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1.
Luis Miguel Menndez Mndez Anthony Deally Donal F. O'Shea Matthias Tacke 《Heteroatom Chemistry》2011,22(2):148-157
From the reaction of 1‐methyl‐1 H‐pyr‐rolo[2,3‐b]pyridine ( 1a ),1‐(methoxymethyl)‐1 H‐pyrrolo[2,3‐b]pyridine ( 1b ), 1‐isopropyl‐1 H‐pyrrolo[2,3‐b]pyridine (1c ), and 1‐(4‐methoxybenzyl)‐1 H‐pyrrolo[2,3‐b]pyridine ( 1d ) under Vilsmeier–Haak conditions, the corresponding aldehydes in position 3 ( 2a–2d ) were synthesized. These aldehydes were transformed in the corresponding fulvenes ( 3a–3d ) by the Knoevenagel condensation and treated with Li[BEt3H] to obtain the corresponding lithiated cyclopentadienide intermediates ( 3′a–3′d ). These intermediates were, finally transmetallated to titanium with TiCl4 to yield the 7‐azaindol‐3‐yl‐substituted titanocenes bis {[(1‐methyl‐1‐H‐pyrrolo[2,3‐b]pyridin‐3‐yl)methyl] cyclopentadienyl} titanium(IV) dichloride ( 4a ), bis{[(1‐methoxymethyl‐1‐H‐pyrrolo[2,3‐b]pyridin‐3‐yl)methyl]cyclopentadienyl} titanium(IV)dichloride ( 4b ), bis{[(1‐Isopropyl‐1‐H‐pyrrolo[2,3‐b]pyridin‐3‐yl)methyl]cyclopentadienyl} titanium(IV) dichloride ( 4c ), and bis{[(4‐methoxybenzyl‐1‐H‐pyrrolo[2,3‐b]pyridin‐3‐yl)methyl]cyclopentadienyl} titanium(IV) dichloride ( 4d ). All the titanocenes had their cytotoxicity investigated through MTT‐based preliminary in vitro testing on the Caki‐1 cell lines to determinate their IC50 values. Titanocenes 4a–4c were found to have IC50 values of 120 ± 10, 83 ± 13, and 54 ± 12, µM respectively, whereas 4d showed no cytotoxic activity. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:148–157, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20668 相似文献
2.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(4):442-451
Metallocene dihalides and derivatives thereof are of great interest as precursors for catalysts in polymerization reactions, as antitumor agents and, due to their increased stability, as suitable starting materials in salt metathesis reactions and the generation of metallocene fragments. We report the synthesis and structural characterization of a series of eleven substituted bis(η5‐cyclopentadienyl)titanium dihalides, namely bis[η5‐1‐(diphenylmethyl)cyclopentadienyl]difluoridotitanium(IV), [Ti(C18H15)2F2], bis{η5‐1‐[bis(4‐methylphenyl)methyl]cyclopentadienyl}difluoridotitanium(IV), [Ti(C20H19)2F2], and bis{η5‐1‐[bis(adamantan‐2‐yl)methyl]cyclopentadienyl}difluoridotitanium(IV), [Ti(C15H19)2F2], together with the bromide and iodide analogues, and the chloride analogues of the diphenylmethyl and adamantyl complexes. These eleven complexes were prepared by the reaction of the corresponding bis(η5:η1‐pentafulvene)titanium complexes with different hydrogen halides (Cl, Br and I). The titanocene fluorides become available via chloride–fluoride exchange reactions. 相似文献
3.
Eleonora Polo Simona Losio Gaetano Zecchi Fabio Bertini Maria Carmela Sacchi 《Macromolecular rapid communications》2004,25(21):1845-1850
Summary: Thanks to the use of a ligand consisting of a saturated ring fused to the cyclopentadienyl moiety, which sensibly increases the stability of titanocenes, it was possible to investigate the oscillating behavior of titanium catalysts in propylene polymerization for the first time. The titanium‐based catalysts yield poly(propylene)s with new and interesting microstructures. Indeed, in spite of the significantly lower isotactic pentad content [mmmm], the average lengths of the isotactic blocks (Niso) are similar or even higher than that obtained with the zirconium‐based homologues. Accordingly, differential scanning calorimetry (DSC) analysis shows melting peaks which are more evident than those obtained with the zirconium homologues. The study of the microstructure of the poly(propylene)s obtained with these catalysts allowed us to participate in the still open discussion on the oscillating mechanism of unbridged metallocenes.
