阳离子碳氟表面活性剂研究I: 水溶液中的胶束特性及生长

利用动态光散射(Dynamic Light Scattering, DLS)、瞬态电双折射(Transient Electric Birefringence, TEB)和粘度测定方法研究了部分氟代阳离子表面活性剂氟代-2-羟基十一烷基二乙羟基甲基氯化铵(diethanolheptadecafluoro-2-undecanol methylammonium chloride, C₈F₁₇CH₂CH(OH)CH₂NCH₃(C₂H₄OH)₂Cl, DEFUMACl)水溶液的胶束化特性. 结果表明: DEFUMACl的临界胶束浓度cmc为3.8 mmol•L^－1. 稀溶液中随着DEFUMACl浓度的增加或者无机盐NaCl的加入, DEFUMACl胶束由球形向棒状转变, 其转变浓度, 即第二临界胶束浓度(cmc_II)为0.2 mol•L^－1; 电导测定的反离子(Cl^－)结合度为0.72. 利用球形和棒状胶束模型确定的DEFUMACl胶束聚集数分别为45和335.     

聚酰胺-胺基两亲树枝状大分子与十二烷基硫酸钠混合体系的分子聚集行为

以浊度分析、动态激光光散射(DLS)、透射电子显微镜(TEM)以及原子力显微镜(AFM)等方法研究了以1.0代(G1)聚酰胺-胺(PAMAM)为核心、以聚环氧丙烷-聚环氧乙烷(PPO-PEO)为辐射臂的树枝状大分子与十二烷基硫酸钠(SDS)之间的相互作用.值得注意的是,当树枝状大分子溶液的浓度为1%(质量分数),SDS的浓度远低于临界胶束浓度(cmc)时,体系的浊度值开始明显升高,DLS、TEM以及AFM的研究结果显示出此时聚集体的尺寸逐渐增加,意味着SDS与树枝状大分子有着很强的分子间相互作用,形成了树枝状大分子与SDS构成的复合物.当SDS浓度增高至0.1mmol·L-1(约为cmc的1%)左右时,体系的浊度值随着SDS浓度的增加变化不大,DLS、TEM、AFM的实验结果显示,聚集体尺寸趋于稳定状态.当SDS的浓度继续升高至0.25和0.5mol·L-1时,体系中形成了SDS分子间的自聚集或者存在多个SDS分子与单个树枝状大分子的分子间聚集.     

麦迪霉素-H2O2缔合/平行催化氢波的研究及其应用

报道了有机化合物极谱催化波的一种新类型--缔合/平行催化氢波.研究麦迪霉素-H₂O₂体系缔合/平行催化氢波的结果表明,质子化麦迪霉素与H₂O₂形成缔合物,引起峰电位负移;麦迪霉素催化氢波被H₂O₂还原中间产物羟基自由基进一步催化,使峰电流显著增加.求得麦迪霉素-H₂O₂缔合物的缔合比为1:1,表观缔合常数为7.18.在0.15 mol·L^-1 KH₂PO₄-NaOH (pH 7.4)-0.02 mol·L^-1 H₂O₂支持电解质中,-1.59 V (vs. SCE)处的缔合/平行催化氢波二阶导数峰峰电流与麦迪霉素浓度在2.0×10^-8～1.0×10^-5 mol·L^-1范围内呈线性关系,检测限为6×10^-9 mol·L^-1.与麦迪霉素的催化氢波相比,该缔合/平行催化氢波提高分析灵敏度两个数量级.     

4-二氰乙烯基-N,N-二甲基苯胺与不同表面活性剂的相互作用

用光谱法研究了荧光分子4-二氰乙烯基-N,N-二甲基苯胺(DCVA)与十二烷基硫酸钠(SDS)、聚氧乙烯(23)月桂醚(BRIJ35)、十二烷基三甲溴化铵(DTAB)胶束间的相互作用.与在水中相比,在上述3类表面活性剂溶液中探针的荧光强度分别增加到3.3、5.4和5.1倍;最大发射波长随表面活性剂浓度的增加分别蓝移了5、11和9nm.由此可知,DCVA在DTAB和BRIJ35胶束中所处微环境的极性相似,而在SDS胶束中DCVA所处微环境的极性较大.通过DCVA在3种表面活性剂溶液中的荧光强度,计算出了DCVA与其胶束的结合常数分别为1.7×10³、1.4×10³和8.8×10².     

