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1.
σ‐Insertive Mechanism versus Concerted Non‐insertive Mechanism in the Intramolecular Hydroamination of Aminoalkenes Catalyzed by Phenoxyamine Magnesium Complexes: A Synthetic and Computational Study 下载免费PDF全文
Dr. Xiaoming Zhang Dr. Sven Tobisch Prof. Dr. Kai C. Hultzsch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7841-7857
The phenoxyamine magnesium complexes [{ONN}MgCH2Ph] ( 4 a : {ONN}=2,4‐tBu2‐6‐(CH2NMeCH2CH2NMe2)C6H2O?; 4 b : {ONN}=4‐tBu‐2‐(CH2NMeCH2CH2NMe2)‐6‐(SiPh3)C6H2O?) have been prepared and investigated with respect to their catalytic activity in the intramolecular hydroamination of aminoalkenes. The sterically more shielded triphenylsilyl‐substituted complex 4 b exhibits better thermal stability and higher catalytic activity. Kinetic investigations using complex 4 b in the cyclisation of 1‐allylcyclohexyl)methylamine ( 5 b ), respectively, 2,2‐dimethylpent‐4‐en‐1‐amine ( 5 c ), reveal a first‐order rate dependence on substrate and catalyst concentration. A significant primary kinetic isotope effect of 3.9±0.2 in the cyclisation of 5 b suggests significant N?H bond disruption in the rate‐determining transition state. The stoichiometric reaction of 4 b with 5 c revealed that at least two substrate molecules are required per magnesium centre to facilitate cyclisation. The reaction mechanism was further scrutinized computationally by examination of two rivalling mechanistic pathways. One scenario involves a coordinated amine molecule assisting in a concerted non‐insertive N?C ring closure with concurrent amino proton transfer from the amine onto the olefin, effectively combining the insertion and protonolysis step to a single step. The alternative mechanistic scenario involves a reversible olefin insertion step followed by rate‐determining protonolysis. DFT reveals that a proton‐assisted concerted N?C/C?H bond‐forming pathway is energetically prohibitive in comparison to the kinetically less demanding σ‐insertive pathway (ΔΔG≠=5.6 kcal mol?1). Thus, the σ‐insertive pathway is likely traversed exclusively. The DFT predicted total barrier of 23.1 kcal mol?1 (relative to the {ONN}Mg pyrrolide catalyst resting state) for magnesium?alkyl bond aminolysis matches the experimentally determined Eyring parameter (ΔG≠=24.1(±0.6) kcal mol?1 (298 K)) gratifyingly well. 相似文献
2.
Peter B. Hitchcock Alexei V. Khvostov Michael F. Lappert Andrey V. Protchenko 《无机化学与普通化学杂志》2008,634(8):1373-1377
The potassium dihydrotriazinide K(LPh,tBu) ( 1 ) was obtained by a metal exchange route from [Li(LPh,tBu)(THF)3] and KOtBu (LPh,tBu = [N{C(Ph)=N}2C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI2(thf)2 yielded the monosubstituted SmII complex [Sm(LPh,tBu)I(THF)4] ( 2 ) or the disubstituted [Sm(LPh,tBu)2(THF)2] ( 3 ), respectively. Attempted synthesis of a heteroleptic SmII amido‐alkyl complex by the reaction of 2 with KCH2Ph produced compound 3 due to ligand redistribution. The YbII bis(dihydrotriazinide) [Yb(LPh,tBu)2(THF)2] ( 4 ) was isolated from the 1:1 reaction of YbI2(THF)2 and 1 . Molecular structures of the crystalline compounds 2 , 3· 2C6H6 and 4· PhMe were determined by X‐ray crystallography. 相似文献
3.
The metal complexes [Ni{N(Ar)C(R)C(H)Ph}2) ( 2 ) (Ar = 2,6‐Me2C6H3, R = SiMe3), [Ti(Cp2){N(R)C(But)C(H)R}] ( 3 ), M{N(R)C(But)C(H)R}I [M = Ni ( 4 a ) or Pd ( 4 b )] and [M{N(R)C(But)C(H)R}I(PPh3)] [M = Ni ( 5 a ) or Pd ( 5 b )] have been prepared from a suitable metal halide and lithium precursor of ( 2 ) or ( 3 ) or, alternatively from [M(LL)2] (M = Ni, LL = cod; M = Pd, LL = dba) and the ketimine RN = C(But)CH(I)R ( 1 ). All compounds, except 4 were fully characterised, including the provision of X‐ray crystallographic data for complex 5 a . 相似文献
4.
