在光动力光疗中类卟啉稀土配合物光敏作用原初反应的特征: 产生自由基I型机制的ESR研究

本文用ESR方法研究了类卟啉稀土配合物[(CO2H-APPC)Gd]Cl2的光敏反应。用4-hydro-tetramethylpiperidine-N-oxide radical(4-hydro-TEMPO)作探针, 通过对其消自旋的作用, 证实[(CO2H-APPC)Gd]Cl2光敏反应中有阳离子自由基[(CO2H-APPC)Gd]^+产生, 加入还原剂可促使[(CO2H-APPC)Gd]^+生成。经由5, 5-Dimethyl-1-pyrrolineN-oxide(DMPO)对超氧阴离子(O2^-)和羟基自由基(.OH)的自旋捕捉及对该自旋加合物[DMPO-O2^-]和[DMPO-OH]的ESR测定, 证实有O2^-和.OH产生, 并用SOD清除O2^-和甲酸钠清除.OH的实验, 进一步证实O2^-和.OH的产生。上述结果说明[(CO2H-APPC)Gd]Cl2光敏反应存在着产生[(CO2H-APPC)Gd]^+和活性氧自由基的I型机制。     

MCM-41分子筛和催化剂的特殊吸附等温线

测定了MCM-41中孔分子筛和催化剂的吸附等温线, 发现它们形状非常特殊, 不仅可逆部分分两段, 并且还存在两个滞后环, 在相对压力0.4以前出现的第一个滞后环可归属于中孔孔道内的毛细凝聚, 在饱和压力附近出现的第二个滞后环可归属于分子筛颗粒之间的毛细凝聚。利用吸附和XRD数据, 可有效地表征MCM-41分子筛和催化剂的结构有序度和孔道畅通情况。     

三齿NS2型配体Cu(Ⅱ)配合物的合成、光谱性质及电化学性质

A variety of complexes Cu(NS₂)(Im)(NO₃)₂ and Cu(NS₂)(Py)(NO₃)₂ where NS₂=HN(CH₂CH₂SR)₂(R=CH₃CH₂CH₂, (CH₃)₂CH,CH₃CH₂CH₂CH₂ and (CH₃)₂CHCH₂), have been synthesized and characterized by elementary analyses, molar conductivity, IR, UV/Vis and ESR spectra as well as by electrochemical methods. The new complexes exhibit exceptionally high redox potentials(500～580 mV) and complexes for HN(CH₂CH₂SCH(CH₃)₂)₂ exihibit rather hyperfine splitting constants(a_‖<70G) in the powder ESR spectra, which are close to those for the blue copper proteins.     

聚乙烯燃烧和阻燃的热分析研究

<正> 聚乙烯是一种极易燃烧的高分子材料,氧指数仅17.6,随着其应用面的拓宽和现代社会对防火要求的提高,聚乙烯的阻燃成了越来越重要的课题。目前,聚乙烯及其共混物的阻燃配方已不计其数,理论探讨也有一些报道,但由于对阻燃效果与阻燃剂的性质之间的内在联系尚缺乏足够的认识,所以阻燃剂的选择仍主要依赖于经验及大量的配方试验,缺少系统有效地选择阻燃剂的方法。     

