Fast and Selective Simultaneous Determination of Acetaminophen,Aspirin and Caffeine in Pharmaceutical Products by Batch Injection Analysis with Multiple Pulse Amperometric Detection

In this work is presented a method for simultaneous determination of paracetamol (PA), acetylsalicylic acid (ASA) and caffeine (CA) in pharmaceutical tablets, using a bare boron‐doped diamond working electrode (BDDE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA‐MPA). The optimized sequence of fast potential pulses were applied on BDDE for acquisition of independent amperograms: +1.0 V for PA oxidation, +1.3 V for oxidation of PA and salicylic acid (SA) generated from a previous alkaline hydrolysis of ASA and +1.6 V in which the three analytes are oxidized (PA, SA and CA). Selective determination of PA is performed using the currents obtained at +1.0 V, while SA and CA signals are indirectly obtained using simple subtraction operations between peak currents from each amperogram and correction factors (CF's). The limitations of such approach on the precision and accuracy as function of BIA‐MPA conditions are discussed. Simultaneous determination of the target drugs in pharmaceutical tablets was performed by BIA‐MPA and the results compared to a HPLC‐DAD method. Under optimized conditions, the proposed method exhibits fast responses (180 injections per hour for the simultaneous determination of the three analytes) and suitable precision (RSD_PA: 0.78 %; RSD_SA: 1.09 %; RSD_CA: 2.73 %). BIA‐MPA method is simple, portable and presents relative low‐cost.     

Simple and Fast Determination of Warfarin in Pharmaceutical Samples Using Boron‐doped Diamond Electrode in BIA and FIA Systems with Multiple Pulse Amperometric Detection

This paper proposes the use of the boron‐doped diamond electrode (BDDE) in flow and batch injection analysis (FIA and BIA) systems with multiple‐pulse amperometric (MPA) detection for the determination of warfarin (WA) in pharmaceutical formulations. The electrochemical behavior of WA obtained by cyclic voltammetry (CV) in 0.1 mol L⁻¹ phosphate buffer shows an irreversible oxidation process at +1.0 V (vs Ag/AgCl). The MPA was based on the application of two sequential potential pulses as a function of time on BDDE: (1) for WA detection at +1.2 V/100 ms and; (2) for electrode surface cleaning at −0.2 V/200 ms. Both hydrodynamic systems (FIA‐MPA and BIA‐MPA) used for WA determination achieved high precision (with relative standard deviations around 2 %, n =10), wide linear range (2.0−400.0 μmol L⁻¹), low limits of detection (0.5 μmol L⁻¹) and good analytical frequency (94 h⁻¹ for FIA and 130 h⁻¹ for BIA). The WA determination made by the proposed methods was compared to the official spectrophotometric method. The FIA‐MPA and BIA‐MPA methods are simple and fast, being an attractive option for WA routine analysis in pharmaceutical industries.     

Synthesis,Crystal Structure and Thermal Behavior of 4,5‐Diacetoxyl‐2‐(dinitromethylene)‐imidazolidine

A new energetic material, 4,5‐diacetoxyl‐2‐(dinitromethylene)‐imidazolidine (DADNI), was synthesized by the reaction of 4,5‐dihydroxyl‐2‐(dinitromethylene)‐imidazolidine (DDNI) and acetic anhydride, and characterized by single crystal X‐ray diffraction. Crystal data for DADNI are monoclinic, space group C2/c, a=15.9167(3) Å, b=8.6816(4) Å, c=8.5209(3) Å, β=103.294(9)°, V=1145.9(3) ų, Z=4, µ=0.150 mm⁻¹, F(000)=600, D_c=1.682 g·cm⁻³, R₁=0.0565 and wR₂=0.1649. Thermal decomposition behavior of DADNI was studied and an intensely exothermic process was observed. The kinetic equation of the decomposition reaction is: dα/dT=(10^16.64/β)×4α^3/4exp(−1.582×10⁵/RT). The critical temperature of thermal explosion is 163.76°C. The specific heat capacity of DADNI was studied with micro‐DSC method and theoretical calculation method. The molar heat capacity is 343.30 J·mol⁻¹·K⁻¹ at 298.15 K. The adiabatic time‐to‐explosion of DADNI was calculated to be 87.7 s.     

