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1.
Reaction of the Nicalon polycarbosilane with the n-BuLi/Me3COK reagent resulted in metalation of approximately one CH2 group in four. Reaction of the metalated polymer with Me2 (CH2 = CH)SiCl gave a Me2(CH2 = CH)Si-substitued Nicalon polycarbosilane. The polymer was heated with different amounts of the [(MeSiH)~0.8(MeSi)~0.2]n polysilane in the presence of azobisisobutyronitrile in refluxing benezene. Hydrosilylation by the Si? H-containing polysilane of the CH2?CH groups of the Me2(CH2?CH) Si-substituted Nicalon polycarbosilane gave a new hybrid polymer (when appropriate quantities of reactant polymers were used) whose pyrolyis in a stream of argon to 1000°C left a ceramic residue in 77% yield whose elemental analysis indicated a nominal composition of 91% by weight SiC and 9% C. 相似文献
2.
采用密度泛函理论(DFT)研究了螺桨烷型分子BX[(CH2)n]3和BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的结构、稳定性、化学键和电子光谱性质.计算结果表明这些分子都是稳定的.BX[(CH2)n]3(X=N,P;n=1-6)的最高占据分子轨道(HOMO)和最低空分子轨道(LUMO)之间的能隙均大于5.20 eV,其中BN[CH2]3和BP[CH2]3的能隙超过7.0 eV,与C5H6的能隙(7.27 eV)很接近,BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的能隙在6.80 eV左右.所研究分子能量的二阶差分表明BN[(CH2)3]3、BP[(CH2)4]3及BX(CH2)[CH(CH2)2CH](X=N,P)是最稳定的.BX[(CH2)n]3的Wiberg键级表明除了BN[(CH2)n]3(n=2和6)中不存在B―N键,其它化合物中B和N均形成了化学键,BP[(CH2)n]3中除了BP[(CH2)2]3不存在B―P键,其它的均存在.电子密度的拓扑分析表明N―B键属于离子键,而P―B键具有共价键特征.BX[(CH2)n]3(X=N,P)的第一垂直激发能分别在191.1-284.8 nm和191.8-270.1 nm之间,BX(CH2)[CH(CH2)n CH](X=N,P)的第一垂直激发能分别在190.5-199.7 nm和209.0-221.3 nm之间. 相似文献
3.
Dr. Ramachandran Azhakar Dr. Rajendra S. Ghadwal Prof. Dr. Herbert W. Roesky Prof. Dr. Ricardo A. Mata Hilke Wolf Regine Herbst‐Irmer Prof. Dr. Dietmar Stalke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3715-3720
Three‐ and five‐membered rings that bear the (Si‐C‐S ) and (Si‐C‐C‐C‐S ) unit have been synthesized by the reactions of L SiCl ( 1 ; L =PhC(NtBu)2) and L′ Si ( 2 ; L′ =CH{(C?CH2)(CMe)(2,6‐iPr2C6H3N)2}) with the thioketone 4,4′‐bis(dimethylamino)thiobenzophenone. Treatment of 4,4′‐bis(dimethylamino)thiobenzophenone with L SiCl at room temperature furnished the [1+2]‐cycloaddition product silathiacyclopropane 3 . However, reaction of 4,4′‐bis(dimethylamino)thiobenzophenone with L′ Si at low temperature afforded a [1+4]‐cycloaddition to yield the five‐membered ring product 4 . Compounds 3 and 4 were characterized by NMR spectroscopy, EIMS, and elemental analysis. The molecular structures of 3 and 4 were unambiguously established by single‐crystal X‐ray structural analysis. The room‐temperature reaction of 4,4′‐bis(dimethylamino)thiobenzophenone with L′ Si resulted in products 4 and 5 , in which 4 is the dearomatized product and 5 is formed under the 1,3‐migration of a hydrogen atom from the aromatic phenyl ring to the carbon atom of the C? S unit. Furthermore, the optimized structures of probable products were investigated by using DFT calculations. 相似文献
4.
