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1.
A series of new α‐diimine nickel(II) catalysts bearing bulky chiral sec‐phenethyl groups have been synthesized and characterized. The molecular structure of representative chiral ligand, bis[N,N′‐(4‐methyl‐2,6‐di‐sec‐phenethylphenyl)imino]‐1,2‐dimethylethane rac‐1c and chiral complexes, {bis[N,N′‐(4‐methyl‐2‐sec‐phenethylphenyl)imino]‐2,3‐butadiene}dibromidonickel rac‐2a and bis{bis[N,N′‐(4‐methyl‐2‐sec‐phenethylphenyl)imino]‐2,3‐butadiene}dibromidonickel rac‐2b, were confirmed by X‐ray crystallographic analysis. Complex rac‐2c bearing two chiral sec‐phenethyl groups in the ortho‐aryl position and a methyl group in the para‐aryl position, activated by diethylaluminum chloride (DEAC), showed highly catalytic activity for the polymerization of ethylene [4.12 × 106 g PE (mol Ni.h.bar)?1], and produced highly branched polyethylenes under low ethylene pressure (branching degree: 104, 118 and 126 branches/1000 C at 20, 40 and 60°C, respectively). Chiral 20‐electron bis‐α‐diimine Ni(II) complex rac‐2b also exhibited high activity toward ethylene polymerization [1.71 × 106 g PE (mol Ni · h · bar)?1]. The type and amount of branches of the polyethylenes obtained were determined by 1H and 13C NMR. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
Synthesis of highly branched polyethylene using para‐phenyl‐substituted α‐diimine nickel catalysts
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A series of para‐phenyl‐substituted α‐diimine nickel complexes, [(2,6‐R2‐4‐PhC6H2N═C(Me))2]NiBr2 (R = iPr ( 1 ); R = Et ( 2 ); R = Me ( 3 ); R = H ( 4 )), were synthesized and characterized. These complexes with systematically varied ligand sterics were used as precatalysts for ethylene polymerization in combination with methylaluminoxane. The results indicated the possibility of catalytic activity, molecular weight and polymer microstructure control through catalyst structures and polymerization temperature. Interestingly, it is possible to tune the catalytic activities ((0.30–2.56) × 106 g (mol Ni·h)?1), polymer molecular weights (Mn = (2.1–28.6) × 104 g mol?1) and branching densities (71–143/1000 C) over a very wide range. The polyethylene branching densities decreased with increasing bulkiness of ligand and decreasing polymerization temperature. Specifically, methyl‐substituted complex 3 showed high activities and produced highly branched amorphous polyethylene (up to 143 branches per 1000 C). 相似文献
3.
Dr. Keith Izod Dr. Ewan R. Clark Pamela Foster Rebecca J. Percival Ian M. Riddlestone Prof. William Clegg Dr. Ross W. Harrington 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6094-6107
Treatment of the thioether‐substituted secondary phosphanes R2PH(C6H4‐2‐SR1) [R2=(Me3Si)2CH, R1=Me ( 1PH ), iPr ( 2PH ), Ph ( 3PH ); R2=tBu, R1=Me ( 4PH ); R2=Ph, R1=Me ( 5PH )] with nBuLi yields the corresponding lithium phosphanides, which were isolated as their THF ( 1 – 5Pa ) and tmeda ( 1 – 5Pb ) adducts. Solid‐state structures were obtained for the adducts [R2P(C6H4‐2‐SR1)]Li(L)n [R2=(Me3Si)2CH, R1=nPr, (L)n=tmeda ( 2Pb ); R2=(Me3Si)2CH, R1=Ph, (L)n=tmeda ( 3Pb ); R2=Ph, R1=Me, (L)n=(THF)1.33 ( 5Pa ); R2=Ph, R1=Me, (L)n=([12]crown‐4)2 ( 5Pc )]. Treatment of 1PH with either PhCH2Na or PhCH2K yields the heavier alkali metal complexes [{(Me3Si)2CH}P(C6H4‐2‐SMe)]M(THF)n [M=Na ( 1Pd ), K ( 1Pe )]. With the exception of 2Pa and 2Pb , photolysis of these complexes with white light proceeds rapidly to give the thiolate species [R2P(R1)(C6H4‐2‐S)]M(L)n [M=Li, L=THF ( 1Sa , 3Sa – 5Sa ); M=Li, L=tmeda ( 1Sb , 3Sb – 5Sb ); M=Na, L=THF ( 1Sd ); M=K, L=THF ( 1Se )] as the sole products. The compounds 3Sa and 4Sa may be desolvated to give the cyclic oligomers [[{(Me3Si)2CH}P(Ph)(C6H4‐2‐S)]Li]6 (( 3S )6) and [[tBuP(Me)(C6H4‐2‐S)]Li]8 (( 4S )8), respectively. A mechanistic study reveals that the phosphanide–thiolate rearrangement proceeds by intramolecular nucleophilic attack of the phosphanide center at the carbon atom of the substituent at sulfur. For 2Pa / 2Pb , competing intramolecular β‐deprotonation of the n‐propyl substituent results in the elimination of propene and the formation of the phosphanide–thiolate dianion [{(Me3Si)2CH}P(C6H4‐2‐S)]2?. 相似文献
4.
