α-芳硒基羰基化合物的合成

茂钛硒化物分别与α－溴代酮和α－溴代酯反应生产了相应的α－硒酮和α－硒代酯，茂钛硒配合物由Ｃｐ２ＴｉＣｌ２／２ｉ－ＢｕＭｇＢｒ／ＴＨＦ体系还原二芳基二硒醚得到。     

6，6－二苯基富烯在Cp_2TiCl_2－i－prMgBr催化下的加氢反应

６，６－二苯基富烯在Ｃｐ_２ＴｉＣｌ_２－ｉ－ｐｒＭｇＢｒ催化下的加氢反应贺峥杰，陈寿山（南开大学元素有机化学研究所，天津，３０００７１）关键词富烯，催化氢化，异构化在温和条件和氢气氛下，Ｃｐ２ＴｉＣｌ２与ｉ－ｐｒＭｇＢｒ组成的低价态钛催化体系对１，５...     

MgCl_2负载(dbm)_2Ti(OPh)_2催化乙烯聚合

烯烃聚合的新型非茂催化剂由于合成相对简便并具有一些新特点,近年来开始受到人们的关注[1,2].ＩＶＢ族金属的β二酮络合物与烷基铝或烷氧基铝形成的催化体系对烯烃聚合也显现出一定的聚合活性.在一定压力下,β二酮锆/ＭＡＯ均相催化乙烯聚合时具有较高聚合活性[3].β二酮钛催化剂对于丙烯无规聚合和苯乙烯间规聚合均有较好结果[4～6].本文将报道用ＭｇＣｌ2负载的二苯氧基二(二苯甲酰甲烷)钛络合物((ｄｂｍ)2Ｔｉ(ＯＰｈ)2),以甲基铝氧烷(ＭＡＯ)为助催化剂,常压催化乙烯聚合的结果.1　原料ＭｇＣｌ2为抚顺301厂产品.ＭＡＯ(1.4ｍｏｌ/Ｌ甲…     

Cp2TiCl2/i-BuMgBr还原断裂Se—Csp键反应研究

Cp₂TiCl₂/i-BuMgBr体系形成的钛氢化试剂与炔硒醚反应生成端炔与深蓝色钛硒化物, 后者在空气中被氧化为二醚, 与酰氯反应, 高产率地形成对应的硒代酯.     

二茂钛苄氧基衍生物的合成及性质研究

Ｃｐ２ＴｉＣｌ２及（ＭｅＣｐ）２ＴｉＣｌ２在Ｅｔ３Ｎ或ＮａＮＨ２存在下与苄醇类化合物反应，高产率地合成了６个未见文献报道的二茂钛（Ⅳ）苄氧基衍生物，甲基二茂钛（Ⅳ）苄氧基化合物，经元素分析，ＨＮＭＲ和ＩＲ光谱确定了化合物的结构，并对其部分性质进行了讨论。     

双环戊二烯基钛衍生物的水相化学及双环戊二烯基二水扬酸钛的晶体结构

（ＲＣｐ）２ＴｉＣｌ２的乙酰丙酮体系在水相中与硫氰酸钾，吡咯烷基二硫代氨基甲酸钠，取代苯甲酸钠等反应，合成得到相应的（单）双环戊二烯基（或甲基环戊二烯基）钛衍生物，双环戊二烯基二水杨酸钛单晶的结构分析表明，水杨酸作为单齿配体通过羧基氧原子与钛键联。     

二碘化钐促进的硒代酯的合成

用SmI2/THF/HMPA体系在室温下使二芳基二硒醚中的Se-Se键还原断裂成硒负离子物种, 继而与酸酐作用得到硒代酯, 该反应条件温和中性, 产率良好, 提供了合成硒代酯的一个新途径。     

简便合成二酰基二硒醚

芳基硒代酰胺与酰氯以1∶1的摩尔比在氯仿溶液中作用, 可以较高的产率得到二酰基二硒醚, 而芳基硒代酰胺与酰氯以1∶2的摩尔比反应时则生成二酰基硒醚. 提出了反应可能的机理.     