4.
Marina Lamberti Mariacarmela Consolmagno Mina Mazzeo Claudio Pellecchia 《Macromolecular rapid communications》2005,26(23):1866-1871
Summary: A binaphthyl‐bridged salen dichlorozirconium (IV ) complex that displays an octahedral structure with a trans‐O, cis‐N, and cis‐Cl arrangement was synthesized and tested as a precatalyst for ethylene and α‐olefin polymerization. While use of methylaluminoxane (MAO) cocatalyst afforded poor catalytic activity, activation by mixtures of aluminium alkyls such as AliBu3 and either MAO or [CPh3][B(C6F5)4] resulted in reasonable polymerization activities for ethylene, propene, and higher α‐olefins. Quite unexpectedly, while the polymerization of propene results in the production of a high‐molecular‐weight stereoirregular polymer, highly isotactic polymers are obtained under similar conditions from polymerization of 1‐butene, 1‐pentene, and 1‐hexene.
5.
Barrie Rhodes Marvin D. Rausch James C. W. Chien 《Journal of polymer science. Part A, Polymer chemistry》2001,39(2):313-319
Several titanium(IV) complexes of the type Cp′Ti(NMe2)3 [Cp′ = cyclopentadienyl ( 1 ), (dimethylaminoethyl)cyclopentadienyl ( 2 ), indenyl ( 3 ), and pentamethylcyclopentadienyl ( 4 )] were prepared, and their catalytic properties in the polymerization of α‐olefins were examined. Complexes 1 and 2 catalyzed the polymerization of ethylene in the presence of methylaluminoxane with a much higher activity than 3 or 4 . Complexes 3 and 4 polymerized ethylene with an activity similar to that of CpTiCl3 ( 6 ). The preactivation of 2 , 3 , or 4 with trimethylaluminum (TMA) resulted in an increase in ethylene polymerization activities. Also, 1 and 2 were successfully used as ethylene/1‐hexene copolymerization catalysts, producing polymers with various amounts of 1‐hexene incorporation, depending on the amount of 1‐hexene in the feed mixture. Complex 1 likewise effectively polymerized styrene with a higher activity and higher syndiospecificity than the other three catalysts. Complexes 3 and 4 polymerized styrene with low syndiospecificity, whereas 2 produced only atactic polystyrene. The preactivation of 3 or 4 with TMA resulted in an increase in styrene polymerization activities and increased the syndiotacticity percentage of the polymers produced. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 313–319, 2001 相似文献
6.
Ad Cohen Geoffrey W. Coates Moshe Kol 《Journal of polymer science. Part A, Polymer chemistry》2013,51(3):593-600
The activities of C1‐symmetric dibenzyl zirconium complexes of Salan ligands that bear a halo‐substituted phenolate ring and an alkyl‐substituted phenolate ring in propylene polymerization with methylaluminoxane as cocatalyst were studied. These {ONNO′}ZrBn2‐type catalysts exhibited moderate‐to‐high activities and yielded polypropylene of low molecular weight. The degree of tacticity was found to depend on the steric bulk of the substituents on both phenolate rings and ranged from practically atactic to substantially isotactic (74–78% [mmmm] for polymerizations at room temperature by Lig5ZrBn2). Hemi‐isotactic polypropylene was not obtained, despite the diastereotopicity of the two positions. The pattern of stereo errors was consistent with the enantiomorphic site control of propylene insertion typically observed for C2‐symmetric catalysts and implied a facile site‐averaging mechanism. A regular 1,2‐insertion and a β‐H transfer to an incoming monomer correspond to the main propagation and termination processes, respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
7.