Haijun Hao Chunming Cui Guangcai Bai Herbert W. Roesky Mathias Noltemeyer Hans‐Georg Schmidt Yuqiang Ding 《无机化学与普通化学杂志》2000,626(7):1660-1664
The reaction of [(ArN)2MoCl2] · DME (Ar = 2,6‐i‐Pr2C6H3) ( 1 ) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN)2MoCl{N(R1)C(R2)N(R1)}] (R1 = Cy (cyclohexyl), R2 = Me ( 2 ); R1 = Cy, R2 = N(i‐Pr)2 ( 3 ); R1 = Cy, R2 = N(SiMe3)2 ( 4 ); R1 = SiMe3, R2 = C6H5 ( 5 )) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN)2MoMe{N(R1)C(R2)N(R1)}] (R1 = Cy, R2 = Me ( 6 ); R1 = Cy, R2 = N(i‐Pr)2 ( 7 )). The analogous reaction of 1 with bulky [N(SiMe3)C(C6H5)C(SiMe3)2]Li · THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2] ( 8 ) in low yield. The molecular structures of 7 and 8 are established by the X‐ray single crystal structural analysis. 相似文献
5.
Hongzhi Du Dr. Aldrik H. Velders Dr. Pieter J. Dijkstra Dr. Jingru Sun Dr. Zhiyuan Zhong Prof. Dr. Xuesi Chen Prof. Dr. Jan Feijen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9836-9845
Synthetic routes to aluminium ethyl complexes supported by chiral tetradentate phenoxyamine (salan‐type) ligands [Al(OC6H2(R‐6‐R‐4)CH2)2{CH3N(C6H10)NCH3}‐C2H5] ( 4 , 7 : R=H; 5 , 8 : R=Cl; 6 , 9 : R=CH3) are reported. Enantiomerically pure salan ligands 1–3 with (R,R) configurations at their cyclohexane rings afforded the complexes 4 , 5 , and 6 as mixtures of two diastereoisomers ( a and b ). Each diastereoisomer a was, as determined by X‐ray analysis, monomeric with a five‐coordinated aluminium central core in the solid state, adopting a cis‐(O,O) and cis‐(Me,Me) ligand geometry. From the results of variable‐temperature (VT) 1H NMR in the temperature range of 220–335 K, 1H–1H NOESY at 220 K, and diffusion‐ordered spectroscopy (DOSY), it is concluded that each diastereoisomer b is also monomeric with a five‐coordinated aluminium central core. The geometry is intermediate between square pyramidal with a cis‐(O,O), trans‐(Me,Me) ligand disposition and trigonal bipyramidal with a trans‐(O,O) and trans‐(Me,Me) disposition. A slow exchange between these two geometries at 220 K was indicated by 1H–1H NOESY NMR. In the presence of propan‐2‐ol as an initiator, enantiomerically pure (R,R) complexes 4 – 6 and their racemic mixtures 7 – 9 were efficient catalysts in the ring‐opening polymerization of lactide (LA). Polylactide materials ranging from isotactically biased (Pm up to 0.66) to medium heterotactic (Pr up to 0.73) were obtained from rac‐lactide, and syndiotactically biased polylactide (Pr up to 0.70) from meso‐lactide. Kinetic studies revealed that the polymerization of (S,S)‐LA in the presence of 4 /propan‐2‐ol had a much higher polymerization rate than (R,R)‐LA polymerization (kSS/kRR=10.1). 相似文献
6.