Cp2TiCl2/n-BuLi催化体系在烯烃加氢反应中的催化活性和稳定性

研究了Ｃｐ２ＴｉＣｌ２／ｎ－ＢｕＬｉ催化体系和构成和Ｔｉ浓度与其催化烯烃加氢反应活性和稳定性的关系。考察了不同结构的烯烃，反应温度和度物浓度对该体系催化性能的影响。结果表明，在高的ｎ（Ｌｉ）／ｎ（Ｔｉ）值和低催化剂浓度时，可得到很高的催化活性。     

三溴化金催化端炔与二芳基二硒醚反应合成炔基硒醚

炔基硒醚是合成一些有机硒化合物的重要起始物。本文研究发现,在三溴化金(Au Br3)催化下,端位炔和二芳基二硒醚在弱碱(如碳酸钾)存在下反应,生成炔基芳基硒醚,产率为69%~98%;在空气参与下,于80℃下进行反应,反应条件简单,且二硒醚的两个硒原子均可以被利用。二甲基亚砜(DMSO)是合适的溶剂,在极性较小的溶剂(如甲苯、四氢呋喃)中,此反应不能进行。芳基炔(如苯乙炔、对甲基苯乙炔、对氯苯乙炔等)、烯基炔(如环己烯乙炔)和烷基炔(如1-壬炔)均能顺利进行此反应。当芳基炔苯环的间位或邻位连有取代基时,反应产率较低(69%~82%),而对位无论是连有吸电子基还是给电子基,该反应均可以得到很高的产率(95%)。     

Theoretical study on the reaction mechanisms of ethylene with Cp2TiR, Cp2Ti(Cl)R, and Cp2Ti(Cl:AlH2Cl)R (R=H and CH3)

The potential energy surfaces for reactions of ethylene with Cp₂Ti⁺R, Cp₂Ti(Cl)R, and Cp₂Ti(Cl:AlH₂Cl)R (R=H and CH₃) were calculated by ab initio molecular orbital methods. These six reaction mechanisms were compared. Of the two possible reaction paths, attack of ethylene at Ti and the Cl and R ligands (path IN) and that from the opposite side of the Cl ligand (path OUT), the former is found to be more favorable, with a very low activation energy for reaction of ethylene with Cp₂Ti(Cl)H. For reaction of ethylene with Cp₂Ti(Cl)CH₃, the insertion transition states on both paths have almost the same energy barrier height above the reactants. For reaction of ethylene with Cp₂Ti(Cl:AlH₂Cl)R, the bond alternation between Ti–Cl and Cl–Al plays an important role in the mechanisms.     

Polymerization of ethylene with (C5Me5)2Zr(NMe2)2 cocatalyzed by common alkyl aluminums

Polymerizations of ethylene have been carried out by using Cp₂^*Zr(NMe₂)₂ (Cp^*=C₅Me₅) compound combined with common alkyl aluminums (AlR₃) and methylaluminoxane (MAO) as cocatalysts. The AlMe₃ cocatalyzed system showed no activity due to the formation of stable but inactive heterodinuclear [Cp₂^*2Zr(μ-Me)₂AlMe₂]⁺ cations; however, the bulkier AlR₃ [AlEt₃, Al(i-Bu)₃ and Al(i-Bu)₂H] cocatalyzed systems showed very high activities. Especially, Cp₂^*Zr(NMe₂)₂/Al(i-Bu)₃ catalyst showed higher catalytic activity and produced higher molecular weight (MW) polymer than Cp₂^*Zr(NMe₂)₂/MAO catalyst, demonstrating both MAO and bulky AlR₃ are effective cocatalysts for Cp₂^*Zr(NMe₂)₂ compound.     

