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1.
Dinuclear Rare‐Earth Metal Alkyl Complexes Supported by Indolyl Ligands in μ‐η2:η1:η1 Hapticities and their High Catalytic Activity for Isoprene 1,4‐cis‐Polymerization 下载免费PDF全文
Guangchao Zhang Yun Wei Liping Guo Prof. Dr. Xiancui Zhu Prof. Dr. Shaowu Wang Prof. Dr. Shuangliu Zhou Xiaolong Mu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2519-2526
Two series of new dinuclear rare‐earth metal alkyl complexes supported by indolyl ligands in novel μ‐η2:η1:η1 hapticities are synthesized and characterized. Treatment of [RE(CH2SiMe3)3(thf)2] with 1 equivalent of 3‐(tBuN?CH)C8H5NH ( L1 ) in THF gives the dinuclear rare‐earth metal alkyl complexes trans‐[(μ‐η2:η1:η1‐3‐{tBuNCH(CH2SiMe3)}Ind)RE(thf)(CH2SiMe3)]2 (Ind=indolyl, RE=Y, Dy, or Yb) in good yields. In the process, the indole unit of L1 is deprotonated by the metal alkyl species and the imino C?N group is transferred to the amido group by alkyl CH2SiMe3 insertion, affording a new dianionic ligand that bridges two metal alkyl units in μ‐η2:η1:η1 bonding modes, forming the dinuclear rare‐earth metal alkyl complexes. When L1 is reduced to 3‐(tBuNHCH2)C8H5NH ( L2 ), the reaction of [Yb(CH2SiMe3)3(thf)2] with 1 equivalent of L2 in THF, interestingly, generated the trans‐[(μ‐η2:η1:η1‐3‐{tBuNCH2}Ind)Yb(thf)(CH2SiMe3)]2 (major) and cis‐[(μ‐η2:η1:η1‐3‐{tBuNCH2}Ind)Yb(thf)(CH2SiMe3)]2 (minor) complexes. The catalytic activities of these dinuclear rare‐earth metal alkyl complexes for isoprene polymerization were investigated; the yttrium and dysprosium complexes exhibited high catalytic activities and high regio‐ and stereoselectivities for isoprene 1,4‐cis‐polymerization. 相似文献
2.
Zhichao Zhang Dongmei Cui Xinli Liu 《Journal of polymer science. Part A, Polymer chemistry》2008,46(20):6810-6818
The syntheses of several dialkyl complexes based on rare‐earth metal were described. Three β‐diimine compounds with varying N‐aryl substituents (HL1=(2‐CH3O(C6H4))N?C(CH3)CH?C(CH3)NH(2‐CH3O(C6H4)), HL2 = (2,4,6‐(CH3)3 (C6H2))N?C(CH3)CH?C(CH3)NH(2,4,6‐(CH3)3(C6H2)), HL3 = PhN?C(CH3)CH(CH3) NHPh) were treated with Ln(CH2SiMe3)3(THF)2 to give dialkyl complexes L1Ln (CH2SiMe3)2 (Ln = Y ( 1a ), Lu ( 1b ), Sc ( 1c )), L2Ln(CH2SiMe3)2(THF) (Ln = Y ( 2a ), Lu ( 2b )), and L3Lu(CH2SiMe3)2(THF) (3). All these complexes were applied to the copolymerization of cyclohexene oxide (CHO) and carbon dioxide as single‐component catalysts. Systematic investigation revealed that the central metal with larger radii and less steric bulkiness were beneficial for the copolymerization of CHO and CO2. Thus, methoxy‐modified β‐diiminato yttrium bis(alkyl) complex 1a , L1Y(CH2SiMe3)2, was identified as the optimal catalyst, which converted CHO and CO2 to polycarbonate with a TOF of 47.4 h?1 in 1,4‐dioxane under a 15 bar of CO2 atmosphere (Tp=130 °C), representing the highest catalytic activity achieved by rare‐earth metal catalyst. The resultant copolymer contained high carbonate linkages (>99%) with molar mass up to 1.9 × 104 as well as narrow molar mass distribution (Mw/Mn = 1.7). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6810–6818, 2008 相似文献
3.
