STUDIES ON REDOX PROPERTIES OF HETEROPOLY ACIDS (SALTS) AND THEIR DERIVATIVES WITH KEGGIN AND DAWSON STRUCTURES

We have systematically studied redox properties of two series of several dozen heteropoly acids (salts) and their derivatives with vanadium and rare-earth elements with Keggin and Dawson structures, e. g. LnHSiMo_(12), SiMo_(12-n)V_n, M_(1.5)PMo_(12), PMo_(12-n)V_n, PW_(12-n_V_n, Ln(PMo_(11))_2, Sm(XMo_(11))_2 and P_2Mo_(18-n)V_n, etc., and obtained their sequence of oxidation. It was found that there is a linear relationship between the reduction potentials of heteropoly anions and the derivatives of heteropoly anions with rare-earth elements with Keggin structure and nq~2 (n and q are the principal quantum number and charge of the central ion respectively). On the basis of the electrostatic model the regularity of oxidation and reduction was rationalized.     

若干1-(N-甲基-4-吡啶鎓基)-3-(N-甲基-4-吡啶亚基)-4-烷基环戊烯-1-酮-5菁化合物可见吸收光谱的溶剂效应

菁是一类很重要的离子型染料和感光材料,也有极少数可用作激光染料,绝大部价菁染料为直链分子。我们最近合成了一系列带有五员桥环的菁,并研究了这些桥环菁化合物的质子化平衡和荧光性质。     

钌的二甲基氯硅烷羰基化合物和衍生物的合成及表征

用SiMe₂ClH与Ru₃(CO)₁₂反应,得到顺式-Ru(CO)₄(SiMe₂Cl)₂(I)和[Ru(CO)₄(SiMe₂Cl)]₂(Ⅱ)。它们的SiMe₂Cl配位基呈现较强的反位效应,由此合成得到一系列含膦(氧磷)或含卤素的衍生物。进行了Ⅰ-Ⅵ的元素分析、IR、¹HNMR和MS表征。     

2-(取代苯乙烯基)-5-取代苯并噁唑的合成及其光性能的研究

通过2-甲基苯并噁唑或2-甲基-5-叔丁基苯并噁唑在KOH/DMF介质中与苯甲醛或取代苯甲醛反应,合成了22个标题化合物,其中13个未见报道。测定了它们的结构和紫外光谱、荧光光谱、荧光量子产率,并对母体化合物的溶剂效应进行了研究。     

甲基氯化锡的核磁共振波谱研究

定性和定量测定甲基氯化锡,文献上报道的方法较多。有薄层色谱,气相色谱,极谱法等。但测定方法麻烦,重现性较差。我们采用核磁共振波谱的方法,利用溶剂化效应对化学位移的影响,分别定性定量测定了水溶液中的SnCl_4,(CH_3)_2SnCl_2和CH_3SnCl_3。并结合薄层分离和原子吸收分光光度法进行了比较,结果较为满意。     

氚核磁共振波谱在氚标记甾族化合物制备中的应用

本文介绍了十一种氚化甾族化合物的氚核磁共振谱。我们依照英国放化中心和英国萨里大学报道数据,(甾体骨架上的CH及CH_2各位置的谱线归属,应用了定位标记化合物作为对照)归属了其氚在化合物中标记的位置,根据其积分曲线定出了各位氚的相对百分含量。同时图谱中又提供了立体构型的信息,为氚化甾族化合物制备过程中,催化剂的选择,实验条件的控制及反应机理等研究提供了理论依据。     

Solid-state binding of dimethyl sulphoxide involving carboxylic host molecules. X-ray crystal structures of four inclusion species

The crystal structures of four dimethyl sulphoxide (DMSO) inclusion compounds with different carboxylic acid hosts,1–4, have been studied by single crystal X-ray analysis. Crystals of thetrans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid inclusion compound (1a), [1 · DMSO (1: 1)] show monoclinic (P2₁/n) symmetry with the unit cell dimensionsa = 11.522(4),b = 18.658(2),c = 8.709(1) Å and = 98.92(2)°. The clathrate of the 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (2a), [2 · DMSO (1: 2)] is triclinic (P) with the cell dimensionsa = 15.043(7),b =9.657(4),c = 8.118(7) Å, = 101.81(5), = 96.05(4) and = 100.04(4)°. Triclinic (P) symmetry is shown also by the inclusion compound of 9,10-dihydro-9,10-ethanoanthracene-11-monocarboxylic acid (3a) [3 · DMSO (1:1)] with the cell dimensionsa=6.3132(1),b=7.9846(2),c=17.5314(4) Å, = 96.46(2), = 87.08(2) and = 106.02(2)°. The 9,9-bianthryl-2-monocarboxylic acid clathrate (4a) [4 · DMSO (1:1)] is monoclinic (P2₁/n) and the cell dimensions area = 19.625(18),b = 8.817(1),c = 14.076(8) Å and = 97.92(6)°. In all these structures, the hosts show the same basic recognition pattern for the DMSO guest, involving a strong O-H ... O bond from the COON to the S=O group, and a possible C-H ... O type interaction between the carbonyl O atom of the host and a CH₃ group of the guest. The crystals consist of discrete host-guest aggregates which are mainly held together by weak intermolecular interactions of the Van der Waals' type. The stoichiometries of the aggregates are, however, different.     

The application of levulinic acid and 5-nitro-2-furylmethylene diacetate in the total synthesis of some novel biologically active (5-nitro-2-furyl)azomethines

Summary The syntheses andin vitro antibacterial and antifungal evaluation of certain (5-nitro-2-furyl)azomethines with different heterocyclic nuclei are described.

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Die Anwendung von Lävulinsäure und 5-Nitro-2-furylmethylendiacetat in der Totalsynthese einiger neuer biologisch aktiver (5-Nitro-2-furyl)azomethine

Zusammenfassung Es wird die Synthese und diein-vitro-antibakterielle und antifungale Wirksamkeit für bestimmte (5-Nitro-2-furyl)azomethine mit verschiedenen heterocyclischen Kernen beschrieben.

     

Adsorption of organics on activated carbon cloth at zero surface coverage

Summary Adsorption properties of activated carbon cloth were investigated by gas-solid chromatography. Retention of several organic compounds was measured in the temperature range from 200 to 250°C. The gas/solid distribution coefficients and the related thermodynamic function of adsorption at zero surface coverage were determined. The obtained experimental data were used to explain the adsorbent-adsorbate interaction.     

Singlet quenching of tetraphenylporphyrin and its metal derivatives by iron(III) coordination compounds

The quenching of fluorescence of the free-base tetraphenylporphyrin, H₂TPP, and its metal derivatives, MgTPP and ZnTPP by diverse iron(III) complexes, [Fe(CN)₆]³⁻, Fe(acac)₃, [Fe(mnt)₂]⁻, Fe(Salen)Cl, [Fe₄S₄(SPh)₄]²⁻·, FeTPPCl and [Fe(Cp)₂]⁺ has been studied both in homogeneous medium (CH₃CN) and micellar media, SDS., CTAB and Triton X-100. The quenching efficiencies are analysed in terms of diffusional encounters and it has been possible to separate static quenching components. The quenching constants are dependent on the nature of the ligating atoms around iron(III) and also on the extent of π-conjugation of the ligands. The quenching mechanism has been investigated using steady-state irradiation experiments. Evidence for oxidative quenching by iron(III) complexes was obtained, though the spin multiplicities of the excited electronic states of iron(III) complexes permit both energy and electron transfer mechanisms for quenching of the singlet excited state of the porphyrins.