含能增塑剂2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四苯甲酸酯的合成及表征

以2,3-二羟甲基-2,3-二硝基-1,4-丁二醇(BHDB)和苯甲酸为原料,4-二甲氨基吡啶(DMAP)为活化剂,N,N'-二环己基碳二亚胺(DCC)为脱水剂,通过酯化反应得到含能增塑剂2,3-二羟甲基-2,3-二硝基-1,4-丁二醇四苯甲酸酯(BHDBTB),对产物进行了~1H NMR、~(13)C NMR、IR等结构表征。X-射线单晶衍射说明,BHDBTB晶系属于三斜晶系,空间群为P-1,Mr=656.58。晶体的数据为:a=8.851 nm,b=9.373 nm,c=10.211 nm,α=82.61°,β=83.31°,γ=67.74°,V=775.3 nm3,Z=2,Dc=1.406 g/cm3,R1=0.083 6,Rw2=0.086 1。     

1,4-二(叠氮乙酰氧基)-2,3-二(叠氮乙酰氧甲基)-2,3-二硝基丁烷的合成

以2,3-二羟甲基-2,3-二硝基-1,4-丁二醇为原料经酯化和叠氮化两步反应合成了1,4-二(叠氮乙酰氧基)-2,3-二(叠氮乙酰氧甲基)-2,3-二硝基丁烷(BDAA),总收率为68.8%。采用1H NMR和IR对目标产物及中间体的结构进行了表征。分别采用甲苯和二甲苯两种溶剂进行酯化反应,发现二甲苯为该反应的较优溶剂;通过对催化剂硫酸﹑磷酸和对甲苯磺酸的比较,得出对甲苯磺酸为该酯化反应的较优催化剂;通过对叠氮化反应的讨论,确定了四丁基溴化铵为该反应较优相转移催化剂。DSC分析表明,BDAA的分解峰温为206.44℃。TG分析表明,BDAA的热分解可能分两步进行,在500℃时,尚未分解完全。     

Electrocatalysis of NADH oxidation with an electropolymerized film of 1,4-bis(3,4-dihydroxyphenyl)-2,3-dimethylbutane

The oxidation of 1,4-bis(3,4-dihydroxyphenyl)-2,3-dimethylbutane, known also as nordihydroguaiaretic acid, on a glassy carbon electrode anodically pretreated in KCl solution gives rise to a stabile redox-active polymer containing the o-quinone moiety. The redox response of the modified electrode is typical for a surface-immobilized species. The modifier thickness can be easy controlled by a number of potential cycles applied during electropolymerization, and a surface coverage up to 1.1 x 10(-9) mol cm(-2) can be achieved. The film exhibits catalytic activity toward NADH oxidation. Characteristic kinetic constants for the mediated oxidation of NADH were derived from rotating disk experiments performed in phosphate or Tris/acetate buffers. The effects of film thickness, solution pH, and the presence of Mg2+ cation on the catalytic efficiency of the modified electrode were discussed and compared with literature data concerning related systems.     

The application of poly(N-isopropylacrylamide)-co-polystyrene nanofibers as an additive agent to facilitate the cellular uptake of an anticancer drug

In this paper, we have fabricated poly(N-isopropylacrylamide)-co-polystyrene (PNIPAM-co-PS) nanofibers by electrospinning and explored the possibility to utilize the PNIPAM-co-PS nanofibers to enhance the permeation and uptake of the anticancer drug daunorubicin in drug-sensitive and drug-resistant leukemia K562 cells. Our MTT assay and electrochemical studies demonstrate that PNIPAM-co-PS nanofibers could play an important role in facilitating the cell track and drug delivery to the cancer cells. Meanwhile, the observations of atomic force microscopy (AFM) and confocal fluorescence microscopy indicate that the relevant interaction of the PNIPAM-co-PS nanofibers with bioactive molecules on the membrane of leukemia cell lines could affect the intracellular drug uptake positively and lead to the efficient accumulation of daunorubicin in drug-sensitive and drug-resistant cancer cells.     