Risa Suzuki Yuto Uziie Wataru Fujiwara Hiroshi Katagiri Takashi Murase 《化学:亚洲杂志》2020,15(8):1330-1338
The partial fluorination of polycyclic aromatic hydrocarbons often produces a layered crystal packing, where fluorinated aromatic surfaces are stacked over nonfluorinated aromatic surfaces. Herein, we report the synthesis and crystal packing of partially fluorinated [4]helicenes with steric congestion resulting from H and F atoms in the fjord region. F6‐[4]Helicene forms head‐to‐tail columnar stacks consisting of an alternate arrangement of perfluorinated and nonfluorinated naphthalene moieties. With decreasing fluorine content, aromatic stacking switched from arene?fluoroarene (ArH?ArF) hetero‐stacking to ArH?ArH/ArF?ArF homo‐stacking with the help of intermolecular C?H???F contacts in the fjord region. As a result, head‐to‐head columnar stacks appear. Therefore, the conventional ArH?ArF stacking motif is not always applicable to Fn‐[4]helicenes with twisted π‐surfaces. 相似文献
5.
The Sodium Silanide t Bu2PhSiNa: Synthesis, Properties, Structure Analysis – a Synthetic Pathway to Introduce the t Bu2PhSi‐Ligand The sodium silanide tBu2PhSiNa is easily obtained by the reaction of sodium metal with tBu2PhSiBr at elevated temperatures in n‐heptane, THF or dibutylether. An X‐ray crystal structure analysis reveals, that the sodium silanide 3 contains chains of tBu2PhSiNa units with η6 sodium–phenyl‐contacts. Oxidation of tBu2PhSiNa with TCNE proceeds with formation of the disilane tBu2PhSi–SiPhtBu2. 相似文献
6.
Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe‐H⋅⋅⋅H‐N Dihydrogen Bond Characterized by Neutron Diffraction 下载免费PDF全文
Dr. Tianbiao Liu Dr. Xiaoping Wang Dr. Christina Hoffmann Dr. Daniel L. DuBois Dr. R. Morris Bullock 《Angewandte Chemie (International ed. in English)》2014,53(21):5300-5304
Hydrogenase enzymes in nature use hydrogen as a fuel, but the heterolytic cleavage of H? H bonds cannot be readily observed in enzymes. Here we show that an iron complex with pendant amines in the diphosphine ligand cleaves hydrogen heterolytically. The product has a strong Fe‐H???H‐N dihydrogen bond. The structure was determined by single‐crystal neutron diffraction, and has a remarkably short H???H distance of 1.489(10) Å between the protic N‐Hδ+ and hydridic Fe‐Hδ? part. The structural data for [CpFe H (PtBu2NtBu2 H )]+ provide a glimpse of how the H? H bond is oxidized or generated in hydrogenase enzymes. These results now provide a full picture for the first time, illustrating structures and reactivity of the dihydrogen complex and the product of the heterolytic cleavage of H2 in a functional model of the active site of the [FeFe] hydrogenase enzyme. 相似文献
7.
Disupersilylperoxo Radical Anion [tBu3SiOOSitBu3]⋅−: An Intermediate of Supersilanide Oxidation 下载免费PDF全文
Alexandra Budanow Dr. Haleh Hashemi Haeri Inge Sänger Frauke Schödel Dr. Michael Bolte Prof. Dr. Thomas Prisner Prof. Dr. Matthias Wagner Dr. Hans‐Wolfram Lerner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10236-10239
In the oxidative process of the supersilanide anion [SitBu3]?, radical species are generated. The continuous wave (cw)‐EPR spectrum of the reaction solution of Na[SitBu3] with O2 revealed a signal, which could be characterized as disupersilylperoxo radical anion [tBu3SiOOSitBu3]?? affected by sodium ions though ion‐pair formation. A mechanism is suggested for the oxidative process of supersilanide, which in a further step can be helpful in a better understanding of the oxidation process of isoelectronic phosphanes. 相似文献
8.
