甲烷氧化偶联Ti-La-Li系混合氧化物催化剂

研究了Ti-La-Li三元氧化物的组成、结构及其对甲烷氧化偶联反应的催化性能；用XRD、IR、XPS和SEM等方法对催化剂进行表征，结果表明：在Li-TixLa1-xO2系列催化剂中，随x值的不同，可生成LaTi1－yLiyO3-λ、、Li2TiO3、La0．66TiO2．993、La2O3和Li1.33Ti1.66O4几种物相，其中，钙钛矿到三元复合氧化物LaTi1-yLiyO3-λ是甲烷氧化偶联反应的主要活性相，活性位Li＋-O－-Ti3＋的形成是活性提高的主要原因．Li2TiO3和La0．66TiO2.993是深度氧化活性相，而Li1.33Ti1．66O4既无偶联活性，也无深度氧化活性.

［Li（THF）_4］［（t－BuCp）Yb（NPh_2）_3］的合成及晶体结

合成了标题配合物［Ｌｉ（ＴＨＦ）＿４］［ｔ－ＢｕＣｐ）Ｙｂ（ＮＰｈ＿２）＿３］，经元素分析、红外光谱表征，并测定了其晶体结构。配合物属正交晶系，Ｐｂｃａ空间群，晶体学参数ａ＝１．４５１５（５），ｂ＝２．２８３３（５），ｃ＝３．３５５４（６）ｎｍ；Ｖ＝１１．１２０９（５）ｎｍ￣３；Ｄ＿ｃ＝１．３１ｇ·ｃｍ￣＿（－３）；Ｆ（０００）＝４４．２３，Ｚ＝８。最后一致性因子Ｒ＝０．０４７，Ｒ＿ｗ＝０．０４５，平均Ｙｂ－Ｎ键长是０．２２６４（９）ｎｍ。

配合物[Li(DME)_3][(t-BuCp)_2Nd(NPh_2)_2]·(1/2)DME的合成及晶体结构

1990年,Schumann,H.等报道了用双(环戊=烯基)稀土甲基化物与二苯胺进行交换反应制得了[Li(THF)_4][Cp_2Sm(NPh_2)_2],并测定了相应配合物镥的结构。但是,到目前为止,类似的轻稀土配合物尚未报道。这里,我们以双(叔丁基环戊二烯基)氯化钛为前体,与等当量的二苯胺基锂反应,制得了阴离子型配合物[Li(DME)_3][(t—BUCP)_2Nd(NPh_2)_2]·1/2DME,并测定了其单晶结构。

〔Li（DME）_3〕〔（η~5－MeCp）Nd（t－Bu）_3〕的合成及其对

将ＭｅＣｐＮｄＣｌ２·２ＬｉＣ１·ｎＴＨＦ和２摩尔ｔ－ＢｕＬｉ于四氢呋喃和戊烷混合溶剂中反应，合成得到一种新的阴离子型配合物〔Ｌｉ（ＤＭＥ）３〕〔（η５－ＭｅＣｐ）Ｎｄ（ｔ－Ｂｕ）３〕，用元素分析，红外光谱等作了表征，配合物溶于苯乙烯，可单独引发苯乙烯本体聚合，得无规聚苯乙烯。

甲烷氧化偶联Ti－La－Li系氧化物催化剂制备方法的研究

考察了用不同来源Ｌｉ（ＬｉＮＯ３和ＬｉＳＯ４）制备的催化剂催化的甲烷氧化偶联（ＯＣＭ）反应的特点，探讨了以ＬｉＮＯ３为锂源制备的催化剂的高温反应失活机理。ＸＲＤ、ＩＲ、ＸＰＳ和ＢＥＴ等方法的研究结果表明，以ＬｉＮＯ３为锂源制备的催化剂具有反应活性高、空速大的特点，而以Ｌｉ２ＳＯ４为锂源制备的催化剂具有Ｃ２选择性高、活性低、空速小等特点。由ＬｉＮＯ３制得的催化剂的失活原因是：在较高的反应温度下由于表面Ｌｉ的流失，使体相晶格中的Ｌｉ向表相扩散进而导致含Ｌｉ活性相ＬａＴｉ１－ｙＬｉｙＯ３－λ的分解（或部分分解），从而减少了体相和表相中氧空位的数量，导致催化剂的活性降低。设计了ＮＨ：（ＳＯ４）２浸渍法来固定表面锂。

THE VALENCE CHANGE FROM RE3+ TO RE2+ (RE-EQUIVALENT-TO-EU, SM, YB) IN SRB4O7-RE PREPARED IN AIR AND THE SPECTRAL PROPERTIES OF RE2+

A valence change from RE3+ to RE2+ (RE=Eu, Sm, Yb) was observed in samples of SrB4O7: RE prepared by solid state reaction at high temperature in air. The phosphors SrB4O7: RE2+ show efficient luminescence at room temperature. The broad band d-f emissions of Eu2+ and Yb2+ are at 367 and 360 nm respectively. The sharp line f-f emissions of the Sm2+ ion (5D0-F-7(J)) are in the range 680-780 nm. The probable reasons for the valence change of Eu, Sm and Yb in this host are discussed.

