Synthesis and characterization of a new double-cubane Mo-Fe-S cluster compound, [NEt(4)](3)[Mo2Fe6S8(mu-OMe)(3)(SPh)(3)Cl-3]

The new double-cubane cluster compound [NEt(4)](3)[Mo2Fe6S8(mu-OMe)(3)(SPh)(3)Cl-3] is synthesized from (NH4)(2)MoS4, FeCl3, Fe powder, S powder, NaSPh and NEt(4)Br in MeOH-DMF, its crystal structure is determined by X-ray crystallography, and results of XPS indicate a valence state of +4 for Mo.

多组分氧化物Ag－Bi－V－Mo－O催化作用的光电子能谱研究

多组分氧化物Ａｇ－Ｂｉ－Ｖ－Ｍｏ－Ｏ催化作用的光电子能谱研究宋伟，李静，窦伯生（中国科学院长春应用化学研究所长春１３００２２）关键词　钼钒酸铋，助剂Ａｇ，ＸＰＳ，Ａｒ~＋刻蚀，氧化还原对于烃类选择氧化反应中复合氧化物的催化作用，普遍认为是Ｒｅｄｏｘ机...

丙烷氧化反应中多组分氧化物Bi－V－Mo－O催化作用的红外光谱研究

丙烷氧化反应中多组分氧化物Ｂｉ－Ｖ－Ｍｏ－Ｏ催化作用的红外光谱研究李静，宋伟，窦伯生（中国科学院长春应用化学研究所长春１３００２２）关键词钼钒酸铋，丙烷，选择氧化，催化作用机理，红外光谱迄今对于含有钼、铋复合氧化物催化剂的活性中心和作用机理存在不同看...

SEMICONDUCTOR TO METAL TRANSITION IN LN(2)MO(3)O(9) COMPOUNDS

Ln(2)Mo(3)O(12) and Ce2Mo3O12.25 are reduced by hydrogen yielding Mo4+ oxides of the formula Ln(2)Mo(3)O(9) (Ln = La, Ce, Pr, Nd, Sm, Gd and Dy). The new compound Ce2Mo3O9 has the same structure as other Ln(2)Mo(3)O(9) compounds. All of the products are single phase materials and crystallize in a tetragonal scheelite type structure with Mo2O6 clusters. The IR spectra of the Ln(2)Mo(3)O(9) oxides show two absorption bands. These compounds are black n-type semiconductors, and exhibit Curie-Weiss Law behavior from 100K to 250K. Temperature dependence of the electrical properties of these compounds were measured for the first time, and a semiconductor-metal transition was found at about 250 degrees C.

异核双金属离子对配合物［Mo（dtc）_4］·［Nd（dtc）_4］的合成、结

合成了一种新型异核双金属离子对配合物［Ｍｏ（ｄｔｃ）＿４］·［Ｎｄ（ｄｔｃ）＿４］，并通过Ｘ－射线衍射法和元素分析确定了其晶体结构和分子结构，在此基础上，经红外光潜分析确定了该配合物的谱学性质。

STRUCTURE AND CATALYTIC ACTIVITY FOR PROPYLENE OXIDATION OF BI-MO-NB COMPLEX OXIDE CATALYSTS

The structure and catalytic,activity for propylene oxidation of series oxides B2Mo3-3X-Nb2XO12-4X (X=0.00, 0.02, 0.05, 0.10, 0.15, 0.20, 0.25) have been studied by means of XRD, IR, Raman, SEM, ESR and so on. The results showed that in the range of X < 0.

Bi－Mo－Nb复合氧化物催化作用机理的ESR和XPS研究

用ＥＳＲ对比研究了掺杂Ｎｂ对α－Ｂｉ２Ｍｏ３Ｏ（１２）催化剂丙烯还原和氧再氧化的影响，并用ＸＰＳ原位Ａｒ＋溅射研究了催化剂的还原与再氧化过程，观察了上述过程中催化剂内金属离子的价态变化和晶格氧的扩散现象。提出了Ｂｉ－Ｍｏ间通过晶格氧扩散所发生的氧化还原作用及模型，探讨了Ｎｂ（５＋）取代Ｍｏ（６＋）产生的氧空位对加速晶格氧扩散所起的作用。

Bi-Mo-Nb复台氧化物的结构与对丙烯氧化的催化活性

本文用XRD,IR,Raman,SEM和ESR等方法研究了系列氧化物Bi_2Mo_(3-3x)Nb_(2x)O_(12-4x)(X=0.00,0.02,0.05,0.10,0.15,0.20,0.25)的结构和对丙烯氧化的催化活性,结果表明,在X≤0.25范围内,催化剂基本保持典型的α-Bi_2Mo_3O_(12)结构,少量Nb~(5+)的掺杂,可取代晶格中的Mo~(6+),产生氧空位,无序分布的氧空位的浓度先随X值的增加而增加,当X=0.15时达最大值,催化剂对丙烯氧化的催化活性与这种氧空位的浓度成正比,反应遵循Redox机理.