Tingting Li Dr. Masayoshi Nishiura Dr. Jianhua Cheng Prof. Dr. Yang Li Prof. Dr. Zhaomin Hou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(47):15079-15085
The reactivity of the cubane‐type rare‐earth methylidene complex [Cp′Lu(μ3‐CH2)]4 ( 1 , Cp′=C5Me4SiMe3) with various unsaturated electrophiles was investigated. The reaction of 1 with CO (1 atm) at room temperature gave the bis(ketene dianion)/dimethylidene complex [Cp′4Lu4(μ3‐CH2)2(μ3,η2‐O‐C?CH2)2] ( 2 ) in 86 % yield through the insertion of two molecules of CO into two of the four lutetium–methylidene units. In the reaction with the sterically demanding N,N‐diisopropylcarbodiimide at 60 °C, only one of the four methylidene units in 1 reacted with one molecule of the carbodiimide substrate to give the mono(ethylene diamido)/trimethylidene complex [Cp′4Lu4(μ3‐CH2)3{iPrNC(=CH2)NiPr}] ( 3 ) in 83 % yield. Similarly, the reaction of 1 with phenyl isothiocyanate gave the ethylene amido thiolate/trimethylidene complex [Cp′4Lu4(μ3‐CH2)3{PhNC(S)=CH2}] ( 4 ). In the case of phenyl isocyanate, two of the four methylidene units in 1 reacted with four molecules of the substrate at ambient temperature to give the malonodiimidate/dimethylidene complex [Cp′4Lu4(μ3‐CH2)2{PhN=C(O)CH2(O)C?NPh}2] ( 5 ) in 87 % yield. In this reaction, each of the two lutetium–methylidene bonds per methylidene unit inserted one molecule of phenyl isocyanate. All the products have been fully characterized by NMR spectroscopy, X‐ray diffraction, and microelemental analyses. 相似文献
4.
Xiancui Zhu Yuzhe Jiang Jun Chen Shaowu Wang Zeming Huang Shan Zhu Xu Zhao Wenrun Yue Jun Zhang Weikang Wu Xiangyang Zhong 《中国化学》2020,38(5):478-488
A series of dinuclear rare‐earth metal alkyl complexes {[μ‐η2:η1:η1‐3‐( L NCH)(CH2SiMe3)Ind]RE(CH2SiMe3)(THF)}2 ( L 1 = 2‐tBuC6H4, RE = Y, Gd, Dy, Er, Yb; L 2 = 2,4,6‐Me3C6H2, RE = Dy, Er; Ind = indolyl) and {[μ‐η2:η1:η1‐3‐( L NCH2)Ind]RE(CH2SiMe3)(THF)}2 ( L 1, RE = Y, Dy, Er, Yb; L 2, RE = Er, Yb) bearing 3‐arylamido functionalized indolyl ligands having diverse bonding modes with metal ions were synthesized either by the insertion reaction of the imino group to the RE—C bond or by the alkane elimination reaction. In the preparation of above complexes, rare‐earth metal alkyl complexes [μ‐η5:η1:η1‐3‐( L 2NCH)(CH2SiMe3)Ind]Gd(CH2SiMe3)(THF)}2 with a μ‐η5:η1:η1 coordination mode to the gadolinium ion and {[μ‐η3:η1:η1‐3‐( L 2NCH2)Ind]Dy(CH2SiMe3)(THF)}2 with a μ‐η3:η1:η1 coordination mode to the dysprosium ion were unexpectedly isolated. The reactions of 3‐( L 2N=CH)Ind with Er(CH2SiMe3)3(THF)2 at room temperature, generated a tetranuclear imino‐indolyl erbium intermediate {[μ‐η1:η1‐3‐( L 2N=CH)Ind]Er(CH2SiMe3)2(THF)}4, which can transform into the amido functionalized indolyl erbium complex in hot toluene. Moreover, the reactivities of the newly synthesized ytterbium complex with N‐heterocyclic compounds were investigated, affording the corresponding products of the mixed pyridyl‐indolyl, imidazolyl‐indolyl, and ortho‐metalated complexes. The yttrium complexes showed a high regioselectivity and steroselectivity for the isoprene polymerization with 1,4‐trans selectivity up to 91.7% and 1,4‐cis selectivity up to 96.1% in the presence of cocatalysts, respectively. 相似文献
5.
