双环戊二烯基二(芳氧基)钛、锆、铪衍生物的13C核磁共振谱

第Ⅳ副族金属的双环戊二烯基二卤化物及取代双环戊:二烯基二卤化物的¹³C NMR谱已有一些报道.但关于双环戊二烯基二(芳氧基)钛、锫、铪类型化合物的¹³C NMR谱则尚未见系统报道.我们研究其¹³C NMR谱,目的在于探讨第Ⅳ副族的不同金属以及芳环对位不同取代基对¹³C化学位移的影响.我们发现环戊二烯环的¹³C化学位移随金属周期数的增加而有规律地移向高场.同时,在钛、锆、铪三个系列的化合物中,不论是芳环还是环戊二烯环,其相应碳原子的¹³C化学位移之间存在着非常好的线性关系,相关系数等于或优于0.99.     

金属有机化合物的分析 Ⅲ、双(烷基环戊二烯基)二芳氧基钛、锆、铪的薄层色谱研究

双环戊二烯基钛、锆、铪化合物的研究工作,近年来取得了迅速的进展。我国科学工作者合成了一系列双环戊二烯基二芳氧基钛、锆、铪化合物。目前,这类化合物的催化特性和抗癌作用已引起有关方面的重视,因此,它们的分离分析工作亟需进行。关于双环戊二烯基钛、锆、铪衍生物的薄层色谱工作,仅Howarth 研究了(C_5H_5)_2TiCl_2及C_5H_5TiCl_3二化合物的分离;谢珍珍报导了双环戊二烯基二芳氧基钛、     

桥环二茂钛、锆、铁金属衍生物的研究

本文用β,β'-双环戊二烯基乙醚二钠与TiCl4, ZrCl4, (C5H5)TiCl3和FeCl2在四氢呋喃中反应合成了新型氧桥环戊二烯基钛、锆和铁衍生物。在企图合成硫桥环戊二烯基化合物时, 得到的却是四亚甲基桥联双环戊二烯基金属衍生物。(苯二亚甲基)双环戊二烯基二钠与FeCl2反应合成了对、间(苯二亚甲基)二茂铁。讨论了新化合物的X射线光电子能谱和Mossbauer谱。     

双环戊二烯基钛衍生物的水相化学及双环戊二烯基二水杨酸钛的晶体结构

（ＫＣｎ）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梭基氧原子与钛键联。     

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。     

双(烯基环戊二烯基)IVB族金属衍生物的研究

本文用烯丙基、丁烯-2-基环戊二烯基钠与IVB族金属氯化物反应,合成了新的双(烯丙基环戊二烯基)和双(丁烯-2-基环戊二烯基)二氯化钛、锆、铪.利用卤素交换或与芳基锂、硫氰酸钾、硫化氢反应制得双(烯基环戊二烯基)二卤、二芳基、二硫氰基和二巯基金属衍生物.考察了双(烯丙基环戊二烯基)二卤化钛、锆和铪中烯丙基与卤化氢、卤素的加成反应;与HX的加成反应均按马可尼可夫规则进行,加成反应活性是HI>HBr>HCl. 文中还研究了双(2-溴丙基环戊二烯基)金属衍生物中C—Br的反应活性,它们与硫氰酸钾、五氯苯酚钠和六次甲基四胺反应得到2-硫氰基、2-五氯苯氧基和2-氨基丙基环戊二烯基金属衍生物。     

二羰基二茂钛和酚类的反应: 合成二芳氧基二环戊二烯基钛的新途径

本文介绍在缓和条件下, 二羰基二茂钛和酚类反应是合成二芳氧基二环戊二烯基钛的新途径, 得到的新化合物都经过元素分析和^1HNMR测定。     

双环戊二烯基二氯化钛催化下格氏试剂与偕二卤代烷的反应

近年来,双环戊二烯基二氯化钛在有机合成中的应用得到迅速发展,从而开发了多种新型反应。其中双环成二烯基二氯化钛催化下,Grignard试剂的还原反应是研究得极为广泛的一类新反应。Cp_2Ticl_2/RMgX体系可以还     

双(甲基环戊二烯基)二芳氧基金属衍生物的合成和光谱

在碱存在下,双(甲基环戊二烯基)二氯化钛、锆和铪与取代酚反应合成了一系列双(甲基环戊二烯基)二芳氧基金属衍生物.它们与氢卤酸如HF,HCI,HBr和HI反应,形成相应的金属双(甲基环戊二烯基)二卤化物.讨论了金属电负性、苯环上取代基的电负性以及取代基的数目、位置对双(甲基环戊二烯基)二芳氧基金属衍生物中环戊二烯基环质子化学位移的影响.探讨了这些金属衍生物的红外吸收峰的归属.     

