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51.
2(3H)‐Furanones 1a–d having exocyclic double bond and N‐acetylisatin nucleus were converted into the corresponding novel amides, pyrrolones, and imidazoles via nitrogen nucleophiles. All purposed structures were confirmed by NMR, mass spectra GC/MS, and chemical evidence. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:434–442, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10175  相似文献   
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The title coordination polymer, [Co(bib)(L)].0.5H2O 1 (bib = 1,1'-(1,4-butanediyl)bis(imidazole) and L = 4,4'-oxy(bisbenzoate) has been hydrothermally synthesized and characterized by IR and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group Cc with a = 8.8568(5), b = 19.936(1), c = 26.209(2) γ, y = 97.510(1)°, V= 4587.8(5) A3, Z = 8, CoC24H23N4O5.5, Mr = 514.39, Dc = 1.489 g/cm3, F(000) = 2128, μ(MoKa) = 0.795 mm^-1, R = 0.0419 and wR = 0.1002. Compound 1 exhibits a rare two-fold interpenetrating CdSO4 type topology. The O-H...O hydrogen bonds stabilize the structure of 1.  相似文献   
54.
One novel 3D 3d-4f coordination polymer, [LaZn(glc)(ox)2(H2O)2]n (1, glc = glycinate, ox = oxalate), was obtained by the in situ synthesis of glycinate from the reaction of tetrazole-1-acetic acid, sodium oxalate, zinc nitrate and lanthanide oxide in the presence of a trace quantity of nitric acid under hydrothermal conditions. Compound 1 is of monoclinic, space group P21/n with a = 0.99601(9), b = 1.14592(10), c = 1.19107(10) nm and β = 108.7150(10)°. 1 exhibits an unusual 3D heterometallic coordination framework constructed by heterometallic dinuclear LaZn subunits and mixed ox and glc linkers with a uninodal 6-connected vme {33 .43 .58 .6} net.  相似文献   
55.
Hydrazonyl bromides 2a,b reacted with active methylene compounds (dibenzoylmethane, acetylacetone, ethyl acetoacetate, phenacyl cyanide, acetoacetanilide, ethyl cyanoacetate, cyanoacetamide and malononitrile) to afford the corresponding 1,3,4,5- tetrasubstituted pyrazole derivatives 5-12a,b. Reaction of 12a,b with formamide, formic acid and triethyl orthoformate give the pyrazolo[3,4-d]pyrimidine, pyrazolo[3,4- d]pyrimidin-4(3H)one and 5-ethoxymethylene-aminopyrazole-4-carbo-nitrile derivatives 13-15a,b, respectively. Compounds 15 a,b reacted with benzhydrazide and hydrazine hydrate to afford pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine and [4-iminopyrazolo- [3,4-d]pyrimidin-5-yl]amine derivatives 16 a,b and 17 a,b. Reactions of compounds 17 a,b with triethyl orthoformate and carbon disulfide give the corresponding pyrazolo[4,3-e]- [1,2,4]triazolo[1,5-c]pyrimidine derivatives 18a,b and 19 a,b, respectively.  相似文献   
56.
Titanium dioxide was deposited from aqueous suspension onto cellulosic surfaces.Titania was sourced from Degussa (P25TM,70:30 anatase:rutile).Dry uptake of particles was shown to be rapid and dominant with one-third of the deposition occurring in less than 30 s and over one-half in the first minute.Isotherms were recorded to compare the rate of titanium deposition on dry and pre-wetted cotton.In the dry case uptake reached a maximum in 30 min whereas in the pre-wetted case the uptake was seen to continue beyond 180 min.A broad trend of higher deposition occurring at lower pH was seen,corresponding to the region where surface charges were opposite and thus attractive.Dry pickup was less significant at high pH.The response to varying ionic strength was complex and was attributed to the combined effect of charge screening,particle aggregation and consequent particle entrapment or occlusion.Titania deposition into the interstices of woven cotton sheets resulted in the formation of inorganic,nanoparticulate skeletons which could be isolated by controlled combustion of the cellulose and thus cotton was suggested to have potential for the templated synthesis of high surface area semiconductor materials.  相似文献   
57.
The inclusive and exclusive measurements were carried out for 7Li projectile breakup on 27Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons. The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions.  相似文献   
58.
从含4,4'-二吡啶胺结构单元的双(二吡啶胺) 桥联配体出发,采用溶剂热法合成了两个结构新颖的配位聚合物:[CdL1Br2]n?7.5nH2O (L1 = N,N,N′,N′-四(4-吡啶)-1,4-苯二胺) (1)和[Cu2L2(μ1,1,3-SCN)2]n?nMeOH (L2 = N,N-二(2-吡啶)-N',N'-二(4-吡啶)-1,4-苯二胺) (2),对它们进行了元素分析、红外光谱等表征,并用X-射线单晶衍射测定了其晶体结构。单晶测试结果显示,配合物1中配体L1的四个吡啶N原子均参与配位,桥联了4个Cd原子,每个Cd原子与四个吡啶 N 原子和两个溴配位,形成六配位的八面体构型。通过这些配位作用,最终形成包含 Kagome 结构的三维超分子网络。配合物2 是由一维柱状 {Cu(SCN)}n 链通过 L2 桥联生成的二维结构。有趣的是,L2中具有螯合能力的2,2'-二吡啶胺单元并未参与配位,只有4,4'-二吡啶胺单元中的两个吡啶N原子分别与一个 Cu(I) 配位,连接了相邻两条平行的{Cu(SCN)}n 链,生成二维结构。  相似文献   
59.
带有阈值转换和启动时间的优先权排队   总被引:1,自引:0,他引:1  
在诸如ISDN的通信网络中,多种信息共用一条线路,为了满足不同类型信息的服务质量要求,带有阈值转换的优先权排队系统应是一种合适的模型。本文研究单服务员、两类顾客的带有阈值转换和启动时间的优先权排队系统,首先,分别就抢占和非抢占情形讨论了具有泊松到达、服务时间和启动时间均有指数贩系统,然后就非抢占情况进上步考虑了服务时间和启动时间有一般分布的系统,求出了系统中两类顾客队长的稳态联合概率母函数,藉助这  相似文献   
60.
In this paper,we study and analyze the regularized least squares for function-on-function regression model.In our model,both the predictors(input data)and respo...  相似文献   
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