Herbert Schumann Frank Erbstein Dirk F. Karasiak Igor L. Fedushkin Jrg Demtschuk Frank Girgsdies 《无机化学与普通化学杂志》1999,625(5):781-788
The stepwise reaction of Me2SiCl2 with K[C5H3 tBuMe‐3] or Li[C9H7] and then with K[C9H6CH2CH2‐ NMe2‐1] followed by double deprotonation with NaH or LiBu, yields the two dimethylsilicon bridged cyclopentadienyl‐indenyl and indenyl‐indenyl donor‐functionalized ligand systems K2[(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)] ( 1 ), and Li2[(1‐C9H6)SiMe2(1‐C9H5CH2CH2NMe2‐3)] ( 2 ), respectively. Treatment of 1 with YCl3(THF)3, SmCl3(THF)1.77, TmI3(DME)3, and LuCl3(THF)3 gives the mixed ansa‐metallocenes [(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)]LnX (X = Cl, Ln = Y ( 3 ), Sm ( 4 ), Lu ( 5 ); X = I, Ln = Tm ( 6 )), respectively. The reaction of 2 with LuCl3(THF)3 yields [(1‐C9H6)SiMe2(1‐C9H5CH2CH2NMe2‐3)]LuCl ( 7 ). Compound 4 reacts with LiMe to give the corresponding alkyl derivative [(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)]Sm(CH3) ( 8 ). The new complexes were characterized by elemental analyses, MS spectrometry, and NMR spectroscopy. The molecular structures of 5 and 6 were determined by single crystal X‐ray diffraction. 相似文献
6.
SmCl3 reacts with Me3SiCH2Li in THF yielding Sm(CH2SiMe3)3(THF)3 ( 1 ). The single crystal X‐ray structural analyses of 1 , Er(CH2SiMe3)3(THF)2 ( 2 ), Yb(CH2SiMe3)3(THF)2 ( 3 ), and Lu(CH2SiMe3)3(THF)2 ( 4 ) show the Sm atom in a fac‐octahedral coordination and the heavier lanthanides Er, Yb, and Lu trigonal bipyramidally coordinated with the three alkyl ligands in equatorial and two THF molecules in axial positions. 相似文献
7.
Xiaomin Shang Xinli Liu Dongmei Cui 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5662-5672
Methoxy‐modified β‐diimines HL 1 and HL 2 reacted with Y(CH2SiMe3)3(THF)2 to afford the corresponding bis(alkyl)s [L1Y(CH2SiMe3)2] ( 1 ) and [L2Y(CH2SiMe3)2] ( 2 ), respectively. Amination of 1 with 2,6‐diisopropyl aniline gave the bis(amido) counterpart [L1Y{N(H)(2,6‐iPr2? C6H3)}2] ( 3 ), selectively. Treatment of Y(CH2SiMe3)3(THF)2 with methoxy‐modified anilido imine HL 3 yielded bis(alkyl) complex [L3Y(CH2SiMe3)2(THF)] ( 4 ) that sequentially reacted with 2,6‐diisopropyl aniline to give the bis(amido) analogue [L3Y{N(H)(2,6‐iPr2? C6H3)}2] ( 5 ). Complex 2 was “base‐free” monomer, in which the tetradentate β‐diiminato ligand was meridional with the two alkyl species locating above and below it, generating tetragonal bipyramidal core about the metal center. Complex 3 was asymmetric monomer containing trigonal bipyramidal core with trans‐arrangement of the amido ligands. In contrast, the two cis‐located alkyl species in complex 4 were endo and exo towards the O,N,N tridentate anilido‐imido moiety. The bis(amido) complex 5 was confirmed to be structural analogue to 4 albeit without THF coordination. All these yttrium complexes are highly active initiators for the ring‐opening polymerization of L ‐LA at room temperature. The catalytic activity of the complexes and their “single‐site” or “double‐site” behavior depend on the ligand framework and the geometry of the alkyl (amido) species in the corresponding complexes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5662–5672, 2007 相似文献
8.
Lewis Base Assisted Magnesium Complexes Incorporating Pyrrolyl and Ketiminate Ligands: Synthesis,Structural Diversity and Characterization 下载免费PDF全文
Li‐Feng Hsueh Min‐Hui Hsieh Shu‐Ya Hsu Cheng‐Yuan Lee Hsiang‐Hua Hsieh Amitabha Datta Jui‐Hsien Huang Chia‐Her Lin Ting‐Yu Lee 《中国化学会会志》2014,61(8):953-959
A series of four, five and six‐coordinated magnesium derivatives integrating with substituted pyrrole and ketimine ligands are conveniently synthesized. Reaction of two equiv of 2‐dimethylaminomethyl pyrrole with Mg[N(SiMe3)2]2 in THF affords the monomeric magnesium complex Mg[C4H3N(2‐CH2NMe2)]2 (THF)2 ( 1 ) in high yield along with elimination of two equiv of HN(SiMe3)2. Similarly, the reaction between two equiv of 2‐t‐butylaminomethyl pyrrole and Mg[N(SiMe3)2]2 in THF renders the magnesium derivative, Mg[C4H3N(2‐CH2NHtBu)]2(THF)22( 2 ) in good yield. Interestingly, reaction between two equiv of 2‐t‐butylaminomethyl pyrrole and Mg[N(SiMe3)2]2 in toluene, instead of THF, generates Mg[C4H3N(2‐CH2NHtBu)]2 ( 3 ), also in high yield. Furthermore, the assembly of two equiv of ketimine ligand, HOCMeCHCMeNAr (Ar = C6H3‐2,6‐iPr2) and Mg[N(SiMe3)2]2, yields five‐coordinated magnesium derivatives, Mg(OCMeCHCMeNAr)2(THF) ( 4 ) and Mg(OCMeCHCMeNAr)2(OEt2) ( 5 ), using THF and diethyl ether, respectively. All the aforementioned derivatives are characterized by 1H and 13C NMR spectroscopy as well as 1 , 3 , 4 and 5 are subjected to X‐ray diffraction analysis in solid state. 相似文献
9.
