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1.
In the presence of n-Bu4NBr acting as phase-transfer reagent, n-Bu4N+ salts of organophosphoryl polyoxotungstate derivatives [RP(O)]2X
n+W11O39
(8–n)– [R = PhCH2CH2P(O), X = P, Si; R = C6H11P(O); X = Ge, Ga] have been prepared and characterized by elemental analysis, i.r., 31P- and 183W-n.m.r. spectroscopy. According to the elemental analysis and spectroscopic data, the hybrid anions consist of an -[XW11O39] framework on which are grafted two equivalent organophosphoryl groups through P—O—W bridges; these new species still retain the Keggin structure. The six-line 183W spectrum indicates that hybrid anions possess C
s symmetry in MeCN. 相似文献
2.
纳米尺寸多酸脂质体复合物的合成及抗肿瘤活性研究 总被引:3,自引:0,他引:3
合成了杂多化合物α-K8H6[Si2W18Ti6O77](α-Si2W18Ti6)的脂质体纳米粒子.通过红外、固体核磁和极谱对其结构进行了表征,使用透射电镜和粒径分析仪研究了纳米粒子的形态和粒径分布.所合成的纳米粒子中多酸化合物仍保持母体的结构,纳米粒子的粒径在60~150nm之间.用MTT法测定了不同粒径纳米粒子的体外抗肿瘤活性.发现多酸化合物形成脂质体纳米粒子后稳定性和活性都有所提高. 相似文献
3.
Yong Tao Jing-Fu Liu Xia-Lin Hu Hong-Cheng Li Thanh Wang Gui-Bin Jiang 《Journal of chromatography. A》2009,1216(35):6259-6266
By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C8MIM][PF6] with 14% TOPO (w/v); donor phase: 4 mL, pH 4.5 KH2PO4 with 2 M Na2SO4; acceptor phase: 25 μL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1–0.4 μg/L, RSD ≤ 5%) and good linear range (1–2000 ng/mL, R2 ≥ 0.999) were obtained for all the analytes. The presence of humic acid (0–25 mg/L dissolved organic carbon) and bovine serum albumin (0–100 μg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2–103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples. 相似文献
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含钆杂多配合物对水氢核的弛豫性能 总被引:1,自引:0,他引:1
核磁共振成像(MRI)技术是继CT扫描仪后又一诊断肿瘤的有力工具,已广泛应用于临床.MRI成像时,不同组织间的区别是由于这些组织中水分子的1H核磁弛豫时间的差别引起的.但病变与正常组织的弛豫速率的差别常常达不到诊断的目的,因此诊断时常使用造影剂,其作用是改变体内局部组织中水质子弛豫时间,提高正常与患病部位的成像对比度[1].造影剂的使用要求具有较高的弛豫效率、较高的稳定性,无毒等条件.弛豫效率与化合物中顺磁原子的未成对电子数有关,未成对电子数越多,则配合物的电子自旋磁矩越大,对邻近水质子的弛豫能力越强.因此,研究较多的是… 相似文献
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7.
Jin Yang Guo-Li Zheng Li Li Fang-Fang Li Yong-Mei Zhang Jing-Fu Liu 《Journal of solid state chemistry》2003,174(1):116-124
A series of divalent transition metal phosphonates containing hydrogen-bonded layers of phosphonate anions, namely [M(phen)3]·C6H5PO3·11H2O [M=Co(1), Ni(2), Cu(3)] and [Cd(phen)3]·C6H5PO3H·Cl·7H2O (4) have been synthesized, structurally characterized by single-crystal X-ray diffraction method. These compounds all crystallize in the triclinic system, space group P-1. The lattice parameters are a=12.1646(5), b=12.4155(6), c=15.4117(10) Å, α=78.216(2), β=79.735(3), γ=77.8380(3)°, V=2205.1(2) Å3, Z=2 for 1; a=12.097(2), b=12.606(3), c=15.742(3) Å, α=76.66(3), β=80.04(3), γ=77.75(3)°, V=2263.4(8) Å3, Z=2 for 2; a=12.058(2), b=12.518(3), c=15.781(3) Å, α=77.77(3), β=80.02(3), γ=77.91(3)°, V=2255.5(8) Å3, Z=2 for 3 and a=12.47680(10), b=12.6693(2), c=16.1504(3) Å, α=82.600(1), β=71.122(1), γ=77.355(1)°, V=2352.37(6) Å3, Z=2 for 4. All structures are refined by full-matrix least-squares methods [for 1, R1=0.0602 using 6458 independent reflections with I>2σ(I); for 2, R1=0.0632 using 4657 independent reflections with I>2σ(I); for 3, R1=0.0634 using 6221 independent reflections with I>2σ(I); for 4, R1=0.0400 using 7930 independent reflections with I>2σ(I)]. In the crystal structures, the phenylphosphonate anions and water molecules are hydrogen-bonded to form layers, and there exist the cationic species [M(phen)3]2+ between the adjacent layers of anions and water. Luminescence, thermal analysis as well as IR spectroscopic studies are also presented. 相似文献
8.
