复合氧化物La_(2-x)(Sr,Th)_xCuO_(4±λ)——一种新型的苯酚羟化催化剂

二酚(邻苯二酚,对苯二酚)是重要的化工原料,二酚生产一直是人们所关注的课题,70年代以前主要采用的一些污染严重的生产过程正被逐渐淘汰。目前,利用过氧化氢和苯酚为原料联产邻苯二酚和对苯二酚,在化工生产中占有重要的地位。常见的催化剂有等。但这些催化剂也具有明显的不足之处,前两者具有均相催化反应本身难以克服的缺点,后者虽具有多相催化过程的优点,但由于此类催化剂难以制取,而且此类催化剂主要反应孔道的孔径较小(<0.9 nm),反应物和生成物难以在孔道中扩散,使得反应速度较慢。当前国际上还正在积极寻找新的催化体系以达到高效无污染生产二酚的目的。

离子型晶体的点电荷电量的确定和晶体的化学键性质MX(M=Mg,Ca,Sr,Ba,X=O,S,Se,Te;不含MgTe)

离子型晶体的点电荷电量的确定和晶体的化学键性质ＭＸ（Ｍ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ，Ｘ＝Ｏ，Ｓ，Ｓｅ，Ｔｅ；不含ＭｇＴｅ）孟庆波武志坚张思远（中国科学院长春应用化学研究所稀土无机材料实验室，长春１３００２２）ＮｅｔＣｈａｒｇｅａｎｄＣｈｅｍｉｃａｌＢｏｎ...

稀土—组氨酸溶液配合物的pH电位法研究

稀土—组氨酸溶液配合物的ｐＨ电位法研究朱元成⒇邓汝温（天水师范高等专科学校化学系天水７４１００１）（兰州大学化学系兰州７３００００）牛春吉倪嘉缵（中国科学院长春应用化学研究所稀土化学与物理开放实验长春１３００２２）Ｌ－组氨酸（以下简称组氨酸）作为生物...

Roles of oxygen vacancy and lower valence metallic ion in direct decomposition of NO over La-2-x(Sr,Th)(x)CuO4+/-lambda

Two systems of La2-xSrxCuO4+/-lambda and La2-xThxCuO4+/-lambda, mixed oxides with K2NiF4 structure were synthesized. The compositions and structures of the catalysts were characterized by means of XRD, XPS, chemical analysis and so on. The catalytic behavior for the direct decomposition of NO has been investigated. The results show that the catalytic activity is closely related to the oxygen vacancy and lower valence metallic ion in the direct decomposition of NO. The presence of oxygen vacancy is necessary for mixed oxide to have steady activity in NO decomposition.

Syntheses and reactions of heterometallic complexes of nickel and copper with tetrathiotungstates. The molecular structures of [Ph(4)P](2)[S2W(mu-S)(2)Ni(S-2)] and W(mu-S)(4)Cu-2(PPh(3))(4)center dot py