Phil Liebing Franziska Stein Liane Hilfert Volker Lorenz Karyna Oliynyk Frank T. Edelmann 《无机化学与普通化学杂志》2019,645(1):36-43
Nine new organoammonium violurates [R1R2R3NH][C4H2N3O4] [R1 = R2 = H, R3 = c‐C3H5 ( 2 ), R3 = tBu ( 3 ), R3 = adamantyl ( 4 ), R3 = C6H2Me2‐4,5‐NH2‐2 ( 5 ); R1 = H, R2 = R3 = Et ( 6 ), iPr ( 7 ); R1 = H, R2/R3 = (–CH2–)4 ( 8 ); R1 = R2 = R3 = Et ( 9 ); R1 = R2 = Me, R3 = (CH2)2NMe2 ( 10 )] were prepared by treatment of violuric acid ( 1 ) with a variety of primary, secondary, and tertiary amines. With the exception of orange 5 , all these violurate salts form bright blue or blue‐purple crystalline solids. The acidic triethylammonium violurate [NHEt3]H[C4H2N3O4]2 · H2O ( 9a ) was isolated in the form of red‐violet, plate‐like crystals by the reaction of violuric acid hydrate with triethylamine in a molar ratio of 2:1 in ethanol. All compounds were fully characterized by their IR and NMR (1H, 13C) data as well as elemental analyses. X‐ray crystal structures determinations of 2 , 7 , and 9a revealed supramolecular self‐assembly through networks of N–H ··· N and N–H ··· O hydrogen bonds in the crystalline state. 相似文献
7.
Nobukazu Taniguchi Takeshi Hata Motokazu Uemura 《Angewandte Chemie (International ed. in English)》1999,38(9):1232-1235
Without any formation of stereoisomers , the intramolecular pinacol cyclization of 1 —planar chiral mono-Cr(CO)3 complexes of 1,1′-biphenyls with carbonyl functionalities at the 2- and 2′-positions—with samarium diiodide gives cyclic trans-1,2-diols 2 . Upon exposure to sunlight, the chromium-complexed diols 2 produce optically pure chromium-free trans-diols 3 . Similarly, the corresponding enantiomerically pure trans-1,2-diamines and amino alcohols are obtained from the planar chiral chromium complexes of biphenyls with diimino or keto-imino functionalities. R1=H, OMe; R2=H, Me; R3=H, Me. 相似文献
8.
Aroop K. Roy Urszula G. Wettermark Gary M. Scheide Patty Wisian-neilson Robert H. Neilson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):147-153
Abstract The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me3Sin°P(Me)(OCH2CF3)CH? 2 (1a), prepared by the deprotonation of the dimethyl precursor Me3SiN[dbnd]P(OCH2CF3)Me2 (1) with n-BuLi in Et2O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me3SiN[dbnd]P(Me)(OCH2CF3)CH2R [2: R = Me, 3: R = CH2Ph, 4: R = CH[sbnd]CH2, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me3SiCl gave the O-silylated products Me3SiN[dbnd]P(Me)(OCH2CF3)CH2°C(OSiMe3)R1R2 [7: R 1 = R 2 = Me; 8: R 1 = Me, R 2 = Ph; 9: R1 = Me, R 2 = CH[sbnd]CH2; and 10: R 1 = H, R 2 = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (1H, 13C, and 31P) and elemental analysis. 相似文献
9.
Intramolecularly‐stabilized Group 14 Alkoxides – Promising Precursors for the Synthesis of Group 14‐Chalcogenides by Hot‐Injection Method
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Monika Rusek Georg Bendt Christoph Wölper Dieter Bläser Stephan Schulz 《无机化学与普通化学杂志》2017,643(11):676-682
Intramolecularly‐stabilized germanium, tin, and lead alkoxides of the type M(OCH2CH2NR2)2 [R = Et, M = Ge ( 1 ); R = Me, M = Sn ( 2 ); R = Me, M = Pb ( 3 )] are suitable precursors for the synthesis of group 14 chalcogenides ME (M = Ge, Sn, Pb; E = S, Se, Te) in scrambling reactions with (Me3Si)2S and (Et3Si)2E (E = Se, Te) at moderate temperatures via hot injection method. The reactions proceed with elimination of the corresponding silylether as was proven by in situ 1H NMR spectroscopy. The solid‐state structures of the homoleptic complex 1 and the heteroleptic complex ClGe(OC2H4NEt2) ( 4 ) were determined by single‐crystal X‐ray diffraction, whereas the group 14 chalcogenides were characterized by XRD, SEM, and EDX. 相似文献
10.