The intersecting parabolas model is used to analyze experimental data for the following radical cyclization and decyclization reactions: RCH=CH(CH2)nN·R1 cyclo-[NR1CH(CH2)n]C·HR,R(CH2)2OOCH2C·HR cyclo-[RCHOCH2] + RCH2CH2O·, cyclo-[(CH2)nOOCHC· HR] cyclo-[RCHOCH](CH2)nO·, cyclo-[(CH2)nOC·RO] RC(O)O(CH2)
n–1C·H2, and cyclo-[(CH2)nCHO·] CH(O)(CH2)
n–1C·H2. The activation energy of the thermally neutral reaction (E
e,0) is calculated for each class of reactions. E
e,0 depends on the electronegativity of the heteroatom Y of the reaction center C
C...Y, the force constants of the reacting bonds, and the strain energy of the ring formed. For the cyclization and decyclization of six-membered rings, the empirical relationship between the elongation of the reacting bonds in the transition state (r
e) and the difference in electronegativity (EA) between the C and Y atoms (Y = C, N, O) has the form r
e ×1011, m = 3.83 – 0.0198(EA, kJ/mol).Translated from Kinetika i Kataliz, Vol. 46, No. 1, 2005, pp. 5–13.Original Russian Text Copyright © 2005 by Denisova, Denisov. 相似文献
5.
Christopher Glidewell 《Structural chemistry》1990,1(6):511-516
The experimentally known reaction between the electron-rich germylene [(Me3Si)2N]2Ge andp-CH3C6H4SO2N3 has been modeled computationally by MNDO calculations on the reaction intermediates formed by [CH3Si)2E]2Ge (E=N or CH) and CH3CON3. Molecular and electronic structures have been established for the acyclic germaketimines [(CH3Si)2E]2Ge=N-N=N-COCH3 (the primary 11 adducts formed by the reactants) and [CCH3Si)2E]2Ge=N-COCH3, and for the cyclic species [(H3Si)2E]2Ge-N=N-N=C(CH3)-O, [(H3Si)2E]2Ge-N=N-N(COCH3), and [(H3Si)2E]2-Ge-N=C(CH3-O. The intermediates [(H3Si)2E]2-GeN(N2)COCH3 were found, upon formation, to undergo smooth dissociation along the N()-N() bond, with loss of N2, to provide acyclic [H3Si)2E]2Ge=N-COCH3; the polymerizations of these latter species to form polygermazanes are extremely exothermic. 相似文献
6.
K. R. Brzezinska K. B. Wagener G. T. Burns 《Journal of polymer science. Part A, Polymer chemistry》1999,37(6):849-856
Methoxydimethylsilane and chlorodimethylsilane‐terminated telechelic polyoctenomer oligomers (POCT) have been prepared by acyclic diene metathesis (ADMET) chemistry using Grubbs' ruthenium Ru(Cl2)(CHPh)(PCy3)2 [Ru] or Schrock's molybdenum Mo(CH CMe2Ph)(N 2,6 C6H3 i Pr2)(OCMe(CF3)2)2 [Mo] catalysts. These macromolecules have been characterized by FTIR, 1H‐, 13C‐, and 29Si‐NMR spectroscopy. The molecular weight distributions of these polymers have been determined by GPC and vapor pressure osmometry (VPO). The number‐average molecular weight (Mn) values of the telechelomers are dictated by the initial ratio of the monomer to the chain limiter. The termini of these oligomers (Mn = 2000) can undergo a condensation reaction with hydroxy‐terminated poly(dimethylsiloxane) (PDMS) macromonomer (Mn = 3300) [HO Si(CH3)2 O { Si(CH3)2O }x Si(CH3)3], producing an ABA‐type block copolymer, as follows: (CH3)3SiO [ Si(CH3)2O ]x [ CHCH (CH2)6 ]y [ OSi(CH3)2 ]x OSi(CH3)3. The block copolymers were characterized by 1H‐ and 13C‐NMR spectroscopy, VPO, and GPC, as well as elemental analysis, and were determined by VPO to have a Mn of 8600. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 849–856, 1999 相似文献
7.
The fragmentation patterns and major metastable ions of the mass spectra of the neopentyl-phosphorus derivatives [(CH3)3CCH2]3P, [(CH3)3CCH2]2P(O)H, [(CH3)3CCH2]nPX3-n (n = 1 and 2; X = H, Cl, C6H5 and CH = CH2), [(CH3)3CCH2]3PS, [(CH3)3CCH2]nP(S)R3-n (n = 1 and 2; R = C6H5 and CH = CH2), [(CH3)3 CCH2]2PCH2CH2P[CH2C(CH3)3]2, ([CH3)3CCH2]2PCH2PCH2-CH2P(H)C6H5 and [(CH3)3CCH2]2PCH2CH2P(S)(CH3)2 are described. Fragmentation of a neopentyl group by elimination of either C4H8 or CH3 is very favourable when the neopentyl group is bonded to either a tricoordinate or tetracoordinate phosphorus atom. In neopentylphosphines with two or three neopentyl groups, stepwise elimination of C4H8 from all of the neopentyl groups occurs very readily. The resulting [(CH3)nPX]+.3-n ions are often the most intense ions in the mass spectra. 相似文献
8.