双环[2,2,1]庚-5-烯-2-甲氧,甲酰氧基二茂钛的合成和催化性能

二氯二茂钛可与醇、酚、酸等反应生成相应的烃氧基或酰氧基二茂钛。当钛一氧键中氧的未共用电子与π键发生共轭,或与氧相连的取代基上带有强吸电子基团时,这类化合物较稳定,所以近年来合成了一系列芳氧基和一些卤素取代的酰氧基二茂钛,二氯二茂钛及其衍生物,能引发某些烯类的聚合。     

二茂二芳氧基钛、锆和铪衍生物的薄层色谱分析

用硅胶G作吸附剂,以甲苯-丙酮(30:1)或甲笨-1,4-二氧陆环作展开剂,对32个二茂二芳氧基钛、锆和铪的衍生物进行薄层色谱分离,获得较满意的分离结果。并根据化合物的R_f值及其茂环质子的δ值看它们在薄层色谱中的分离规律。     

Rate constants for hydrogen atom transfer reactions from bis(cyclopentadienyl)titanium(III) chloride-complexed water and methanol to an alkyl radical

Rate constants for hydrogen atom transfer reactions of the water, deuterium oxide, and methanol complexes of bis(cyclopentadienyl)titanium(III) chloride with the secondary alkyl radical 1-cyclobutyldodecyl (2) were determined using indirect kinetic methods. The rate constant for reaction of Cp2Ti(III)Cl-H2O in THF at ambient temperature was 1.0 x 10(5) M(-1) s(-1), and the kinetic isotope effect was kH/kD = 4.4. In benzene containing 0.95 M methanol, the rate constant for reaction of the Cp2Ti(III)Cl-MeOH at ambient temperature was 7.5 x 10(4) M(-1) s(-1). An Arrhenius function for reaction of the Cp2Ti(III)Cl-H2O complex in THF was log k = 9.1 - 5.5/2.3 RT (kcal/mol). The entropic term for reaction of Cp2Ti(III)Cl-H2O was normal, whereas the entropic term previously found for reaction of the Et3B-H2O complex with radical 2 was unusually small (Jin, J.; Newcomb, M. J. Org. Chem. 2007, 72, 5098).     

有机钛化学——Ⅳ.某些新型双和单(烯基环戊二烯基)钛衍生物的合成与催化烯烃异构化

用几种不同路线设计和合成了16个新型的烯基取代环戊二烯及其钛衍生物。取代环戊二烯基钛催化剂在烯烃异构化反应中具有较高的活性和选择性。对反应机理进行了初步的研究。     

Preparation and structures of aryloxy- and alkoxy-Ti(IV) complexes and their evaluation in ethylene oligomerisation and polymerisation

A range of aryloxy and alkoxy ligands, both monodenate and chelating, have been coordinated to Ti(IV) to yield complexes of the form [Ti(OAr)(2)Cl(2)], [Ti(RO^O)Cl(3)] and [Ti(RO^O)(2)Cl(2)] (R = aryl, alkyl). The complexes vary in their Lewis base solvation and/or aggregation state, as revealed by X-ray crystallography of selected examples. The complexes have been evaluated as catalysts for ethylene oligomerisation and polymerisation following activation with alkylaluminium reagents (AlEt(3), methylaluminoxane). While polyethylene is the major product, ethylene oligomers also result, ranging from dimers to higher oligomers. The results indicate a number of different active species are formed upon activation, with oligomers likely arising through a metallacyclic mechanism. The findings are discussed in the context of the commercial Alphabutol dimerisation system [Ti(OR)(4)], and the development of group 4 based ethylene trimerisation catalysts.     

Unexpected cyclopentadienyl/alkoxo ligand exchange in titano- and zirconocene. New opportunities

A simple new route to access heterometallic alkoxo precursors for a wide range of materials is reported. This unique synthetic method comprises elimination of the cyclopentadienyl ring from Cp2MCl2 (M = Ti, Zr) as CpH in the presence of M'(OR)2 (M' = Ca, Mn; OR = OCH2CH2OCH3 or OEt) in an alcohol as a source of protons. In one-pot reactions, we have prepared four different compounds with Ti2Ca4(mu6-O), Cp2Zr2Ca4(mu4-Cl), Zr10Mn10(mu3-O) 14, and Cp3Ti2(mu-OEt)2 motifs. The compounds were characterized by single-crystal X-ray structural analysis and NMR spectroscopy.     