Alvaro Delgadillo Paola Romo AnaMaria Leiva Brbara Loeb 《Helvetica chimica acta》2003,86(6):2110-2120
A series of substituted pyrazino[2,3‐f][1,10]‐phenanthroline (Rppl) ligands (with R=Me, COOH, COOMe) were synthetized (see 1 – 4 in Scheme 1). The ligands can be visualized as formed by a bipyridine and a quinoxaline fragment (see A and B ). Homoleptic [Ru(R1ppl)3](PF6)2 and heteropleptic [Ru(R1ppl){(R2)2bpy}2](PF6)2 (R1=H, Me, COOMe and R2=H, Me) metal complexes 5 – 7 and 8 – 13 , respectively, based on these ligands were also synthesized and characterized by conventional techniques (Schemes 2 and 3, resp.). In the heteroleptic complexes, the R1‐ppl ligand reduces at a less‐negative potential than the bpy ligand, reflecting the acceptor property conferred by the quinoxaline moiety. The potentiality of some of these complexes as solar‐cell dyes is discussed. 相似文献
11.
Guangrong Tang Yue‐Jian Lin Guo‐Xin Jin 《Journal of polymer science. Part A, Polymer chemistry》2008,46(2):489-500
A series of new indanimine ligands [ArN?CC2H3(CH3)C6H2(R)OH] (Ar = Ph, R = Me ( 1 ), R = H ( 2 ), and R = Cl ( 3 ); Ar = 2,6‐i‐Pr2C6H3, R = Me ( 4 ), R = H ( 5 ), and R = Cl ( 6 )) were synthesized and characterized. Reaction of indanimines with Ni(OAc)2·4H2O results in the formation of the trinuclear hexa(indaniminato)tri (nickel(II)) complexes Ni3[ArN = CC2H3(CH3)C6H2(R)O]6 (Ar = Ph, R = Me ( 7 ), R = H ( 8 ), and R = Cl ( 9 )) and the mononuclear bis(indaniminato)nickel (II) complexes Ni[ArN?CC2H3(CH3)C6H2(R)O]2 (Ar = 2,6‐i‐Pr2C6H3, R = Me ( 10 ), R = H ( 11 ), and R = Cl ( 12 )). All nickel complexes were characterized by their IR, NMR spectra, and elemental analyses. In addition, X‐ray structure analyses were performed for complexes 7 , 10 , 11 , and 12 . After being activated with methylaluminoxane (MAO), these nickel(II) complexes can polymerize norbornene to produce addition‐type polynorbornene (PNB) with high molecular weight Mv (106 g mol?1), highly catalytic activities up to 2.18 × 107 gPNB mol?1 Ni h?1. Catalytic activities and the molecular weight of PNB have been investigated for various reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 489–500, 2008 相似文献
12.
Synthesis of a “Masked” Terminal Nickel(II) Sulfide by Reductive Deprotection and its Reaction with Nitrous Oxide
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Nathaniel J. Hartmann Dr. Guang Wu Prof. Dr. Trevor W. Hayton 《Angewandte Chemie (International ed. in English)》2015,54(49):14956-14959
The addition of 1 equiv of KSCPh3 to [LRNiCl] (LR={(2,6‐iPr2C6H3)NC(R)}2CH; R=Me, tBu) in C6H6 results in the formation of [LRNi(SCPh3)] ( 1 : R=Me; 2 : R=tBu) in good yields. Subsequent reduction of 1 and 2 with 2 equiv of KC8 in cold (?25 °C) Et2O in the presence of 2 equiv of 18‐crown‐6 results in the formation of “masked” terminal NiII sulfides, [K(18‐crown‐6)][LRNi(S)] ( 3 : R=Me; 4 : R=tBu), also in good yields. An X‐ray crystallographic analysis of these complexes suggests that they feature partial multiple‐bond character in their Ni? S linkages. Addition of N2O to a toluene solution of 4 provides [K(18‐crown‐6)][LtBuNi(SN?NO)], which features the first example of a thiohyponitrite (κ2‐[SN?NO]2?) ligand. 相似文献
13.