超声法制备1，4-双(二甲基硅基)苯

以THF为溶剂,对二溴苯与Mg在超声辐照下反应得到格式试剂,然后与二甲基一氯硅烷反应制得1,4-双(二甲基硅基)苯(BDSB),并用质谱、红外光谱、紫外光谱等对产物进行了表征。     

聚(2,5-二丁氧基)对苯乙炔的制备及其离子注入改性研究

通过双醚化反应、氯甲基化反应以及在强碱性条件下进行的脱氯化氢反应,制备出新型光电功能材料聚(2,5 二丁氧基)对苯乙炔(PDBOPV)。采用能量为10～35keV,剂量为3.0×1015～4.8×1017ions/cm2的氮离子(N+)对PDBOPV进行离子注入改性。PDBOPV薄膜的电导率随注入离子能量和剂量的增加而提高。当注入N+的能量为35keV,剂量为4.8×1017ions/cm2时,PDBOPV薄膜的电导率为0.136S/cm,比本征态的电导率提高了8个数量级。通过超高阻测试仪研究了PDBOPV薄膜表面电导率与温度的关系,发现N+注入PDBOPV薄膜的电导活化能为0.155eV。离子注入PDBOPV薄膜的电导率的环境稳定性能优于Br2、I2和FeCl3掺杂的PDBOPV。对离子注入PDBOPV薄膜的导电机理进行了初步探讨。     

Effect of fullerene intercalation on the conformation and packing of poly-(2-methoxy-5-(3'-7'-dimethyloctyloxy)-1,4-phenylenevinylene)

Photoluminescence (PL) and resonance Raman spectroscopy are used to track changes in the conformations and packing of poly-(2-methoxy-5-(3'-7'-dimethyloctyloxy)-1,4-phenylenevinylene) (MDMO-PPV) chains with the addition of [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) molecules. PL lineshapes of MDMO-PPV thin films as a function of annealing time were first measured to determine the spectroscopic signatures of chain conformations and packing in the absence of PCBM. Annealing results in enhanced interchain interactions leading to red-shifts of PL 0-0 transitions by up to ～300 cm(-1) and apparent increases of the line shape Huang-Rhys factors. Wavelength-dependent PL lifetimes of as-cast and films annealed for short times (～30 s) are nonexponential with an instrument-limited component of ～100 ps and a ～350 ps component. With longer annealing times, decays become single exponential with an average lifetime of ～1 ns indicating that all excitations efficiently funnel to strongly coupled interchain sites. Addition of PCBM disrupts MDMO-PPV interchain interactions causing PL 0-0 transitions to blue-shift, increases in line width, and decreases in apparent Huang-Rhys factors. Resonance Raman spectra of MDMO-PPV/PCBM thin films with variable PCBM weight fractions (～50:1 up to 1:8 w/w) were then measured using short (488 nm) and long (568 nm) excitation wavelengths. The out-of-plane vinylene C-H wag mode of MDMO-PPV (～964 cm(-1)) showed pronounced increases in intensity of up to ～30% and red-shifts of up to 5 cm(-1) with increasing PCBM content. These changes result from a decrease of planarity between chain segments that suppresses interchain interactions. Furthermore, red-shifts of up to ～4 cm(-1) were observed for the C═C symmetric stretch of the MDMO-PPV vinylene group (～1625 cm(-1)) with 488 nm excitation. The sensitivity of the MDMO-PPV vinylene group vibrations with PCBM indicates preferential interactions between these two molecules and is consistent with intercalation of PCBM into the polymer structure. This assignment was confirmed by thermally annealing of MDMO-PPV/PCBM films to remove intercalated PCBM molecules, which partially restores interchain interactions as seen from smaller intensity increases (～15%) and red-shifts (～2 cm(-1)) of the ～964 cm(-1) mode. Overall, the spectroscopic results show that MDMO-PPV chains adopt distorted conformations (i.e., less intrachain order and shorter conjugation lengths) that have important implications for explaining the structural origins for large improvements in charge mobilities in MDMO-PPV/PCBM blends.     

