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优化了双(2-苯并咪唑基)烷烃的合成反应条件,以邻苯二胺和丙二酸,丁二酸及癸二酸为原料,在4mol/L HCI为溶剂,邻苯二胺:脂肪二酸的比例为2.3:1条件下,在油浴中加热回流,反应完全后,经两种后处理方法,合成了三种双(2-苯并咪唑基)烷烃,通过红外,质普,核磁等检测手段对其结构进行了确认.并得到了双(2-苯并咪唑基)癸烷的有机晶体,通过X射线单晶衍射对其结构进行了表征. 相似文献
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把K2(F2[C4×C4])的计算归结为计算截断多项式环F2C4[t]/(t4)的相对K2-群K2(F2C4[t]/(t4),(t)).运用Dennis-Stein符号及它们之间的关系进行细致的分析计算,给出了K2(F2[C4×C4])的一个极小生成元集并最终确定了K2(F2[C4×C4])=C34C92. 相似文献
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以2-乙烯-5-甲氧基-1H-吡咯并[3,2-b]吡啶(化合物A)、三氟甲烷亚磺酸钠、过氧化叔丁醇(70%水溶液)、四水醋酸钴、磷酸钾、无水乙腈为原料合成了2-(1-(过氧叔丁基)-3,3,3-三氟丙基)-5-甲氧基-1H-吡咯[3,2-b]吡啶(化合物B)。设计了正交试验来确定了最佳合成工艺参数为:化合物A与四水醋酸钴摩尔比100:10,化合物A与过氧化叔丁醇摩尔比1:5,反应温度75°C,反应时间10h。该方法在最佳条件下的合成收率为92.3%,纯度99%以上。 相似文献
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摘 要 用密度泛函理论B3LYP方法,结合6-31G(d,p)和6-311 +G(d,p)基组,研究苯基取代的六元碳链双烯酮阴离子自由基的分子内环加成反应.探讨反应物分别通过[4+2]和[2+2]环加成反应生成六元环产物(i)和四元环产物(ii)的反应机理.结果表明,2个反应都是分步进行的,都先经过第1个过渡态得到中间体.然后从该中间体出发,反应(i)经过第2个过渡态得到六元环产物;反应(ii)经过另外一个过渡态得到四元环产物.计算表明反应(i)是主反应通道. 相似文献
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在水热条件下,通过簇阴离子[PW12O40]3-为建筑单元,并充分考虑簇阴离子的结构特点,以两种金属有机配合物单元[Cu（4,4＇-bipy）]2＋和[Cu（O-2,2＇-bipy）]为修饰基团,合成了一个二维的新结构的多酸盐[Cu（O-2,2＇-bipy）]8[PW12O40{Cu（4,4＇- bipy ）2}2]·OH。用X射线单晶衍射对化合物进行了数据收集,并对其结构进行解析。 相似文献
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把K2(F2[C4×C4])的计算归结为计算截断多项式环F2C4[t]/(t4)的相对K2-群K2(F2C4[t]/(t4),(t)).运用Dennis-Stein符号及它们之间的关系进行细致的分析计算,给出了K2( F2[C4×C4])的一个极小生成元集并最终确定了K2(F2[C4×C4])=C34⊕C92. 相似文献
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Tunable luminescent materials are becoming more and more important owing to their broad application potential in various fields. Here we construct a pillar[5]arene-based hybrid material with stimuli-responsive luminescent properties and ion-sensing abilities from a pyridine-modified conjugated pillar[5]arene and a planar chromophore oligo(phenylenevinylene) upon coordination of Cd (II) metal cores. This new material not only shows an optimized luminescence due to the minimized π–π stacking and efficient charge transfer properties benefitting from the existence of pillar[5]arene rings, but also exhibits tunable multicolor emission induced by different external stimuli including solvent, ions and acid, indicating great application potential as a fluorescent sensory material, especially for Fe3+. With this pillar[5]arene-based dual-ligand hybrid material, valid optimization and regulation on the fluorescence of the original chromophore have been achieved, which demonstrates a plausible strategy for the design of tunable solid-state luminescent materials and also a prototypical model for the effective regulation of fluorescent properties of planar π systems using synthetic macrocycle-based building blocks. 相似文献
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李林初 《中国科学院研究生院学报》1986,24(5):376-381
本文首次报道秃杉的核型为K(2n)=22=16m+6sm, 3号染色体具“长着丝点区 域”。似具比同属的台湾杉(18m+4sm)进化的趋势。它们均为"2B"。从国产杉科植物的 核型类型看,似见"2B"的台湾杉属与"1B"的杉木属和"1A"的水杉属、水松属、柳杉属的亲缘关系依序由近到远并比它们进化。本作者还观察了秃杉的核仁数目和多微核现象。 相似文献
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利用简单的手性有机配体L-酒石酸成功地合成出了一系列类似DNA螺旋构型的左、右旋的一维链状聚合物：{A[Mo2VIO4LnIII(H2O)6(C4H2O6)2]·4H2O}n (Ln = Sm, Eu, Gd, Ho, Yb, Y; C4H2O6 = L- 或 D-酒石酸； A = NH4 或 H3O)。通过水热法，巧妙地把传统的钼氧单核{MoO4}、双核{Mo2O7}以及{Mo8O26}等结构单元，通过有机配体配位的过渡金属单元交错地连接成零、一、二、三维的一系列结构新颖的化合物，这类化合物大多数具有可以容纳客体小分子的隧道或空穴，如 [Cu(4,4’-bpy)]2MoO4·2H2O，[Cu(4,4’-bpy)]2Mo2O7，[Cu(4,4’-bpy)(Hnic)(H2O)]2Mo8O26等。首次利用水热法合成出了含稀土的杂多酸类化合物，[Gd(H2O)3]3[GdMo12O42]·3H2O。该化合物是由Silverton-型的 [GdMo12O42]9- 阴离子和配位的Gd3+ 阳离子组成的。在[GdMo12O42]9- 离子中首次把顺磁性的钆(III)离子引入到该构型的中心，并且通过九配位的钆(III)离子把它们连接成具有介孔结构的三维网状化合物。该化合物的获得为今后合成类似化合物提供了一个很好的范例。在水热法合成出的化合物，[Cu2(C8H6N2)2(C7H6N2)]2[Mo8O26] 中，首次捕捉到喹喔啉的氧化产物苯并咪唑，证明了在水热条件下含氮的芳香杂环类的有机配体可以被二价铜氧化，其氧化产物进而作为配体直接与铜原子配位，最终形成新颖的上述化合物。 相似文献
