排序方式: 共有42条查询结果,搜索用时 15 毫秒
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Hai-Ning Chang Yong-Guang Liu Zeng-Chuan Hao Guang-Hua Cui Sheng-Chun Wang 《Transition Metal Chemistry》2016,41(6):693-699
Two coordination polymers (CPs), namely [Ni(L)(chdc)] n (1) and [Mn(L)(ndc)(H2O)] n (2) (L = 4,4′-bis(imidazol-1-ylmethyl)biphenyl, H2chdc = 1,2-cyclohexanedicarboxylic acid, H2ndc = 2,6-naphthalenedicarboxylic acid), have been hydrothermally synthesized and characterized by physicochemical and spectroscopic methods and also by single-crystal diffraction. Both CPs feature 3D-diamond-like networks with point symbol of 66; CP-1 displays a 2-fold interpenetrated net, while CP-2 presents a non-interpenetrated framework. The thermal stabilities, solid-state luminescence properties and catalytic activities of both CPs for degradation of methyl orange in a Fenton-like process were investigated. 相似文献
2.
Sheng-Chun Chen Meng Hu Zhi-Hui Zhang Fu-An Sun Liang Wang Wei-You Zhou Ming-Yang He Qun Chen 《Transition Metal Chemistry》2012,37(7):619-627
The coordination chemistry of a rigid periodinated ligand, 2,3,5,6-tetraiodo-1,4-benzenedicarboxylic acid (H2BDC-I4), with a series of transition metal ions has been explored to afford five new coordination polymers {[M(BDC-I4)(MeOH)4](H2BDC-I4)(MeOH)2} n (M?=?ZnII for 1, CdII for 2, CoII for 3 and MnII for 4) and {[Mn(BDC-I4)(MeOH)4](DMF)} n (5). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and X-ray crystallography. Single-crystal X-ray diffraction reveals that complexes 1?C4 are isostructural and have a one-dimensional chain structure. Upon the addition of the solvent DMF, the infinite linear chain array in 4 is converted to a 1-D wave-like chain motif in 5 with a different space group ( $ P\overline{1} $ for 4 and P21/c for 5). The difference between structures 1?C4 and 5 can be attributed to the coordination mode of carboxylate changing from trans to cis fashion. The ZnII and CdII complexes 1 and 2 display similar emissions in the solid state, which essentially are intraligand transitions. 相似文献
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金纳米粒子的阳光光化学合成和晶种媒介生长 总被引:3,自引:1,他引:3
在柠檬酸盐-HAuCl4溶液体系中, 于高原太阳紫外线辐射下光化学合成了分散良好、尺寸分布窄的胶体金纳米粒子. 研究了溶液的酸度和太阳辐射条件对Au(Ⅲ)离子光化学还原反应速率和形成金纳米粒子尺寸的影响; 采用晶种媒介生长技术, 通过改变Au(0)/Au(Ⅲ)比合成了平均直径为4.9~9.7 nm的球形金粒子. 根据紫外-可见吸收光谱和透射电子显微镜的表征和分析, 讨论了光化学反应中自由基反应、金纳米粒子成核和生长机理. 相似文献
4.
Solvent Suppression in Intermolecular Magnetic Resonance Spectra Multiple-Quantum Coherence Nuclear with Only z-axis Gradients
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The solvent peak in the intermolecular multiple-quantum coherence spectra can be suppressed by either applying pulse field gradients or spinning sample along the magic angle direction (φ = 54.7). However, these two methods also suppress the signals of the solute. We design two pulse sequences with only z-axis gradients to suppress the solvent peak without reducing the intensity of solute signals. Compared to the former pulse sequence, the latter pulse sequence is insensitive to the imperfection of pulse flip angles. When the flip angles of the second pulse sequence are purposely deviated 1/10 from the optimal values, the solvent peak is still weak. Theoretical expressions, experimental observations and computer simulations demonstrate that the two methods can be used to effectively suppress solvent peak in intermolecular multiple-quantum coherence spectra. 相似文献
5.