《无机化学与普通化学杂志》2018,644(2):114-120
Alkane elimination reactions of the tethered bis(urea) proligand 1,4‐(tBuNHCONH)2‐C4H8 ( 1 ) with ZnR2 (R = Me, Et, nPr) yielded trimetallic zinc complexes [RZn‐1,4‐(tBuNHCON)2‐C4H8]2Zn [R = Me ( 2 ), Et ( 3 ), and nPr ( 4 )]. 2 – 4 were characterized by heteronuclear NMR (1H, 13C) and IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. 相似文献
14.
Isamu Shiina Prof. Dr. Kenya Nakata Dr. Keisuke Ono Masuhiro Sugimoto Akihiro Sekiguchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):167-172
A variety of optically active 2‐hydroxyalkanoates and the corresponding 2‐acyloxyalkanoates are produced by the kinetic resolution of racemic 2‐hydroxyalkanoates by using achiral 2,2‐diarylacetic acid with hindered carboxylic anhydrides as the coupling reagents. The combined use of diphenylacetic acid, pivalic anhydride, and (+)‐(R)‐benzotetramisole ((R)‐BTM) effectively produces (S)‐2‐hydroxyalkanoates and (R)‐2‐acyloxyalkanoates from the racemic 2‐hydroxyalkanoates (s‐values=47–202). This protocol directly provides the desired chiral 2‐hydroxyalkanoate derivatives from achiral diarylacetic acid and racemic secondary alcohols that do not include the sec‐phenethyl alcohol moiety by using the transacylation process to generate the mixed anhydrides from the acid components with bulky carboxylic anhydrides under the influence of the chiral acyl‐transfer catalyst. The transition state that provides the desired (R)‐2‐acyloxyalkanoate from (R)‐2‐hydroxyalkanoate included in the racemic mixture is disclosed by DFT calculations, and the structural features of the transition form are also discussed. 相似文献
15.
Dr. Tetsuya Fukuda Dr. Hisako Hashimoto Prof. Dr. Shigeyoshi Sakaki Prof. Dr. Hiromi Tobita 《Angewandte Chemie (International ed. in English)》2016,55(1):188-192
Treatment of pyridine‐stabilized silylene complexes [(η5‐C5Me4R)(CO)2(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe3)3) with an N‐heterocyclic carbene MeIiPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η5‐C5Me4R)(CO)2W?SiH(Tsi)][HMeIiPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η2‐silaaldehydetungsten complexes [(η5‐C5Me4R)(CO)2W{η2‐O?SiH(Tsi)}][HMeIiPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis. 相似文献
16.
Jií Bserle Roman Jambor Milan Erben Filip Horký Petr tpni
ka Ale Ri
ka Libor Dostl 《无机化学与普通化学杂志》2019,645(9):671-678
Treatment of N,N‐chelated germylene [(iPr)2NB(N‐2,6‐Me2C6H3)2]Ge ( 1 ) with ferrocenyl alkynes containing carbonyl functionalities, FcC≡CC(O)R, resulted in [2+2+2] cyclization and formation of the respective ferrocenylated 3‐Fc‐4‐C(O)R‐1,2‐digermacyclobut‐3‐enes 2 – 4 [R = Me ( 2 ), OEt ( 3 ) and NMe2 ( 4 )] bearing intact carbonyl substituents. In contrast, the reaction between 1 and PhC(O)C≡CC(O)Ph led to activation of both C≡C and C=O bonds producing bicyclic compound containing two five‐membered 1‐germa‐2‐oxacyclopent‐3‐ene rings sharing one C–C bond, 4,8‐diphenyl‐3,7‐dioxa‐2,6‐digermabicyclo[3.3.0]octa‐4,8‐diene ( 5 ). With N‐methylmaleimide containing an analogous C(O)CH=CHC(O) fragment, germylene 1 reacted under [2+2+2] cyclization involving the C=C double bond, producing 1,2‐digermacyclobutane 6 with unchanged carbonyl moieties. Finally, 1 selectively added to the terminal double bond in allenes CH2=C=CRR′ giving rise to 3‐(=CRR′)‐1,2‐digermacyclobutanes [R/R′ = Me/Me ( 7 ), H/OMe ( 8 )] bearing an exo‐C=C double bond. All compounds were characterized by 1H, 13C{1H} NMR, IR and Raman spectroscopy and the molecular structures of 3 , 4 , 5 , and 8 were established by single‐crystal X‐ray diffraction analysis. The redox behavior of ferrocenylated derivatives 2 – 4 was studied by cyclic voltammetry. 相似文献
17.
