Study on the structure and miscibility of PBPI-E/PTI-E blends

The crystallization, miscibility and structure of polyimide PBPI-E/PTI-E blends were studied by DSC, DMA, NMR and fluorescence techniques, where PBPI-E is a biphenyldianhydride-based polyimide, and PTI-E is a polyimide from 4,4'-thiodiphthalic anhydride and 4,4'-oxydianiline. The results obtained show that PBPI-E/PTI-E blends are miscible at a molecular level for all the compositions studied. However, the glass transition temperature of the blends is well below the value predicted by the Fox equation, and the blends are not stable at high temperature, i.e. phase separation will occur when the blends are annealed about T-g. Moreover, the melting point T-m, differential enthalpy Delta H and spin-lattice relaxation time T-l(c) of the blends increase with the annealing time. (C) 1997 Elsevier Science Ltd. All rights reserved.

Eu~(2+)激活的LiAl_5O_8和Al_2O_3的荧光性质

通过研究Eu~(2+)在LiAl_5O_8和Al_2O_3基质中的荧光性质,发现Eu~(2+)在LiAl_5O_8和a-Al_2O_3基质中产生f→f跃迁发射,在a-Al_2O_3和r-Al_2O_3的混合相中Eu~+2的f→f跃迁发射消失,产生一新的带状发射.运用晶场和共价理论及晶体结构数据对实验结果进行详细讨论,采用电负性平均化原理和Sanderson电负性标度计算基质中Eu~(2+)所带分电荷及Eu-O键的离子性百分数,合理地解释了实验结果.

一种新型塑料增韧剂——核壳结构聚合物

本文综述了核－壳结构聚合物用于通用塑料和工程塑料增韧的最新进展，并对该领域的研究进行了展望

Synthesis and molecular structures of di- and trinuclear molybdenum complexes containing pyridine-2-thiolato (pyS) ligand

Dinuclear complexes [Mo-2(mu-pyS)(2)(CO)(4)(PPh(3))(2)] (1), [Mo-2(mu-pyS)(2)(CO)(5)(PPh(3))] (2) and a trace quality of trinuclear complex [Mo-3(mu-pyS)(2)(mu(3)-pyS)(2)(CO)(6)] (3) were obtained from the reaction of [Mo(CO)(3)(MeCN)(3)] with pyridine-2-thione (pySH) and PPh(3) in THF. The crystal structures of 1.2C(7)H(8) and 3.7 C7H8 have been determined by X-ray diffraction studies. Crystals of 1.2C(7)H(8) are monoclinic, space group C2/c and Z = 4, with a = 18.797(3), b = 11.143(4), c = 28.157(7) Angstrom, beta = 101.23(2)degrees. The structure was refined to R = 0.050 and Rw = 0.057 for 3146 observed reflections, Crystals of 3.7 C7H8 are monoclinic, space group P2(1)/a and Z = 4, with a = 13.912(2), b = 17.161(2), c = 15.577(3) Angstrom, beta = 101.17(1)degrees. The structure was refined to R = 0.046 and Rw = 0.051 for 4357 observed reflections. The molecule of 1 consists of two Mo(CO)(2)(PPh(3)) fragments linked by an Mo-Mo bond (2.974(2)Angstrom) and by two doubly-bridging pyS ligands. The compound 3 contains a bent open geometry of three molybdenum atoms (Mo(1)-Mo(2)-Mo(3) angle 122.99(3)degrees) linked by two Mo-Mo bonds (2.943(1) and 2.950(1) Angstrom) and by two doubly- and two triply-bridging pyS ligands.

Relationship between the dissolution behaviours and current efficiencies of La, Ce, Pr and Nd in their chloride molten salts

The dissolution behaviours of La and Nd in their chloride molten salts were studied by means of the see-through cell, electrochemical weak polarization and quantum chemistry (extended Huckel molecular orbital). The reasons for the low current efficiencies of rare earth metals and the difference between La and Nd in their own chloride electrolytes on the basis of the solubility, rate of dissolution, and existing state of the metals dissolved as well as the structure of the melts, are discussed.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE DAWSON-TYPE TUNGSTOPHOSPHATE HETEROPOLY COMPLEXES SUBSTITUTED BY NIOBIUM

Eight new complexes alpha(2)-M(7-m)H(m)[P2W17NbO62]. H2O and alpha-1, 2, 3-M(g-m)H(m) [P2W15Nb3O62]. XH(2)O(M=K, TMA, TEA, TBA) were synthesized and characterized by IR and UV spectroscopy, polarography, XPS and XRD methods. P-31 and W-183 NMR studies show that the niobium atoms in the anions are on the polar sites. The crystal of alpha-1, 2, 3-K7H2 [P2W15Nb3O62]. 30H(2)O is hexagonal, its cell parameters: a=1.9836(4), b=1.9836(9), c=1.5498(6)nm, alpha=beta=90 degrees, gamma=120 degrees.

SYNTHESIS AND CHARACTERIZATION OF TRISUBSTITUTED HETEROPOLYTUNGSTOGERMANATES CONTAINING GROUP 3A ELEMENTS

Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1 as expected for trisubstituted heteropoly anions. The intensity ratio of alpha-Ga compound is 1:2, which is different from others(a:1). With the help of FAB mass spectrum, we concluded that it is a dimer with D-3h structure in aqueous, and the others exist by monomers with C-3v structures.