金纳米粒子自球形向棒状的转变和生长的光化学法研究 总被引:8,自引:0,他引:8
在含有HAuCl4和十六烷基三甲基氯化铵(CTMAC)的DMF-H2O-丙酮介质中, 以CTMAC形成的胶束为模板, 丙酮为光敏剂, 光化学还原法制备了不同长径比的棒状金纳米粒子. 通过改变DMF∶H2O (V/V)的比例来改变溶液的极性, 增加胶束聚集数, 实现了自球形胶束向棒状的转变, 从而得到以金纳米棒占优势的金胶体溶液. 研究了HAuCl4和CTMAC的浓度以及照射时间对金纳米棒生长的影响, 在最佳实验条件下, 获得了直径在20~22 nm, 长为0.5~3 μm的金纳米棒, 讨论了光化学反应和金纳米粒子在形成的棒状胶束中的自组装生长机理. 相似文献
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针对水下低频声源的方位估计问题,基于基元紧密排列的二维矢量阵,建立了一种超指向性波束形成方法.根据矢量基元差分运算构建各阶多极子模型,获得了几乎与频率无关的模态函数,并经加权计算可在低频条件下实现超指向性波束,以解决阵列孔径对波束性能的限制.同时,结合输出信噪比最大准则所得波束,分析了超指向性波束形成算法的稳定性与波导的影响程度,探索模态阶数与阵列参数的选取原则.通过阵列性能的仿真计算与实际阵列的测量数据表明,该算法可在小尺寸阵列孔径下获得良好的阵列波束,兼具了水下线型超指向性阵和环形超指向性阵的优点,可有效实现水下低频声源的水平方位估计;且波束性能可通过调节模态阶数与基元间距以达到最佳,并受水下声波导多途与频散效应影响有限. 相似文献
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Hai-Ning Chang Yu-Feng Li Guang-Hua Cui Sheng-Chun Wang 《Transition Metal Chemistry》2017,42(6):509-515
Two silver(I)-mixed ligand coordination polymers (CPs), {[Ag(L)(Hmip)]·H2O} n (1) and {[Ag(L)]·0.5(DCTP)·H2O]} n (2) (H2mip = 5-methylisophthalic acid, H2DCTP = 2,5-dichloroterephthalic acid, and L = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl) have been hydrothermally synthesized and structurally characterized. Two CPs display 1D zigzag chain and linear chain structures, respectively. Furthermore, these 1D chains are extended into 2D supramolecular networks through hydrogen bonding interactions. The luminescence properties and photocatalytic behaviors of both CPs are reported. 相似文献
9.
Jin-Ping Si Wen-Jing Wang Jun Chang Kun-Lin Huang Zhi-Hui Zhang Sheng-Chun Chen Ming-Yang He Qun Chen 《无机化学与普通化学杂志》2020,646(21):1739-1747
Reactions of the aromatase inhibitor letrozole derivative 4,4'-(1H-1,2,4-triazol-1-yl)methylene-bis(benzonic acid) (H2tzmb) with ZnII, CdII, or PbII salts under similar conditions resulted in the generation of three coordination polymers, namely, {[Zn(tzmb)(H2tzmb)] · H2O}n ( 1 ), [Cd(tzmb)(H2O)2]n ( 2 ), and {[Pb(tzmb)(H2O)] · DMF}n ( 3 ), respectively. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, and thermogravimetric analyses. Complex 1 features a twofold 2D → 2D interpenetrated network based on corrugated 63- hcb layers, and complex 2 exhibits a flat 2D 4.82- fes network, whereas complex 3 presents a 3D hex net based on infinite rod-shaped secondary building units. The remarkable structural diversity may illustrate the powerful effect of metal ions on coordination assemblies. The spectroscopic, thermal, and photoluminescent properties of complexes 1 – 3 were investigated. In addition, the catalytic activity of 1 in the solvent-free ring-opening polymerization of ε-caprolactone was also discussed. 相似文献
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