Studies on the redox properties of the heteropolytungstosilicates substituted by transition elements
The redox properties of the tri-heteropolytungstosilicates of transition elements KnSiZ(H2O)W11O39 (Z ? Mn2+, Fe3+, Co2+, Ni2+, Zn2+, Cd2+). In solution have been studied with polarography and cyclic voltammetry as well as with ultraviolet spectroscopy and X-ray photoelectron spectroscopy. The order of the polarographic half-wave potentials (E1/2) of these heteropolyanions is as follows: Z?Ni2+>Co2+>Zn2+>Fe2+>Mn2+. We have found that the E1/2 of heteropolyanions could be correlated linearly with both the electronegativities X of the transition elements and the logarithm of the rate constants (log ke) of reaction of transition metal ions with hydrated electrons. The reduction mechanism and effects of transition elements on the redox properties of the heteropolyanions have been discussed. 相似文献
9.
Yan-Jun Li Peng Wang Jing-Fu Ni Liang Meng Xiao-Bo Wang Chun-Qi Sheng Hong-Nian Li Wen-Hua Zhang Yang Xu Fa-Qiang Xu Jun-Fa Zhu 《Journal of Electron Spectroscopy and Related Phenomena》2011,184(7):414-419
We have measured and analyzed the photoemission spectra (PES) of a C70 film in the photon energy region from 13.4 eV to 98.4 eV. The photoelectron intensities of two C 2p π-derived features (denoted by A and B) oscillate regularly in the whole energy region with some fine structures below ∼30 eV. To obtain the detailed information of the oscillations, we have developed a sophisticated but practical procedure for intensity calculation. The procedure consists of two core concepts. The first is ascribing the PES features to their corresponding molecular orbitals with the help of density functional calculations. The second is a background subtraction algorithm. With this procedure, we obtained the oscillating behavior for individual features (A and B), which is by and large consistent with the predictions based on the spherical symmetric approximation although C70 has the ellipsoidal shape. Owing to the solid state effect, the oscillating amplitudes of the A/B intensity ratios are smaller than those of gas phase C70, but an orbital shift reported recently was not observed on our sample. The oscillating curve of a deeper feature, which consists of both σ and π states, are also reported. 相似文献
10.
Solid-phase microextraction (SPME) with a disposable ionic liquid (IL) coating was developed for headspace extraction of benzene, toluene, ethylbenzene, and xylenes (BTEX) in paints. The SPME fiber was coated with IL prior to every extraction, then the analytes were extracted and desorbed on the injection port of gas chromatography, and finally the IL coating on the fiber was washed out with solvents. The coating and washing out of IL from the fiber can be finished in a few minutes. This disposable IL-coated fiber was applied to determine BTEX in water-soluble paints with results in good agreement with that obtained by using commercially available SPME fibers. For all the four studied paints samples, the benzene contents were under the detection limits, but relatively high contents of toluene, ethylbenzene and xylenes (56-271 microg g(-1)) were detected with spiked recoveries in the range of 70-114%. Compared to the widely used commercially available SPME fibers, this proposed disposable IL-coated fiber has much lower cost per determination, comparable reproducibility (RSD < 11%), and no carryover between each determination. Considering that IL possess good extractability for various organic compounds and metals ions, and that task-specific IL can be designed and synthesized for selective extraction of target analytes, this disposable IL coating SPME might has great potential in sample preparation. 相似文献