INDIGO-CARMINE-MODIFIED POLYPYRROLE FILM ELECTRODE

Functionalized polypyrrole films were prepared electrochemically in the presence of indigo-carmine from aqueous solution. The film shows a couple of reversible redox peaks superimposed on a large background of polypyrrole. The redox reaction is pH dependent. The film has good stability in air and can be cycled between -0.1 and 0.4 V (Ag/AgCl) for several hours without any significant changes in the voltammograms. UV-visible spectra indicate the incorporation of indigo-carmine into the polymer matrix.

Li-Ni-La-O系复合氧化物催化剂上甲烷氧化偶联的研究

考察了Li-Ni-La-O系催化剂的组成、结构及反应条件对甲烷氧化偶联反应活性的影响.在780℃、CH_4:O_2:N_2=2:1:7、空速15000h~(-1)时,C_2烃收率可达25.8％.XRD、IR、XPS及SEM等的结构分析表明,在LiLa_(1-x)Ni_xO_2催化剂中,当0.1≤x≤0.9时,该催化剂由LiNiO_2和LaNi_(1-y)Li_yO_(4-λ)两相组成,x<0.3时出现了LiLaO_2相,La_2Ni_(1-y)Li_yO_(4-λ)是甲烷氧化偶联的主要活性相,活性位Li~+-O~--Ni~(2+)数量的增加是活性提高的主要原因.LiNiO_2和LiLaO_2也有催化活性,它们与La_2Ni_(1-y)Li_yO_4间的协同作用也可能是催化活性增强的原因.

轻稀土配合物[Li·(DME)_3ⅡCH_3C_5H_4Ln(NPh_2)_3l(Ln=La、Pr、Nd)的合成和镧配合物的晶体结构

CH_3C_5H_4LnCl_2·2LiCl·nTHF与2mol的LiNPh_2在THF、已烷和甲苯混合液中反应,经DME萃取,得到[Li·(DME)_3][(η~5-CH_3C_5H_4)Ln(NPh_2)_3](Ln=La,Pr,Nd)。对其进行了元素分析、IR和NMR表征。镧配合物单晶结构测定表明,属单斜晶系,P2_1/a空间群,晶胞参数为α=1.7461(6)nm,b=1.6576(5)nm,c=1.8335(6)nm,β=96.04°,V=5.277um~3,Z=4,D_c=1.26g/cm_3,R=0.057,R_w=0.048。该配合物是一个离子对,La-N和La-C(环)键的平均距离分别为0.2459(8)和 0.2843(11)nm。稀土离子形成一个六配位的扭曲四面体。

甲烷氧化偶联La-Mn-Li系复合氧化物催化剂的研究

用XRD、IR、XPS和SEM等方法研究了混合氧化物LiLa_(1-x)Mn_xO_2的结构和它们对甲烷氧化偶联的催化性能。结果表明,随着MnO_2的变化,可形成一系列复合氧化物,其中三元复合氧化物La_2Mn_(1-y)Li_yO_4是甲烷氧化偶联的活性相,由于Li~+部分取代Mn~(2+)形成Li~+-O~--Mn(2+)缺陷簇,增加了活性氧种的浓度和再生速度是这种氧化物具有较高甲烷偶联活性的主要原因。脉冲实验证明,CH_4脱氢生成CH_3·偶联生成C_2H_6,进一步氧化脱氢生成C_2H_4都可在催化剂表面完成,而CO和CO_2是在气相反应中生成的。在780℃C_2收率可达23.9%。

SYNTHESES OF METHYLCYCLOPENTADIENYL DERIVATIVES OF LANTHANIDES (LN = LA-ND) AND CRYSTAL-STRUCTURES OF [(THF)2LI(MU-CL)2]2[MECPND(THF)] AND [LI(DME)3][MECPLA(NPH2)3]