配位聚合物[Cu(pa)(vim)2]n的合成、晶体结构和电化学性质研究

本文合成了一种新型配位聚合物[Cu(pa)(vim)2]n(pa为邻苯二甲酸阴离子,vim为1-乙烯基-1H-咪唑),并用x射线单晶衍射仪和元素分析表征了其单晶结构。晶体属单斜晶系,C2/c空间群,晶胞参数分别为：a＝1.6527(3) nm, b＝0.81800(16) nm, c＝1.4463(3) nm, β＝113.19(3)°, V＝1.7973(7) nm3, Z＝4, Dc＝1.537 g?cm－3。 [I＞2σ(I)]时：R1＝0.0476, wR2＝0.1235,对所有数据：R1＝0.0693, wR2＝0.1355。配合物的结构中存在沿着c轴的zigzag聚合链。每个铜原子位于晶体中心,与两个N原子和两个O原子进行配位,形成了扭曲的平面结构。电化学研究表明在配合物中Cu2+/Cu+的氧化还原是一个单电子的准可逆过程。     

Antiprotozoal Activity and Cytotoxicity of Novel 1,7‐Dioxadispiro[5.1.5.2]pentadeca‐9,12‐dien‐11‐one Derivatives from Amomum aculeatum

Cytotoxicity against the KB cancer cell line as a lead bioactivity‐guided fractionation of the petroleum ether extract of rhizomes of Amomum aculeatum Roxb. led to the isolation of three novel dioxadispiro[5.1.5.2]pentadeca‐9,12‐dien‐11‐one derivatives. The structures of aculeatin A ( 1 ), aculeatin B ( 2 ), and aculeatin C ( 3 ) were established as rel‐(2R,4R,6S)‐ and rel‐(2R,4R,6R)‐4‐hydroxy‐2‐tridecyl‐1,7‐dioxadispiro[5.1.5.2]pentadeca‐9,12‐dien‐11‐one ( 1 and 2 , resp.) and rel‐(2R,4R,6R)‐2‐[4‐(3‐dodecyl‐2‐heptyl‐3‐hydroxy‐6‐oxocylohexa‐1,4‐dienyl)‐2‐oxobutyl]‐4‐hydroxy‐1,7‐dioxadispiro[5.1.5.2]pentadeca‐9,12‐dien‐11‐one ( 3 ) by extensive spectroscopic analyses, particularly ¹³C‐NMR, inverse‐gated ¹³C, HMQC, HMBC, NOESY, and INADEQUATE NMR experiments as well as mass spectrometry. The aculeatins represent a novel type of natural products. All compounds showed high cytotoxicity against the KB cell line: 1 , IC₅₀=1.7 μM ; 2 , IC₅₀=2.0 μM ; 3 , IC₅₀=1.6 μM . Additional testing against two Plasmodium falciparum strains as well as against trypomastigote forms of Trypanosoma brucei rhodesiense and Trypanosoma cruzi showed strong activities, particularly against P. falciparum strain K1 ( 1 , IC₅₀=0.18 μM ; 2 , IC₅₀=0.43 μM ; 3 , IC₅₀=0.37 μM ).     