Yosi Kratish Daniel Pinchuk Alexander Kaushansky Victoria Molev Boris Tumanskii Dmitry Bravo‐Zhivotovskii Yitzhak Apeloig 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(52):19025-19029
Reactions of carbon monoxide (CO) with tBu2MeSiLi and (E)‐(tBu2MeSi)(tBuMe2Si)C=Si(SiMetBu2)Li?2 THF ( 4 ) were studied both experimentally and computationally. Reaction of tBu2MeSiLi with CO in hexane yields the first stable tetra‐silyl di‐ketyl biradical [(tBu2MeSi)2COLi].2 ( 3 ). Reaction of 4 with CO yields selectively and quantitatively the first reported 1‐silaallenolate, (tBu2MeSi)(tBuMe2Si)C=C=Si(SiMetBu2)OLi?THF ( 5 ). Both 3 and 5 were characterized by X‐ray crystallography and biradical 3 also by EPR spectroscopy. Silaallenolate 5 reacts with Me3SiCl to produce siloxy substituted 1‐silaallene (tBu2MeSi)(tBuMe2Si)C=C=Si(SiMetBu2)OSiMe3. The reaction of 4 with CO provides a new route to 1‐silaallenes. The mechanisms of the reactions of tBuMe2SiLi and of 4 with CO were studied by DFT calculations. 相似文献
10.
Isoprene polymerization with indolide‐imine supported rare‐earth metal alkyl and amidinate complexes
Yi Yang Qiaoyi Wang Dongmei Cui 《Journal of polymer science. Part A, Polymer chemistry》2008,46(15):5251-5262
Reaction of 7‐{(N‐2,6‐R)iminomethyl)}indole ( HL1 , R = dimethylphenyl; HL2 , R = diisopropylphenyl) and rare‐earth metal tris(alkyl)s, Ln(CH2SiMe3)3(THF)2, generated new rare‐earth metal bis(alkyl) complexes LLn(CH2SiMe3)2(THF) [L = L1: Ln = Lu ( 1a ), Sc ( 1b ); L = L2: Ln = Lu ( 3a ), Sc ( 3b )] and mono(alkyl) complexes L22Lu(CH2SiMe3) ( 4a ). Treatment of alkyl complexes 1a and 4a with N,N′‐diisopropylcarbodiimide afforded the corresponding amidinates L1Lu{iPr2NC(CH2SiMe3)NiPr2}2 ( 2a ) and L22Lu{iPr2NC(CH2SiMe3)NiPr2} ( 5a ), respectively. These new rare‐earth metal alkyls and amidinates except 4a in combination with aluminum alkyls and borate generated efficient homogeneous catalysts for the polymerization of isoprene, providing high cis‐1,4 selectivity and high molar mass polyisoprene with narrow molar mass distribution (Mn = 2.65 × 105, Mw/Mn = 1.07, cis‐1,4 98.2%, −60 °C). The environmental hindrance around central metals arising from the bulkiness of the ligands, the Lewis‐acidity of rare‐earth metal ions, the types of aluminum tris(alkyl)s and borate, and polymerization temperature influenced significantly on both the catalytic activity and the regioselectivity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5251–5262, 2008 相似文献
11.