Reaction of [Ph(4)P]2WS4 With NiCl2 in methanol solution in the presence of NaOCH3 leads to the formation of [Ph(4)P](2) [S2W(mu-S)(2)Ni(S-2)] (I) A Similar reaction between (NH4)(2)WS4 and NiCl2 under O-2 atmosphere in the presence of Ph(4)PCl or (n)Bu(4)NCl affords [Ph(4)P](2)([(S-2)W(O)(mu-S)(2)]Ni-2] (IIa) and [(n)Bu(4)N](2)([(S-2)W(O)(mu-S)(2)]Ni-2} (IIb) Under argon the same reaction gives [Ph(4)P](2)[Ni(WS4)(2)] (IIIa) and [(n)Bu(4)N](2)[Ni(WS4)(2)] (IIIb). [Ph(4)P](2)[Ni(WOS3)(2)] (IV) and [Ph(4)P](2)[Ni(WO2S2)(2)] (V) can be prepared from the reaction of [Ph(4)P]2WOS3 and [Ph(4)P]2WO2S2 with NiCl2. Treatment of (NH4)(2)WS4 with CuCl in the presence of PPh(3) in boiling pyridine produces W(mu-S)(4)Cu-2(PPh(3))(3) (VI), which can further react with excess PPh(3) to give W(mu-S)(4)Cu-2(PPh(3))(4) . py (VII). Complex I crystallizes in the space group P2(1)/n with the cell parameters: a = 20.049(4), b = 17.010(4), c = 14.311(7) Angstrom; beta = 110.24(3)degrees and Z = 4; R = 0.058 for 4267 independent reflections. The structural study confirms that complex I contains two terminal sulfide ligands, two bridging sulfide ligands, a side-on disulfide ligand, and a planar central W(mu-S)(2)Ni four membered ring. Complex VII crystallizes in the space group C2/c with the cell parameters: a = 26.436(8), b = 20.542(6), c = 19.095(8) Angstrom; beta = 125.00(3)degrees and Z = 4; R = 0.080 for 3802 independent reflections. The structural study reveals a perfect linear arrangement of the three metal atoms Cu-W-Cu.

Comparative study on the doping effect of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M=Sc,Ti,V,Cr,Mn,Fe,Co,Ni, or Zn)

With XRD, R-T, and ac chi measurements a comparative study on the doping effects of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Zn) has been carried out. The effects of the former five members are significantly different, both on phase formed and on T-c, from the latter four. It seems that the effect on phase stabilization correlates with the valency of the doped cation. In connection with the instability of the 2223 phase, the correlation has been discussed.

Magnetic and electric properties of Bi(La)Sr(Ca)Mn2O6

Bi1-xLaxSrMn2O6 and BiSr1-xCaxMn2O6 are prepared by solid state reaction. They are n-type semiconductors with ferromagnetism at room temperture. When Bi is substituted partly by rare earth, a negative magnetoresistance effect is observed in the pellet of Bi1-xLaxSrMn2O6. There are semiconductor-metal transitions at 820 K in BiSrMn2O6. The transitions are attributed to the magnetic transition at high temperature. The substitution of Ca for Sr makes the transition temperature increase. However, when Bi is partly substituted by La, the solid solution does not change into metal. (C) 1996 Academic Press, Inc.

MMgF_4(M=Ca,Sr,Ba)体系中Eu和Tb的电荷迁移

于不同气流中,合成了MMgF_4:xEU,yTb复合氟化物燐光体.该体系中Eu~(3+)和Eu~(2+)共存.Tb的存在影响Eu的价态存在形式.ESR测试表明,随Tb的掺入浓度增加,Eu~(2+)的浓度呈规律性变化.随Eu的掺入,样品的XPS谱中出现了四价铽的Tb_3d(5/2)特征伴峰.认为Eu~(3+)和Tb~(3+)之间存在电荷迁移平衡.即Eu~(3+)+Tb~(3+)(?)Eu~(2+)+Tb~(4+).通过半定量手段研究了SrMgF_4中这一平衡的平衡常数.

稀土－谷氨酸配合物的pH电位法研究

报道了在生理条件（３７℃，Ｉ＝０．１５ｍｏｌ·Ｌ－１ＮａＣｌ）下用ｐＨ电位法对１５种稀土元素与Ｌ－谷氨酸配合物稳定常数的测定结果。玻璃电极校正用ＭＡＧＥＣ程序进行，各体系中配合物物种的选择及其稳定常数的计算用程序ＭＩＮＩＱＵＡＤ－８２Ａ完成，讨论了“四分组效应”及钇的位置。

Ce~（3＋）在钙钛矿型KMF_3（M＝Mg、Ca、Sr、Ba）基质中的发光特性

采用高温固相反应法，在Ａｒ气氛中合成了ＫＭＦ３（Ｍ＝Ｍｇ、Ｃａ、Ｓｒ、Ｂａ）基质化合物和掺杂Ｃｅ３＋的磷光体。经Ｘ射线衍射分析确定，ＫＭｇＦ３和ＫＣａＦ３属于立方晶系、钙钛矿型结构，ＫＳｒＦ３和ＫＢａＦ３具有类似的结构。测定了ＫＭＦ３∶Ｃｅ３＋的发光光谱，观察到与其结构对应的分为二种不同的光谱结构，讨论了Ｃｅ３＋的取代格位