Sequential Barium‐Catalysed N−H/H−Si Dehydrogenative Cross‐Couplings: Cyclodisilazanes versus Linear Oligosilazanes 下载免费PDF全文
Clément Bellini Dr. Thierry Roisnel Prof. Dr. Jean‐François Carpentier Dr. Sven Tobisch Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15733-15743
Starting from Ph3SiH, the barium precatalyst Ba[CH(SiMe3)2]2?(THF)3 was used to produce the disilazane Ph3SiN(Bn)SiPh2NHBn ( 4 ) by sequential N?H/H?Si dehydrogenative couplings with BnNH2 and Ph2SiH2. Substrate scope was extended to other amines and hydrosilanes. This smooth protocol gives quantitative yields and full chemoselectivity. Compound 4 and the intermediates Ph3SiNHBn and Ph3SiN(Bn)SiHPh2 were structurally characterised. Further attempts at chain extension by dehydrocoupling of Ph2SiH2 with 4 instead resulted in cyclisation of this compound, forming the cyclodisilazane c‐(Ph2Si‐NBn)2 ( 5 ) which was crystallographically authenticated. The ring‐closure mechanism leading to 5 upon release of C6H6 was determined by complementary experimental and theoretical (DFT) investigations. Ba[CH(SiMe3)2]2?(THF)3 and 4 react to afford the reactive Ba{N(Bn)SiPh2N(Bn)SiPh3}2, which was characterised in situ by NMR spectroscopy. Next, in a stepwise process, intramolecular nucleophilic attack of the metal‐bound amide on the terminal silicon atom generates a five‐coordinate silicate. It is followed by turnover‐limiting β‐C6H5 transfer to barium; this releases 5 and forms a transient [Ba]?Ph species, which undergoes aminolysis to regenerate [Ba]?N(Bn)SiPh2N(Bn)SiPh3. DFT computations reveal that the irreversible production of 5 through such a stepwise ring‐closure mechanism is much more kinetically facile (ΔG≠=26.2 kcal mol?1) than an alternative σ‐metathesis pathway (ΔG≠=48.2 kcal mol?1). 相似文献
9.
Dr. Pei Jen Tiong Laura R. Groom Dr. Eric Clot Prof. Dr. Philip Mountford 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(13):4198-4216
We report a detailed study of the reactions of the Ti?NNCPh2 alkylidene hydrazide functional group in [Cp*Ti{MeC(NiPr)2}(NNCPh2)] ( 8 ) with a variety of unsaturated and saturated substrates. Compound 8 was prepared from [Cp*Ti{MeC(NiPr)2}(NtBu)] and Ph2CNNH2. DFT calculations were used to determine the nature of the bonding for the Ti?NNCPh2 moiety in 8 and in the previously reported [Cp2Ti(NNCPh2)(PMe3)]. Reaction of 8 with CO2 gave dimeric [(Cp*Ti{MeC(NiPr)2}{μ‐OC(NNCPh2)O})2] and the “double‐insertion” dicarboxylate species [Cp*Ti‐{MeC(NiPr)2}{OC(O)N(NCPh2)C(O)O}] through an initial [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(O)O}], the congener of which could be isolated in the corresponding reaction with CS2. The reaction with isocyanates or isothiocyanates tBuNCO or ArNCE (Ar=Tol or 2,6‐C6H3iPr2; E=O, S) gave either complete NNCPh2 transfer, [2+2] cycloaddition to Ti?Nα or single‐ or double‐substrate insertion into the Ti?Nα bond. The treatment of 8 with isonitriles RNC (R=tBu or Xyl) formed σ‐adducts [Cp*Ti{MeC(NiPr)2}(NNCPh2)(CNR)]. With ArF5CCH (ArF5=C6F5) the [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(ArF5)C(H)}] was formed, whereas with benzonitriles ArCN (Ar=Ph or ArF5) two equivalents of substrate were coupled in a head‐to‐tail manner across the Ti?Nα bond to form [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(Ar)NC(Ar)N}]. Treatment of 8 with RSiH3 (R=aryl or Bu) or Ph2SiH2 gave [Cp*Ti{MeC(NiPr)2}{N(SiHRR′)N(CHPh2)}] (R′=H or Ph) through net 1,3‐addition of Si? H to the N? N?CPh2 linkage of 8 , whereas reaction with PhSiH2X (X=Cl, Br) led to the Ti?Nα 1,2‐addition products [Cp*Ti{MeC(NiPr)2}(X){N(NCPh2)SiH2Ph}]. 相似文献
10.