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Despite extensive research and several stunning breakthroughs in the synthesis of interlocked molecular species, [3]catenanes, Borromean rings and ring-in-ring complexes are exceedingly rare and their targeted synthesis remains a formidable challenge. Herein, a series of Cp*Rh-based homogeneous and heterogeneous interlocked structures have been prepared by coordination-driven self-assembly, not only including metalla[2]catenanes and molecular Borromean rings, but also linear metalla[3]catenanes and ring-in-ring complexes. The interlocked structures are all based on bithiophenyl groups. The bithiophenyl groups effectively enhance the strength of the inter-ring interactions and play a crucial role in the formation of these interlocked structures. By taking advantage of the strong interaction between π-donor (D) and π-acceptor (A) groups, the electron-deficient methylviologen cation was introduced into a cationic metallarectangle based on bithiophenyl groups. Taking inspiration from these results, a cationic metallarectangle based on A units was threaded into a metallarectangle based on D units, leading to a heterogeneous D–A ring-in-ring structure. 相似文献
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BackgroundPretreatment is the critically important step for the production of ethanol from lignocelluloses. In this study, hardwood birch (Betula pendula) and softwood spruce (Norway spruce) woods were pretreated with a newly synthesized morpholinium ionic liquid, 1-H-3-methylmorpholinium chloride ([HMMorph][Cl]), followed by enzymatic hydrolysis and fermentation to ethanol.Results[HMMorph][Cl] was synthesized using inexpensive raw materials, i.e., hydrochloric acid and N-methyl morpholine, following a simple process. The influence of pretreatment time (2, 3, 5, and 8 h) and temperature (120 and 140°C) in terms of hydrolysis efficiency was investigated. Glucose yields from enzymatic hydrolysis were improved from 13.7% to 45.7% and 12.9% to 51.8% after pretreatment of birch and spruce woods, respectively, under optimum pretreatment conditions (i.e., at 140°C for 3 h) as compared to those from pristine woods. Moreover, the yields of ethanol production from birch and spruce were increased to 34.8% and 44.2%, respectively, while the yields were negligible for untreated woods.ConclusionsThis study demonstrated the ability of [HMMorph][Cl] as an inexpensive agent to pretreat both softwood and hardwood.How to cite: Mohammadi M, Shafiei M, Karimi K. Improvement of ethanol production from birch and spruce pretreated with 1‐H‐3‐methylmorpholinium chloride. Electron J Biotechnol 2019;41. https://doi.org/10.1016/j.ejbt.2019.07.004. 相似文献
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[目的/意义]通过实验分析不同特征提取算法对新闻文本聚类效果的影响。[方法/过程]选取搜狗实验室的搜狐新闻语料库以及澳大利亚广播公司2003-2017年间的新闻标题语料库,对TF-IDF、Word2vec以及Doc2vec三种单一特征,TF-IDF+Word2vec、TF-IDF+Doc2vec、Word2vec+Doc2vec以及TF-IDF+Word2vec+Doc2vec四种组合特征在K-means、凝聚以及DBSCAN算法上分别进行聚类分析,通过Purity以及NMI两个评测指标对聚类效果进行评价。[结果/结论]单类特征中三个特征的聚类质量呈Word2vec> TF-IDF> Doc2vec关系;组合特征中TF-IDF+Word2vec的效果最优。Word2vec在单一特征中的表现最优,其也是不同组合特征间差异的主要因素,特征组合是否可以提升聚类性能需基于多因素进行综合判定。 相似文献
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命题公式"2+2=4"究竟是基于经验和直觉的判断,还是数学严格化的推论?巴恩斯和布鲁尔坚持对上述公式进行囿于科学知识社会学视域的归因,虽有其合理性但却显偏颇。命题公式"2+2=4"具有经验性、真理性、理想化等多个维度下的广深差异性,在数学的严格性、演绎性与其经验性、应用性之间形成的谱系,关联着数学知识的多样内在化和层级同一性。 相似文献
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李林初 《中国科学院研究生院学报》1988,26(5):371-377
本文分析了池杉Taxodium ascendens 的核型，全由中部和近中部着丝点染色体组成，
核型公式为K(2n)=22=20m+2sm，属“1A”类型。它的特点是10号染色体具“长着
丝点区域”结构。池杉染色体的相对长度组成为2n=2L+8M2+12M1。通过与落羽杉
的“1A”和墨西哥落羽杉的“2A”核型进行比较，似见它们的进化水平以落羽杉、池杉，墨西
哥落羽杉之序递增。 落羽杉属植物的核型公式均为K(2n)=22= 20m+2sm。 本文还就
核型、生态环境和地理分布(包括化石)资料讨论了落羽杉属的次生遗传歧异中心和可能的演
化式样。 相似文献