5,10,15,20-四(4-羧基苯基)卟啉(TCPP)检测水体痕量Hg~(2+)的研究

由于羧基卟啉在水中良好的溶解性及对Hg⁽²⁺⁾的高亲和性,利用5,10,15,20-四(4-羧基苯基)卟啉与Hg(2+)的高亲和性,利用5,10,15,20-四(4-羧基苯基)卟啉与Hg⁽²⁺⁾反应前后的荧光特性变化,实现水体Hg(2+)反应前后的荧光特性变化,实现水体Hg⁽²⁺⁾的痕量检测。结果显示,该探针与Hg(2+)的痕量检测。结果显示,该探针与Hg⁽²⁺⁾具有良好的配位性,且检测前后体系出现的颜色变化具有可视性。在中性条件下,四羧基卟啉荧光被Hg(2+)具有良好的配位性,且检测前后体系出现的颜色变化具有可视性。在中性条件下,四羧基卟啉荧光被Hg⁽²⁺⁾猝灭,荧光强度与汞离子浓度之间存在良好的指数函数关系,相关系数为0.998。因此,5,10,15,20-四(4-羧基苯基)卟啉可作为一种高效、可靠的探针用于水体中Hg(2+)猝灭,荧光强度与汞离子浓度之间存在良好的指数函数关系,相关系数为0.998。因此,5,10,15,20-四(4-羧基苯基)卟啉可作为一种高效、可靠的探针用于水体中Hg⁽²⁺⁾的痕量检测。     

对称性中位取代羟基卟啉荧光检测水体痕量汞离子研究

利用两种具有对称性结构的羟基中位取代卟啉meso-5,15-二-(4-羟基苯基)10,20-二苯基卟啉(P_(2OH))和meso-5,10,15,20-四-(4-羟基苯基)卟啉(P_(4OH))作为荧光探针,检测水体中痕量汞离子。比较两种探针对汞离子的选择性、检测灵敏性及对时间和pH的稳定性。并对其检测机理进行初步讨论,总结两种对称性羟基卟啉与水体Hg⁽²⁺⁾的相互作用规律。结果显示,两种对称性羟基卟啉在其他金属离子存在条件下对汞离子显示荧光强度变化和显色反应,其浓度变化显示两种卟啉都呈现荧光比率探针的变化规律,荧光比率与水体中汞离子的浓度呈线性关系,相关系数均大于0.99。在不同的pH值变化范围和10 min内,两种对称性探针分子的荧光发射峰和荧光比率值均保持稳定。P_(4OH)的检测灵敏性和稳定性较强,这主要是因为中位羟基数目的对称性增加,可增强其分子中中位羟基与Hg(2+)的相互作用规律。结果显示,两种对称性羟基卟啉在其他金属离子存在条件下对汞离子显示荧光强度变化和显色反应,其浓度变化显示两种卟啉都呈现荧光比率探针的变化规律,荧光比率与水体中汞离子的浓度呈线性关系,相关系数均大于0.99。在不同的pH值变化范围和10 min内,两种对称性探针分子的荧光发射峰和荧光比率值均保持稳定。P_(4OH)的检测灵敏性和稳定性较强,这主要是因为中位羟基数目的对称性增加,可增强其分子中中位羟基与Hg⁽²⁺⁾的相互结合作用,从而引起荧光光谱变化。     

5,10,15,20-四(4-甲氧基-3-磺酸苯基)卟啉的合成及其特性的研究

讨论了新水溶性卟啉5,10,15,20-四(4-甲氧基-3-磺酸苯基)卟啉[T(4-MOP)PS_4]的合成,提出用凝胶型阴树脂去除磺化产物中大量 SO_4~(2-)的方法。探讨了试剂的特性及其与 Cu~(2+)、Pb~(2+)、Zn~(2+)、Cd~(2+)、Co~(2+)和 Mn~(2+)反应的最适条件。测得了这些配合物的配位比、摩尔吸光系数。测得试剂的离解常数 pK_(?)=6.61,pK_(a4)=4.53。     

5,10,15,20-四(2-羟基-5-磺酸苯基)卟啉光度法测定水中痕量锌的研究

研究了5,10,15,20-四(2-羟基-5-磺酸苯基)卟啉与 Zn~(2+)的显色反应。最适 pH5.4。试剂及其锌配合物的最大吸收波长分别为412.6和420.5nm。试剂与 Zn~(2+)的配合比为1:1。表观摩尔吸光系数ε_(420.5)=3.5×10~5。可不经分离和富集直接光度测定自来水和某些天然水中的痕量锌。     

5,10,15,20-四[3,5-二(癸酰氧基)苯基]卟啉及其金属配合物的合成与性质研究

通过5,10,15,20-四[3,5-二(羟基)苯基]卟啉与癸酰氯反应,合成出5,10,15,20-四[3,5-二(癸酰氧基)苯基]卟啉,并通过金属化得到该卟啉的锌、铜配合物。通过紫外-可见吸收光谱,红外光谱,核磁共振氢谱等对产物进行了表征,并且研究了卟啉的液晶性质和荧光性质。     