The synthesis, characterization and ε‐caprolactone polymerization behavior of lanthanide amido complexes stabilized by ferrocene‐containing N‐aryloxo functionalized β‐ketoiminate ligand FcCOCH2C(Me)N(2‐HO‐5‐But‐C6H3) (LH2, Fc = ferrocenyl) are described. The lanthanide amido complexes [LLnN(SiMe3)2(THF)]2 [Ln = Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] were synthesized in good yields by the amine elimination reactions of LH2 with Ln[N(SiMe3)2]3(µ‐Cl)Li(THF)3 in a 1:1 molar ratio in THF. These complexes were characterized by IR spectroscopy and elemental analysis, and 1H NMR spectroscopy was added for the analysis of complex 4 . The definitive molecular structures of complexes 1 and 3 were determined by X‐ray diffraction studies. Complexes 1 – 4 can initiate the ring‐opening polymerization of ε‐caprolactone with moderate activity. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
12.
Diana Pohl Jochen Ellermann Matthias Moll Falk A. Knoch Walter Bauer 《无机化学与普通化学杂志》1996,622(2):283-291
Chemistry of Polyfunctional Molecules. 119 [1]. Tetracarbonyl-dicobalt-tetrahedrane Complexes with the Ligands Bis(diphenylphosphanyl)-amine, 2-Butin-1,4-diol, and tert.-Butylphosphaacetylene — Crystal Structure of the Phosphaalkyne Derivative Co2(μ-CO)2(CO)4(μ-Ph2P? NH? PPh2—P,P′) · 1/2C6H5CH3 ( 4 · 1/2C6H5CH3) reacts with 2-butine-1,4-diol, HOCH2? C?C? CH2OH ( 5 ), to the dark-red tetrahedrane complex Co2(CO)4(μ-η2,η2-HOCH2? C?C? CH2OH? C2, C3) · (μ-Ph2P? NH? PPh2? P,P′) · THF (6 · THF). With t-butyl-phosphaacetylene, tBu? C?P ( 7 ), 4 · THF forms Co2(CO)4(μ-η2,η2-tBu? C?P)(μ-Ph2P? NH? PPh2? P,P′) ( 8 ), which also belongs to the tetrahydrane type. The compounds were characterized by their mass, IR, 31P{1H} NMR, 13C{1H} NMR, and1H NMR spectra. Crystals suitable for X-ray structure analyses have been obtained for 8 from dioxane. The dark red blocks crystallize in the monoclinic P21/c space group with the lattice constants a = 1404,1(5), b = 1330,0(7), c = 2578,8(10)pm; β = 90,82(3)°. 相似文献
13.
Andreas Mommertz Roland Leo Werner Massa Klaus Harms Kurt Dehnicke 《无机化学与普通化学杂志》1998,624(10):1647-1652
Synthesis of a Titana-Oxacyclohexane Ring by Controlled Ring Opening of Tetrahydrofurane. Crystal Structures of [Ti(CH2)4O{Me2Si(NBut)2}]2, [TiCl{Me2Si(NBut)2}]3(μ3-O)(μ3-Cl), and [Li2(THF)3{Me2Si(NBut)2}] [TiCl3(THF)3] reacts with [(ButNLi)2SiMe2]2 in diethyl ether at –35 °C under redox disproportionation and formation of the yellow titana(IV)-oxacyclohexane complex [Ti(CH2)4O{Me2Si(NBut)2}]2. According to the crystal structure analysis the titanium atoms are linked to form centrosymmetric dimers via the oxygen atoms of the Ti(CH2)4O six-membered rings, which are in chair conformation. Along with the nitrogen atoms of the chelating [Me2Si(NBut)2]2– ligands the titanium atoms obtain a distorted trigonal-bipyramidal surrounding. While [TiCl{Me2Si(NBut)2}]3(μ3-O)(μ3-Cl) with a cluster-like structure is obtained as a by-product. According to the crystal structure analysis of [Li2(THF)3 · {Me2Si(NBut)2}], which is involved in the synthesis reaction, the two lithium atoms are connected with both the nitrogen atoms of the t-butyl amide groups and bridged via an oxygen atom of one of the THF molecules. 相似文献
14.
Fengying Zhou Suyun Zhang Yang Zhao Chongguang Zhang Xiaojuan Cheng Lina Zheng Yong Zhang Yahong Li Prof. Dr. 《无机化学与普通化学杂志》2009,635(15):2636-2641
Reaction of DyCl3 with two equivalents of NaN(SiMe3)2 in THF yielded {Dy(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln3+. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H2dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)2]2 ( 2 ) and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and 1H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl3 (Ln = Dy and Yb), LiN(SiMe3)2, and H2dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma2– ligand. 相似文献
15.