Simultaneous Determination of Caffeine,Ibuprofen, and Paracetamol by Flow‐injection Analysis with Multiple‐pulse Amperometric Detection on Boron‐doped Diamond Electrode

This work presents a simple, fast and low‐cost method for the simultaneous determination of three drugs by flow‐injection analysis with multiple‐pulse amperometric (MPA) detection using a wall‐jet flow cell with a boron‐doped diamond electrode. The amperometric determination of caffeine (CF), ibuprofen (IB) and paracetamol (PC) was performed by the application of a four‐potential waveform using the MPA technique. PC is oxidized at E₁ (1.20 V/70 ms) and thus selectively detected; PC and CF are oxidized at E₂ (1.49 V/40 ms); PC, CF and IB are oxidized at E₃ (1.70 V/70 ms); and E₄ (1.80 V/100 ms) is applied for electrode cleaning. The subtraction of currents obtained at the different potentials did not provide accurate determinations of CF and IB, thus it was required to investigate correction factors to determine CF and IB without the interference from PC and CF using the respective amperometric signals obtained at E₂ and E₃. The proposed method was successfully applied for the determination of three drugs in pharmaceutical samples with low generation of residues and a high analytical frequency (150 h^?1) in comparison with HPLC‐DAD method.     

Diversification of ortho‐Fused Cycloocta‐2,5‐dien‐1‐one Cores and Eight‐ to Six‐Ring Conversion by σ Bond C−C Cleavage

Sequential treatment of 2‐C₆H₄Br(CHO) with LiC≡CR¹ (R¹=SiMe₃, tBu), nBuLi, CuBr?SMe₂ and HC≡CCHClR² [R²=Ph, 4‐CF₃Ph, 3‐CNPh, 4‐(MeO₂C)Ph] at ?50 °C leads to formation of an intermediate carbanion (Z)‐1,2‐C₆H₄{C_A(=O)C≡C_BR¹}{CH=CH(CH^?)R²} ( 4 ). Low temperatures (?50 °C) favour attack at C_B leading to kinetic formation of 6,8‐bicycles containing non‐classical C‐carbanion enolates ( 5 ). Higher temperatures (?10 °C to ambient) and electron‐deficient R² favour retro σ‐bond C?C cleavage regenerating 4 , which subsequently closes on C_A providing 6,6‐bicyclic alkoxides ( 6 ). Computational modelling (CBS‐QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H⁺ gave 1,2‐dihydronaphthalen‐1‐ols, or under dehydrating conditions, 2‐aryl‐1‐alkynylnaphthlenes. Enolates 5 react in situ with: H₂O, D₂O, I₂, allylbromide, S₂Me₂, CO₂ and lead to the expected C ‐E derivatives (E=H, D, I, allyl, SMe, CO₂H) in 49–64 % yield directly from intermediate 5 . The parents (E=H; R¹=SiMe₃, tBu; R²=Ph) are versatile starting materials for NaBH₄ and Grignard C=O additions, desilylation (when R¹=SiMe) and oxime formation. The latter allows formation of 6,9‐bicyclics via Beckmann rearrangement. The 6,8‐ring iodides are suitable Suzuki precursors for Pd‐catalysed C?C coupling (81–87 %), whereas the carboxylic acids readily form amides under T3P® conditions (71–95 %).     

N-(4-甲基苯甲酰氨基) N’-[5-(2-三氟甲基苯基)-2-呋喃甲酰硫脲的合成、晶体结构测定与生物活性测定

本文首次合成标题化合物N-(4-甲基苯甲酰氨基)-N’-[5-(2-三氟甲基苯基)-2-呋喃甲酰硫脲。化合物(C21H16F3N3O3S, Mr = 447.43)单晶经测定为单斜晶体,空间群为P -1。在晶体中,存在一些分子内和分子间的相互作用,分子间还有C—H···π 的相互作用,这可能导致晶体更稳定的原因。目标产物的结构经IR, H NMR和元素分析测定确证。初步生物活性测试表明,部分化合物对棉花枯萎病、黄瓜灰霉病、苹果轮纹病和棉花炭疽病有较好的选择性杀菌活性;部分目标化合物有较好的除草活性。     

Carbon‐nanotube Modified Screen‐printed Electrode for the Simultaneous Determination of Nitrite and Uric Acid in Biological Fluids Using Batch‐injection Amperometric Detection