一种基于水溶性半菁染料的Hg~(2+)识别探针

合成并表征了一种半菁染料Hcy-Np,采用荧光发射光谱,在4-羟乙基哌嗪乙磺酸(HEPES)(pH值=7.40)水溶液中,研究了Hcy-Np作为检测探针对Hg~(2+)的识别能力。结果表明,在1.0×10~(-5)mol/L的Hcy-Np溶液中Hg~(2+)浓度达到2.0×10~(-4)mol/L后,荧光强度增强89.5倍,继续增加Hg~(2+)浓度,荧光增强不明显。与Hg~(2+)作用后的荧光发射强度不受其它常见阳离子的干扰,该探针对Hg~(2+)具有高选择性和灵敏性。     

单分散四臂聚乙二醇衍生的高选择性Hg2+荧光探针的合成和性能研究

为了提高荧光探针的潜在应用价值,研究开发了一种基于单分散四臂聚乙二醇的罗丹明B衍生物荧光探针,该探针在水溶液中对Hg~(2+)金属离子具有高选择性。与其他竞争性金属阳离子相比,在有Hg~(2+)存在的情况下,探针在572 nm处表现出显著的荧光增强。探针的荧光信号变化是基于严格的"开-关"机制,由Hg~(2+)诱导罗丹明B的构型从内酰胺螺环(无色无荧光)转变为开环酰胺形态(粉色荧光)。在0～10μmol/L的浓度范围内,探针的荧光强度与Hg~(2+)浓度呈现较好的线性相关性,检出限为0.385μmol/L。此外,通过MALDI-TOF-MS分析实验论证了探针与Hg~(2+)的结合行为和感应机制,充分说明探针中聚乙二醇(PEG)结构在检测Hg~(2+)过程中起着不可或缺的作用。     

Meso-四(4-羧基苯基)卟啉及其金属配合物的合成及光谱性质研究

文章用Adler法将吡咯和羧基苯甲醛反应合成了5,10,15,20-四(4-羧基苯基)卟啉(TCPP),用反复调pH法得到了较纯净的TCPP,解决了TCPP分离纯化困难的问题;并合成了其Zn(II)和Co(II)的配合物,并利用紫外,1H-NMR荧光,红外和EPR对其光谱进行了研究。     

卟啉锌/锰配合物的合成与表征

用5,10,15,20-四(4氯苯基)卟啉或5-(4-羟基苯基)-10,15,20三(4-氯苯基)卟啉与四水氯化锰、醋酸锌反应,合成了5,10,15,20-四(4-氯苯基)卟啉锌、5,10,15,20-四(4-氯苯基)卟啉锰、5-(4-羟基苯基)-10,15,20-三(4-氯苯基)卟啉锌、5(4-羟基苯基)-10,15,20-三(4-氯苯基)卟啉锰四种金属卟啉,并用UV-Vis、IR对其结构进行了表征。     

Meso-5,10,15,20-四(对氯苯基)卟啉及其金属配合物的合成与性质表征

以丙酸为溶剂,直接用对氯苯甲醛与吡咯反应合成了Meso-5,10,15,20-四(对氯苯基)卟啉,简称TP-ClPPH_2。利用室温固相法合成了卟啉化合物与Zn~(2+),Pd~(2+),Cu~(2+),Mn~(2+),Co~(2+),Ni~(2+)等金属离子形成的配合物,产率为70%~85%。利用UV-Vis、IR、荧光、元素分析,对卟啉配体及其配合物进行了性质表征;并利用TG研究了它们的热稳定性。     

Victrex® poly(ethersulfone) (PES) and Victrex® poly(etheretherketone) (PEEK)

Properties of two high performance engineering thermoplastics, amorphous polyethersulfone (PES) and semicrystalline polyetheretherketone (PEEK), are discussed. Both resins can be processed by conventional techniques, compounded with high performance fibers, and have high service temperature (up to 300°C). Due to the amorphous character PES can be dissolved and spray coated into metals.     

(Ba_(1-α)Sr_α)_(4.8)(Sm_(0.7)La_(0.3))_(8.8)Ti_(18)O_(54)陶瓷的微波介电性能

采用固相合成法制备了(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54(α=0.1～0.5)系陶瓷,表征了该陶瓷的相组成和显微结构,测试了微波介电性能.结果表明:α=0.3时,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷为单相的新钨青铜结构固溶体.α>0.3时,相继出现了第二相BaLa2Ti4O12和La0.66TiO2.993.随α的增加,(Ba(1-α)Srα)4.8(Sm0.7La0.3)8.8Ti18O54系陶瓷的相对介电常数(εr)先增大后有所波动,品质因数(Qf)先增大后减小,谐振频率温度系数(τf)单调减小.α=0.3时,在1 350℃烧结的陶瓷的微波介电性能最佳:εr=98.77,Qf=5184GHz,τf=10.9×10-6/℃,优于不掺杂的BaO-Sm2O3-TiO2陶瓷的.     