Takayuki Otsu Shuzo Aoki Masato Nishimura Masami Yamaguchi Yoshihiro Kusuki 《Journal of polymer science. Part A, Polymer chemistry》1969,7(12):3269-3277
The polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH3)nSiCl4?n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl4 > CH3SiCl3 > (CH3)2SiCl2 > (CH3)3SiCl ? 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH3)3SiCl > (CH3)2SiCl2 > CH3SiCl3 ? SiCl4. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed. 相似文献
9.
S. V. Kirpichenko A. T. Abrosimova A. I. Albanov M. G. Voronkov 《Russian Journal of General Chemistry》2001,71(12):1874-1878
Unsaturated organosilicon amines [CH2 = CH(CH2)
n
]Me2Si[(CH2)
m
NHPh] at the action of Hg(OAc)2 in THF solution transform to corresponding heterocycles. Regioselectivity of this intramolecular electrophilic heterocyclization is defined by the position of double bond relatively to the silicon atom. This is caused by -effect of the silyl group. 相似文献
10.
S. F. Zhil’tsov M. A. Dydykina O. N. Druzhkova 《Russian Journal of General Chemistry》2010,80(9):1767-1770
Praseodymium and ytterbium phenylethynyl cuprates [(PhC≡C)3Cu]3Pr2(THF)6 and {[(PhC≡C)3Cu]·Yb(THF)2}2 react with acetyl chloride in tetrahydrofuran with elimination of phenylethynylcopper and formation of alkoxides [PhC≡C-CCl(CH3)O]
n
Ln (n = 3, Ln = Pr; n = 2, Ln = Yb). Then praseodymium alkoxide forms ester [methyl (phenylethynyl)chloromethylethanoate] and praseodymium chloride,
alkoxy derivative. Itterbium alkoxide is oxidized to unsymmetrical dialkoxyitterbium chloride PhC≡C-CH(CH3)-O-Yb(Cl)-O-CCl(CH3)C≡CPh·2THF. 相似文献
11.
Numerous experimental data for the cyclization of free radicals C·H2(CH2)nCH=CH2 cyclo-[(CH2)n+1CH(C·H2)], and C·H2(CH2)nCH=CHR cyclo-[(CH2)n+1C·HCHR] were analyzed in the framework of the parabolic model. The activation energy of thermoneutral (H
e = 0) cyclization E
e0 decreases linearly with an increase in the energy of cycle strain E
rsc: E
e0(n) (kJ mol–1) = 85.5 – 0.44E
rsc(n) (n is the number of atoms in the cycle). The activation entropy of cyclization S
# also depends on the cycle size: the larger the cycle, the lower S
#. A linear dependence of S
# on the difference between the entropies of formation S° of cyclic hydrocarbon and the corresponding paraffin was found: S
# = 1.00[S°(cycle) – S°(CnH2n+2)]. The E
e0 values coincide for cyclization reactions with the formation of the six-membered cycle and the bimolecular addition of alkyl radicals to olefins. 相似文献
12.
Four new mixed‐ring zirconium completes, [CH2 = CH(CH2)n ‐C5H4](RC5H4)ZrCl2 [n = l, R = CH3OCH2CH2(3); n = 2, R = CH3OCH2CH2 (4); n = 2, R=Me3Si (5); n = 2, R = allyl (6)], have been prepared by the reaction of CH2 = CH(CH2)n C5H4ZrCl3, DME[n = l (1); n = 2 (2)] with RC5H4Li. When activated with methylaluminoxane (MAO), the catalytic activities of the above complexes in ethylene polymerization were tested. Complexes 5 and 6 show high activities similar to Cp2ZrCl2. Introduction of methoxyethyl group into Cp‐ligand dramatically decreases the catalytic activities of complexes 3 and 4, which can be overcome by increasing the amount of MAO. For complex 5, the dependence of activity and molecular weight (Mη) on the Al/Zr ratio, the polymerization time (tP), polymerization temperature (TP) and the polymerization solvent volume (V) was investigated. 相似文献
13.
Silicon‐ and Tin‐Containing Open‐Chain and Eight‐Membered‐Ring Compounds as Bicentric Lewis Acids toward Anions
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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
14.
