0(10)°,Z=8,V=5.200 9(2)nm3,Dc=1.386 g.cm-3,μ(Mo Kα)=1.108 mm-1,F(000)=2 240,R1=0.043 7,wR2=0.138 0。化合物2,a=2.005 44(14)nm,b=1.355 58(10)nm,c=1.911 38(14)nm,β=107.260(3)°,Z=8,V=4.962 2(6)nm3,Dc=1.361 g.cm-3,μ(Mo Kα)=1.052 mm-1,F(000)=2 112,R1=0.035 2,wR2=0.112 5。中心锡原子均为五配位三角双锥构型。分子间存在氢键作用,配合物1、2分别形成二维结构。利用量子化学G98W软件,在LANL2DZ基组对配合物的稳定性、前沿分子轨道组成及能量进行研究。     

Synthesis and Electrochemical,Fluorescent and Magnetic Properties of a New Cadmium(II) Complex with 2-Benzoylbenzoic Acid

A new cadmium(II) complex Cd(OBBA)2(2,2A-bipy)2 with 2-benzoylbenzoic acid(HOBBA) and 2,2-bipyridine(2,2A-bipy) as ligands has been synthesized. Crystal data for the complex are as follows: monoclinic, space group P21/c with a = 16.402(3), b = 10.4191(18), c = 23.395(4) A, β = 91.765(2)o, V = 3996.2(12) A3, Dc = 1.455 gAcm-3, Z = 4, μ(Mo Kα) = 0.603 mm-1, F(000) = 1784, the final R = 0.0218 and w R = 0.0558. In the electrode reaction, its electron transfer is quasi reversible and the electrode reaction corresponds to Cd(II)/Cd(0). Under 618 nm radiation, the title complex shows a strong fluorescent band at around 326 nm. In addition, in the range of 2~300 K, this complex displays diamagnetic property.     

Synthesis,structure, and catalytic activity of rare-earth metal amides with a neutral pyrrolyl-functionalized indolyl ligand

<正>1 Representation of complexes and selected bond distances and bond angles Figure S1 Structure of complex 4. Hydrogen atoms were omitted for clarity, ellipsoids set at the 30% probability level. Selected bond distances() and angles(°): Er(1)–Cl(1) 2.6180(18), Er(1)–N(1) 2.301(6), Er(1)–N(4) 2.232(6), Er(1)–N(5) 2.229(6), N(1)–Er(1)–Cl(1) 87.41(14), N(4)–Er(1)–Cl(1) 101.16(14), N(5)–Er(1)–Cl(1) 118.60(16), N(4)–Er(1)–N(1) 114.1(2), N(5)–Er(1)–N(1) 108.7(2), N(5)–Er(1)–N(4) 121.9(2).Figure S2 Structure of complex 5. Hydrogen atoms were omitted for clarity, ellipsoids set at the 30% probability level. Selected bond distances(o) and angles(°): Y(1)–Cl(1) 2.6212(12), Y(1)–N(1) 2.280(3), Y(1)–N(4) 2.214(3), Y(1)–N(5) 2.228(3), N(1)–Y(1)–Cl(1) 87.67(8), N(4)–Y(1)–Cl(1) 121.32(8), N(5)–Y(1)–Cl(1) 102.88(8), N(4)–Y(1)–N(1) 107.75(11), N(5)–Y(1)–N(1) 111.64(11), N(4)–Y(1)–N(5) 120.78(10).     

Electrochemical tyrosine sensor based on a glassy carbon electrode modified with a nanohybrid made from graphene oxide and multiwalled carbon nanotubes

We report on a glassy carbon electrode that was modified with a composite made from graphene oxide (GO) and multiwalled carbon nanotubes (MWCNT) that enables highly sensitive determination of L-tyrosine. The sensor was characterized by transmission electron microscopy and electrochemical impedance spectroscopy, and its electrochemical properties by cyclic voltammetry, chronocoulometry and differential pulse voltammetry. The GO/MWCNT hybrid exhibits strong catalytic activity toward the oxidation of L-tyrosine, with a well defined oxidation peak at 761 mV. The respective current serves as the analytical information and is proportional to the L-tyrosine concentration in two ranges of different slope (0.05 to 1.0 μM and 1.0 to 650.0 μM), with limits of detection and quantification as low as 4.4 nM and 14.7 nM, respectively. The method was successfully applied to the analysis of L-tyrosine in human body fluids. The excellent reproducibility, stability, sensitivity and selectivity are believed to be due to the combination of the electrocatalytic properties of both GO and MWCNT. They are making this hybrid electrode a potentially useful electrochemical sensing platform for bioanalysis.

α-取代苯并噻吩钌乙炔及钌乙烯配合物的合成、表征、电化学及光谱电化学性质

以α-取代苯并噻吩乙炔及乙烯基为配体,与不同辅助配体键合的金属钌为氧化还原活性端基,分别合成并表征了α-取代苯并噻吩钌乙炔及钌乙烯配合物1和2,两个配合物均经X射线单晶衍射的确证。电化学性质表明配合物1具有较好的氧化还原可逆性,金属氧化态相对于2比较稳定。红外光谱电化学研究表明配合物1和2分别形成1⁺和2⁺后,与金属相连的ν(C≡C)和ν(C≡O)伸缩振动吸收均发生变化,其中ν(C≡C)变化较大,可能由于形成了Ru=C=C结构;紫外可见近红外光谱电化学研究发现电解后,中性分子1和2在紫外区域的强吸收峰均逐渐降低,1⁺分别在可见及近红外580 nm,698 nm及874 nm处出现较弱的3个吸收峰,3个吸收峰可能归属于LMCT吸收。2⁺在296 nm处出现1个很弱的吸收峰,这不同于配合物1⁺,可能源于2⁺的稳定性。     

2-羰基-3-苯基丙酸芳甲酰腙二(2,4-二氯苄基)锡配合物的合成、晶体结构及生物活性

二（2,4-二氯苄基）二氯化锡分别与2-羰基-3-苯基丙酸苯甲酰腙及2-羰基-3-苯基丙酸水杨酰腙反应,合成了2个取代苄基锡配合物（C1、C2）,通过元素分析、IR、¹H NMR、¹³C NMR、¹¹⁹Sn NMR、X射线单晶衍射以及热重分析等表征了配合物结构。测试了配合物对癌细胞Hela、MCF7、HepG2、Colo205、NCI-H460以及正常人体胚肾细胞HEK293、正常人体肝细胞HL7702的体外抑制活性;在Tris-HCl缓冲溶液中,以EB做为荧光探针,用荧光光谱法初步研究了配合物与小牛胸腺DNA的相互作用。结果表明：配合物C1、C2对5种癌细胞都有明显的抑制作用,配合物C2对HEK293、HL7702的细胞毒性远小于C1;配合物C1与小牛胸腺DNA作用是插入结合与静电结合共同作用所致,配合物C2与小牛胸腺DNA作用是插入结合作用所致。