Synthesis and photoreaction of polymethylenediamine bis(4-methyl-7-coumarinyl)oxyacetic amides

A series of polymethylenediamine bis(4-methyl-7-coumarinyl)oxyacetic amides have been synthesized and their intramolecular photochemical cyclodimerizations have been investigated It was found that only syn-HT configuration products were obtained when these bisamides were directly irradiated in dimethyl sulfoxide solution and the yields of the products decreased with the intrease of the chain length.The structures of long chain amides and their intramolecular photoryrlizatum products were determined by IR,MS,1H NMR and elemental analysis.     

C2对称的手性双噁唑啉和双噻唑啉的质谱碎裂机理研究

The electron impact mass spectra of ten new C2-symmetric chiral bis(oxazoline) and bis(thiazoline) have been studied. Bis(thiazoline) and bis(oxazoline) possess the same fragmentation mechanism under EI conditions. An unusual fragmentation pathway has been found in the compounds studied. Due to the presence of phenyl group, compounds 6 and 10 undergo a new fragmentation pathway except for the common way as the other eight compounds.Mass analyzed ion kinetic energy spectra experiments and high resolution accurate mass measurement were conducted to confirm the proposed fragmentation pathways.     

二苯胺连结的双嗯唑啉配体的修饰：电子效应和配体骨架刚性的调节

通过在4和4′位引入吸电子的溴和硝基取代基,调节二苯胺连结的双嗯唑啉配体的电子效应．NH键的酸性变化通过NH的不同化学位移确定．在吲哚与β-硝基烯烃的不对称Friedel—Crafts烷基化反应中考察了修饰配体的催化活性和对映选择性．通过合成亚胺二苄基连结的双嚼唑啉配体并考察它们在Friedel—Crafts烷基化反应中催化活性,对配体骨架刚性的影响进行了探讨．     

发泡剂含量对YAG多孔陶瓷的性能影响研究

采用共沉淀法合成YAG粉体,经过配料、干压成型和真空烧结制备YAG多孔陶瓷材料,并研究发泡剂含量对YAG多孔陶瓷的性能影响.结果表明:YAG多孔陶瓷随着发泡剂含量逐渐增多,其气孔率逐渐增高,抗压强度逐渐降低.烧结温度升高,气孔率下降,抗压强度升高.保温时间延长,气孔率降低,抗压强度升高,但是YAG多孔陶瓷的性能对于烧结温度和保温时间而言,烧结温度相对更为敏感.综合整个烧结工艺及性价比,YAG多孔陶瓷发泡剂含量为15wt;并在1550℃烧结保温lh较为适宜.