THE CLEAVAGE REACTION OF THE MO-MO TRIPLE BOND - THE CRYSTAL-STRUCTURES OF MOLYBDENUM COMPLEXES [CPMO(CO)(2)(C(5)H(4)NS)], [CPMO(CO)(2)(C(9)H(6)NS)]O=PPH(3) AND [CPMO(CO)(2)(S(2)CNME(2)]

The reactions of [Cp2Mo2(CO)4] (1) with 2,2'-dipyridyl disulphide (C5H4NS-)2, 8,8'-diquinolyl disulphide (C9H6NS-)2 and tetramethyl thiuram disulphide (Me2NC(S)S-)2 in toluene solution resulted in the cleavage of the Mo-Mo triple bond to yield molybdenum complexes [CpMo(CO)2(C5H4NS)] (2), [CpMo(CO)2(C9H6NS)] (3) and [CpMo(CO)2(S2CNMe2)] (4), respectively. The molecular structures of 2, 3 . O=PPh3 and 4 were determined by X-ray diffraction studies. Crystals of 2 are monoclinic, space group P2(1)/n, with Z = 4, in a unit cell of dimensions a = 6.448(1), b = 12.616(2), c = 14.772(2) angstrom, beta = 92.85(1)-degrees. The structure was refined to R = 0.028 and R(w) = 0.039 for 1357 observed reflections. Crystals of 3 . O=PPh3 are triclinic, space group P1BAR, with Z = 2, in a unit cell of dimensions a = 11.351(3), b = 13.409(3), c = 9.895(2) angstrom, alpha = 94.59(2), beta = 90.35(2), gamma = 78.07(2)-degrees. The structure was refined to R = 0.033 and R(w) = 0.037 for 3260 observed reflections. Crystals of 4 are monoclinic, space group P2(1)/a and Z = 4 with a = 12.468(5), b = 7.637(2), c = 13.135(4) angstrom, beta = 96.62(3). The structure was refined to R = 0.032 and R(w) = 0.042 for 1698 observed reflections. Each of complexes 2-4 contains a cyclopentadienyl ligand, a cis pair of carbonyls and a chelate ligand (S,N donor or S,S donor). All the compounds have distorted square-pyramid structures.

STUDIES ON DEFECT STRUCTURE AND CATALYTIC PROPERTIES OF SN-MO OXIDES

The present work is devoted to the studies on relationship of structure and activity of Sn-Mo oxides by using XRD, ESR, IR, XPS, TEM and SEM. Eight samples with Mo/(Mo + Sn) rations: 0.0, 0.1, 0.2, 0.4, 0.6, 0.8, 0.9, 1.0 were prepared. On the basis of structure characterization, Sn-Mo oxides can be divided into three groups: Catalysts I with Mo/(Mo + So) less-than-or-equal-to 0.2, Catalysts II with 0.2 < Mo/(Mo + Sn) < 0.8, and catalysts III with Mo/(Mo + Sn) greater-than-or-equal-to 0.8. The solid solution of Mo5+ in tin oxide was formed and the cation vacancy was formed in catalysts I. The solid solution of Sn4+ in molybdenum oxide was formed in catalysts III. The lattice oxygen in catalysts III has higher mobility and reactivity than that in catalysts I. The catalysts III showed higher activity but lower selectivity than that of catalysts I.

用ESR方法研究Sn-Mo氧化物固溶体形成的机理

本文研究了Sn-Mo混合氧化物催化剂的活性与焙烧温度的关系。对Sn_(0.975)Mo_(0.025)催化剂进行了不同焙烧温度的ESR研究,跟踪观察了Sn-Mo混合氧化物固溶体随焙烧温度变化的形成过程。结果表明,焙烧温度在100—300℃之间,钼以钼酸铵微晶高度分散在氧化锡表面;300—550℃时,随温度升高钼逐渐向氧化锡体相扩散;550℃时可能形成嵌入型固溶体,催化活性最好;600℃开始形成置换型固溶体,Mo以Mo~(5+)形式取代氧化锡晶格中的Sn~(4+),此时ESR信号gzz>gxx>gyy。

水煤气变换催化剂Co-Mo-K/Al_2O_3的酸性对活性的影响

用吡啶吸附法研究了Co-Mo-K/Al_2O_3催化剂的酸性,K的加入,由于改变了催化剂的酸性,使其活性得以提高,硫的丢失也可改变酸性,但使催化剂的活性降低。初步探讨了催化剂酸性对活性影响的实质,提出了新的反应机理。

K助化Co-Mo/Al_2O_3催化剂的表征

以XRD,XPS和TPR研究了一系列K助化的Co-Mo/Al_2O_3催化剂,考察了K对Co和Mo在载体上分散的影响。实验表明,K的加入分解了原来存在於催化剂中的CoMoO_4,促进了Mo的硫化还原,是提高水煤气变换反应的一个因素。

Sb-Mo复合氧化物单一相催化剂上的醇类氧化酯化

制备了三种单一相Sb-Mo-O系复合氧化物催化剂并用于C_1—C_4的醇类氧化反应,在反应条件下均可保持其晶体结构与酯化活性的稳定性。对氧化酯化来说,唯有以乙醇为原料时才可以高收率地获得酯类,其活性顺序为Y相>X相>Z相。异丙醇和异丁醇在同一催化剂上的反应结果,因反应温度高低而异,低温时发生脱氢反应,高温时发生脱水反应。利用体相晶格氧,乙醇氧化生成乙醛;而进一步氧化酯化生成乙酸乙酯则是利用气相氧。