H-1 and C-13 NMR studies of TTHA complexes with diamagnetic rare earth ions

TTHA complexes with diamagnetic rare earth ions (La3+, Y3+ and LU(3+)) were studied by H-1 and C-13 NMR spectroscopy. A symmetric structural model was suggested for La(TTHA) complex and an asymmetric model for Y(TTHA) and Lu(TTHA) complexes. The complex formation was dependent on the pH value of the solution. The interactions of La(TTHA) with the additional metal ions (La3+, Y3+ and Ca2+) were relatively weak, but relatively strong for that of Lu(TTHA) with the additional Lu3+.

Studies on the synthetic, structural, electrical and magnetic properties of Ln(n)MCo(n)O(3n+1) (Ln=Sm, Gd; M=Sr, Ba; n=1,2)

Three new oxides Sm2SrCo2O7, Sm2BaCo2O7 and Gd2SrCo2O7 have been synthesized successfully by solid state reaction mathod. The X-Ray diffraction spectra show that they are all isostructural with Sr3Ti2O7, and Ln(2)SrCo(2)O(7)(Ln=Sm,Gd) crystallized in tetragonal system, Sm2BaCo2O7 in orthrhombic system. The Co-O bonds in CoO2 planes of Ln(2)SrCo(2)O(7) are shorter than those of LnSrCoO(4)(Ln=Sm, Gd), and so their delectrons are more delocalized and their electrical resistivities are smaller. The electrical resistivities versus temperature in the range 300 similar to 1100K showed that the five brides show the characters of weakly localized systems. In the lower temperature range, the magnetic behaviors of Gd2SrCo2O7 and GdSrCoO4 fit Curie-Weiss law well, and the magnetic exchange reaction in CoO2 sublattices of Gd2SrCo2O7 is ferromagnetic, but that of GdSrCoO4 is antiferromagnetic. The other three oxides with Sm3+ showed complex magnetic behaviors which is perhaps related with the complexity of Sm3+.

THE EFFECT ON PHYSICAL-PROPERTIES OF THE SUBSTITUTION OF CA OR BA FOR SR IN NDSRNIO4

A new solid solution series, NdSr(1-x)M(x)NiO(4) (M = Ca: 0.0 less than or equal to x less than or equal to 1.0; M = Ba: 0.0 less than or equal to x less than or equal to 0.6), was synthesized by solid state reaction, and the structures, magnetic and electrical properties and optical spectra of this series have been studied. All the samples crystalized in tetragonal systems, with the exception of NdCaNiO4, which crystallized in the orthohombic system. IR spectra of NdSr1-xCaxNiO4 indicated that the lengths of two Ni-O bonds decrease with increasing Ca content. The electrical conduction changed from metallic-type to semiconductive-type when x greater than or equal to 0.4 (M = Ca, Ba), and the room temperature resistivities of NdSr1-xCaxNiO4 increased with the increase of Ca content. Magnetic susceptibility measurements revealed that Ni+3 ions in all the samplies were in low-spin state over the temperature range 77-300 K.

THE EFFECT OF SOLUTION PH ON SYNCHRONOUS FLUORESCENCE-SPECTRA OF CYTOCHROME-C SOLUTIONS

Synchronous fluorescence spectra of cytochrome c solutions were studied. It was found that synchronous fluorescence spectra of tyrosine and tryptophan residues in cytochrome c molecules can be separated using different wavelength intervals. The changes in synchronous fluorescence spectra of cytochrome c solutions with the solution pH are different from that of free tyrosine and tryptophan and reflect the pH-induced conformational transitions of cytochrome c molecules. (C) 1995 Academic Press, Inc.