SYNTHESIS AND CHARACTERIZATION OF ALPHA,BETA-TRIINDIUM SUBSTITUTED HETEROPOLYTUNGSTATES

The complexes of alpha,beta-K(a)H(b)XW(9)O(37)(InH2O)(3) . xH(2)O (X = Si, Ge; a+b = 7) were synthesized from their lacunary precursors alpha,beta-XW(9)O(34)(10-) (X = Si, Ge) and characterized by elemental analysis, W-183 NMR, IR and UV spectroscopy and polarography. W-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1, as expected for the C-3 nu structure of trisubstituted A alpha- and A beta-Keggin anions.

COMPARATIVE-STUDIES ON PERIODATOCUPRATE(II, III) AND TELLURATOCUPRATE(II, III)

The crystal structures, electronic spectra, and Cu2p XPS of Cu(III) complexes Na4H[Cu(H2TeO6)(2)]. 17H(2)O and Na4K[Cu(HlO(6))(2)]. 12H(2)O have been described. The characterizations of a Cu(III) atom in a complex are as follows: (i) In a square-planar coordination, the average bond length of Cu-O is 0.183 nm, shorter than the 0.190-0.200 nm found for a Cu(II) complex. (2) The ''blue shift'' occurs for d-d transitions in the electronic spectrum of the Cu(III) complex compared to those of its related Cu(II) complex, resulting from the higher valence state. (3) Cu(III) compounds with CuO4 square-planar coordination are expected to be diamagnetic whereas Cu(II) compounds to be paramagnetic. (4) Comprehensive investigations on Cu2p XPS show that the binding energy of Cu2p(3/2) of a pure Cu(III) compound is about 2.0 eV higher than that of its corresponding Cu(II) compound: the shake-up satellites do not appear in the Cu2p XPS for a pure diamagnetic Cu(III) compound, the same as found for a diamagnetic Ni(II) compound: the FWHM of the signal of Cu2p XPS may become broader for Cu(III) compound because its core hole's lifetime shortens due to the higher valence state of copper. (C) 1995 Academic Press, Inc.

SYNTHESIS AND PROPERTIES OF ALPHA-MOLYBDOTUNGSTONIOBIC DIPHOSPHATES

Four kinds of new molybdotungstoniobic diphosphates with the Dawson structure, formulated as alpha-P2W15Mo2Nb62(7-), are prepared and characterized by IR, UV spectra, polarography and W-183 NMR which show that the same ''polar'' W atoms in the Dawson frames-are substituted. The mean value of W-183 chemical shifts of the ''polar'' group varies linearly with the number of substituted atoms in the opposite polar group.

交替马来酸酐共聚物多缩乙二醇酯盐络合物的离子传导性（Ⅲ）

研究了交替马来酸酐共聚物多缩乙二醇酯（ＢＭ３５０）－ＬｉＢＦ４络合物的离子传导性能．实验表明：络合物的侧链玻璃化转变温度随盐含量的增加而上升电导率随盐浓度的变比而出现一极大值室温电导率最大可达４１９×１０－５Ｓ·ｃｍ－１．电导率随温度升高而增加．络合物的导电行为符合ＶＴＦ方程．无定形相中分子链热运动是离子传输的动力。

α－一铌二钼十五钨磷杂多酸盐的合成和性质研究

合成了通式为α－Ｍ＿（７－ｘ）Ｈ＿ｘ［Ｐ＿２Ｗ＿（１５）Ｍｏ＿２ＮｂＯ＿（６２）］·ｘＨ＿２Ｏ［Ｍ＝Ｋ~＋，（ＣＨ＿３）＿４Ｎ~＋，（Ｃ＿２Ｈ＿５）＿４Ｎ~＋，（Ｃ＿４Ｈ＿９）＿４Ｎ~＋］的４种盐．用ＩＲ、ＵＶ吸收光谱、极谱、~（１８３）ＷＮＭＲ、ＸＰＳ和ＸＲＤ等方法对其进行了表征，确认三取代的位置是在Ｄａｗｓｏｎ结构的同一“极位”．研究了取代Ｗ原子数目对~（１８３）ＷＮＭＲ化学位移的影响，发现“极位”Ｗ原子的~（１８３）ＷＮＭＲ化学位移平均值与取代原子数目呈线性关系.

铌取代Dawson结构钨磷杂多配合物的合成及其结构表征

本文报道了八种新化合物α_2-M_(7-m)H_m[P_2W_(17)NbO_(62)]·xH_2O,α-1,2,3-M_(9-m)H_m[P_2W_(15)Nb_3O_(62)]·xH_2O(M=K,TMA,TEA,TBA)的合成和表征.红外和紫外光谱表明两种阴离子具有Dawson结构,~(31)P和~(183)W NMR测定结果表明铌原子确系“极位”一、三取代.α-1,2,3-K_7H_2[P_2W_(15)Nb_3O_(62)]·30H_2O为六方晶系,晶胞参数为:a=1.9836(4),b=1.9836(9),C=1.5498(6)nm,a=β=90°,γ=120°.此外,还报道了极谱、XPS和XRD结果.

Characterization of 1:12 Phosphomolybdic Anions Doped Polypyrrole (PMo12/PPy) Film Electrode

1:12 phosphomolybdic anion doped polypyrrole film electrode was characterized by in-situ UV-vis spectroelectrochemistry, X-ray photoelectron spectroscopy(XPS), scan electronic microscopy(SEM) and electron spin resonance(ESR) spectroscopy.