十二烷基甜菜碱与聚乙烯吡咯烷酮相互作用的研究

通过表面张力测定和13CNMR、ESR波谱研究了十二烷基甜菜碱（C12BE）与聚乙烯吡咯烷酮（PVP）的相互作用．表面张力测定表明,在pH＝6．5及NaCI存在下,C12BE与PVP之间有明显的相互作用,可形成C12BE／PVP复合物,且C12BE－PVP混合溶液的β－lgc曲线出现2个转折点,第一个转折点时C12BE浓度c1（C12BE－PVP开始缔合）低于C12BE的cmc值;而第二个转折点时C12BE浓度c2（C12BE－PVP缔合达饱和）大于cmc值．（c2─c1）与PVP浓度呈线性关系．PVP降低C12BE胶束化标准自由能（△G0）随PVP浓度增加而增大．13CNMR测定表明,PVP骨架上α-CH、β-CH2和吡咯环上与N相连的亚甲基吸附于C12BE胶束表面的碳氢链部位,屏蔽了C12BE胶束表面碳氢链与水的接触．ESR波谱表明,PVP－C12BE聚集体"界面"的粘度高于C12BE胶束"界面"的粘度．     

PVP与C~1~4BE之间的相互作用

通过表面张力和胶束聚集数的测定,研究了聚乙烯吡咯烷酮(PVP)与两性表面活性剂十四烷基甜菜碱(C~1~4BE)之间的相互作用。结果表明,PVP与C~1~4BE可通过其分子间的疏水作用和极性基团间的静电力形成PVP大分子/表面活性剂聚集体。因此,混合溶液的表面张力-浓度曲线表现出两个转折点,C~1~4BE的胶束聚集数随PVP浓度增大而减小。     

树枝聚醚改性聚丙烯酰胺和阴离子表面活性剂的缔合行为

采用粘度法、荧光探针技术和^1H NMR驰豫和自扩散方法，研究了树枝聚醚疏 水改性丙烯酰胺共聚物(PDAM)和十二烷基硫酸钠(SDS)在水溶液中的相互作用．这 种共聚物含有少量的树枝聚醚，具有疏水性，容易和SDS发生相互作用，在表面活 性剂浓度远低于临界胶束浓度(cmc)的情况下，生成混合胶束状聚集体．它们的缔 合行为和溶液性质明显地取决于表面活性剂的浓度，随着聚合物溶液中加入SDS， 溶液粘度发生急剧变化，并在较低的表面活性剂浓度处出现很大的最高点．荧光和 ^1H NMR测定结果表明，这是由于在不同SDS浓度范围内，PDAM/SDS形成的聚集体结 构不同的缘故．     

全氟辛酸钠与十二烷基三甲基溴化铵混合胶束微环境性质的NMR,ESR研究

应用表面张力法、NMR法和ESR法研究了全氟辛酸钠(SPFO)-十二烷基三甲基溴化铵(DTAB)混合体系水溶液胶束形成及混合胶束的微环境性质(微观粘度、微观极性等)。结果表明, 碳氟表面活性剂碳氟链和碳氢表面活性剂碳氢链之间具有强烈的相互作用, DTAB与SPFO在水溶液中形成混合胶束。DTAB与SPFO混合体系的表面活性高于单一的DTAB或SPFO, 混合体系cmc较单一的DTAB和SPFO低。DTAB与SPFO混合胶束的微观粘度较DTAB胶束的大, 而微观极性较DTAB的小。     

调控金纳米花表面凸起的策略及其表面增强拉曼散射活性

以聚乙烯吡咯烷酮(PVP)与十二烷基硫酸钠(SDS)通过阳离子架桥形成的拟聚阴离子为软模板,通过改变PVP、SDS和纳米材料前驱体氯金酸(HAu Cl₄)浓度以及反应时间等因素,调控还原产物金纳米花形貌及粒径。表面张力、电导率、毛细管电泳及Zeta电位等实验结果表明PVP-SDS-HAu Cl₄形成新的拟聚阴离子,透射电子显微镜和X射线衍射结果表明SDS、PVP和HAu Cl₄的较低浓度组合更易获得表面凸起丰富的金纳米花。PVP-SDS拟聚阴离子发挥了二级软模板作用,在PVP (50 g·L^-1)-SDS (2 mmol·L^-1)-HAu Cl₄ (0.25 mmol·L^-1)溶液中调控合成的金纳米花为{111}晶面为主的面心立方结构,其平均等效粒径为108 nm,且表面上密集分布约16.5 nm的凸起。该金纳米花有较强的表面增强拉曼散射(SERS)活性,探针分子罗丹明6G的SERS信号强度依赖于金纳米花的表面凸起形貌。该研究中金纳米...     