Calcium silicate hydrate (II) (“C-S-H(II)”)

This semicrystalline phase, originally named ‘calcium silicate hydrate(II)’ by Taylor (1950), has been studied with X-rays, electron optics, chemical investigation of silicate anion type, infrared spectra, and thermal methods. It is structurally related to jennite (C₉S₆H₁₁) and probably also to the fibrous CSH of cement pastes, the three phases forming a sequence of decreasing crystallinity. The specimen studied had approximate composition C₂SH_3.2 after standing over saturated CaCλ₂ at about 15°C. CSH(II) contains metasilicate chains and pyrosilicate groups and has a disordered layer structure. Much of the water can be lost reversibly without significant change in lattice parameters.     

Photopyroelectric Spectroscopic Studies of ZnO-MnO(2)-Co(3)O(4)-V(2)O(5) Ceramics

Photopyroelectric (PPE) spectroscopy is a nondestructive tool that is used to study the optical properties of the ceramics (ZnO + 0.4MnO(2) + 0.4Co(3)O(4) + xV(2)O(5)), x = 0-1 mol%. Wavelength of incident light, modulated at 10 Hz, was in the range of 300-800 nm. PPE spectrum with reference to the doping level and sintering temperature is discussed. Optical energy band-gap (E(g)) was 2.11 eV for 0.3 mol% V(2)O(5) at a sintering temperature of 1025 °C as determined from the plot (ρhυ)(2)versushυ. With a further increase in V(2)O(5), the value of E(g) was found to be 2.59 eV. Steepness factor 'σ(A)' and 'σ(B)', which characterize the slope of exponential optical absorption, is discussed with reference to the variation of E(g). XRD, SEM and EDAX are also used for characterization of the ceramic. For this ceramic, the maximum relative density and grain size was observed to be 91.8% and 9.5 μm, respectively.     

Poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid)

Summary In the present work we describe, the synthesis and characterization of a new gel obtained by crosslinking a cooligomer of butadiene-acrylic acid (BuAA), by reaction with acrylonitrile and acrylic acid. The purified product was characterized by FTIR, elemental analyses and scanning electronic microscopy. The thermal properties were studied and swelling indexes were determined in different solvents and at different pH values. The capacity of poly(butadiene-acrylic acid(g)acrylonitrile(g)acrylic acid) [gel A] to separate different organic substances, such as amino acids and colorants, was determined.     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.     

Photooxidative stability of substituted poly(phenylene vinylene) (PPV) and poly(phenylene acetylene) (PPA)

The addition of side groups to improve the photooxidative stability of polymers used in polymer-based light-emitting diodes (LEDs) is explored. Infrared spectroscopy and computational chemistry techniques are used to study the effects of chemical substitution of the reactive vinylene moiety in poly(phenylene vinylene) (PPV). The bond order of the vinylene group in small oligomers is calculated using semiempirical techniques to assess the improvement in stability toward oxidants such as singlet oxygen. We find that PPV dimers allow relative comparisons across a range of possible substitutions. Experimental results correlate well with these calculations. The addition of electron-withdrawing substituents, such as nitrile groups, to the vinylene moiety is found to be particularly effective in reducing the reactivity of alkoxy-substituted PPV toward singlet oxygen. The photooxidative stability of a poly(phenylene acetylene) (PPA) derivative is also studied. It appears that this family of polymers is more stable toward photooxidation than are its PPV analogs. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2451–2458, 1998     

Chemical cross-linking of conducting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) using poly(ethylene oxide) (PEO)

Hybrid films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were prepared with different molecular weights of poly(ethylene oxide) (PEO). The cross-linking reaction between PEO and PEDOT:PSS was performed at high temperature and confirmed by using differential scanning calorimeter (DSC), contact angle measurement, and solid-state ¹H NMR. The effect of chemical reaction on the conductivity and morphology of these hybrid films was studied by using 4-point probe and atomic force microscope (AFM), respectively. As-spun PEO/PEDOT:PSS films have lower electric conductivity due to the addition of nonconductive PEO, and exhibits no molecular weight dependence on conductivity. After chemical cross-linking reaction at high temperature, only PEDOT:PSS films with lowest molecular weight PEO additives show enhanced conductivity with increasing reaction time. AFM result indicates that the heat-treated PEO/PEDOT:PSS hybrid films show grain-like morphology compared to ethylene glycol treated PEDOT:PSS films which shows continuous PEDOT domain. In the present work we demonstrate that the cross-linking reaction can be used to improve the wet stability of PEDOT:PSS nanofiber, showing good water resistance and excellent dimensional stability.