Synthesis,crystal structure and two-photon property studies on a series of complexes derived from a novel Schiff base ligand

A new Schiff base ligand derived from S-benzyldithiocarbazate and 4-[N-hydroxy ethyl-N-(methyl)amino]benzaldehyde (HL, where H is a dissociable proton) and its Ni^II, Cu^II, Zn^II and Pd^II complexes were prepared and fully characterized. The structures of HL and Ni(L)₂ were determined by X-ray diffraction analysis, which revealed that the geometry of the Ni^II ion is square-planar with two equivalent Ni=N and Ni=S bonds, and that the two neighboring molecules in two layers have weak contact. The electronic spectra and solution fluorescence of the ligand and the complexes were studied, and the quantum yields of single-photon fluorescence for the compounds were determined. The compounds possess two-photon absorption (t.p.a.) character and the t.p.a. coefficient and t.p.a. cross-section were determined by the Z-scan technique. Especially, the Zn(L)₂complex and the HL ligand exhibit intensive two-photon fluorescence (t.p.f.) at 800 nm laser pulses in the femtosecond regime.     

分子离子NO+激发态的势能函数

100公里以上的大气分子离子主要为NO~+。它的辐射特点及它与电子、原子或分子的相互作用,对于理解大气的化学过程具有特别重要的意义。为了研究这些过程,确定NO~+分子离子基态及其各个激发态的分子势能函数是非常重要的。精确的X~1Σ~+,A~1Ⅱ和a~3∑~+势能曲线已发表;基于光电子谱的研究发现了NO~+的其它激发态,但对于这些激发态的研究尤其是势能函数的研究不多。本文研究并导出NO~+的基态和10个激发态的势能函数。     

钇对Nd-Fe-Al-Ni非晶合金热稳定性与晶化行为的影响

采用差示扫描量热法（DSC）、X射线衍射（XRD）和透射电镜（TEM）研究了Y对Nd-Fe-Al-Ni非晶合金热稳定性和晶化行为的影响。结果表明,淬火态的Nd60Fe20Al10Ni10-xYx（x=0,2）合金基本为非晶组织同时还含有少量的淬态相,Y的加入抑制了淬态相的析出。加入Y后,非晶合金的晶化开始温度和晶化峰值温度都向高温方向移动,证明其热稳定性提高。Y的加入改变了合金的晶化方式和最终晶化产物,使非晶基体中析出的晶化相更加弥散圆整细小。并且Y具有在化学上钝化氧杂质的作用,从而抑制了氧的有害作用。利用Kissinger方程获得了Nd60Fe20Al10Ni8Y2非晶合金的晶化开始和晶化峰值激活能分别为1.21和1.16 eV。     

Investigation of transitions and relaxation processes in polystyrene by using positron annihilation

The glass transition and relaxation processes in polystyrene resins with the number average molecular weight ranging from 7.0·10² to 9.8·10⁴ were studied with the positron annihilation technique. The pick-off annihilation lifetime of ortho-positronium (₃) and its intensity (I ₃) were measured in the temperature range from 20 to 430 K. The glass transition temperature (T _g) was determined as an onset temperature coefficient of ₃.T _g shows the molecular weight dependence in these samples. BelowT _g, local motions were detected by measurements ofI ₃. The local motions could be observed above 100 K in this experiment.I ₃ show the minimum at around 250 K and it does not show molecular weight dependence.     

基于芘的荧光熄灭的单质碘荧光敏感膜的研究

单质碘熄灭固定于增塑的ＰＶＣ膜中的芘的荧光，且这种熄灭作用可逆。本据此研制了用于测定单质碘浓度的荧光敏感膜，最佳膜组成为２～４ｍｇ芘、５０ｍｇＰＶＣ粉、１００ｍｇ邻苯二甲酸二异辛酯，测定碘的浓度范围为２．２６×１０＾－５～１．０４×１０＾－３ｍｏｌ／Ｌ。此膜测定单质碘的重现性好，响应时间小于４０ｓ。除Ｆｅ＾３＋、Ｂｉ＾３＋外，其它常见离子均无干扰。将此膜用于食盐中碘的测定，结果令人满意。     

Studies on the Physicochemical Properties, Structure and Antitumor Activity of an Oligosaccharide Homologue SnS-2 from the Root of Scrophularia ningpoensis Hemsh

An oligosaccharide homologue named SnS-2 was isolated from the root of Scrophularia ningpoensis Hemsl.SnS-2 was purified by means of gel-permeation chromatography and ion-exchange chromatography. Its physicochemical properties, including carbohydrate content and molecular weight were determined. The structure of SnS-2 was elucidated by chemical methods along with ^1H and ^13C NMR spectroscopy, including two-dimensional DQCOSY and H-detected ^1H, ^13C HMQC experiments. These results show that SnS-2 possesses a backbone consisting of terminal α-Galp-(1→, α-Galp-(1→6), α-Glcp-(1→6) and nonreducing end β-Fruf-(2→. The bioactive assay showed that it could inhibit the growth of Lewis pulmonary carcinoma implanted in mice.     

A new lignan from the seeds of Sphaerophysa salsula

A novel lignan: sphaerophyside SC was isolated from ethanolic extract of the seeds of Sphaerophysa salsula (Pall.) DC. The structure of the compound was elucidated mainly on the basis of the 1D NMR and 2D NMR data.     

Template-free, polymerase-free DNA polymerization

A combination of a DNA ligase and a restriction endonuclease provides a DNA polymerase activity, which might suggest a novel strategy for polymer synthesis.     

Poly[[aqua­tetra­imidazole­di‐μ‐phthalato‐dicopper(II)] monohydrate]

The title complex, {[Cu₂(C₈H₄O₄)₂(C₃H₄N₂)₄(H₂O)]·H₂O}_n, is a three‐dimensional polymer formed through bridging by phthalate dianions of two different Cu^II cations and a network of O(N)—H⋯O hydrogen bonds. The Cu—O and Cu—N inter­action distances are in the ranges 2.0020 (16)–2.4835 (17) and 1.968 (2)–1.9855 (19) Å, respectively. The structure is composed of alternating polymer chains parallel to the c axis, with a shortest Cu⋯Cu distance of 6.3000 (5) Å.