Hg2+ recognition by triptycene-derived heteracalixarenes: selectivity tuned by bridging heteroatoms and macrocyclic cavity

The binding properties of triptycene-derived oxacalixarenes containing 1,8-naphthyridine subunits 1a and 1b toward metal ions were investigated in detail by spectroscopic methods. A couple of new N,O-bridged diazadioxacalixarenes 2a, 2b were synthesized and their binding properties to metal ions were also evaluated. The results showed that the oxacalixarene 1a, a cis-isomer with a boat-like 1,3-alternate conformation and a symmetrical cavity structure, exhibited a highly selective fluorescence response toward Hg(2+) ions, while 1b, 2a and 2b did not show selective response towards any specific metal ions. Such selectivity can thus be controlled by the bridging heteroatoms and cavity structures of the macrocycles. Moreover, it was found that the fluorescence of 1a was considerably quenched upon the addition of Hg(2+), and a 1?:?2 stoichiometry host-guest complex was proposed on the basis of the Job plot and (1)H NMR titrations.     

低损耗193 nm增透膜

计算了适用于193nm增透膜设计与制备的基底与薄膜材料的光学常数,并在此基础上对193nm增透膜进行了设计、制备与性能分析.发现基底材料的吸收损耗对增透膜元件的影响很大,超过一定值时,增透膜元件的设计透过率将达不到理想水平.对单面增透膜的设计与制备结果表明,当吸收损耗降低到一定程度,散射损耗成为不可忽略的因素.采用热舟蒸发方法实现了性能良好的193 nm减反射膜,剩余反射率在0.2%以下. 关键词： 193nm 增透膜 光学损耗 剩余反射率     

A pair of unique sesquiterpene-chalcone conjugates isolated from the seeds of Alpinia katsumadai

Sumadains A (1) and B (2), a pair of unique isomeric sesquiterpene-chalcone conjugates with unprecedented skeletons, were isolated from the seeds of Alpinia katsumadai. Their structures and relative configurations were established by NMR spectroscopy and X-ray crystallography.     

新型NO供体的合成及其体外释放NO性能

新型NO供体的合成及其体外释放NO性能;金属卟啉;NO载体;合成;体外释NO作用     

聚氨酯动态拉伸红外光谱分析

聚氨酯薄膜在5Hz拉伸频率作用下,测得其同相和正交的动态偏振红外光谱.由此可知,薄膜拉伸初期的粘弹性在分子水平上主要由代表软硬段界面游离的氨酯键1719 cm^-1和有强相互作用的酯键1732 cm^-1界面有相互作用的氨酯键1709 cm^-1和游离的酯键1748 cm^-1,四种官能团代表的链段来表现:前者主要提供弹性变化,后者主要提供粘性变化.     

Green synthesis of caffeine based on methylating reagent dimethyl carbonate and environmental friendly separating method

In this paper, a green process for the synthesis and separation of caffeine was reported. Theophylline sodium is used as the raw material, diazabicyclo[5.4.0]undec-7-ene as the catalyst, and Turkey red oil as the solvent, particularly, dimethyl carbonate was adopted in place of high toxic dimethyl sulfate to form a mixture of caffeine and by-product sodium bicarbonate. After converting sodium bicarbonate to sodium carbonate, the solubility difference between caffeine and sodium carbonate at 40°C was for the first time utilized to achieve the purpose of separating caffeine with an excellent yield of 98.4% and a purity of greater than 99.0%. Furthermore, both the reaction mother liquor and separation mother liquor can be recycled and reused during the reaction and separation processes, respectively, with little caffeine loss. No industrial waste was discharged in the process of the improved synthesis and separation, which is therefore environmental friendly.     

近边X射线吸收精细结构光谱法研究土壤腐殖质组分含碳官能团组成及磷酸根影响

应用同步辐射近边X射线吸收精细结构(NEXAFS)光谱技术研究了土壤腐殖质各组分(富里酸、胡敏酸及胡敏素等)的含碳官能团组成信息,并通过分析PO43-存在条件下胡敏酸、胡敏素的官能团组成变化特征,探讨了PO43-与土壤腐殖质之间的微观作用机制。结果表明,土壤腐殖质不同组分的官能团分布具有类似的光谱特征,但组成比例存在明显差异。随着腐殖质组分的酸不溶性增加,胡敏酸、胡敏素疏水性脂肪基官能团比例显著高于富里酸,芳构化程度也明显增加,而亲水性羧基官能团比例趋于降低;PO43-通过静电作用、取代反应可以选择性释放胡敏酸中部分小分子羧基官能团,从而改变胡敏酸官能团的组成特征。此研究结果对于应用NEXAFS研究有机碳官能团形态、结构及理解PO43-在土壤微界面上的反应机制具有重要意义。     

电感耦合等离子体-质谱法同时测定地下水中微量B、P、Br和I

研究并建立了电感耦合等离子体-质谱法(ICP-MS)同时测定地下水中B、P、Br和I的方法,考察了标准之间的相互影响,B、P、Br、I的检出限分别为0.8864、1.286、0.6875、0.1242μg/L.加标回收率在98.60％-104.4％之间,研究了乙酸和乙醇在ICP-MS中的增强效果,发现乙酸的增敏效果优于乙醇.     

热舟蒸发LaF3薄膜的紫外性能研究

研究了沉积温度对热舟蒸发氟化镧薄膜结构和光学性能的影响,沉积温度从200℃上升到350℃.间隔为50℃.采用分光光度计测量了样品的透射率和反射率光谱曲线,并在此基础上进行了光学损耗、光学常数以及带隙和截止波长的计算.采用表面轮廓仪进行了表面形貌和表面粗糙度的标定,采用X射线衍射(XRD)方法测量了不同沉积温度下样品的微结构.发现在短波长波段,随着沉积温度的升高,光学损耗增加,晶粒尺寸增大,表面粗糙度略有增加.不过散射损耗在光学损耗中所占比例均很小,光学损耗的增加主要由吸收损耗引起.随着沉积温度的升高,折射率与消光系数增大,带隙变小,相对应的截止波长向长波方向移动.     

金属间化合物PrMn6Sn6的结构、磁性与119Sn穆斯堡尔谱研究

采用电弧熔炼法制备了金属间化合物PrMn₆Sn₆.X射线衍射表明该化合物具有HoFe₆Sn₆型(空间群为Immm)晶体结构.磁测量表明该化合物为铁磁性，居里温度为325　K.在15—360　K范围内测量了¹¹⁹Sn穆斯堡尔谱，得到了8个Sn原子晶位的转移超精细场随温度的变化，并且讨论了Mn亚晶格与Pr亚晶格的磁有序方向. 关键词： 6Sn₆')" href="#">PrMn₆Sn₆ 穆斯堡尔谱 磁结构