Hydrothermal synthesis and structure of [{Mo8V4O36(VO4)(VO)(2)}(n)](7n-) bi-capped alpha-Keggin fragments linked to a chain

The title compound, (H(2)en)(3)H3O {MO8V4O36 (VO4) (VO)(2)} . 4H(2)O, was hydrothermally synthesized and structurally characterized by means of IR, ESR spectrum and single crystal X-ray diffraction. It crystallized in a monoclinic system with space group P2(1)/c, a=1. 980 4(4) nm, b=2. 063 4(4) nm, c=1. 192 0(2) nm, (beta =94. 76(3)degrees and deep black colour. The compound contains V-centered bi-capped alpha -Keggin fragments {Mo8V7O42} that are linked together by edge-shared units (VO5)-O-N via V-O-V bonds, forming a chain.

Photochemical synthesis and crystal structure of a charge transfer salt [HMDH2][(H2PMoMo11O40)-Mo-v]center dot 2AA center dot 3H(2)O center dot DMF

The title supramolecular compound, [HMDH2][(H2PMoMo11O40)-Mo-V] . 2AA . 3H(2)O . DMF (HMD = hexamethylene diamine; AA=acetaldehyde; DMF=N,N-dimethyl formamide), has been photochemically synthesized by using elemental analysis, IR, solid diffusion reflectance, electronic spectra, ESR spectra and X-ray single-crystal analysis. The crystallographic data: triclinic, P (1) over bar, a=14.092(2), b=14.347(3), c=14.358(3)Angstrom, alpha = 75.10(3), beta = 80.70(3), gamma = 80.73(3)degrees, V = 2746.6(10)Angstrom (3), Z = 2, M-r = 2081.68, D-c=2.517g/cm(3), F(000) =1970, mu (MoK alpha) =2.766mm(-1). The structure has been refined to R =0.0832 and wR=0.2638, by full-matrix least-squares method. The title compound is composed of hexamethylene diamine, two acetaldehyde molecules, three water molecules, one N,N-dimethylformamide and [(H2PMoMo11O40)-Mo-V](2-) heteropoly anion.

Spectrometric investigation on the thermooxidative degradation of ethylene oxide and tetra-hydrofuran co-polyether

The thermooxidative degradtion of ethylene oxide and tetra-hydrofuran (EO-THF) co-polyether has been studied by electron spin resonance (ESR), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The initial degradation site was found to be at the a-carbon of the ether bond. Two free radicals which derived from dehydrogenation and oxygen addition were successfully detected by spin-trapping technique which used alpha -phenyl-N-tert-butyl nitrone(PBN) as spin trap. Both FT-IR and NMR have been used to follow structural changes of the copolyether during degradation. Nearly 20 product fragments including formate, carbonate, methyl, alcohol, methylene-dioxy, hydroperoxide and semiformal have been characterized by D-1 and D-2 NMR. The thermooxidtion of co-polyether preferred to occur on the THF units especially at the alternating linkage of EO and THF. Antioxidant (BHT) not only retarded the thermooxidation but also modified the degradation products with less ester and methylene-dioxy groups hut more hydroxyl and methyl groups.

Production of active oxygen species from Taxus cuspidata induced by far-UV radiation

In order to understand the role of active oxygen species in mediating plant injuries induced by far-UV radiation, seedlings of Taxus cuspidata Sieb. et Zucc. were irradiated by far-UV rays in laboratory for 4 weeks. The production of organic free-radicals in detached needles, and the production of O-2(radical anion) and O-1(2) in isolated chloroplasts were detected weekly by electron spin resonance (ESR) to evaluate their relative importance. The results show that the cumulative effect of far-UV irradiation, is best indicated by the production of organic free radicals in the needles, O-2(radical anion) production in chloroplasts is the next. The enhancement of O-1(2) production in chloroplasts by the cumulative far-UV irradiation seems to be not so important as O-2(radical anion) in mediating injuries induced by, far-UV radiation because of its high background value.