Monomeric, dimeric and polymeric [Cp2MoH2] complexes with Ag---S bonds

The reaction of [Cp₂MoH₂] and AgBF₄ with the dithio ligands Na(S₂CPh) and K(S₂COⁱPr) afforded the complexes [(Cp₂MoH₂AgS₂CPh)₂] (1) and [(Cp₂MoH₂AgS₂COⁱPr)₂] (2). Using the monothio ligands Na(SC(O)Ph), K(SC(O)CH₃) and Na(S(NHPh)C=C(CN)₂) the complexes [(Cp₂MoH₂AgSC(O)Ph)₂] (3), [((Cp₂MoH₂)₂(AgSC(O)CH₃)₃)_n] (4) and [(Cp₂MoH₂)₂AgS(NHPh)C=C(CN)₂] (6) were formed. The reaction of thiobenzamide and [(Cp₂MoH₂)₂AgCl] gave the complex [(Cp₂MoH₂Ag(Cl)S(NH₂)CPh)₂] (5). Complexes 1 and 2 have a dimeric structure with the two dithio ligands bridging the two silver atoms. Complex 3 is also a dimer, however, the monothio ligands are coordinated with their single sulphur atoms to the silver atoms. In the polymer 4 the thioacetate ligand has the same bonding mode as in 3. The three-dimensional structure of 4 is built-up of parallel strings. In the dimer 5 the thiobenzamide ligands bind with the sulphur atom to a silver atom each. Complex 6 has a monomeric structure in which the silver atom is coordinated to two [Cp₂MoH₂] ligands and to the sulphur atom of the S(NHPh)C=C(CN)₂ ligand. Compounds 1–6 were characterised analytically and spectroscopically and the structures were determined by single crystal X-ray analyses.     

Synthesis and characterisation of [(C5Me4R)2NbS2]2M complexes (M = Fe, Co; R = Me, Et) : organometallic tetrathiometalates with niobocene ligands

Irradiation of Cp₂^* Nb(η²---S₂)H (Cp^* = C₅Me₅) 1a in the presence of Fe(CO)₅ gives the CO-free complex [Cp₂^*NbS₂]₂Fe 2a. The core of 2a contains an FeS₄ tetrahedron which is ligated by two niobocene ligands as shown by X-ray diffraction analysis. In the reaction of 1a or Cp₂^xNb(η²---S₂)H (CP^x = C₅Me₄Et) 1b with Co₂(CO)₈, compounds 3a and 3b of the same type are formed. Electrochemical studies of 2a and 3a,b show that they undergo three reversible 1e⁻ steps. The oxidation of 3b exerts a considerable influence on its absorption spectrum. A qualitative EHMO analysis is in agreement with a strong delocalisation of electron density over the whole NbS₂MS₂Nb system.     

Das Reaktionsverhalten von Cp2NbCl2 gegenüber WF6—Struktur von [Cp2NbCl2]4[WF6]2[WCl6]

The oxidation of Cp₂NbCl₂ with pure WF₆ in SO₂ solution yielded the cationic metallocene species [Cp₂NbCl₂]⁺[WF₆]⁻ essentially in quantitative yield. The same reaction carried out in the presence of either equimolar amounts or a two-fold excess of HCN led to the preparation of the new niobocenium salt [Cp₂NbCl₂]₄⁺[WF₆]²⁻ which was studied by single crystal X-ray diffraction. This compound represents the first example of a structurally characterized metallocene-WF₆⁻ complex, and crystallizes in the tetragonal system: space group, P4₁2₁2(No. 92), a = 11.083(8) Å, c = 48.285 (9) Å; Z = 8; R = 0.0759, R_W = 0.0841. ab]Die Oxidation von Cp₂NbCl₂ mit reinem WF₆ führt in SO₂-Lösung zur Synthese von [Cp₂NbCl₂ ]⁺[WF₆]⁻ in nahezu quantitativer Ausbeute. Die analoge Reaktion führt unter Anwesenheit der äquimolaren Menge oder eines zweifachen Überschusses an HCN zur Ausbildung des Niobocenium-Komplexsalzes [Cp₂NbCl₂]₄⁺ [WF₆]₂⁻[WCl₆]²⁻, von dem eine Röntgenstrukturanalyse angefertigt wurde. Diese Verbindung repräsentiert den ersten structurell charakterisierten Vertreter eines Metallocen-WF₆⁻-Komplexes und kristallisiert im tetragonalen System: Raumgruppe P4₁2₁2 (Nr. 92), a = 11.083(8) Å, c = 48.285(9) Å; Z = 8; R = 0.0759, R_W = 0.0841. kw]Niobium; X-ray diffraction; Oxidation; Metallocenes     