Juan Forniés Violeta Sicilia Pilar Borja José M. Casas Alvaro Díez Elena Lalinde Carmen Larraz Antonio Martín M. Teresa Moreno 《化学:亚洲杂志》2012,7(12):2813-2823
The neutral compounds [Pt(bzq)(CN)(CNR)] (R=tBu ( 1 ), Xyl ( 2 ), 2‐Np ( 3 ); bzq= benzoquinolate, Xyl=2,6‐dimethylphenyl, 2‐Np=2‐napthyl) were isolated as the pure isomers with a trans‐Cbzq,CNR configuration, as confirmed by 13C{1H} NMR spectroscopy in the isotopically marked [Pt(bzq)(13CN)(CNR)] (R=tBu ( 1′ ), Xyl ( 2′ ), 2‐Np ( 3′ )) derivatives (δ13CCN≈110 ppm; 1J(Pt,13C)≈1425 Hz]. By contrast, complex [Pt(bzq)(C≡CPh)(CNXyl)] ( 4 ) with a trans‐Nbzq,CNR configuration, has been selectively isolated from [Pt(bzq)Cl(CNXyl)] (trans‐Nbzq,CNR) using Sonogashira conditions. X‐ray diffraction studies reveal that while 1 adopts a columnar‐stacked chain structure with Pt–Pt distances of 3.371(1) Å and significant π???π interactions (3.262 Å), complex 2 forms dimers supported only by short Pt???Pt (3.370(1) Å) interactions. In complex 4 the packing is directed by weak bzq???Xyl and bzq???C≡E (C, N) interactions. In solid state at room temperature, compounds 1 and 2 both show a bright red emission (?=42.1 % 1 , 57.6 % 2 ). Luminescence properties in the solid state at 77 K and concentration‐dependent emission studies in CH2Cl2 at 298 K and at 77 K are also reported for 1 , 1·CHCl3 , 2 , 2' , 2·CHCl3 , 3 , 4 . 相似文献
11.
Xiaoming He Wai Han Lam Nianyong Zhu Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(35):8842-8851
Two calixarene‐based bis‐alkynyl‐bridged AuI isonitrile complexes with two different crown ether pendants, [{calix[4]arene‐(OCH2CONH‐C6H4C≡C)2}{Au(CNR)}2] (R=benzo[15]crown‐5 ( 1 ); R=benzo[18]crown‐6 ( 2 )), together with their related crown‐free analogue 3 (R=C6H3(OMe)2‐3,4) and a mononuclear gold(I) complex 4 with benzo[15]crown‐5 pendant, have been designed and synthesized, and their photophysical properties have been studied. The X‐ray structure of the ligand, calix[4]arene‐(OCH2CONH‐C6H4C?CH)2 has been determined. The cation‐binding properties of these complexes with various metal ions have been studied using UV/Vis, emission, 1H NMR, and ESI‐MS techniques, and DFT calculations. A new low‐energy emission band associated with Au???Au interaction could be switched on upon formation of the metal ion‐bound adduct in a sandwich fashion. 相似文献
12.
Harald Krautscheid Eberhard Matern Jolanta Olkowska‐Oetzel Jerzy Pikies Gerhard Fritz 《无机化学与普通化学杂志》2001,627(5):999-1002
Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXV. Formation and Structure of [{ cyclo ‐P3(PtBu2)3}{Ni(CO)2}{Ni(CO)3}] tBu2P–P=P(R)tBu2 (R = Br, Me) reacts with [Ni(CO)4] yielding [{cyclo‐P3(PtBu2)3}{Ni(CO)2}{Ni(CO)3}]. The two cis‐tBu2P substituents of the cyclotriphosphane, which results from the trimerization of the phosphinophosphinidene tBu2P–P, are coordinating to a Ni(CO)2 unit forming a five‐membered P4Ni chelate ring. The trans‐tBu2P group is linked to a Ni(CO)3 unit. The compound crystallizes in the orthorhombic space group Pbca (No. 61) with a = 933.30(5), b = 2353.2(1) and c = 3474.7(3) pm. 相似文献
13.