Synthesis and electrochemistry of 1,1′-bis(phosphino)cobaltocenium compounds

The electrochemistry of 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate ([dppc][PF₆]), 1,1′-bis(dicyclohexylphosphino)cobaltocenium hexafluorophosphate ([dcpc][PF₆]), 1,1′-bis(di-iso-propylphosphino)cobaltocenium hexafluorophosphate ([dippc][PF₆]), and 1-(di-tert-butylphosphino)cobaltocenium hexafluorophosphate ([1-dtbpc][PF₆]) was examined in methylene chloride with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. A reversible reductive wave followed by an irreversible wave at more negative potentials was observed. Ten new phosphinothioyl ([dppcS₂][PF₆], [dcpcS₂][PF₆], [dippcS₂][PF₆], [1-dtbpcS][PF₆], and 1,1′-bis(dicyclohexylphosphinothioyl)ferrocene) and phosphinoselenoyl derivatives ([dppcSe₂][PF₆], [dcpcSe₂][PF₆], [dippcSe₂][PF₆], [1-dtbpcSe][PF₆], and 1,1′-bis(dicyclohexylphosphinoselenoyl)ferrocene) were prepared and characterized, and the structures of eight of these compounds were determined. The electrochemistry of these phosphinochalcogenyl cobaltocenium compounds, as well as the previously prepared [dppcO₂][PF₆], displayed two reversible reductive waves at potentials less negative than that of the free phosphines. A correlation was found to exist between the Hammett substituent constant σ_p and the reduction potentials of these compounds. In addition, the phosphinoselenoyl [dppcSe₂][PF₆], [dcpcSe₂][PF₆], and [dippcSe₂][PF₆] displayed an electrochemically irreversible oxidative wave, potentially indicating an intramolecular Se-Se bonded trication. The electrochemistry of three new and five previously reported transition metal complexes of the general formula [M_nCl₂(P^∩P)][PF₆] (M = Pd or Pt, n = 1, P^∩P = dppc, dcpc or dippc; M = Au, n = 2, P^∩P = dppc or dcpc)) was also examined displaying at least two reductive waves at potentials less negative than that of the free phosphines. Comparison of the electrochemical data with that previously obtained for analogous ferrocenes indicates that a correlation exists between the reduction potentials of the cobaltocenium phosphines and the potentials at which oxidation of the ferrocene phosphines occurs. In addition, the structure of [Au₂Cl₂(dppc)][PF₆] was determined.     

GC-MS测定桔子皮中的挥发性成分

桔子皮经水蒸汽蒸馏,乙醚萃取挥发性成分。通过气－质联用（ＧＣ－ＭＳ）测定,发现桔子皮中含有３８个组分,确定了其中２３个组分的结构。     

Dynamics of radiation induced isomerization for HCN-CNH

We have analyzed the dynamics underlying the use of sequential radiation pulses to control the isomerization between the HCN and the CNH molecules. The appearance of avoided crossings among Floquet eigenphases as the molecule interacts with the radiation pulses is the key to understanding the isomerization dynamics, both in the adiabatic and nonadiabatic regimes. We find that small detunings of the incident pulses can have a significant effect on the outcome of the isomerization process for the model we consider.     

Ab initio determination of the optical properties of bulk Au and free surfaces of Au

The optical properties of bulk Au and a (100) free surface of Au are determined by solving the Helmholtz–Fresnel equations for a geometry reflecting layered systems. This approach is based on the use of the microscopical conductivity tensor evaluated fully relativistically and, for later purposes, does include the option of choosing an arbitrary uniform direction of a possibly present magnetization. It will be shown that, while so-called experimental bulk data agree reasonably well with their theoretically obtained counterparts, in the case of free surfaces of Au (semi-infinite systems) they not only disagree substantially in size between different experiments but also with the theoretical values. The shapes of the curves for the real and the imaginary parts of the diagonal permittivity tensor elements ? _xx and ? _zz , however, are rather similar.     

Intramolecular stacking interaction in mixed-ligand complexes containing ATP4- and aromatic N-heterocyclic ligands

The stability constants of the binary ML2+ and ternary M(ATP)L2- complexes,where L=Iq (isoquinoline) or BIm (benzimidazole) and M=Zn2+ or Cd2+,have been determined by poten-tiometric pH titration in aqueous solution at I=0.1 mol/L (NaClO4),T=25℃.The stability of the ternary complexes characterized by corresponding to the equilibrium M(ATP)2-+ML2+=M(ATP)L2-+M2+ is higher than what would be expected on statistical grounds.The increase may be related to the stacking interaction between the aromatic ring of the ligands L and the purine moiety of ATP4- 1H NMR studies of Zn2+/ATP4-/L confirm the presence of stacking in the ternary complexes.It is concluded that the strength of the intramolecular stacking interaction is dependent on the structure of the aromatic ring of the ligand L and the formation of a metal ion bridge.Possible implications are discussed briefly.     

金刚石薄膜在多晶铜和磷脱氧铜基片上的生长

分别采用99.99%的多晶铜片和99.95%的磷脱氧铜片作为沉积金刚石薄膜的基片,通过热丝化学汽相沉积法在两种基片上都获得了大面积、自支撑的多晶金刚石膜.使用高分辨率光学显微镜、扫描电子显微镜、Raman光谱和X射线衍射比较分析了两种铜基片上的金刚石膜.脱氧铜上的金刚石膜质量并不亚于多晶铜上的金刚石膜,而且它的成核密度、生长速率以及应力都高于多晶铜上金刚石膜的同类参数.特别采用了退火工艺和优化的生长条件来获得大面积的连续金刚石膜.关键词：