The reaction of LnCl3.2LiCl with 1 equiv of MeCpNa in THF gives the complexes [(THF)2Li(mu-Cl)2]2[MeCpLn(THF)] (Ln = Nd (1), La (2)) in good yield. These precursors react further with 2 equiv of LiNPh2 to produce the new complexes [Li(DME)3][MeCpLn(NPh2)3] (Ln = La (3), Pr (4), Nd (5)). They have been characterized by elemental analyses and IR and NMR spectra, as well as by structural analyses of 1 and 3. The chloride 1 crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 12.130 (5) angstrom, b = 17.343 (5) angstrom, c = 17.016 (5) angstrom, beta = 108.54 (3)-degrees, V = 3393.87 angstrom3, Z = 4, and D(c) = 1.45 g/cm3. Least-squares refinement led to a final R value of 0.051 (I greater-than-or-equal-to 3-sigma(I(o))) for 2004 independent reflections. Complex 3 crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 18.335 (6) angstrom, b = 16.576 (5) angstrom, c = 17.461 (6) angstrom, beta = 96.04 (3)-degrees, V = 5277.17 angstrom3, D(c) = 1.26 g/cm3, Z = 4, and R = 0.057 (I greater-than-or-equal-to 2.5-sigma(I(o))) for 3378 reflections. The structure of 3 consists of discrete ion pairs [Li(DME)3]+ and [MeCpLa(NPh2)3]- with average La-N and La-C(ring) distances of 2.459 (8) and 2.84 (1) angstrom, respectively.

THE CHARACTERIZATION OF 2 COPPER PHTHALOCYANINE LANGMUIR-BLODGETT-FILMS AND THEIR GAS-SENSITIVE PROPERTIES

The monolayer and deposition behaviour of a symmetrically substituted copper tetra-4-(2, 4-di-t-amylphenoxy) phthalocyanine (tapCuPc) and an asymmetrically substituted copper [tri-4-(2, 4-di-t-amylphenoxy)-mono-4-(-2-methoxyethoxy)]phthalocyanine (AsyCuPc) were investigated. The results on monolayer behaviour and spectroscopic characterization of the LB films show that both CuPc molecules in a monolayer at the air-water interface and the LB films are stacked and inclined. The gas-sensitive properties show that the responding speed of AsyCuPc LB film is faster than that of tapCuPc LB film.

SYNTHESIS AND CRYSTAL-STRUCTURE OF THE TRIS(CYCLOPENTADIENYL)PHENYL COMPLEX OF NEODYMIUM, (LI-BULLET-3DME)[(ETA-5-C5H5)3NDC6H5]

(Li.3DME)[eta(5)-C5H5)3NdC6H5], 1 was synthesized by the reaction of NdCl3.2LiCl, 2 equivalents of cyclopentadienylsodium and one equivalent of phenyllithium in THF at -78-degrees-C, and crystallized from THF and DME. The crystal structure of 1 was determined by X-ray diffraction method at -80-degrees-C. The crystal of 1 is triclinic, space group P1BAR with a = 15.752(6), b = 16.232(3), c = 23.038(7) angstrom, alpha = 108.81(2), beta = 93.31(3), gamma = 108.38(2)-degrees, Z = 6 and D = 1.33 g/cm3. Least-squares refinement (5732 observed reflections) led to a final R of 0.053. The complex consists of disconnected ion pairs of (Li.3DME)+ and [(eta(5)-C5H5)3NdC6H5]-. The neodymium atom was connected to three eta(5)-bonded cyclopentadienyls and one sigma-bonded phenyl in a distorted tetrahedral arrangement with Nd-C(sigma-) 2.593(17), 2.613(13) and 2.601(13) angstrom.

LaF_3-XF(X=Li,K)熔盐的X-射线衍射分析

利用1083K 时的 X-射线衍射数据,导出了 LaF_3-4LiF 和 LaF_3-4KF 系熔盐溶液的径向分布函数;获得了熔盐的离子间距数据,其中 LaF_3-4LiF 熔盐系中 La~(3+)-F~-的相互作用距离为0.238nm,LaF_3-4KF 系中的为0.233nm。还就熔盐离子间距结果讨论了温度与 La~(3+)的库伦力的问题。

[Li(THF)_4][GdCl_4(THF)_2]的晶体结构

氯化钆与对-甲基苯基锂在四氢呋喃中反应得到产物之一为[Li(THF)_4][GdCl_4-(THF)_2],(M_r=738.2),在-70℃下进行X-射线衍射研究。其晶体属单斜晶系,P2/n空间群。晶体学参数为a=13.263(2),b=8.474(1),c=14.961(0);β=99.72(1)°,V=1657.23(?)~3,Z=2,D_c=1.48g/cm~3,F(000)=750,μ_c=24.2cm~(-1),最终偏离子为R=0.0614。研究结果表明,本题晶体是离子型晶体,围绕Gd~(3+)的四个Cl~-离子和两个THF分子的氧原子构成畸变的八面体。Li~+周围的四个THF分子的氧原子构成一个近似的四面体。