Junfeng Zou Chengang Cao Jin‐Yong Dong Youliang Hu Tze‐Chiang Chung 《Macromolecular rapid communications》2004,25(20):1797-1804
Summary: Copolymerization of propylene and 1,4‐divinylbenzene was successfully performed by a MgCl2‐supported TiCl4 catalyst, yielding isotactic poly(propylene) (i‐PP) polymers containing a few pendant styrene groups. With a metalation reaction with butyllithium and a hydrochlorination reaction with dry hydrogen chloride, the pendant styrene groups were quantitatively transformed into benzyllithium and 1‐chloroethylbenzene groups, respectively, which allowed the synthesis of i‐PP‐based graft copolymers by living anionic and atom transfer radical (ATRP) polymerization mechanisms.
8.
Junji Saito Makoto Mitani Shigekazu Matsui Norio Kashiwa Terunori Fujita 《Macromolecular rapid communications》2000,21(18):1333-1336
1‐Hexene polymerization was investigated with bis[N‐(3‐tert‐butylsalicylidene)phenylaminato]titanium(IV) dichloride ( 1 ) using iBu3Al/Ph3CB(C6F5)4 as a cocatalyst. This catalyst system produced poly(1‐hexene) having a high molecular weight (Mw = 445 000–884 000, 0–60°C). 13C NMR spectroscopy revealed that the high molecular weight poly(1‐hexene) possesses an atactic structure with about 50 mol‐% of regioirregular units. 相似文献
9.
Hwa Kyu Kim Seong Kyun Kim Dr. Jun Ha Park Seung Woong Yoon Min Hyung Lee Dr. Youngkyu Do Prof. Dr. 《化学:亚洲杂志》2008,3(11):1912-1921
A series of ortho or meta Lewis base functionalized unbridged zirconocenes, [{1‐(En‐Ph)‐3,4‐Me2C5H2}2ZrCl2] (E=NMe2, OMe; n=1, 2), and a half‐functionalized zirconocene, [{1‐(p‐Me2NC6H4)‐3,4‐Me2C5H2}{1‐(p‐tolyl)‐3,4‐Me2C5H2}ZrCl2], were prepared. The crystal structures of these compounds determined by X‐ray diffraction revealed the presence of only C2‐symmetric rac‐like isomers in the asymmetric units. In combination with methylaluminoxane (MAO) cocatalyst, the meta‐functionalized complexes afforded mixtures of polymers that exhibit multimelting transition temperatures and broad molecular‐weight distributions (MWDs) in propylene polymerization at atmospheric monomer pressure, whereas the ortho‐functionalized complexes did not give rise to polymerization. Stepwise solvent extraction of the polymer mixtures showed that the polymers consist of amorphous, moderately isotactic, and highly isotactic portions, the weight ratio of which is dependent on the reaction temperature. 13C NMR spectral analysis indicated that the [mmmm] methyl pentad value of the isotactic portion reached around 90 %. Among the meta‐functionalized zirconocenes, the di‐OMe‐substituted one afforded the largest amount of the isotactic portion at all temperatures, and the portion comprised 82 wt % of the crude polymer obtained at 25 °C. In contrast, propylene polymerization with the half‐functionalized unbridged zirconocene resulted in the formation of nearly atactic polypropylene with a narrow MWD of around 2. These results corroborate the proposition that the rigid rac‐like cation–anion ion pair of type [rac‐L2ZrP]+[Me‐MAO]? generated in situ, through Lewis acid–base interactions between the functional groups and [Me‐MAO]?, is responsible for the isospecific propylene polymerization with the given class of functionalized unbridged zirconocenes and further indicate that the formation of such ion pairs can be favored by difunctionalization at the meta position of the phenyl ring with OMe groups. 相似文献
10.