A portable electroanalytical system applied for rapid and simultaneous determination of uric acid (UA) and nitrite (NIT) in human biological fluids (urine, saliva and blood) is reported. The system is based on batch‐injection analysis with multiple‐pulse amperometric (BIA‐MPA) detection using screen‐printed electrodes (SPEs) modified with multi‐walled carbon nanotubes. Sample dilution in optimized electrolyte (0.1 mol L⁻¹ Britton‐Robinson buffer pH 2) followed by injection of 100 μL on the electrode surface using an electronic micropipette is performed. UA is detected at +0.45 V and both UA+NIT at +0.70 V. Linear calibration plots for UA and NIT were obtained over the range of 1–500 μmol L⁻¹ with detection limits of 0.05 and 0.06 μmol L⁻¹, respectively. For comparison, a differential‐pulse voltammetric (DPV) method was optimized, and linear calibration plots for UA and NIT were obtained over range of 1–30 μmol L⁻¹ and 1–40 μmol L⁻¹ with detection limits of 0.1 and 0.3 μmol L⁻¹, respectively. BIA‐MPA is highly precise (RSD<1.3 %), fast (160 h⁻¹) and free from sample‐matrix interferences as recovery values ranged from 77 to 121 % for spiked samples (short contact time of sample aliquot with SPE). Contrarily, recovery tests conducted using DPV did not provide adequate recovery values (>150 %), probably due to the longer contact time of the SPE with the biological samples during analysis leading to a severe interference of sample matrices.     

Cobalt(III) Complex [CoL3] Derived from an Asymmetric Bidentate Schiff Base Ligand L (L=(5‐Bromo‐2‐hydroxybenzyl‐2‐furylmethyl)‐imine): Synthesis,Characterization and Crystal Structure

Cobalt(III) complex [CoL₃], where L=(5‐bromo‐2‐hydroxybenzyl‐2‐furylmethyl)imine, has been synthesized by reacting cobalt(II) nitrate with L. The complex has been characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure of [CoL₃] was determined by X‐ray crystallography from single crystal data. It crystallizes in the triclinic space group$ P {\bar 1} $ with unit cell parameters:a=9.6644(10) Å,b=11.5657(11) Å,c=16.5809(17) Å,α=102.833(4)°,β=102.999(3)°,γ=105.480(3)°,V=1659.9(3) ųandZ=2. Thermal decomposition of [CoL₃] was studied by thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathways.     

Determination of Amantadine Residue in Honey by Solid‐phase Extraction and High‐performance Liquid Chromatography with Pre‐column Derivatization and Fluorometric Detection

Amantadine (AMA) is an anti‐viral drug used in apiculture to protect honeybee against the sacbrood virus (Morator aetatulae). This study described a reliable high‐performance liquid chromatographic (HPLC) method for analyzing AMA in honey using a solid‐phase extraction (SPE) cartridge (Plexa PCX) for purification, 4‐fluoro‐7‐nitro‐2,1,3‐benzoxadiazole (NBD‐F) as a pre‐column derivatization agent, and fluorometric detection (λ_ex=470 nm, λ_em=530 nm). The chromatographic separation was performed on an XDB C18 column (150×4.6 mm i.d.) using 0.1% trifluoroacetic acid/acetonitrile (35:65,V/V) as the mobile phase at a flow rate of 1.0 mL·min⁻¹ with a run time of 20 min. Under these optimal conditions, a linear relationship was observed in the range of 0.025–1.0 µg· mL⁻¹ with a good correlation coefficient (0.998) and low limit of detection (0.0080 µg·g⁻¹), the recoveries were all above 90%, and the intra‐day and inter‐day precision (RSD) ranged from 3.4%–5.1%.     