In reactions with transition metal compounds, tBu2P? P?P(X)tBu2 (X = Br, Me) acts mainly as a precursor of the tBu2P? P ligand, whereas tBu(Me3Si)P? P?P(Me)tBu2 acts as a precursor of the (Me3Si)P?PtBu ligand. Up to now, only Pt(0) d10 ML2 metal centres were found to be able to stabilize the tBu2P? P group in ‘pure form’ by means of η2‐coordination (side on). Several compounds of the [{η2 ? tBu2P? P}Pt(PR3)2] type were sufficiently stable to be isolated and characterized; however, not all of them gave single crystals suitable for X‐ray structure determinations. The X‐ray structures of these compounds and of [{µ ? (1,2:2 ? η ? tBu2P? P)Pt(PR3)2} {M(CO)5}] strongly suggest the ethene‐like form of 1,1‐di‐tert‐butyldiphosphene in these complexes. Such a form is also in agreement with RI DFT calculations with SVP basis for free tBu2P? P. However, in trapping experiments with cyclic olefins and cyclic dienes tBu2P? P exhibits, to some extent, electrophilic ‘singlet carbene’ properties. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
14.
Chun‐Yan Qi Zhong‐Xia Wang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(15):4621-4631
A series of Al(III) and Sn(II) diiminophosphinate complexes have been synthesized. Reaction of Ph(ArCH2)P(?NBut)NHBut (Ar = Ph, 3 ; Ar = 8‐quinolyl, 4 ) with AlR3 (R = Me, Et) gave aluminum complexes [R2Al{(NBut)2P(Ph)(CH2Ar)}] (R = Me, Ar = Ph, 5 ; R = Me, Ar = 8‐quinolyl, 6 ; R = Et, Ar = Ph, 7 ; R = Et, Ar = quinolyl, 8 ). Lithiated 3 and 4 were treated with SnCl2 to afford tin(II) complexes [ClSn{(NBut)2P(Ph)(CH2Ar)}] (Ar = Ph, 9 ; Ar = 8‐quinolyl, 10 ). Complex 9 was converted to [(Me3Si)2NSn{(NBut)2P(Ph)(CH2Ph)}] ( 11 ) by treatment with LiN(SiMe3)2. Complex 11 was also obtained by reaction of 3 with [Sn{N(SiMe3)2}2]. Complex 9 reacted with [LiOC6H4But‐4] to yield [4‐ButC6H4OSn{(NBut)2P(Ph)(CH2Ph)}] ( 12 ). Compounds 3–12 were characterized by NMR spectroscopy and elemental analysis. The structures of complexes 6 , 10 , and 11 were further characterized by single crystal X‐ray diffraction techniques. The catalytic activity of complexes 5–8 , 11 , and 12 toward the ring‐opening polymerization of ε‐caprolactone (CL) was studied. In the presence of BzOH, the complexes catalyzed the ring‐opening polymerization of ε‐CL in the activity order of 5 > 7 ≈ 8 > 6 ? 11 > 12 , giving polymers with narrow molecular weight distributions. The kinetic studies showed a first‐order dependency on the monomer concentration in each case. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4621–4631, 2006 相似文献
15.