Several 6‐substituted‐3‐[(5‐mercepto‐1,3,4‐oxadiazol‐2‐yl)methyl]‐2‐substituted quinazolin‐4(3H)‐one or 6‐substituted‐3‐[4‐(5‐mercepto‐1,3,4‐oxadiazol‐2‐yl)phenyl]‐2‐substituedquinazolin‐4(3H)‐one 2(a‐l) and 6‐substituted‐3‐[(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)methyl]‐2‐substitutedquinazolin‐4(3H)‐one or 6‐substi‐tuted‐3‐[4‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl) phenyl]‐2‐substitutedquinazolin‐4(3H)‐one 3(a‐l) were synthesized using conventional and microwave techniques respectively and were screened for antibacterial and antifungal activity. 相似文献
11.
Athina Hatziyiannakou Cleanthis Froussios 《Journal of polymer science. Part A, Polymer chemistry》2001,39(8):1180-1186
The polymerization of 9‐phenyl‐10,10‐dioxo‐thioxanthen‐9‐yl and 9‐phenyl‐10‐oxo‐9,10‐dihydroanthracen‐9‐yl methacrylates obtained under radical initiation (α,α‐azobisisobutyronitrile) in benzene solution proceeds with high isotactic specificity to afford homopolymers with a triad mm content higher than 95%, having presumably a helical main‐chain structure and showing significant resistance to solvolytic degradation in methanol. 9‐Phenyl‐10,10‐dipropyl‐9,10‐dihydroanthracen‐9‐yl methacrylate similarly affords isotactic polymers with an mm of 98% but is much less durable in contact with methanol. The high isotacticity observed for the aforementioned polymethacrylates as well as for poly(1‐phenyl‐dibenzosuberyl methacrylate), previously reported in the literature, reveal a tendency of ortho‐bridged triarylcarbinols to enforce isotacticity on their methacrylate polymers obtained under radical initiation. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1180–1186, 2001 相似文献
12.
Studies on [PtCl2]‐ or [AuCl]‐Catalyzed Cyclization of 1‐(Indol‐2‐yl)‐2,3‐Allenols: The Effects of Water/Steric Hindrance and 1,2‐Migration Selectivity 下载免费PDF全文
Youai Qiu Prof. Dr. Chunling Fu Prof. Dr. Xue Zhang Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10314-10322
The [PtCl2]‐ or [AuCl]‐catalyzed reaction of 1‐(indol‐2‐yl)‐2,3‐allenols occurred smoothly at room temperature to afford a series of poly‐substituted carbazoles efficiently. Compared with the [PtCl2]‐catalyzed process, the [AuCl]‐catalyzed reaction represents a significant advance in terms of the scope and the selectivity. Selective 1,2‐alkyl or aryl migration of the gold carbene intermediate was observed: compared with the methyl group, the isopropyl, cyclopropyl, cyclobutyl, and cyclohexyl groups migrate exclusively; the cyclopropyl group shifts selectively over the ethyl group; the 1,2‐migration of a non‐methyl linear alkyl is faster than methyl group; the phenyl group migrates exclusively over methyl or ethyl group. DFT calculations show that water makes the elimination of H2O facile requiring a much lower energy and validates the migratory preferences of different alkyl or phenyl groups observed. 相似文献
13.
Xiaowu Wang Wanli Nie Fang Ge Maxim V. Borzov 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):m255-m259
Achiral {2‐[2‐(η5‐cyclopentadienyl)‐2‐methylpropyl]‐1H‐imidazolyl‐κN1}bis(N,N‐diethylamido‐κN)titanium(IV), [Ti(C4H10N)2(C12H14N2)], (I), and closely related racemic (SR)‐{2‐[(η5‐cyclopentadienyl)(phenyl)methyl]‐1H‐imidazolyl‐κN1}bis(N,N‐diethylamido‐κN)titanium(IV), [Ti(C4H10N)2(C15H12N2)], (II), have been prepared by direct reactions of Ti(NEt2)4 and the corresponding 1H‐imidazol‐2‐yl side‐chain functionalized cyclopentadienes. In compound (II), there are two crystallographically independent molecules of very similar geometries connected by a noncrystallographic pseudosymmetry operation akin to a 21 screw axis. All Ti‐ligating N atoms in both (I) and (II) are in planar environments, which is indicative of an additional N→Ti pπ–dπ donation. This fact and the 18ē nature of both (I) and (II) are additionally supported by quantum chemical single‐point density functional theory (DFT) computations. 相似文献
14.