Homologous series of alkylsilylphenyl‐substituted poly (p‐phenylenevinylene)s for light‐emitting diodes

Substituent‐induced electroluminescence polymers—poly[2‐(2‐dimethyldodecylsilylphenyl)‐1,4‐phenylenevinylene] [(o‐R₃Si)PhPPV], poly[2‐(3‐dimethyldodecylsilylphenyl)‐1,4‐phenylenevinylene] [(m‐R₃Si)PhPPV], and poly[2‐(4‐dimethyldodecylsilylphenyl)‐1,4‐phenylenevinylene] [(p‐R₃Si)PhPPV]—were synthesized according to the Gilch polymerization method. The band gap and spectroscopic data were tuned by the dimethyldodecylsilyl substituent being changed from the ortho position to the para position in the phenyl side group along the polymer backbone. The weight‐average molecular weights and polydispersities were 8.0–96 × 10⁴ and 3.0–3.4, respectively. The maximum photoluminescence wavelengths for (o‐R₃Si)PhPPV, (m‐R₃Si)PhPPV, and (p‐R₃Si)PhPPV appeared around 500–530 nm in the green emission region. Double‐layer light‐emitting diodes with an indium tin oxide/poly(3,4‐ethylenedioxythiophene)/polymer/Al configuration were fabricated with these polymers. The turn‐on voltages and the maximum brightness of (o‐R₃Si)PhPPV, (m‐R₃Si)PhPPV, and (p‐R₃Si)PhPPV were 6.5–8.7 V and 1986–5895 cd/m², respectively. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2347–2355, 2004     

Metal‐Free Addition/Head‐to‐Tail Polymerization of Transient Phosphinoboranes,RPH‐BH2: A Route to Poly(alkylphosphinoboranes)

Mild thermolysis of Lewis base stabilized phosphinoborane monomers R¹R²P? BH₂?NMe₃ (R¹,R²=H, Ph, or tBu/H) at room temperature to 100 °C provides a convenient new route to oligo‐ and polyphosphinoboranes [R¹R²P‐BH₂]_n. The polymerization appears to proceed via the addition/head‐to‐tail polymerization of short‐lived free phosphinoborane monomers, R¹R²P‐BH₂. This method offers access to high molar mass materials, as exemplified by poly(tert‐butylphosphinoborane), that are currently inaccessible using other routes (e.g. catalytic dehydrocoupling).     

Synthesis of linear and 4‐arm star block copolymers of poly(methyl acrylate‐b‐solketal acrylate) by SET‐LRP at 25 °C

The new SET‐LRP (using Cu(0) powder for organic synthesis) was successfully used to produce well‐defined linear and star homo‐ and diblock‐copolymers of PMA, PSA, and P(MA‐b‐GA)_n (where n = 1 or 4). The kinetic data showed that all SET‐LRP were first order and reached high conversions in a short period of time. The other advantage of using such a system is that the copper can easily be removed through filtration, allowing the production of highly pure polymer. The molecular weight distributions were well controlled with polydispersity indexes below 1.1 and the number‐average molecular weight close to theory, especially upon the addition of Cu(II)Br₂/Me₆‐TREN complex. The linear and star block copolymers were then hydrolyzed to produce the biocompatible amphiphilic P(MA‐b‐GA)_n, where the glycerol side‐groups make the outer block hydrophilic. These blocks were micellized into water and found to have a R_g/R_H equal to 0.8 and 1.59 for the liner and star blocks, respectively. This together with the TEM's supported that the linear blocks formed the classical core‐shell micelles, where as, the star blocks formed vesicles. We found direct support for the vesicle structure from a TEM where one vesicle squashed a second vesicle consistent with a hollow structure. Such vesicle structures have potential applications as delivery nanoscaled devices for drugs and other important biomolecules. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6346–6357, 2008     

4- (4,6-二甲基嘧啶-2-基)-3-硫代脲酸甲酯的合成晶体结构及量子化学研究

4-（4,6-Dimethylpyrimidin-2-yl）-3-thio-allophanic acid methyl ester was synthesized with mixing 2-amino-4,6- dimethylpyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray diffraction measurement were obtained by recrystallization from dimethylformamide at room temperature. The crystal belongs to monoclinic symmetry with space group C2/m, and crystal parameters of a= 1.7537（5） nm, b= 0.6759（2） nm, c=1.1148（3） nm, β=118.557（4）°, V=1.1605（6） nm^3, Z=4, De= 1.375 g/cm^3,μ=0.271 mm^-1, F（000）=504, and 1519 [1〉2σ（I）] observable independent reflections were used for the determination and refmement of the crystal structures with final R1 of 0.0372 and wR2 of 0.0992. The theoretical investigation of the title compound was carried out with DRT-B3LYP/6-311G, HF/6-311G and MP2/6-311G methods, and the atomic net charges and the population were discussed.     

