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31.
具有不同类型桥基的双核Cu(Ⅱ)-Schiff碱配合物的合成和晶体结构 总被引:1,自引:0,他引:1
合成了3个分别以C2O2-4([Cu2(L1)2(ox)],1),AcO-([Cu2(AcO)(L2)2]BF4,2)和酚氧([Cu2(L3)2](ClO4)2,3)为桥基的双核铜配合物,并测定了1的复配合物[Cu2(L1)2(ox)]·[Fe(OH)2(H2O)4]ClO4·H2O(1′)及2和3的晶体结构.X射线衍射结果表明:1′,2和3分别属于Fddd,P21/c和P21/c空间群.晶胞参数:[Cu2(L1)2(ox)][Fe(OH)2(H2O)4]ClO4·H2O,a=2.4390(4)nm,b=3.0538(6)nm,c=1.8494(6)nm,α=β=γ=90.00°;2,a=0.847(1)nm,b=2.6542(8)nm,c=1.4100(6)nm,β=91.34(6)°;3,a=0.7646(3)nm,b=1.6983(3)nm,c=2.4417(3)nm,β=97.11° 相似文献
32.
Soluble platinum(Ⅱ)polyyne polymers trans-{Pt-[P(C_4H_8N)_3]_2(C≡C)_2R(C≡C)_(2-)}_n and trans-{Pt-[P(C_4-H_3O)_3]_2(C≡C)_2R(C≡C)_(2-)}_n(R=9,9-dihexylfluorene-2,7-diyl)have been prepared in good yields by CuI-catalyzedpolymerization involving the dehydrohalogenating coupling of trans-{PtCl_2[P(C_4H_8N)_3]_2} and trans-{PtCl_2[P-(C_4H_3O)_3]_2} with H(C≡C)_2R(C≡C)_2H,respectively.We report the optical spectroscopy of these polyplatinaynes.The influence of the heavy metal atom in these metal alkynyl systems on the intersystem crossing rate and the spa-tial extent of lowest singlet and triplet excitons was systematically characterized.Our investigations indicate that theorganic triplet emissions can be harvested by the heavy-atom effect which enables efficient intersystem crossingfrom the S_1 singlet excited state to the T_1 triplet excited state. 相似文献
33.
用Hagihara脱氢卤代法合成了三种新的9,9-二(十六烷基)芴基二聚炔铂(d8)、金和汞(d10)化合物反式- [Pt(Ph)(PEt3)2C≡CRC≡CPt(Ph)(PEt3)2, [(PPh3)AuC≡CRC≡CAu(PPh3)]和[MeHgC≡CRC≡CHgMe] [R=9,9-二(十六烷基)芴基]. 用1H NMR, 13C NMR, 31P NMR, FT-IR, FAB-MS, UV-Vis, 荧光和磷光光谱对其进行了表征. 结果表明, 体系中的铂、金和汞产生的重原子效应可以有效地促进单线激发态S1与三线激发态T1的系间跃迁, 使标题化合物产生有机三线态发光. 相似文献
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自修复材料作为一种拥有结构上自愈合能力的智能材料近年来得到了快速发展。具备自修复性能的聚合物材料主要包括外援型和本征型。由于本征型自修复聚合物材料具有潜在的自修复能力,且能实现多次修复,所以该领域对于本征型自修复聚合物材料的关注越来越多。由氢键、π-π堆积、疏水作用、离子作用和主客体作用等非共价键力形成的本征型自修复聚合物体系不需要或需要极少外界能量就能实现快速、高效修复。这将是实现节约能源,社会可持续发展的重要途径。本文以不同类型的非共价键为线索,综述了近年来基于非共价键的本征型自修复聚合物材料的发展及其应用,并展望了其未来的发展方向。 相似文献
37.
Roderick WONG 《数学年刊B辑(英文版)》2007,28(1):1-34
In this paper, we study the asymptotics of the Krawtchouk polynomials KnN(z;p,q) as the degree n becomes large. Asymptotic expansions are obtained when the ratio of the parameters n/N tends to a limit c∈(0,1) as n→∞. The results are globally valid in one or two regions in the complex z-plane depending on the values of c and p; in particular, they are valid in regions containing the interval on which these polynomials are orthogonal. Our method is based on the Riemann-Hilbert approach introduced by Deift and Zhou. 相似文献
38.
以含有共轭大π键的2,5-双(乙炔基二茂铁)噻吩(BFET)和二甲基双十八烷基铵(DMDOA)与Keggin结构和Dawson结构钨磷杂多酸做成膜材料, 用LB技术组装了两种新型无机-有机杂化LB膜. 用π-A曲线、UV-vis吸收光谱、原子力显微镜(AFM)、扫描隧道显微镜(STM)、荧光光谱和表面光电压谱(SPS)对标题LB膜的成膜性能、结构及光电性质进行了研究, 发现标题杂化LB膜的粒子具有纳米尺寸, 在可见光区有较强的光电压响应, 在电压为±2.0 V时, 隧道电流值达到±100 nA. 相似文献
39.
The synergistic effect can help improve the electrocatalyst performances by combining the advantages of individual components. In particular, such an effect has been more important in the atomic catalysts. In this review, we have summarized the synergistic effect of N, X co-doping graphdiyne[X=B, S, F or transition metal(TM)] electrocatalysts and graphdiyne-based dual-atom catalyst(GDY-DAC). In general, the synergistic cooperation between two different dopants in co-doped GDY and adjacent active sites in GDY-DAC not only promotes their catalytic activity but also greatly enhances the thermodynamic stability of the catalysts. For the N, X co-doping GDY electrocatalysts, doping the heteroatoms like boron, sulphur, phosphorus, and fluorine with nitrogen can further tune the charge density distribution and electronic structure. Meanwhile, the electron exchange between two doping atoms and GDY substrate has been discussed, where the TM-based GDY-DAC is a very promising catalyst for electrocatalysis. More importantly, electronic interactions between different elements on GDY have been carefully discussed. In the end, we have also supplied perspectives to the future developments of the GDY-based electrocatalysts. 相似文献
40.
IP Waicheung 《中国科学A辑(英文版)》2006,49(9):1211-1222
In the nonparametric regression models, a homoscedastic structure is usually assumed. However, the homoscedasticity cannot be guaranteed a priori. Hence, testing the heteroscedasticity is needed. In this paper we propose a consistent nonparametric test for heteroscedasticity, based on wavelets. The empirical wavelet coefficients of the conditional variance in a regression model are defined first. Then they are shown to be asymptotically normal, based on which a test statistic for the heteroscedasticity is constructed by using Fan's wavelet thresholding idea. Simulations show that our test is superior to the traditional nonparametric test. 相似文献