[(LL′)Pd(H2O)](OTf)2 complexes, in which LL′ is a chelate ligand containing the chiral 4‐benzyl‐4,5‐dihydrooxazole moiety and either pyridin‐2‐yl or 2‐(diphenylphosphino)phenyl substituents, catalyze the copolymerization of styrene with carbon monoxide with an isotactic or prevailingly syndiotactic microstructure, respectively. The chiroptical properties of the copolymers and model studies for carbon monoxide and olefin insertion on related Pd complexes suggest that the reason for the different stereochemistry of the copolymers is a site‐selective coordination of the olefin in the intermediates containing the PN ligand; a lower regioselectivity in the coordination and a different coordination site lead to the different diastereoselectivity for the copolymer formation by the complex containing the NN′‐ligand. 相似文献
15.
Junji Saito Mitsuhiko Onda Shigekazu Matsui Makoto Mitani Rieko Furuyama Hidetsugu Tanaka Terunori Fujita 《Macromolecular rapid communications》2002,23(18):1118-1123
The catalytic behavior of three bis(phenoxy‐imine) group‐4 transition‐metal complexes (M = Ti, Zr, Hf), with iBu3Al/Ph3CB(C6F5)4 cocatalyst systems towards propylene polymerization was investigated under atmospheric pressure at 25 °C. The Ti complex produced ultrahigh‐molecular‐weight atactic poly(propylene), whereas Zr and Hf complexes formed high‐molecular‐weight isotactic poly(propylene)s via a site‐control mechanism. The isotactic poly(propylene) obtained with the Hf complex displayed a high melting temperature of 123.8 °C.
16.
Luigi Resconi Isabella Camurati Cristina Fiori Davide Balboni Pierluigi Mercandelli Angelo Sironi 《Helvetica chimica acta》2006,89(8):1497-1523
The acid‐catalyzed reaction between formaldehyde and 1H‐indene, 3‐alkyl‐ and 3‐aryl‐1H‐indenes, and six‐membered‐ring substituted 1H‐indenes, with the 1H‐indene/CH2O ratio of 2 : 1, at temperatures above 60° in hydrocarbon solvents, yields 2,2′‐methylenebis[1H‐indenes] 1 – 8 in 50–100% yield. These 2,2′‐methylenebis[1H‐indenes] are easily deprotonated by 2 equiv. of BuLi or MeLi to yield the corresponding dilithium salts, which are efficiently converted into ansa‐metallocenes of Zr and Hf. The unsubstituted dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[1H‐inden‐1‐yl]}zirconium ([ZrCl2( 1′ )]) is the least soluble in organic solvents. Substitution of the 1H‐indenyl moieties by hydrocarbyl substituents increases the hydrocarbon solubility of the complexes, and the presence of a substituent larger than a Me group at the 1,1′ positions of the ligand imparts a high diastereoselectivity to the metallation step, since only the racemic isomers are obtained. Methylene‐bridged ‘ansa‐zirconocenes’ show a noticeable open arrangement of the bis[1H‐inden‐1‐yl] moiety, as measured by the angle between the planes defined by the two π‐ligands (the ‘bite angle’). In particular, of the ‘zirconocenes’ structurally characterized so far, the dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[4,7‐dimethyl‐1H‐inden‐1‐yl]}zirconium ([ZrCl2( 5′ )] is the most open. The mixture [ZrCl2( 1′ )]/methylalumoxane (MAO) is inactive in the polymerization of both ethylene and propylene, while the metallocenes with substituted indenyl ligands polymerize propylene to atactic polypropylene of a molecular mass that depends on the size of the alkyl or aryl groups at the 1,1′ positions of the ligand. Ethene is polymerized by rac‐dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[1‐methyl‐1H‐inden‐1‐yl]}zirconium ([ZrCl2( 2′ )])/MAO to polyethylene waxes (average degree of polymerization ca. 100), which are terminated almost exclusively by ethenyl end groups. Polyethylene with a high molecular mass could be obtained by increasing the size of the 1‐alkyl substituent. 相似文献
17.