硫酰杯[4]芳烃与铜(II)双核配合物的合成与晶体结构

The X-ray crystallographic structure was reported for a dinuclear copper（Ⅱ） complex with a tetraanionic ligand of p-tert-butylsulfonylcalix[4]arene [Cu2L（CH3OH）6]·4CH3OH （H4L=p-tert-butylsuffonylcalix[4]arene）. The complex belongs to triclinic system, P1^-- space group, with a = 1.2303（3） nm, b = 1.2377（3） nm, c = 1.3110（3） nm, a =66.862（4）°, β= 67.206（4）°, γ=61.711（3）°, Z= 1, V= 1.5659（7） nm^3, Dc= 1.371 g/cm^3, F（000） = 682,μ（Mo Kα） = 0.883 mm^-1, R1 =0.0325, wR2=0.0870. In this complex, the calix[4]arene acts as a bis-tridentate chelating ligand with the 1,2-alternate conformation.     

Synthesis,pH‐ and temperature‐induced micellization and gelation of doubly hydrophilic triblock copolymer of poly(N,N‐dimethylamino‐2‐ethylmethacrylate)‐b‐poly(ethylene glycol)‐b‐poly(N,N‐dimethylamino‐2‐ethylmethacrylate) in aqueous solutions

A doubly hydrophilic triblock copolymer of poly(N,N‐dimethylamino‐2‐ethyl methacrylate)‐b‐Poly(ethylene glycol)‐b‐poly(N,N‐dimethylamino‐2‐ethylmethacrylate) (PDMAEMA‐b‐PEG‐b‐PDMAEMA) with well‐defined structure and narrow molecular weight distribution (M_w/M_n = 1.21) was synthesized in aqueous medium via atom transfer radical polymerization (ATRP) of N,N‐dimethylamino‐2‐ethylmethacrylate (DMAEMA) initiated by the PEG macroinitiator. The macroinitiator and triblock copolymer were characterized with ¹H NMR and gel permeation chromatography (GPC). Fluorescence spectroscopy, dynamic light scattering (DSL), transmittance measurement, and rheological characterization were applied to investigate pH‐ and temperature‐induced micellization in the dilute solution of 1 mg/mL when pH > 13 and gelation in the concentrated solution of 25 wt % at pH = 14 and temperatures beyond 80 °C. The unimer of R_h = 3.7 ± 0.8 nm coexisted with micelle of R_h = 45.6 ± 6.5 nm at pH 14. Phase separation occurred in dilute aqueous solution of the triblock copolymer of 1 mg/mL at about 50 °C. Large aggregates with R_h = 300–450 nm were formed after phase separation, which became even larger as R_h = 750–1000 nm with increasing temperature. The gelation temperature determined by rheology measurement was about 80 °C at pH 14 for the 25 wt % aqueous solution of the triblock copolymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5869–5878, 2008     

Thermotropic Liquid Crystals Based on Extended 2,5‐Disubstituted‐1,3,4‐Oxadiazoles: Structure–Property Relationships,Variable‐Temperature Powder X‐ray Diffraction,and Small‐Angle X‐ray Scattering Studies