Chiral (1,2)‐Diphenylethylene‐Salen Complexes of Triel Metals: Coordination Patterns and Mechanistic Considerations in the Isoselective ROP of Lactide 下载免费PDF全文
Nicolas Maudoux Dr. Thierry Roisnel Dr. Vincent Dorcet Prof. Dr. Jean‐François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6131-6147
The synthesis of enantiomerically pure aluminium, gallium and indium complexes supported by chiral (R,R)‐(HHONNOHH) ( 1 ), (R,R)‐(MeHONNOHMe) ( 2 ), (R,R)‐(tButBuONNOtButBu) ( 3 ), (R,R)‐(MeNO2ONNOMeNO2) ( 4 ), (R,R)‐(HOMeONNOHOMe) ( 5 ) and (R,R)‐(ClClONNOClCl) ( 6 ) (1,2)‐diphenylethylene‐salen ligands is described. Several of these complexes have been crystallographically authenticated, which highlights a diversity of coordination patterns. Whereas all Ga complexes form [Ga2(CH2SiMe3)4(ONNO)] bimetallic species (ONNO= 1 – 3 ), aluminium [AlR(ONNO)] (R=Me, CH2SiMe3) and indium [In(CH2SiMe3)(ONNO)] derivatives are monometallic for ONNO= 1 , 2 and 4 – 6 , and only form the bimetallic complexes [Al2R4(ONNO)] and [In2(CH2SiMe3)4(ONNO)] for the most sterically crowded ligand 3 . The [AlMe(ONNO)] complexes react with iPrOH to give [AlOiPr(ONNO)] complexes that are robust towards further iPrOH. The [In(CH2SiMe3)(ONNO)] congeners are inert towards excess alcohol, whereas the Ga compounds decompose easily. All these alkyl complexes, as well as the [AlOiPr(ONNO)] derivatives, catalyse the ring‐opening polymerisation (ROP) of racemic lactide (rac‐LA). The [AlMe(ONNO)] complexes require additional alcohol to afford controlled reactions, but [AlOiPr(ONNO)] complexes are single‐component catalysts for the isoselective ROP of rac‐LA, with values of Pm in the range 0.80–0.90. Experimental evidence unexpectedly shows that chain‐end control leads to the isoselectivity of these aluminium catalysts; also, the more crowded the coordination sphere, the higher the isoselectivity. The bimetallic Ga complexes do not afford controlled reactions, but the binary [In(ONNO)(CH2SiMe3)/(PhCH2OH)] systems competently mediate non‐stereoselective ROP; evidence is given that an activated monomer mechanism is at work. Kinetic studies show that catalytic activity decreases when electronic density and steric congestion at the metal atom increase. 相似文献
16.
Silicon‐ and Tin‐Containing Open‐Chain and Eight‐Membered‐Ring Compounds as Bicentric Lewis Acids toward Anions 下载免费PDF全文
Dr. Anicet Siakam Wendji Dr. Christina Dietz Dr. Silke Kühn Michael Lutter Dr. Dieter Schollmeyer Dr. Wolf Hiller Prof. Dr. Klaus Jurkschat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):404-416
Herein, we report the syntheses of silicon‐ and tin‐containing open‐chain and eight‐membered‐ring compounds Me2Si(CH2SnMe2X)2 ( 2 , X=Me; 3 , X=Cl; 4 , X=F), CH2(SnMe2CH2I)2 ( 7 ), CH2(SnMe2CH2Cl)2 ( 8 ), cyclo‐Me2Sn(CH2SnMe2CH2)2SiMe2 ( 6 ), cyclo‐(Me2SnCH2)4 ( 9 ), cyclo‐Me(2?n)XnSn(CH2SiMe2CH2)2SnXnMe(2?n) ( 5 , n=0; 10 , n = 1, X= Cl; 11 , n=1, X= F; 12 , n=2, X= Cl), and the chloride and fluoride complexes NEt4[cyclo‐ Me(Cl)Sn(CH2SiMe2CH2)2Sn(Cl)Me?F] ( 13 ), PPh4[cyclo‐Me(Cl)Sn(CH2SiMe2CH2)2Sn(Cl)Me?Cl] ( 14 ), NEt4[cyclo‐Me(F)Sn(CH2SiMe2CH2)2Sn(F)Me?F] ( 15 ), [NEt4]2[cyclo‐Cl2Sn(CH2SiMe2CH2)2SnCl2?2 Cl] ( 16 ), M[Me2Si(CH2Sn(Cl)Me2)2?Cl] ( 17 a , M=PPh4; 17 b , M=NEt4), NEt4[Me2Si(CH2Sn(Cl)Me2)2?F] ( 18 ), NEt4[Me2Si(CH2Sn(F)Me2)2?F] ( 19 ), and PPh4[Me2Si(CH2Sn(Cl)Me2)2?Br] ( 20 ). The compounds were characterised by electrospray mass‐spectrometric, IR and 1H, 13C, 19F, 29Si, and 119Sn NMR spectroscopic analysis, and, except for 15 and 18 , single‐crystal X‐ray diffraction studies. 相似文献
17.
