化学合成

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012

吉林大学化学学院，无机合成与制备化学国家重点实验室，长春 130012

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry

吉林大学无机合成与制备化学国家重点实验室，化学学院

A plausible charge distribution of Fe and Mo valence states is proposed, and the stability of the compounds is discussed. Polycrystalline samples of 〓(0.8≤x≤1. 5) are prepared by solid-state reaction at high temperature. The alteration of the relative content between Fe and Mo in 〓 exhibits a significant effect on the crystal structure and the ionic ordering of the compounds.

采用传统高温固相烧结反应法合成了非化学配比的双钙钛矿型〓系列化合物。X射线粉末衍射数据分析结果表明，非化学配比的双钙钛矿结构〓（0.8≤x≤1.5）系列化合物的晶体结构随着Fe含量x的变化在x=1.2附近有一个由四方14/mmm对称向立方Fm〓m对称的结构结构相变发生。

Utilization of carbon dioxide and propylene as starting material for direct synthesis of methacrylic acid has an attractive alternative to organic synthesis, environmental protect and utilization of carbon.

以CO_2和丙烯为原料直接合成甲基丙烯酸，在合成化学、碳资源利用和环境保护等方面均有重大意义。

Smell is tougher to implant than colour because it not only matters whether a plant can make odoriferous chemicals, it also matters what it does with them.

在花中加入香味要比加入颜色难，因为前者涉及植物能否合成有味化学物质以及如何处理这些化学物质。

Several transient compounds were synthesized by the homo- and heterogeneous reactions of reactive halogen compounds, In-situ ultraviolet photoelectron spectroscopy and photoionization mass spectroscopy as well as theoretical calculations were used to study their molecular structures, stability and molecular orbital properties, their electronic structures and geometric structures were obtained for the first time; Simultaneously, the electronic structure and thermal dissociation of acetyl peroxynitrate and trifluoroacetyl peroxynitrate which have great importance in the atmospheric chemistry were studied; The substituent effects of series of halopyridines and halothiophenes were studied by the ultraviolet photoelectron spectroscopy method for the first time. The atmospheric chemical reaction between peroxyacetyl radicals with IO radicals as well as the dissociation of the most stable isomer of CH3COIO3 were calculated by density functional theory, it was found that the CH3COOIO2 isomer may be act as a new reservoir of inorganic iodine in the stratosphere.

通过活性卤素的系列均相与非均相化学反应合成了几种瞬态物种，采用原位紫外光电子能谱和光电离质谱结合量子化学理论计算对化合物的分子结构、稳定性以及分子轨道特性进行了研究，首次获得了这些物种的电子结构和几何结构的信息；同时研究了大气中有重要作用的乙酰过氧硝酸酯和三氟乙酰过氧硝酸酯的电子结构性质及热解过程；采用紫外光电子能谱手段首次研究了系列卤代吡啶和噻吩的取代基效应；通过量子化学理论计算研究了乙酰基过氧自由基与IO自由基的大气化学反应及其最稳定异构体CH3COOIO2的解离，发现该物种可能是无机碘化合物在平流层中的储库物种。

In particular, although there has been some success demonstrating that 'activated' ribonucleotides can polymerize to form RNA6, 7, it is far from obvious how such ribonucleotides could have formed from their constituent parts.

实验模型表明，从40亿年前就已在地球上存在的简单化学物质中形成RNA的所有成分是完全可能的，他们已合成了RNA的三个组成部分中的两个，并首次成功合成出一种类RNA。

After extensive experimental studies,the optimum baking conditions were determined as follow:the molar ratios of potash feldspar powder and soda is 1.30,the baking temperature is 845℃,and baking time is 150 min.The optimum hyd...

对合成样品化学成分分析、X射线物相分析、红外光谱分析、扫描电镜分析表明，合成13X沸石分子筛结晶完好，性能优良，水热反应经由溶解水合反应和聚合浓缩反应两大阶段。

By ~(31)P NMR, it was found that the racemization of amino acids was minimized. And it seams that L-amino acid has different reaction acticity from the D-amino acids.

其次，从磷化学的角度研究了氨基酸的立体化学对酯交换反应的结构效应，发现了以磷酰基保护的氨基酸以及含磷缩合试剂的方法进行多肽的合成，氨基酸消旋现象很少发生。

The synthesis was typically finished in less than 50 min with overall radiochemical yields of 20%-30% and radiochemical purity more than 98%.

总合成时间约为50min，放射化学产率为20％-30％，放射化学纯度大于98％。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失