Ingo Krossing Ulli Englert Eberhard Matern Jolanta Olkowska‐Oetzel Jerzy Pikies Gerhard Fritz 《无机化学与普通化学杂志》2002,628(2):446-452
tBu2P‐P=P(Me)tBu2 reacts with [Fe2(CO)9] to give [μ‐(1, 2, 3:4‐η‐tBu2P1‐P2‐P3‐P4tBu2){Fe(CO)3}{Fe(CO)4}] ( 1 ) and [trans‐(tBu2MeP)2Fe(CO)3]( 2 ). With [(η2‐C8H14)2Fe(CO)3] in addition to [μ‐(1, 2, 3:4‐η‐tBu2P1‐P2‐P3‐P4tBu2){Fe(CO)2PMetBu2}‐{Fe(CO)4}] ( 10 ) and 2 also [(μ‐PtBu2){μ‐P‐Fe(CO)3‐PMetBu2}‐{Fe(CO)3}2(Fe‐Fe)]( 9 ) is formed. 1 crystallizes in the monoclinic space group P21/c with a = 875.0(2), b = 1073.2(2), c = 3162.6(6) pm and β = 94.64(3)?. 2 crystallizes in the monoclinic space group P21/c with a = 1643.4(7), b = 1240.29(6), c = 2667.0(5) pm and β = 97.42(2)?. 9 crystallizes in the monoclinic space group P21/n with a = 1407.5(5), b = 1649.7(5), c = 1557.9(16) pm and β = 112.87(2)?. 相似文献
16.
Aggregation of Dinuclear Cations [{Au(PR3)}2(μ‐OH)]+ into Dimers Induced by Polyoxometalate (POM) Template Effects 下载免费PDF全文
Takuya Yoshida Eri Nagashima Hidekazu Arai Satoshi Matsunaga Kenji Nomiya 《无机化学与普通化学杂志》2015,641(10):1688-1695
Intercluster compounds, [{(Au{P(p‐XPh)3})2(μ‐OH)}2][α‐SiMo12O40(Au{P(p‐XPh)3})2] · nEtOH [X = F ( 1 ), Cl ( 2 )] were synthesized by polyoxometalate (POM)‐mediated clusterization, and were unequivocally characterized by X‐ray crystallography, elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), Fourier transform infrared (FT‐IR), solid‐state cross‐polarization magic‐angle‐spinning (CPMAS) 31P nuclear magnetic resonance (NMR), and solution (1H, 31P{1H}) NMR spectroscopy. The “dimer‐of‐dinuclear phosphanegold(I) cation”, i.e., [{(Au{P(p‐XPh)3})2(μ‐OH)}2]2+ was formed by the self‐assembly of dinuclear phosphanegold(I) cations, i.e., [(Au{P(p‐XPh)3})2(μ‐OH)]+, through inter‐cationic aurophilic interactions as the crossed‐edge arrangement (or tetrahedral Au4 structure) for 1 , while as the parallel‐edge arrangement (or rectangular Au4 structure) for 2 . The latter arrangement was first attained only by assistance of the POM. The POM anions in 1 and 2 contained two mononuclear phosphanegold(I) cations, i.e., [Au{P(p‐XPh)3}]+, linked to the OMo2 oxygen atoms of edge‐sharing MoO6 octahedra. In the solution 31P{1H} NMR of 1 and 2 , we observed single signals due to the rapid exchange of the phosphanegold(I) units. This shows that the OMo2 oxygen atoms of edge‐sharing MoO6 octahedra in the Keggin POM act as multi‐centered active binding sites for the formation of [{(Au{P(p‐XPh)3})2(μ‐OH)}2]2+. 相似文献
17.
Yuushou Nakayama Yuuichi Sogo Zhengguo Cai Takeshi Shiono 《Journal of polymer science. Part A, Polymer chemistry》2013,51(5):1223-1229
A series of titanium complexes with ansa‐(fluorenyl)(cyclododecylamido) ligands, Me2Si(η3‐R)(N‐c‐C12H23)TiMe2 [R = fluorenyl ( 5 ), 2,7‐tBu2fluorenyl ( 6 ), 3,6‐tBu2fluorenyl ( 7 )], was synthesized. The crystal structure of complex 6 revealed η3‐coordination of the fluorenyl moiety to the metal. Upon activation with trialkylaluminum‐free modified methylaluminoxane, complexes 5 – 7 as well as the corresponding tBu amide complexes, Me2Si(η3‐R)(NtBu)TiMe2 [R = fluorenyl ( 2 ), 2,7‐tBu2fluorenyl ( 3 ), 3,6‐tBu2fluorenyl ( 4 )], were adopted as the catalysts for the copolymerization of ethylene (E) and isobutylene (IB). Among these complexes, complex 6 was found to achieve the highest IB incorporation to produce alternating E‐IB copolymers. Complex 6 system also achieved copolymerization of E and limonene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
18.