全氟辛酸钠与十二烷基三甲基溴化铵混合胶束微环境性质的NMR, ESR研究

应用表面张力法、NMR法和ESR法研究了全氟辛酸钠(SPFO)-十二烷基三甲基溴化铵(DTAB)混合体系水溶液胶束形成及混合胶束的微环境性质(微观粘度、微观极性等).结果表明,碳氟表面活性剂碳氟链和碳氢表面活性剂碳氢链之间具有强烈的相互作用,DTAB与SPFO在水溶液中形成混合胶束.DTAB与SPFO混合体系的表面活性高于单一的DTAB或SPFO,混合体系cmc较单一的DTAB和SPFO低.DTAB与SPFO混合胶束的微观粘度较DTAB胶束的大,而微观极性较DTAB的小.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

Multi-instrument characterization of HiPIMS and DC magnetron sputtered tungsten and copper films

In this work, copper and tungsten were sputtered onto silicon wafers by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS). The resulting films were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and X-ray diffraction (XRD). By EDX and XPS, all the sputtered films showed only the expected metal peaks. By XPS, the surfaces sputtered by DCMS were richer in oxygen than those produced by HiPIMS. By AFM, the surfaces were quite smooth. The root mean square (RMS) roughness values are as follows: 0.83 nm (W, HiPIMS), 1.10 nm (W, DCMS), 0.85 nm (Cu, HiPIMS), and 1.78 nm (Cu, DCMS). By SEM, the HiPIMS films exhibited smaller grain sizes, which was confirmed by XRD. The crystallite sizes estimated by XRD are as follows: 4 nm (W, body-centered cubic, HiPIMS), 13 nm (W, body-centered cubic, DCMS), 7 nm (W, cubic, HiPIMS), 14 nm (W, cubic, DCMS), 25 nm (Cu, HiPIMS), and 35 nm (Cu, DCMS). By SE, the HiPIMS surfaces showed higher refractive indices, which suggested that they were denser and less oxidized than the DCMS surfaces.     

HCOO在Cu(110)、Ag(110)和Au(110)表面的吸附

采用密度泛函理论(DFT)以及广义梯度近似方法(GGA)计算了甲酸根(HCOO)在Cu(110)、Ag(110)和Au(110)表面的吸附. 计算结果表明, 短桥位是最稳定的吸附位置, 计算的几何参数与以前的实验和计算结果吻合. 吸附热顺序为Cu(110)(-116 kJ·mol-1)>Ag(110)(-57 kJ·mol-1)>Au(110)(-27 kJ·mol-1), 与实验上甲酸根的分解温度相一致. 电子态密度分析表明, 吸附热顺序可以用吸附分子与金属d-带之间的Pauli 排斥来关联, 即排斥作用越大, 吸附越弱. 另外还从计算的吸附热数据以及实验上HCOO的分解温度估算了反应CO2+1/2H2→HCOO的活化能, 其大小顺序为Au(110)>Ag(110)>Cu(110).     

Mononuclear and homobinuclear cobalt(II), nickel(II) and copper(II) complexes with mono and bis-azocompounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol

Two new series of mononuclear and homobinuclear Co(II), Ni(II) and Cu(II) complexes with mono- and bis-azo compounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol are prepared and characterized by elemental and thermal analyses, conductance, IR, electronic, ESR spectra and magnetic moment measurements. The ligand field splitting parameters and Racah constant are calculated. The spectral and magnetic results obtained are utilized to determine the geometries around the metal(II) ion. The geometry of the complex formed depends on the structure of the ligand and the type of metal(II) ion. The mode of bonding of the ligand with the metal ions is deduced from IR spectra.     

Synthesis and Characterization of A Vic-Dioxime Derivative and Investigation of its Complexes with Ni(II), Co(II), Cu(II) and UO2(VI) Metals

In this study, 1,2-dihdroxyimino-3,7-di-aza-9,10-O-iso-propylidene decane (LH₂ ) was synthesized starting from 1,2-O-iso-propylidene-4-aza-7-aminoheptane (RNH₂ ) and anti-chloroglyoxime. Complexes of this ligand with Ni(II), Co(II), Cu(II) and UO₂(VI) salts were prepared. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C and ¹H NMR spectra magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Magnetism of metal-nitroxide compounds involving bis-chelating imidazole and benzimidazole substituted nitronyl nitroxide free radicals