A transient mesophase on drawing polymers based on polyethylene terephthalate (PET) and polyethylene naphthoate (PEN)

This paper is centred around the identification of a transient mesophase during the drawing of PET and PEN and their associated random copolymers. While the observation of the mesophase has previously been announced as a note (Macromolecules, 31, 1998, p. 7562), this paper sets out the work in appropriate detail. Samples across the full random copolymer composition range are hot drawn, and, either immediately quenched or examined in-situ using synchrotron radiation. In each case a mesophase has been observed under drawing conditions which produced little or no crystallinity. That the phase was not the product of the quench was confirmed by the high temperature dynamic measurements. The signature of the mesophase is a sharp, meridional peak in the WAXS fibre diagram which shows no other sharp peaks suggesting crystallinity; the equatorial maxima, while equiaxial and indicating a high level of chain orientation, are diffuse. The mesophase is thus classified as smectic A. SAXS measurements on quenched samples, give no indication that the mesophase is associated with a particular microstructure. The mesophase is seen across the PET/PEN composition range, its observation being more straightforward in the random copolymers where the rate of crystallisation is significantly reduced. Subsequent crystallisation of the fibres by suitable annealing, replaces the meridional mesophase peak on the first layer line with off-meridional crystal reflections characteristic of the triclinic unit cell. The layer line is at a slightly lower angle after crystallisation indicating a longer axial repeat in the crystal than in the mesophase. The development of crystallinity gives rise to a distinct SAXS pattern indicative of a two phase microstructure. The transition from smectic A mesophase to triclinic crystal provides a rationale for the occurrence of oblique lamellae in PET, and associated random copolymers with more than 70% ethylene terephthalate units, as indicated by the four point SAXS patterns, and also for the c axis tilt observed in the WAXS patterns. Similarly, for the PEN rich copolymers, the absence of obliquity and consequent c-axis tilt, coupled with the marked layer line streaking of the triclinic reflections, can be rationalised in terms of the c-shear of the transition being compensated by faulting in the crystal.     

Structural,thermal, dielectric,nonlinear optical properties and DFT investigations of a novel material 2-(6-chloropyridin-3-yl)-N'-(2,3-dihydro-1,4-benzodioxin-6-ylmethylidene)acetohydrazide for optoelectronic applications

A new organic nonlinear optical (NLO) material 2-(6-chloropyridin-3-yl)-N'-(2,3-dihydro-1,4-benzodioxin-6-ylmethylidene)acetohydrazide (CDA) has been synthesized by reflux method. Single crystals were grown by slow evaporation technique and the crystal structure was elucidated by single crystal X-ray diffraction method. Density functional theory (DFT) calculations at B3LYP/6–31+?+?G(d, p) basis set was used to predict the molecular geometry and were carried out further to comprehend the electronic structure, vibrational spectra, natural bonding orbitals (NBO), frontier molecular orbitals (FMO) and molecular electrostatic potential (MEP). An optical transparency at the cut-off wavelength of 355 nm was determined by UV–Vis–NIR spectroscopy. Thermal behavior of CDA was studied by TGA/DTA analysis. The dielectric constant (ε), dielectric loss (tan δ) and AC conductivity as a function of frequency and temperature was studied. Second Harmonic Generation (SHG) efficiency of the CDA was determined using Kurtz and Perry powder technique and was 0.5 times greater than that of the KDP crystal. The third-order nonlinear optical properties were investigated in solution by Z-scan technique using a continuous wave (CW) DPSS laser at the wavelength of 532 nm. The title compound exhibited significant two-photon absorption (β?=?2.228?×?10–4 cm W^?1), nonlinear refraction (n₂?=?1.095?×?10–8 cm² W^?1) and optical limiting (OL threshold?=?2.511?×?103 W cm^?2) under the CW regime. The nonlinear optical parameters were calculated using time-dependent Hartree–Fock (TDHF) method. The overall obtained results suggested that the studied CDA molecule could be a potential NLO material for frequency generator, optical limiters and optical switching applications.

     

Structural and electrical properties of thermally evaporated 1,4-Bis-(2-hydroxyethylamino)-9,10-anthraquinone films

Nowadays applications of organic materials as the active element in microelectronic devices is broadly investigated. In the present paper, 1,4-Bis-(2-hydroxyethylamino)-9,10-anthraquinone compound has been synthesized. The films of this compound has been deposited by thermal evaporation technique on to the glass substrates which are kept at different temperatures in vacuum of ～1.33 × 10^?3 Pa. Scanning electron microscope (SEM) shows that the films are polycrystalline in nature. Wire like crystal of width 0.204 μm is observed at higher substrate temperature (333 K). The conduction in these films is ohmic in nature. The electrical conductivity and carrier concentration of these films increases with increase in substrate temperature as well as absolute temperature of the films. The analysis of optical absorption measurements on the films indicates that the optical band gap lies in the range 1.48–1.55 eV.     