Juanjuan Wang Gengwen Tan Dongli An Dr. Hongping Zhu Dr. Ying Yang 《无机化学与普通化学杂志》2011,637(11):1597-1601
The N‐heterocyclic carbene‐stabilized chromium(II) alkyl, aryl, and alkynyl complexes (IPM)2CrR2 [R = Me ( 2 ), Ph ( 3 ), C≡CPh ( 3 ); IPM = 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene] were prepared by metathesis reactions of (IPM)2CrCl2 ( 1 ) with the corresponding organolithium reagents. Further reaction of 3 with an organic azide, 1‐azidoadamantane, yielded an organonitridochromium(V) compound (IPM)2Ph2Cr≡N ( 5 ). Compounds 2 – 5 are fully characterized by 1H NMR and IR spectroscopy, X‐ray crystallography as well as by elemental analysis. The structural analysis shows that the metal atom adopts a nearly square‐planar arrangement in the respective 2 , 3 , and 4 and a square‐pyramidal one in 5 . The reaction of 3 with the organic azide to 5 appears a novel way to the organonitridochromium compound. 相似文献
18.
Kazushi Mashima 《Macromolecular Symposia》2000,159(1):69-76
Half‐metallocene diene complexes of niobium and tantalum catalyzed three‐types of polymerization: (1) the living polymerization of ethylene by niobium and tantalum complexes, MCl2(η4‐1,3‐diene)(η5‐C5R5) ( 1‐4 ; M = Nb, Ta; R = H, Me) combined with an excess of methylaluminoxane; (2) the stereoselective ring opening metathesis polymerization of norbornene by bis(benzyl) tantalum complexes, Ta(CH2Ph)2(η4‐1,3‐butadiene)(η5‐C5R5) ( 11 : R = Me; 12 : R = H) and Ta(CH2Ph)2(η4‐o‐xylylene)(η5‐C5Me5) ( 16 ); and (3) the polymerization of methyl methacrylate by butadiene‐diazabutadiene complexes of tantalum, Ta(η2‐RN=CHCH=NR)(η4‐1,3‐butadiene)(η5‐C5Me5) ( 25 : R = p‐methoxyphenyl; 26 : R = cyclohexyl) in the presence of an aluminum compound ( 24 ) as an activator of the monomer. 相似文献
19.
Cationic Ir/Me‐BIPAM‐Catalyzed Asymmetric Intramolecular Direct Hydroarylation of α‐Ketoamides
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Tomohiko Shirai Prof. Dr. Hajime Ito Prof. Dr. Yasunori Yamamoto 《Angewandte Chemie (International ed. in English)》2014,53(10):2658-2661
Asymmetric intramolecular direct hydroarylation of α‐ketoamides gives various types of optically active 3‐substituted 3‐hydroxy‐2‐oxindoles in high yields with complete regioselectivity and high enantioselectivities (84–98 % ee). This is realized by the use of the cationic iridium complex [Ir(cod)2](BArF4) and the chiral O‐linked bidentate phosphoramidite (R,R)‐Me‐BIPAM. 相似文献
20.
Herbert Schumann Jens Kaufmann Birgit C. Wassermann Frank Girgsdies Nimer Jaber Jochanan Blum 《无机化学与普通化学杂志》2002,628(5):971-978
The enantiomerically pure dimeric N, O‐5‐chelates [Me2In(μ‐OCH2CH(R)NMe2)]2 {R = Me (S) ( 2 ); R = iPr (S) ( 3 ); R = iBu (S) ( 4 ); R = Bz (S) ( 5 )}, and [Me2In‐{μ‐(1R, 2S)‐OCH(Ph)CH(Me)NMe2}]2 ( 6 ), as well as the achiral dimeric N, O‐6‐chelate [Me2In(μ‐O(CH2)3NMe2)]2 ( 7 ) have been synthesized from trimethylindium and equimolar amounts of the corresponding enantiomerically pure dimethylamino alcohols or of the achiral dimethylaminopropanol by elimination of methane. Their 1H NMR, 13C NMR, and mass spectra as well as the X‐ray single crystal structure analyses of [Me2In{μ‐O(CH2)2NMe2}]2 ( 1 ), 3, 5, 6 and 7 are described and discussed. The coordinative N→In bonds of the five‐coordinate indium complexes show dynamic dissociation/association processes. 1—6 were found to be useful reagents for the partial kinetic resolution of 2‐carbomethoxy‐1, 1′‐binaphthyl triflate. 相似文献