Coordination compounds based on imidazole and benzimidazole substituted nitronyl nitroxide radicals with transition metal ions and trivalent lanthanide ions are described from the perspective of their magnetic properties.For the transition metal compounds the crystal structures show various metal-nitroxide dimensionalities including mononuclear (0D), one-dimensional (1D) and two-dimensional (2D) complexes. The mononuclear complexes were isolated with most metal ions of the first transition series. One copper(II) complex shows a copper(II)-radical ferromagnetic coupling (J = +75 cm⁻¹) while for the other mononuclear compounds, mainly with manganese(II), the metal-radical interactions are antiferromagnetic. The one-dimensional and two-dimensional complexes are manganese(II) compounds which show canting effects leading to weak ferromagnetism.For the trivalent lanthanide ions [La(III), Gd(III) and Eu(III)], three series of mononuclear complexes were obtained in which the metal center is bound to four, two or one nitroxide radicals depending on the counter ions and ancillary ligands. Unexpectedly, in most gadolinium(III) complexes, the Gd(III)-radical interactions were found to be antiferromagnetic in contradiction with other foundings and previous theoretical models. In support to the magnetic studies, the optical properties of the lantanide complexes have also been investigated and are briefly described.     

Silicification and biosilicification

Biosilicification takes place at or very close pH 7.0 and under ambient conditions of temperature and pressure in vivo. The silicic acid transporters and the proteins facilitating biosilicification in diatoms have been identified. Silica synthesis under mild conditions in vitro has been demonstrated using synthetic polymers with control over the resulting silica morphology. The results presented herein show that the silica synthesis in vitro is not specific to particular enzymes/polypeptides due to their particular chemical structure and activity but that many other synthetic macromolecules are also capable of facilitating silica formation at neutral pH. We also report the synthesis of organic-inorganic hybrid materials that have potential in optoelectronic applications.     

Synthesis and Multinuclear NMR Study of Benzoyl Methylene Triparatolylphosphorane Ylide and the Reaction of this Ylide with Mercury(II) Halides

The reaction of the title ylide {PhCOCHP(p-tolyl)₃} with Pd(II), Pt(II). Hg(II), and Ag(I) in equimolar ratios using CH₃CN, CH₃OH, and CH₂Cl₂ as solvents have yielded [{(p-tolyl)₃PCHCOC₆H₅} PdCl₂]₂ (I), [{(p-tolyl)₃ PCHCOC₆H₅} PtCl₂]₂(2), [Hg(NO₃)₂ {(p-tolyl)₃ PCHCOC₆H₅}](3), and [Ag{(p-tolyl)₃ PCHCOC₆H₅ < eqid1 > ₂]⁺ (4). The IR, ¹H ¹³C, and ³¹P NMR together with micro analysis data of the products were obtained.     

Simultaneous determination of mercury and arsenic by anodic stripping voltammetry

An electrochemical method for the simultaneous determinations of Hg^II concentration and total As^III and As^V concentration has been developed. The method does not require the additional preliminary step of the chemical reduction of As^V to As^III, or oxidation of As^III to As^V before stripping analysis takes place. Also, the method for the simultaneous determination of Hg^II concentration and As^III concentration is described. Measurements were performed in 0.1 M HCl using a gold-plated graphite electrode as sensor. Detection limits for both methods are below 0.4 ppb. Relative standard deviation did not exceed 15%. The possible interference by other trace metals was investigated. Analyses of natural water and industrial solutions were made using proposed methods and AAS. The t-test demonstrates that there was no significant difference between the results obtained with these methods. Proposed methods decrease the time of analysis because concentrations of the Hg^II and arsenic ions were measured simultaneously. Also, the removal of the additional step of chemical reduction of As^V to As^III or oxidation of As^III to As^V decreases analysis time, and also reduces the chance of contamination due to the use of additional reagents.     

Complexation and the laser luminescence studies of Eu(III), Am(III), and Cm(III) with EDTA,CDTA, and PDTA and their ternary complexation with dicarboxylates

Spectroscopy has been used to determine the number of coordinated water molecules bound to Eu(III) and Cm(III) in a series of binary complexes of polyaminocarboxylate and their ternary complexes with dicarboxylates as well as with similar ligands with additional O-, N-, and S-donors. Complexes of Eu(III) and Cm(III) with polyaminocarboxylate alone contain ca. 2.5–3.0 waters of hydration. Increasing the steric requirement of a polyaminocarboxylate by increasing the number of groups in the ligand backbone does not appreciably change the hydration of these cations. The stability constants of the binary and ternary complexes of Cm(III), Am(III), and Eu(III) with these ligands were measured by solvent extraction in a solution of 0.1 M (NaClO₄). The size, basicity, specific M³⁺-second ligand interactions, and steric requirement of the ligands are the factors which affect the ternary complexation. Knowledge of the chemical species formed by actinide cations with organic ligands (carboxylates and aminocarboxylates), which are present in all nuclear waste, is important to understand the behavior of waste forms and the migration behavior of actinides in the environment.