Junji Saito Makoto Mitani Mitsuhiko Onda Jun‐Ichi Mohri Sei‐Ichi Ishii Yasunori Yoshida Takashi Nakano Hidetsugu Tanaka Tomoaki Matsugi Shin‐Ichi Kojoh Norio Kashiwa Terunori Fujita 《Macromolecular rapid communications》2001,22(13):1072-1075
Highly syndiotactic “living” poly(propylene)s were synthesized at 25°C using a bis[N‐(3‐tert‐butylsalicylidene)‐2,3,4,5,6‐pentafluoroanilinato]titanium (IV) dichloride/MAO catalyst system, and microstructures of the polymer were analyzed by means of 13C NMR spectroscopy. The syndiotactic poly(propylene) contains isobutyl, isopentyl and propyl end groups, suggesting that the living polymerization of propylene was initiated via 1,2‐insertion, followed by 2,1‐insertion as the principal mode of polymerization. Pentad distribution analysis revealed that the syndiospecific polymerization proceeds under chain‐end control. 相似文献
18.
Takehiro Kawauchi Minori Ohara Masaru Udo Mariko Kawauchi Tsutomu Takeichi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(8):1677-1682
A vinylphosphonate monomer, dimethyl vinylphosphonate (DMVP), has been polymerized by anionic initiators. Anionic polymerization of DMVP with tert‐butyllithium (t‐BuLi) in combination with a Lewis acid, tributylaluminum (n‐Bu3Al), in toluene proceeded smoothly to give an isotactic‐rich poly(dimethyl vinylphosphonate) (PDMVP) with relatively narrow molecular weight distribution. Although all the PDMVPs were soluble in water, the isotactic‐rich PDMVP was insoluble in acetone and in chloroform which are good solvents for an atactic PDMVP prepared by radical polymerization. The isotactic‐rich PDMVP showed higher thermal property than that of the atactic PDMVP. Moreover, we successfully prepared poly(vinylphosphonic acid) (PVPA) through the hydrolysis of the isotactic‐rich PDMVP, which formed a highly transparent, self‐standing film. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1677–1682, 2010 相似文献
19.
Yan Shi Zhifeng Fu Wantai Yang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(6):2069-2075
The copolymerization of N‐phenyl maleimide and p‐chloromethyl styrene via reversible addition–fragmentation chain transfer (RAFT) process with AIBN as initiator and 2‐(ethoxycarbonyl)prop‐2‐yl dithiobenzoate as RAFT agent produced copolymers with alternating structure, controlled molecular weights, and narrow molecular weight distributions. Using poly(N‐phenyl maleimide‐alt‐p‐chloromethyl styrene) as the macroinitiator for atom transfer radical polymerization of styrene in the presence of CuCl/2,2′‐bipyridine, well‐defined comb‐like polymers with one graft chain for every two monomer units of backbone polymer were obtained. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2069–2075, 2006 相似文献
20.
Eleven novel 5‐methyl‐2‐[(un)substituted phenyl]‐4‐{4,5‐dihydro‐3‐[(un)substituted phenyl]‐5‐(1,2,3,4‐tetrahydroisoquinoline‐2‐yl)pyrazol‐1‐yl}‐oxazole derivatives were synthesized and characterized by elemental analysis, ESI‐MS, 1H NMR and 13C NMR. All of the compounds have been screened for their antiproliferative activities against PC‐3 cell (human prostate cancer) and A431 cell (human epidermoid carcinoma cancer) lines in vitro. The results revealed that compounds 4g , 4j and 4k exhibited the strong inhibitory activities against the PC‐3 cell lines (with IC50 values of 2.8±0.11, 3.1±0.10 and 3.0±0.06 μg/mL, respectively). 相似文献