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981.
982.
Keggin结构的磷钨钒稀土四元杂多配合物对过氧化氢分解的催化作用 总被引:4,自引:0,他引:4
在磷钨钒稀土四元杂多配合物中,由于V原子的使用,使其对H2O2分解的催化活性显著增加。因配合物中心原子稀土元素不同。催化活性也随之变化,其活化能与三阶稀土离子的电离能有密切关系。动力学曲线为S型。实验证明,在反应过程中有反应活性中间体生成。 相似文献
983.
Synthetic nylon-6 single molecular mass oligomers were studied by matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) mass spectrometry. These oligomers, considered as model compounds for the study of nylon-6 polymers, gave good mass spectrometric results using both MALDI and ESI. In spite of the gentle nature of both techniques, the MALDI and ESI spectra showed evidence of end-group cleavage from the oligomer chains. MALDI-MS was found to give similar fragmentation patterns for all of the oligomer samples. An increase in doubly charged ion signals with increasing oligomer mass was observed in the ESI mass spectra, as was end-group fragmentation. Signals from oligomer clusters were observed in ESI-MS for the dimer, tetramer and hexamer, most likely due to non-covalent bonding among the low-mass oligomer molecules. 相似文献
984.
985.
一维链状4-羧基苯氧乙酸桥联钴配位聚合物[Co(p-CPOA)(2,2′-bipy)(H2O)]n的合成与晶体结构 总被引:3,自引:0,他引:3
A novel coordination polymer of [Co(p-CPOA)(2,2′-bipy)(H2O)]n (p-CPOA2-=4-carboxylphenoxyacetate dianion, 2,2′-bipy=2,2′-bipyridine) was synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction. The title complex crystallizes in monoclinic space group C2/c, with a=1.424 4(3) nm, b=1.316 6(3) nm, c=1.947 7(4) nm, β=104.56(3)°. V=3.535 3(14) nm3, Z=8, R=0.028 5, wR=0.089 1. The cobalt(Ⅱ) ion displays a distorted octahedral coordination geometry, defined by three carboxyl oxygen atoms from different p-CPOA2- groups, two nitrogen atoms from 2,2′-bipyridine ligand and one water molecule. The cobalt atoms are bridged by p-CPOA2- groups, forming a one-dimensional chain structure along a axis. The adjacent Co…Co atoms distance is 0.996 8 nm. A layer supramolecular network is contrsucted by the hydrogen bonds and π-π stacking interactions. CCDC: 220039. 相似文献
986.
A novel borophosphate compound has been synthesized under solvothermal conditions using ionic liquid as a medium and structurally characterized by single-crystal X-ray diffractions. The compound crystallizes in the monoclinic, space group P2(1)/n, a=8.089(8) Å, b=13.977(12) Å, c=8.441(8) Å, β=112.517(11)°, Z=2, V=881.7(14) Å3, R1=0.03, wR2=0.079 and S=1.01. Its structure consists of a 1-D straight chain that is built of the alternative linkage of mutually perpendicular four-member rings. Other characterizations by IR and thermal and elemental analyses are also described. 相似文献
987.
镝的钼硅杂多配合物的合成,结构和振动光谱 总被引:3,自引:0,他引:3
合成了镝的钼硅杂多配合物K_(10)H_3[Dy(SiMo_(11)O_(39))_2]·20H_2O,用X射线单晶结构分析,确定其空间群为P2_1/n,晶胞参数.结果表明:SiMo_(11)O_(39)~(8-)作为四齿配体与Dy配位,Dy与8个氧原子配位,形成四方反棱柱.K离子的配位数有6、7、8、和94种.讨论了该配合物的振动光谱. 相似文献
988.
The mechanism of palladium matrix modification is studied for the determination of lead and bismuth by graphite-furnace atomic absorption spectrometry. The binding energies of the charring products for lead and bismuth in the presence or absence of palladium obtained at the initial stage of atomization were measured. The binding energies indicated the formation of PbPd and BiPd bonds, thus explaining the increase in appearance temperatures of lead and bismuth in the presence of palladium. 相似文献
989.
990.
Improvement of pulse amperometric detection (PAD) method is demonstrated in determination of ethylenethiourea (imidazolidine‐2‐thione, ETU). The anodic detection of ETU will produce polymeric film on an electrode leading to an inactive electrode surface. Here, the PAD method was used to remove the polymeric film formed on the electrode surface between ETU detection. Further, the scheme was integrated with automated flow injection analysis (AFIA) for determining ETU. The operational parameters of PAD in the AFIA system were discussed thoroughly. The analytical characteristics of the system were evaluated at optimum conditions. The linear range of calibration plot was between 20 to 300 μM (the correlative coefficient, r = 0.999) and the detection limit was 0.9 μM (S/N = 3). The relative standard deviations of detection of 50 μM ETU were 0.82% with and 9.07% without PAD scheme. The results indicate the system is a very promising tool for ETU determination. Finally, the matrix effects of two water samples that were collected from a campus and a farm show good recoveries of 92% and 96%. 相似文献