Bis(1,2,3-triazol-5-ylidenes) (i-bitz) as Stable 1,4-Bidentate Ligands Based on Mesoionic Carbenes (MICs)

Direct metalation of bis(1,2,3-triazolium) salts affords mononuclear rhodium(I) complexes, which feature a 1,4-bidentate bis(1,2,3-triazol-5-ylidene) (i-bitz) ligand. The topology of the ligand is similar to 2,2'-bipyridines (bpy) and their congeners, as well as bis(1,2,4-triazol-5-ylidenes) (bitz). As the former, but in contrast to the latter, the free i-bitz can be isolated, which paves the way for various applications.     

Synthesis, labeling, and biological evaluation of 2-{[benzyl(cyanomethyl)amino]methyl}-3-(ethoxycarbonyl)-quinoxaline 1,4-dioxide in ascites bearing mice

Quinoxaline 1,4-dioxide derivative, 2-{[benzyl(cyanomethyl)amino]methyl}-3-(ethoxycarbonyl) quinoxaline 1,4-dioxide (Q₃D), was synthesized and labeled with radioiodine via direct electrophilic substitution giving labeling yield above 90%. The product was examined by paper electrophoresis. ¹²⁵I-Q₃D was prepared using Chloramine T as oxidizing agent. ¹²⁵I-Q₃D was stable for up to 72 h post labeling, in contrast to ^99m Tc-AQCD which is stable only for a short time. Biodistribution study of ¹²⁵I-Q₃D in ascites tumor bearing mice revealed large uptake of the labeled compound in tumor sites. In addition, in vitro incubation of the labeled compound with Ehrlich cells indicated incorporation of these compounds in DNA of tumor cells. This uptake of ¹²⁵I-Q₃D in DNA of tumor cells may be helpful in tumor diagnosis and therapy.     

Temperature effects on photoluminescence of poly [2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylene vinylene]

We present photoluminescence studies as a function of temperature from poly [2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). The photoluminescence transition energies are red-shifted with decreasing temperatures that can be explained by the suppression of the torsional motion in the polymer backbone, which increased the effective conjugation length of the polymer. The enhancement of the relative intensity of the 0–1 to 0–0 vibronic band can be attributed to the formation of aggregates in coincidence with the vibronic 0–1 bands.     

Novel poly(aryl ether)s containing benzimidazole pendants derived from 1,4-bis(2-benzimidazolyl)-2,5-difluorobenzene

A new difluoride monomer bilaterally substituted with rigid benzimidazole groups was synthesized efficiently. A series of new poly(aryl ether)s (PAEs) containing benzimidazole pendants were prepared from the novel difluoride monomer with various commercially available aromatic bisphenols using nucleophilic aromatic substitution reaction. All the PAEs show high glass transition temperatures (T _g > 205 °C), excellent thermal stability (T _d > 420 °C), and good solubility in common organic solvents. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Uphill transport of organic electrolytes using polyethylene films photografted with 2-(dimethylamino)ethyl methacrylate

Uphill transport of organic electrolytes, benzoic acid, benzenesulfonic acid, and p-aminobenzoic acid, was examined using polyethylene films photografted with 2-(dimethylamino)ethyl methacrylate (DMA). The transport fractions had the maximum values around the grafted amount of 5.0 mmol/g at which the ungrafted layers in the inside of DMA-grafted PE (PE-g-PDMA) films disappeared. Uphill transport of organic anions from the acidic to the alkaline sides occurred most favorably only when the initial pH value in the alkaline side was adjusted to 12.0 while the initial pH values in the acidic side agreed to the pH values of each aqueous solution of the organic electrolytes at 10 mmol/dm³. Under these conditions each organic electrolyte was concentrated by 1.7–1.8 times the initial concentration. In case either the initial H⁺ or OH^- ion concentration was too high or low, the transport fractions of organic anions decreased. When the initial pH value in the acidic side was decreased to 1.5, p-aminobenzoic electrolytes were transported from the alkaline to the acidic sides and the transport fraction amounted to 80%. It was experimentally confirmed that the pH difference across the PE-g-PDMA films was a driving force for uphill transport of organic anions.     