多种谱学方法研究环氧乙烷/四氢呋喃共聚醚的热氧降解

采用电子自旋共振 (ESR)、傅里叶变换红外光谱 (FT IR)和多种核磁共振 (NMR)技术研究了环氧乙烷 /四氢呋喃共聚醚的热氧降解 ,表征了近 2 0种产物结构碎片 ,并对EO和THF两种链节的降解作了定量讨论。共聚醚的氧化降解发生在醚键氧碳上 ,遵循自由基氧化机理 ,最后形成大量的甲酸酯、碳酸酯等酯类以及甲基、亚甲二氧基和醇 ,此外还检测到过氧化氢和半缩甲醛结构。分析表明共聚醚中THF链节的降解程度明显大于EO链节 ,而且降解容易发生在两种链节交替连接处。抗氧剂 2 ,6 二叔丁基 4 甲基酚 (BHT)不仅降低了共聚醚的氧化降解程度 ,还改变了降解产物的结构分布 ,显著抑制了碳酸酯和亚甲二氧基结构的生成 ,相对增加了羟基和端甲基结构

己二胺-12-钼磷酸电荷转移盐的光化学合成与晶体结构

采用光化学法合成一种有机-无机电荷转移盐，（HMDH2）[H2PMo12O40]·AA·3H2O·DMF（HMD = 1,6-己二胺，AA = 乙醛，DMF = N,N-二甲基甲酰胺）超分子化合物。用元素分析，IR，固体漫反射电子光谱，ESR进行了表征。X-射线四圆衍射测定其晶体结构属三斜晶系，空间群 Pī，Mr=2081.68，晶胞参数a = 14.092(3)，b =14.347(3)，c =14.358(3)?，α=75.10(3)，β=80.70(3)，γ=80.73(3)°,V=2746.6(10)?3，Z=2，Dc=2.517g/cm3，F(000)=1970，μ(MoKα)=2.766mm- 1，全矩阵最小二乘法修正至R=0.0832，wR=0.2638。标题化合物是由1个质子化的1,6-己二胺、12-钼磷混合价杂多阴离子 [PMo12O40]4ˉ、3个水分子、2个乙醛分子和1个二甲基甲酰胺分子构成。

Hydrothermal synthesis and crystal structure of Co(En)(3)MoO4

Co(En)(3)MoO4 was synthesized by using the method of hydrothermal synthesis and characterized by elemental analysis, IR, ESR and single-crystal X-ray methods. It crystallizes in hexagonal space group P (3) over bar C1 with a=1.596 4(2) nm, b=1.596 4(2) nm, c = 0.993 5(2) nm, alpha=beta=90 degrees gamma=120 degrees, M-c=399.18, V=2.192 6(6) nm(3), D-c=1.814 g/nm(3), Z=6, F(000)=1 2181 R-1=0.070 3, R-w=0.220 7. According to separation of anion which acted on electrostatic potential, the anion and cation ions formed a type of organic and inorganic material.

Synthesis, electrical properties and crystal structure of a new radical-ion salt based on pi-extended bis(TTF) and a Keggin heteropolymolybdate

By electrocrystallization of 2,6-[4,5-bis(n-butylsulfanyl)-1,3-dithiol-2-ylidene]-4,8-bis(6-iodo-n-hexyloxy)-1,3,5,7-tetrathia-s-indacene (BHBDTI) and [NBu4](4)[SiMo12O40] in the mixed solvent CHCl2CH2Cl and CH3CN, the new radical-ion salt [C42H60Cl2O2S12](2)[SiMo12O40] was prepared. It was characterized by means of IR and ESR spectroscopy and X-ray diffraction. In the crystal structure, organic radical dications and silicomolybdate anions are alternatively arranged along the a axis to form a 1-D conducting layer. The organic layer consists of two isolated groups of BHBDTI divided by the (011) plane without short interatomic contacts. However, in each group, BHBDTI molecules associate with each other in a head to tail manner running along the [011] direction and face-to-face overlapping with a relative shift by approximately one TTF subunit along the long axis of the molecule and a slight shift along the short axis of the molecule with significantly short S ... S contacts. The room-temperature d.c. conductivity determined by the two-probe method is 10(-4) S cm(-1), suggesting that the compound is a semiconductor.