Ansa‐Complexes of [Mn(η5‐C5H5)(η6‐C6H6)]: Preparation,Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3) 下载免费PDF全文
Prof. Dr. Holger Braunschweig Dr. Alexander Damme Dr. Klaus Dück Dr. Marco Fuß Dr. Christian Hörl Dr. Thomas Kramer Dr. Ivo Krummenacher Dr. Thomas Kupfer Valerie Paprocki Christoph Schneider 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14797-14803
We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa‐bridging elements. Their preparation was achieved by salt‐elimination reactions of the dilithiated precursor [Mn(η5‐C5H4Li)(η6‐C6H5Li)]?pmdta (pmdta=N,N,N′,N′,N′′‐pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single‐atom‐bridged derivatives, [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] and [Mn(η5‐C5H4)(η6‐C6H5)SiPh2], could also be determined by X‐ray structural analysis. We investigated for the first time the reactivity of these ansa‐cyclopentadienyl–benzene manganese compounds. The reaction of the distannyl‐bridged complex [Mn(η5‐C5H4)(η6‐C6H5)Sn2tBu4] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn?Sn bond to give a triatomic ansa‐bridge. The investigation of the ring‐opening polymerization (ROP) capability of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] with [Pt(PEt3)3] showed that an unexpected, unselective insertion into the Cipso?Sn bonds of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] had occurred. 相似文献
19.
Nitric Oxide Insertion Reactivity with the Bismuth–Carbon Bond: Formation of the Oximate Anion, [ON(C6H2tBu2O)]−, from the Oxyaryl Dianion, (C6H2tBu2O)2− 下载免费PDF全文
Dr. Douglas R. Kindra Dr. Ian J. Casely Dr. Joseph W. Ziller Prof. William J. Evans 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15242-15247
The first example of NO insertion into a Bi?C bond has been found in the direct reaction of NO with a Bi3+ complex of the unusual (C6H2tBu2‐3,5‐O‐4)2? oxyaryl dianionic ligand, namely, Ar′Bi(C6H2tBu2‐3,5‐O‐4) [Ar′=2,6‐(Me2NCH2)2C6H3] ( 1 ). The oximate complexes [Ar′Bi(ONC6H2‐3,5‐tBu2‐4‐O)]2(μ‐O) ( 3 ) and Ar′Bi(ONC6H2‐3,5‐tBu2‐4‐O)2 ( 4 ) were formed as a mixture, but can be isolated in pure form by reaction of NO with a Bi3+ complex of the [O2C(C6H2tBu2‐3‐5‐O‐4]2? oxyarylcarboxy dianion, namely, Ar′Bi[O2C(C6H2tBu2‐3‐5‐O‐4)‐κ2O,O’]. Reaction of 1 with Ph3CSNO gave an oximate product with (Ph3CS)1? as an ancillary ligand, (Ph3CS)(Ar′)Bi(ONC6H2‐3,5‐tBu2‐4‐O) ( 5 ). 相似文献
20.
Christian P. Sindlinger Paul Niklas Ruth 《Angewandte Chemie (International ed. in English)》2019,58(42):15051-15056
The pentaaryl borole (Ph*C)4BXylF [Ph*=3,5‐tBu2(C6H3); XylF=3,5‐(CF3)2(C6H3)] reacts with low‐valent Group 13 precursors AlCp* and GaCp* by two divergent routes. In the case of [AlCp*]4, the borole reacts as an oxidising agent and accepts two electrons. Structural, spectroscopic, and computational analysis of the resulting unprecedented neutral η5‐Cp*,η5‐[(Ph*C)4BXylF] complex of AlIII revealed a strong, ionic bonding interaction. The formation of the heteroleptic borole‐cyclopentadienyl “aluminocene” leads to significant changes in the 13C NMR chemical shifts within the borole unit. In the case of the less‐reductive GaCp*, borole (Ph*C)4BXylF reacts as a Lewis acid to form a dynamic adduct with a dative 2‐center‐2‐electron Ga?B bond. The Lewis adduct was also studied structurally, spectroscopically, and computationally. 相似文献