Sorption of Strontium and Lead by Impregnated Sorbents Based on Di(tert-butylcyclohexano)-18-crown-6 and an Ionic Liquid

Radiochemistry - Sorption of Sr(II) and Pb(II) onto impregnated sorbents based on di(tert-butylcyclohexano)-18-crown-6 and an ionic liquid, 1-butyl-3-methylimidazolium...     

镍-磷-碳-氧化学镀层的制备、表征及1,4-丁炔二醇在体系中的作用

以铜片为基体,采用中心组合规则得到优化的化学镀镍-磷工艺配方.在优化的配方中加入一定量的1,4-丁炔二醇(BOZ),所得镀层表面形貌及组成结构用扫描电镜与X射线衍射仪进行表征,得到了光亮的Ni-P-C-O镀层,镀层硬度高,耐酸蚀性强;探讨了BOZ在反应体系中的作用机理.结果表明,BOZ不仅是光亮剂,而且参与该体系的氧化还原反应,BOZ分解反应的宏观动力学表现为准一级;当BOZ的初始含量为60～123 mg/dm3时,其参与氧化还原的量与温度和初始浓度呈正相关性,温度起主导作用;当BOZ的初始含量为123～240 mg/dm3时,其参与氧化还原的量与温度和初始浓度呈负相关性,浓度起主导作用.     

Normal-incidence reflectance of crystalline K(6)C(60), Rb(6)C(60), and Cs(6)C(60)

The structure factors and normal-incidence reflectances of the alkali-metal-doped fulleride crystals M(6)C(60) (where M = K, Rb, or Cs) were calculated, and the peak reflectances are in the 2-20% range for incident wavelengths of 9-17 ?, which indicates that C(60) may be a promising transmissive (spacer) material for normal-incidence mirrors that have relatively high normal-incidence reflectance in the x-ray region.     

Omega phase formation in RMI (38-6-44) beta titanium alloy

The stabilized beta titanium alloy RMI (38-6-44) was designed to limit the formation of omega-phase during quenching and subsequent ageing. It has been shown in the present paper, however, that both athermal and thermal omega do form and that the growth kinetics of the thermal omega follows aD=Ct ^0.45 relationship. As expected from the alloy additions, the maximum volume fraction of omega phase observed is considerably less than in other beta titanium alloys and the severe embrittlement due to omega phase formation is not a serious problem in this alloy. This is an important consideration for engineering applications in the service temperature range below 900?F (480?C).     

Spectro-thermal decomposition study of 1,4-dinitroglycoluril (DINGU)

Simultaneous thermal analysis and high temperature FTIR study of 1,4-dinitroglycoluril (DINGU) is reported. TG showed 90% weight loss in the temperature range 225-250 degrees C. Isothermal TG of DINGU showed about 70% weight loss in the temperature range 210-230 degrees C. Kinetic parameters evaluated using a computer program showed that alpha-t data are best described by the Avrami-Erofeev's equation for n=2 with an activation energy of 165 kJ/mol. The kinetics of decomposition of DINGU was followed by studying NH (3388 cm(-1)), CO (1770-1810 cm(-1)) and NO2 symmetric stretching (1565-1570 cm(-1)) IR bands. All three bands showed loss of intensity with temperature and time. alpha-t data of decomposition with respect to NO2 stretching was again best described by the Avrami-Erofeev's equation for n=2. Gaseous decomposition products observed in the IR were N2O, NO2, CO2, HCN and NO. PM3 and Hartree-Fock level calculations on various bond lengths, bond angles and dihedral angles were computed to support the analysis of decomposition study using TG and IR. The data showed that CN and NH bonds are much shorter than the NN bonds, indicative of the weaker NN bond and hence, the possibilities of rupture of the same bond preferentially. This paper also discusses the sensitivity and performance properties of DINGU.