Hydrozirconierung von nitrilen: Die bildung ein- und zweikerniger (alkylidenamido)zirconocen-komplexe

Cp₂Zr(-N=CHR)Cl compounds (9a–9c: R = CH₃, C₆H₅, CH₂Ph,respectively) are formed upon hydrozirconation of nitriles. Subsequent reaction with an aryllithium reagent yields Cp₂Zr(-N=CHR)Ar (14). The (alkylidene amido)zirconocene complexes are characterized by a linear heteroallene-type structure possessing an sp-hybridized nitrogen atom. 9 reacts with the oligomeric metallocene dihydrides (Cp₂ZrH₂)_x (15) and (Cp₂HfH₂)_c, (17), respectively, to form the binuclear compounds Cp₂Zr(μ-N=CHR)(μ-Cl)MC_p2 (16, M = Zr) and (18, M = Hf). The formation of these thermally very stable metal complexes is discussed.     

Triphosphane formation from the terminal zirconium phosphinidene complex [Cp2Zr=PDmp(PMe3)] (Dmp=2,6-Mes2C6H3) and crystal structure of DmpP(PPh2)2

The new terminal phosphinidene complex [Cp₂Zr=PDmp(PMe₃)] (Dmp=2,6-Mes₂C₆H₃; 1) was prepared in 81% yield by the reaction of [Li(Et₂O)][P(H)Dmp] with [Cp₂Zr(Me)Cl] in the presence of excess PMe₃. Compound 1 reacts with Ph₂PCl to produce selectively the sterically congested triphosphane DmpP(PPh₂)₂ (2) and [Cp₂ZrCl₂] in high yields. The structure of 2 obtained by X-ray diffraction analysis of a single crystal reveals phosphorus–phosphorus bond lengths of 2.251(2) and 2.234(2) Å and a PPP bond angle of 105.46(6)°.     

Acetylen-Komplexe von Di(η-cyclopentadienyl)molybdän: Synthesen und Protonierung. Struktur von [Cp2MoH{η-C2(SiMe3)2}]PF6

Cp₂MoH₂ reacts with methyl acrylate in the presence of acetylenes (L = C₂H₂, C₂Me₂, HCC^tBu, HCCSiMe₃, C₂(SiMe₃)₂, HCCCH₂OMe, HCCCH₂NMe₂) to form acetylene complexes Cp₂Mo(L) 5. Protonation takes place with CF₃CO₂H at −80°C to give short-lived cations [Cp₂MoH(L)⁺ (8) (L = C₂Me₂, HCCSiMe₃, C₂(SiMe₃)₂). The structure of [Cp₂MoH{η²-C₂(SiMe₃)₂}]PF₆(9) was determined by an X-ray diffraction study.     

The electrochemical reduction of CP2TiCl2 in the presence of trimethylphosphine

The electrochemistry of the complexes Cp₂TiCl_x(PMe₃)_2-x in anhydrous THF has been studied. The most stable complexes at the three oxidation states of titanium are Cp₂TiCl₂, Cp₂TiCl(PMe₃) and Cp₂Ti(PMe₃)₂, and each of these species is readily formed by electrolysis. It has also been demonstrated that oxidation/reduction of these species is followed by facile and rapid ligand exchange to form the preferred species in the new oxidation state provided a stoichiometric concentration of the required ligand is present. The consequences of this redox and ligand exchange chemistry for the synthetic reactions catalyzed by lower oxidation states of Ti are discussed. Finally, the voltammetry of a titanocycle is reported, and it is shown that the corresponding Ti^III metallocycle is stable.     

The crystal structure of a phenyliminomethyldicyclopentadienyltitanium(III) complex, Cp2Ti-η-C6H5CN-2,6-(CH3)2C6H3

The crystal structure of Cp₂TiC₆H₅CN-2,6-(CH₃)₂C₆H₃ is reported. The iminoacyl ligand is η²-coordinated at the metal (Ti---C 2.096(4), Ti---N 2.149(4) Å). The cyclopentadienyl ligands show the normal bent Cp₂Ti structure.