Diversification of ortho‐Fused Cycloocta‐2,5‐dien‐1‐one Cores and Eight‐ to Six‐Ring Conversion by σ Bond C−C Cleavage 下载免费PDF全文
Lee Eccleshare Leticia Lozada‐Rodríguez Phillippa Cooper Dr. Laurence Burroughs John Ritchie Dr. William Lewis Prof. Dr. Simon Woodward 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(35):12542-12547
Sequential treatment of 2‐C6H4Br(CHO) with LiC≡CR1 (R1=SiMe3, tBu), nBuLi, CuBr?SMe2 and HC≡CCHClR2 [R2=Ph, 4‐CF3Ph, 3‐CNPh, 4‐(MeO2C)Ph] at ?50 °C leads to formation of an intermediate carbanion (Z)‐1,2‐C6H4{CA(=O)C≡CBR1}{CH=CH(CH?)R2} ( 4 ). Low temperatures (?50 °C) favour attack at CB leading to kinetic formation of 6,8‐bicycles containing non‐classical C‐carbanion enolates ( 5 ). Higher temperatures (?10 °C to ambient) and electron‐deficient R2 favour retro σ‐bond C?C cleavage regenerating 4 , which subsequently closes on CA providing 6,6‐bicyclic alkoxides ( 6 ). Computational modelling (CBS‐QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H+ gave 1,2‐dihydronaphthalen‐1‐ols, or under dehydrating conditions, 2‐aryl‐1‐alkynylnaphthlenes. Enolates 5 react in situ with: H2O, D2O, I2, allylbromide, S2Me2, CO2 and lead to the expected C ‐E derivatives (E=H, D, I, allyl, SMe, CO2H) in 49–64 % yield directly from intermediate 5 . The parents (E=H; R1=SiMe3, tBu; R2=Ph) are versatile starting materials for NaBH4 and Grignard C=O additions, desilylation (when R1=SiMe) and oxime formation. The latter allows formation of 6,9‐bicyclics via Beckmann rearrangement. The 6,8‐ring iodides are suitable Suzuki precursors for Pd‐catalysed C?C coupling (81–87 %), whereas the carboxylic acids readily form amides under T3P® conditions (71–95 %). 相似文献
18.
Reactivity of TpMe2‐Supported Yttrium Alkyl Complexes toward Aromatic N‐Heterocycles: Ring‐Opening or CC Bond Formation Directed by CH Activation 下载免费PDF全文
Dr. Weiyin Yi Prof. Dr. Jie Zhang Shujian Huang Prof. Dr. Linhong Weng Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):867-876
Unusual chemical transformations such as three‐component combination and ring‐opening of N‐heterocycles or formation of a carbon–carbon double bond through multiple C–H activation were observed in the reactions of TpMe2‐supported yttrium alkyl complexes with aromatic N‐heterocycles. The scorpionate‐anchored yttrium dialkyl complex [TpMe2Y(CH2Ph)2(THF)] reacted with 1‐methylimidazole in 1:2 molar ratio to give a rare hexanuclear 24‐membered rare‐earth metallomacrocyclic compound [TpMe2Y(μ‐N,C‐Im)(η2‐N,C‐Im)]6 ( 1 ; Im=1‐methylimidazolyl) through two kinds of C–H activations at the C2‐ and C5‐positions of the imidazole ring. However, [TpMe2Y(CH2Ph)2(THF)] reacted with two equivalents of 1‐methylbenzimidazole to afford a C–C coupling/ring‐opening/C–C coupling product [TpMe2Y{η3‐(N,N,N)‐N(CH3)C6H4NHCH?C(Ph)CN(CH3)C6H4NH}] ( 2 ). Further investigations indicated that [TpMe2Y(CH2Ph)2(THF)] reacted with benzothiazole in 1:1 or 1:2 molar ratio to produce a C–C coupling/ring‐opening product {(TpMe2)Y[μ‐η2:η1‐SC6H4N(CH?CHPh)](THF)}2 ( 3 ). Moreover, the mixed TpMe2/Cp yttrium monoalkyl complex [(TpMe2)CpYCH2Ph(THF)] reacted with two equivalents of 1‐methylimidazole in THF at room temperature to afford a trinuclear yttrium complex [TpMe2CpY(μ‐N,C‐Im)]3 ( 5 ), whereas when the above reaction was carried out at 55 °C for two days, two structurally characterized metal complexes [TpMe2Y(Im‐TpMe2)] ( 7 ; Im‐TpMe2=1‐methyl‐imidazolyl‐TpMe2) and [Cp3Y(HIm)] ( 8 ; HIm=1‐methylimidazole) were obtained in 26 and 17 % isolated yields, respectively, accompanied by some unidentified materials. The formation of 7 reveals an uncommon example of construction of a C?C bond through multiple C–H activations. 相似文献
19.