The reduction of Eu3+ in SrB6O10 prepared in air and the luminescence of SrB6O10 : Eu

The reduction of Eu3+ to Eu2+ in SrB6O10 prepared in air by a high-temperature solid state reaction was studied. The luminescent properties of Eu2+ in this matrix show f-d broad band emission peaking at about 386 and 432 nm at room temperature. A charge compensation mechanism is proposed as a possible explanation. The luminescence of Eu3+ with f-f transitions was studied in this sample and reflected that the Eu3+ ion occupied a site with non-centro-symmetry. The ESR spectrum was used to detect the existence of Eu2+ in the samples. (C) 1998 Elsevier Science S.A.

Synthesis, properties and crystal structure of organic-inorganic radical salt (DBTTF)(6)HPMo12O40 center dot 2H(2)O

Organic-inorganic radical salt (DBTTF)(6)PMo12O40 . 2H(2)O was synthesized by electrocrystallization and characterized by IR spectrum, electronic spectrum and ESR technology, Its magnetic property, conductivity and crystal structure were determined. The title compound crystallized in a triclinic system with P1 space group, a = 1.378 7(7), b = 1.420 4 (2), c = 1.570 2(2) nm, alpha = 104.57(1)degrees, beta = 103.41(2)degrees, gamma = 95.80(2)degrees, V = 2.853(2) nm(3) Z = 1 and a final R = 0.072 7.

Effects of La3+ on lipid fluidity land structural transitions in human erythrocyte membranes

The effects of La3+ on the structure and function of human erythrocyte membranes were investigated by fluorescence polarization, spin-labeled electron spin resonance (ESR) and differential scanning calorimetry (DSC). The results showed that increasing concentrations of La3+ inhibited (Na++K+)-ATPase and Mg2+-ATPase activities. La3+ lowered the lipid fluidity of erythrocyte membranes and induced structural transitions in erythrocyte membranes.

Synthesis and structural characterization of V(IV) and V(V) containing mixed-valence heteropolytungstogermanates

V(IV) and V(V) containing mixed-valence heteropolytungstogermanates have been prepared by controlled potential reduction of corresponding GeW9V3O407-, their electronic spectra have been recorded. The ESR spectra of one-electron-reduced anions in solution at 340K consist of more than 40 equally spaced lines, showing that the three VO6 octahedra in both alpha- and beta-forms are corner-shaped and one of the bridging oxygen atoms is protonated at pH 4.7.

Effect of the fold surface of the lamellae on the behavior of the trapped radicals in irradiated polyamide-1010

Two types of macromolecular free radicals -CH2CONHCHCH2- (a) and -CH2C=O (b) trapped in irradiated Polyamide-1010 (PA1010) and PA1010 filled with neodymium oxide (Nd2O3) were characterized by an ESR approach. It was found out that a was mainly trapped in the fold surface of the lamellae and b in the amorphous phase. This result suggested that trapped radicals mainly existed in the noncrystalline phases. The effect of the fold surface area of the lamellae on the behavior of the trapped radicals are discussed in this article. Whether for the specimens with similar crystallinities but different crystallite sizes or for those with the same concentration of neodymium oxide but different crystallinities, radical a exists dominantly in a specimen with a larger fold surface area of the lamellae. Under a certain circumstance, radical a can transform into radical b for a specimen with a larger fold surface area of the lamellae. It means that the fold surface area of the lamellae plays an important role in the transformation of radical a to b. (C) 1998 John Wiley & Sons, Inc.

含钒(Ⅳ)和钒(Ⅴ)的钨锗混合价杂多酸盐的合成及其结构表征

报道了含钒(Ⅳ)和钒(Ⅴ)的钨锗混合价杂多酸盐的合成、电子吸收光谱及单电子还原态的ESR谱.α—和β—[HGeV~ⅣV_2~ⅤW_9O_(40)]~(7-)的溶液ESR谱是由40余条超精细线组成的,表明在阴离子中3个VO_6八面体是角顶共用,且其中一个桥氧原子是质子化的.

Single crystal growth and spectroscopic properties of KZnF3:Eu3+

Single crystal of KZnF3 : Eu3+ has been grown by means of Bridgman-Stockbarger technique in Ar atmosphere, The emission and excitation spectra of europium ion were measured, The results show that a small amount of Eu2+ exists in the crystal, The existence of Eu2+ ions was also confirmed by ESR data, The valence change of Eu ions during the crystal growth is due to unequivalent substitution of Eu3+ ions for the lattice ions. The sites possibly occupied by Eu ions in this crystal were also discussed.