A class of extended 2,5‐disubstituted‐1,3,4‐oxadiazoles R¹‐C₆H₄‐{OC₂N₂}‐C₆H₄‐R² (R¹=R²=C₁₀H₂₁O 1 a , p‐C₁₀H₂₁O‐C₆H₄‐C?C 3 a , p‐CH₃O‐C₆H₄‐C?C 3 b ; R¹=C₁₀H₂₁O, R²=CH₃O 1 b , (CH₃)₂N 1 c ; F 1 d ; R¹=C₁₀H₂₁O‐C₆H₄‐C?C, R²=C₁₀H₂₁O 2 a , CH₃O 2 b , (CH₃)₂N 2 c , F 2 d ) were prepared, and their liquid‐crystalline properties were examined. In CH₂Cl₂ solution, these compounds displayed a room‐temperature emission with λ_max at 340–471 nm and quantum yields of 0.73–0.97. Compounds 1 d , 2 a – 2 d , and 3 a exhibited various thermotropic mesophases (monotropic, enantiotropic nematic/smectic), which were examined by polarized‐light optical microscopy and differential scanning calorimetry. Structure determination by a direct‐space approach using simulated annealing or parallel tempering of the powder X‐ray diffraction data revealed distinctive crystal‐packing arrangements for mesogenic molecules 2 b and 3 a , leading to different nematic mesophase behavior, with 2 b being monotropic and 3 a enantiotropic in the narrow temperature range of 200–210 °C. The structural transitions associated with these crystalline solids and their mesophases were studied by variable‐temperature X‐ray diffractometry. Nondestructive phase transitions (crystal‐to‐crystal, crystal‐to‐mesophase, mesophase‐to‐liquid) were observed in the diffractograms of 1 b, 1 d , 2 b, 2 d , and 3 a measured at 25–200 °C. Powder X‐ray diffraction and small‐angle X‐ray scattering data revealed that the structure of the annealed solid residue 2 b reverted to its original crystal/molecular packing when the isotropic liquid was cooled to room temperature. Structure–property relationships within these mesomorphic solids are discussed in the context of their molecular structures and intermolecular interactions.     

配合物[Cu2(bpe)X2] n (bpe =1, 2–trans–(4–pyridyl)ethene, X=Cl, Br, I )的合成、晶体结构及热稳定性研究

以1,2-反式-二（4-吡啶基）乙烯桥连卤化铜分别得到配合物[Cu₂(bpe)Cl ₂] _n (1), [Cu₂(bpe)Br₂] _n (2) 和 [Cu₂(bpe)I₂] _n (3)。通过X-射线单晶衍射法对配合物1的结构进行了研究,晶体学数据：单斜晶系, P 2(1)/c空间群, a = 0.3788(8) nm, b = 1.5059(3) nm, c = 1.0875(2)nm, β = 96.262(4) °, V = 616.5(2)ų, Z = 2, S = 1.002,最终残差因子( I >2 σ ( I )) R ₁ = 0.0288, wR ₂ = 0.0579,对于全部数据 R ₁ = 0.0509, wR ₂ = 0.0615。元素分析及红外光谱分析表明,该类配合物为同晶化合物。另外,通过热重分析对配合物的热稳定性进行了研究。     

Development of an Amperometric Immunosensor for the Quantification of Staphylococcus aureus Using Self‐Assembled Monolayer‐Modified Electrodes as Immobilization Platforms

Amperometric immunosensors for the detection and quantification of S. aureus using MPA self‐assembled monolayer modified electrodes for the immobilization of the immunoreagents are reported. Two different immunosensor configurations were compared. A competitive mode, in which protein A‐bearing S. aureus cells and antiRbIgG labeled with horseradish peroxidase (HRP) compete for the binding sites of RbIgG immobilized onto the 3‐mercaptopropionic acid (MPA) modified electrode, was evaluated. Moreover, a sandwich configuration in which S. aureus cells were immobilized onto the MPA SAM, and RbIgG and antiRbIgG labeled with HRP were further linked to the electrode surface, was also tested. In both cases, TTF was used as the redox mediator of the HRP reaction with H₂O₂, and it was co‐immobilized onto the MPA‐modified gold electrode. After optimization of the working variables for both configurations, the analytical performance of the amperometric measurements carried out at 0.00 V (vs. Ag/AgCl) showed that the competitive immunosensor exhibited a lower limit of detection (1.6×10⁵ S. aureus cells mL^?1), as well as a better repeatability and reproducibility of the measurements.