Igor L. Fedushkin Prof. Dr. Anton N. Lukoyanov Markus Hummert Herbert Schumann Prof. Dr. 《无机化学与普通化学杂志》2008,634(2):357-361
At elevated temperatures, the aluminum complex [(dpp‐BIAN)AlI(Et2O)] ( 1 ) splits the C‐O bonds of diethyl ether and tetrahydrofurane yielding the dimeric alkoxides [(dpp‐BIAN)AlOEt]2 ( 2 ) and [(dpp‐BIAN)AlO(CH2)4I]2 ( 3 ), respectively. Already at ambient temperatures, a cleavage of the C‐O bond of THF is to observe in the reaction of 1 with CpNa in THF as confirmed by the formation of [(dpp‐BIAN)AlO(CH2)4C5H5]2 ( 4a ) and [(dpp‐BIAN)Al{O(CH2)4C5H5}(THF)] ( 4b ) in a molar ratio of 1:2. The reaction of 1 with t‐BuOK affords the monomeric alkoxide [(dpp‐BIAN)AlO‐t‐Bu(Et2O)] ( 5 ). Compounds 2 , 3 , and 4a/b were characterized by elemental analyses and IR spectra. Additionally, the structures of 2 and 3 were determined by single crystal X‐ray diffraction. 相似文献
20.
3‐Rhoda‐1,2‐diazacyclopentanes: A Series of Novel Metallacycle Complexes Derived From CN Functionalization of Ethylene 下载免费PDF全文
Marcus W. Drover Daniel W. Beh Prof. Dr. Pierre Kennepohl Prof. Dr. Jennifer A. Love 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13345-13355
Rh‐containing metallacycles, [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NR)2‐]Cl; TPA=N,N,N,N‐tris(2‐pyridylmethyl)amine have been accessed through treatment of the RhI ethylene complex, [(TPA)Rh(η2‐CH2CH2)]Cl ([ 1 ]Cl) with substituted diazenes. We show this methodology to be tolerant of electron‐deficient azo compounds including azo diesters (RCO2N?NCO2R; R=Et [ 3 ]Cl, R=iPr [ 4 ]Cl, R=tBu [ 5 ]Cl, and R=Bn [ 6 ]Cl) and a cyclic azo diamide: 4‐phenyl‐1,2,4‐triazole‐3,5‐dione (PTAD), [ 7 ]Cl. The latter complex features two ortho‐fused ring systems and constitutes the first 3‐rhoda‐1,2‐diazabicyclo[3.3.0]octane. Preliminary evidence suggests that these complexes result from N–N coordination followed by insertion of ethylene into a [Rh]?N bond. In terms of reactivity, [ 3 ]Cl and [ 4 ]Cl successfully undergo ring‐opening using p‐toluenesulfonic acid, affording the Rh chlorides, [(TPA)RhIII(Cl)(κ1‐(C)‐CH2CH2(NCO2R)(NHCO2R)]OTs; [ 13 ]OTs and [ 14 ]OTs. Deprotection of [ 5 ]Cl using trifluoroacetic acid was also found to give an ethyl substituted, end‐on coordinated diazene [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NH)2‐]+ [ 16 ]Cl, a hitherto unreported motif. Treatment of [ 16 ]Cl with acetyl chloride resulted in the bisacetylated adduct [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NAc)2‐]+, [ 17 ]Cl. Treatment of [ 1 ]Cl with AcN?NAc did not give the Rh?N insertion product, but instead the N,O‐chelated complex [(TPA)RhI ( κ2‐(O,N)‐CH3(CO)(NH)(N?C(CH3)(OCH?CH2))]Cl [ 23 ]Cl, presumably through insertion of ethylene into a [Rh]?O bond. 相似文献