查询词典 unsymmetrically

In this dissertation, the efforts were focused on design and synthesis of chiral tmsymmetrical urea, cholic acid and heteroaromatic molecular tweezers and their molecular recognition as well as enantioselective recognition. A series of useful and creative results have been obtained.Three new types of chiral molecular tweezers containing unsymmetrically disubstituted urea unit, four new types of chiral molecular tweezers based on steroid cholic acid and one type of heteroaromatic molecular tweezers involving multiple hydrogen-bonding site have been designed and synthesized.

本文致力于新型手性不对称脲、胆甾和芳杂环类分子钳受体的设计合成及其对阴离子、中性分子和手性分子的识别及对映选择性识别性能研究，取得了一系列具有重要学术意义与应用前景的创新性结果。

A general novel synthetic method to Symmetrically or unsymmetrically 2,3,6,7- substituted thieno[2,3-d:5,4-d\']dipyrimidine-4,5(3H,6H)-diones and 2-substituted benzothieno[3,2-d] pyrimidin-4(3H)-dione by utilizing aza-Wittig reaction was proposed firstly. This synthetic method has the advantage of easily accessible starting material, mild condition and good yields.

具体研究内容如下：1、首次研究了应用aza-Wittig反应方法合成2，3，6，7-对称与不对称四取代噻吩并[2，3-d；5，4-d\']双嘧啶-4，5(3H，6H)-二酮以及2-取代苯并噻吩并[3，2-d]嘧啶-4(3H)-酮衍生物的通用新方法，该方法原料易得，条件温和，收率较高。

Further studies on the sulfinatodehalogenation of I〓 with olefinsindicated that either symmetrically and unsymmetrically disubstituted adducts could beobtained depending on the amount of 〓 and temperature. Non-fluorinated compounds (such as dichloro-, chloroacetates, chloroform) andCFCs e.g.

由于此反应能被对二硝基苯和对苯二酚（HQ阻止，光照反应加速，且与二烯丙基醚反应时得到的产物为四氢呋喃衍生物，所以我们推断反应历程是一个自由基反应过程。

The optimum reaction condition for preparation of CoPcY is as follows: a , using CoCl2 as the exchanged salt ; b , complexation temperature of 180 ; c . complexation catalyst of NH4C1 and A1C13 .2, The unsymmetrically substituted cobalt phthalocyanine complexes were synthesized by statistical condensation of phthalic anhydride and tetrabromophthalic anhydride, and further immobilized in MCM-41 molecular sieves by zeolite synthesis method, as well as characterized by XRD,FT-IR,DRS, 1HNMRetc. The catalytic property of CoPcBrx/MCM-41was tested by cyclohexane oxidation using H2O2 or t-BOOH as oxidant.

2采用本路线制备CoPcY的最佳条件为：a、采用氯化钴作为待交换的金属盐；b、络合温度以180℃为宜；c、起始反应物为苯酐、尿素、氯化铵、氯化铝、CoY时，制备出的CoPcY的催化性能最好； 2、首次采用苯酐和四溴苯酐均相浓缩统计合成法制得了不对称取代的金属钴酞菁络合物，并采用~1HNMR、FTIR、DRS等对其进行了结构表征；此外，采用沸石合成法将其固定于MCM-41中孔分子筛，并对其催化性能进行了考察。

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