具有生物活性有机硅化合物的研究(XIV)──含硅四配位双(单)硫代磷酸酯化合物的研究

共合成了13个含硅四配位二硫代磷酸酯和2个含硅四配位单硫代磷酸酯的新化合物,经元素分析、IR、¹HNMR、MS确定了新化合物结构,对部分化合物进行了生物活性的测定,结果表明个别化合物有较好的生物活性。     

寡糖快原子轰击质谱中碱金属加合离子应用技术的研究

生命科学的研究成果^[1～3]表明,糖蛋白和糖脂中的糖基可作为细胞的识别信号,能控制细胞的分裂和分化.快原子轰击(FAB)质谱是测定寡糖的重要手段^[4,5],但目前还存在不少问题.我们在对麦芽各糖的研究中.     

New Diterpenoid Alkaloids from Delphinium Souliei Franch

Inourpreviouspapers'-',wehavereportedtheisolationandelucidationofaseriesofnewditerpenoidalkaloidsfromDelphinillnlsolllieiFranch.ContinuedphytochemcalinvestigationsontheconstituentsofthisplanthaveledtotheisolationoftwoothernewditerpenoidalkaloidssoulineE(l)andsoulineF(2).SoulineE(2.6mg)wasobtainedascolorlesscrystals,mpf77-78'C(fromethanol).[a]."8.0(c=0.05,CHCI;).itsmolecularformulaC,=H;,NO,wasderivedfromHkEIMS(M-f361.2613,cafe.361.2608).TheiHnmrspectrum(400MHz)exhibitedthefollowingsign…     

Synthesis of Macrocyclic Arsinous Acid Estcrs

MacrocyclicarsinousacidestersareusuallypreparedbycondensationofdichloroalkylarsinesRAsCI,Iwithdidsinthepresenceoforganicalkali].ThemethoddescribedhereinvolvesthetransformationofintermediatefromItohis(dimethylamino)alkylarsineRAs(NMe,),2andthereactionof2withdidsindryTHFtoleadtotheformationoftitlecompounds.2canreactsmoothlywithdidsintheabsenceoforganicalkalitogeneratecorrespondingmacrocyclicarsinousacidesters4anddimethylaminewhichescapesfromthereactingsystemasagasinreflux.Althoughonemoreste…     

Composition-ratio determination of Chrome Azurol S (CAS) with Cu(2+) and research on dynamic reaction process of CAS with EDTA

The composition-ratio of Chrome Azurol S (CAS) with Cu(2+) and dynamic reaction process of CAS with EDTA were studied by spectrophotometry. The composition-ratio of Cu(2+) with CAS (2:1) was successfully determined using the method of lines and EDTA complexing substitution. The effects of temperature, time, pH, concentration of cetyltrimethylammonium bromide (CTMAB), and concentration of Cu(2+) on the absorption spectrum were also discussed. By optimizing experimental conditions, the dynamic process of displacement of CAS, which forms the ternary compound Cu-CAS-CTMAB, by EDTA were determined. The test results indicated that EDTA can replace 99.6% of the CAS quickly when heated. The system reached equilibrium finally. This research method can be applied to the qualitative and quantitative analysis of related Cu complexes.     

活性炭孔径和比表面积对TiO2/AC光催化性能的影响

采用"同步物理-化学活化法"二次活化商品活性炭,制备不同孔径和比表面积的系列活性炭(AC)载体,以偏钛酸为钛源,利用均匀沉淀法制备TiO2负载型光催化剂(TiO2/AC),用氮吸附、XRD、SEM等方法表征,研究活性炭的孔径和比表面积对TiO2/AC性能的影响;并通过降解水溶液中的亚甲基蓝(MB)研究TiO2/AC光催化氧化特性,考察催化剂投加量、不同MB浓度等因素对光催化氧化的影响.结果表明,负载的TiO2粒子粒径为12-20 nm,活性炭的比表面积大、平均孔径大有利于TiO2的均匀分散,阻止TiO2晶粒生长,有利于充分发挥TiO2小尺度效应;另外,活性炭吸附和TiO2光解的协同效应使TiO2/AC光催化剂对MB降解的效率显著提高.动力学研究表明,TiO2/AC光催化降解MB反应符合表观一级动力学特征.     

Radical dynamics of puerarin as revealed by laser flash photolysis and spin density analysis

Puerarin, a C-glycoside of daidzein, forms upon direct photoexcitation in acetonitrile an excited-state with a lifetime of 4.2 micros assigned by oxygen quenching and sensitized formation of triplet zeaxanthin as a triplet and phenoxyl radicals of ms lifetime insensitive to oxygen and with spin density delocalized over the ACB isoflavonoid ring system, [ACB]*, as shown by laser flash photolysis and theoretical spin density calculations. Photoexcitation of A-ring 7-phenolate puerarin yields a [AC]* radical, which converts into the [ACB]* radical with a rate constant of 3.6 x 10(5) s(-1) in 5% methanolic acetonitrile in a process triggered by B-ring deprotonation (4'-phenol). For the 7-phenolate with the 4'-phenol derivatized to yield a propyl anisole, no rearrangement of the initially formed [AC]* radical was observed. With the A-ring phenol derivatized, the 7-propyl-4'-phenolate forms a radical with spin density delocalized over the CB ring system, [CB]*, together with a minor fraction of [ACB]* due to propyl radical dissociations confirmed by BDE-calculations. Dianionic puerarin forms initially the [ACB]* radical, which is converted into the [CB]* radical in a slower process (1.6 x 10(4) s(-1)) assigned to 7-methylation. The radical dynamics is discussed in relation to puerarin/carotenoid antioxidant synergism at water/lipid interphases.     

Starburst triarylamine based dyes for efficient dye-sensitized solar cells

We report here on the synthesis and photophysical/electrochemical properties of a series of novel starburst triarylamine-based organic dyes (S1, S2, S3, and S4) as well as their application in dye-sensitized nanocrystalline TiO2 solar cells (DSSCs). For the four designed dyes, the starburst triarylamine group and the cyanoacetic acid take the role of electron donor and electron acceptor, respectively. It was found that the introduction of starburst triarylamine group to form the D-D-pi-A configuration brought about superior performance over the simple D-pi-A configuration, in terms of bathochromically extended absorption spectra, enhanced molar extinction coefficients and better thermo-stability. Moreover, the HOMO and LUMO energy levels tuning can be conveniently accomplished by alternating the donor moiety, which was confirmed by electrochemical measurements and theoretical calculations. The DSSCs based on the dye S4 showed the best photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 85%, a short-circuit photocurrent density (J(sc)) of 13.8 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.63 V, and a fill factor (ff) of 0.69, corresponding to an overall conversion efficiency of 6.02% under 100 mW cm(-2) irradiation. This work suggests that the dyes based on starburst triphenylamine donor are promising candidates for improvement of the performance of the DSSCs.     

A Simple Method for Controlling the Degree of PEGylation of Dynorphin A (1-13)

Dynorphin A (1–13) was chemically modified by reaction with succinimidyl propionate‐monomethoxy polyethylene glycol (mPEG‐SPA). To determine the degree and the optimized condition for PEGylation of dynorphin A, the reactions were monitored in different pH buffers at different molar ratios by reversed‐phase high performance liquid chromatography (RP‐HPLC) and matrix‐assisted laser desorption/ionization time‐of‐?ight mass spectrometry (MALDI‐TOF MS). The results showed that the degree of PEGylation for dynorphin A could easily be controlled through adjustment of the molar ratios and the pH. The degree of PEGylation of dynorphin A increased as the molar ratio of dynorphin to MPEG‐SPA and the pH increased.