Organic-soluble tri-, tetra-, and pentanuclear titanium(IV) phosphates

Bulky 2,6-disubstituted aryl esters of phosphoric acid, 2,6-dimethylphenyl phosphate (dmppH 2), and 2,6-diisopropylphenyl phosphate (dippH 2) react differently with Cp*TiCl 3 (Cp* = C 5Me 5) under identical reaction conditions. While dippH 2 and Cp*TiCl 3 react in THF at 25 degrees C to yield air-stable trinuclear titanophosphate cage [(Ti 3Cp*Cl(mu 2 -O)(dipp) 2(dippH) 4(THF)].(toluene) ( 1), the similar reaction involving dmppH 2 yields the tetranuclear titanophosphate [Ti 4Cl 2(mu 2 -O) 2(dmpp) 2(dmppH) 6(THF) 2].(toluene) 2 ( 2). Interestingly, the change of titanium source to Ti(O iPr) 4 in the reaction with dippH 2 produces a pentanuclear titanophosphate, [Ti 5(mu 3-O)(O iPr) 6((dipp) 6(THF)] ( 3). Compounds 1- 3 were the only products isolated as single crystals from the respective reaction mixtures in 59, 75, and 54% yield, respectively. The new clusters 1- 3 have been characterized by elemental analysis, IR and NMR ( (1)H and (31)P) spectroscopy, and single crystal X-ray diffraction studies. The structural elucidation reveals that in the reactions leading to 1 and 2, extensive Cp*-Ti bond cleavage occurs, leaving only one residual Cp*-ligand in cluster 1 and none in 2. Closer analysis of the structures of 1- 3 shows common structural features which in turn imply that the formation of all three products could have proceeded via a common Ti-O-Ti dimeric building block.     

Reactions of Cp2MCl2 (M=Ti or Zr) with imine-oxime ligands. Formation of metallacycles

The reactions of bis(cyclopentadienyl)titanium(IV)/zirconium(IV) dichloride with a series of imine-oxime ligands (LH2), derived by condensing benzil-alpha-monoxime and 2-phenylenediamine, 4-phenylenediamine, 4-methyl-2-phenylenediamine, 2,6-diamino-pyridine, have been studied in anhydrous tetrahydrofuran in the presence of base and metallocycles of the [Cp2M(L)] (M=Ti or Zr) type have been isolated. Tentative structures have been proposed for the products based on elemental analysis, electrical conductance and spectral (electronic, IR and (1)H-NMR) data. Proton NMR spectra indicate that on the NMR time scale there is rapid rotation of the cyclopentadienyl ring around the metal-ring axis at 25 degrees C. Studies were conducted to assess the growth inhibiting potential of the complexes synthesized and the ligands against various bacterial strains.     

Latest News: Reactions of Group 4 Bis(trimethylsilyl)acetylene Metallocene Complexes and Applications of the Obtained Products

Recently published reactions of group 4 metallocene bis(trimethylsilyl)acetylene (btmsa) complexes from the last two years are reviewed. Complexes like Cp’₂Ti(η²-Me₃SiC₂SiMe₃) and Cp₂Zr(py)(η²-Me₃SiC₂SiMe₃) with Cp’ as Cp (cyclopentadienyl) and Cp* (pentamethylcyclopentadienyl) have been considered (py=pyridine). These complexes can liberate a reactive low-valent titanium or zirconium center by dissociation of the ligands and act as ‘‘masked’’ M^II complexes (M=Ti, Zr). They represent excellent sources for the clean generation of the reactive coordinatively and electronically unsaturated complex fragments [Cp’₂M]. This is the reason why they were used for many synthetic and catalytic reactions during the last years. As an update to several review articles on this topic, this contribution provides an update with recent examples of preparative organometallic and organic chemistry of these complexes, acting as reagents for a wide range of coordinating and coupling reactions. In addition, applications and investigations concerning reaction products derived from this chemistry are mentioned, too.     

由两相体系(C~6H~6/H~2O)合成一些新的二茂锆二芳氧基配合物的研究

本文首次报道用两相法(C~6H~6/H~2O)合成二茂锆二芳氧基配合物,并与绝对无水条件下的合成结果进行了比较,共合成了五个新的配合物, 同时对二氧二茂锆的环戊二烯基钠合成法加以改进,使产率由66%提高到81%.