Barbara Gehrhus Peter B. Hitchcock Helen Jansen 《Journal of organometallic chemistry》2006,691(4):811-816
Reaction of the thermally stable silylene Si[(NCH2But)2C6H4-1,2] (1) [abbrev. as Si(NN)] with SiX4 (X = Cl or Br) afforded the disilanes (NN)SiX(SiX3) and [(NN)SiX]2 (X = Br only), the trisilane (NN)SiX-[(SiX3)Si(NN)] and the monosilane (NN)SiX2 (X = Br only), whereas treatment of 1 with MCl4 (M = Ge or Sn) yielded (NN)SiCl2 and MCl2. [(NN)SiBr]2 and (NN)SiBr2 were also obtained by reaction of 1 with Br2. Reaction of 1 with PhSiCl3 yielded the disilane (NN)SiCl(SiCl2Ph) and trisilane [(NN)SiCl]2SiClPh, whereas the disilane (NN)SiCl(SiCl2Me) was obtained with MeSiCl3. The trisilane (NN)SiCl-[(SiCl3)Si(NN)] was thermally labile and converted to [(NN)SiCl]2SiCl2. 相似文献
15.
Spontaneous Double Hydrometallation Induced by N→M Coordination in Organometallic Hydrides of Group 14 Elements
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Miroslav Novák Dr. Libor Dostál Dr. Jan Turek Dr. Mercedes Alonso Prof. Frank De Proft Prof. Aleš Růžička Dr. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(16):5620-5628
Our attempts to synthesise N→M intramolecularly coordinated diorganometallic hydrides L2MH2 [M=Si ( 4 ), Ge ( 5 ), Sn ( 6 )] containing the CH=N imine group (in which L is C,N‐chelating ligand {2‐[(2,6‐iPr2C6H3)N=CH]C6H4}?) yielded 1,1′‐bis(2,6‐diisopropylphenyl)‐2,2′‐spriobi[benzo[c][1,2]azasilole] ( 7 ), 1,1′‐bis(2,6‐diisopropylphenyl)‐2,2′‐spriobi[benzo[c][1,2]azagermole] ( 8 ) and C,N‐chelated homoleptic stannylene L2Sn ( 10 ), respectively. Compounds 7 and 8 are an outcome of a spontaneous double hydrometallation of the two CH=N imine moieties induced by N→M intramolecular coordination (M=Si, Ge) in the absence of any catalyst. In contrast, the diorganotin hydride L2SnH2 ( 6 ) is redox‐unstable and the reduction of the tin centre with the elimination of H2 provided the C,N‐chelated homoleptic stannylene L2Sn ( 10 ). Compounds 7 and 8 were characterised by NMR spectroscopy and X‐ray diffraction analysis. Because the proposed N→M intramolecularly coordinated diorganometallic hydrides L2MH2 [M=Si ( 4 ), Ge ( 5 ), Sn ( 6 )] revealed two different types of reduction reactions, DFT calculations were performed to gain an insight into the structures and bonding of the non‐isolable diorganometallic hydrides as well as the products of their subsequent reactions. Furthermore, the thermodynamic profiles of the different reaction pathways with respect to the central metal atom were also investigated. 相似文献
16.
Christopher Glidewell 《Structural chemistry》1990,1(4):317-323
The reactions between methyl diazoacetate, HC(N2)COOMe, and a range of germylenes L2Ge [L = CH3], NH2, OCH3, Ph, CH=CH2, SiH3, (H3Si)2N, and (H3Si)2CH] have been studied using MNDO calculations. Molecular and electronic structures have been determined for the transoid germaketimines L2Ge=N-N=C(H)COOMe [the primary 11 adducts of L2Ge and HC(N2)COOMe], for their cyclic cisoid isomers, and for the germaethenes L2Ge=C(H)COOMe. The intermediate L2GeCH(N2)COOMe was found to dissociate smoothly along the unique GeC bond when L = NH2, OCH3, or (H3Si)2N (so leading to no net reaction) but to undergo facile loss of N2, forming the germaethene L2Ge=C(H)COOMe, when L = CH3, Ph, CH=CH2, SiH3, or (H3Si)2CH. The calculations thus enable the prediction of substantially different patterns of reactivity, and hence different products, in the reactions between diazo compounds and the two closely similar germylenes [(Me3Si)2N]2Ge and [(Me3Si)2CH]2Ge. 相似文献
17.
The group [(CH3)3Si]2CH is effectively bulkier than the (CH3)3C group in inhibiting rotation about the PC bond in R2PCI compounds. In phosphonamidous chlorides, RP(CI)NR2′, increasing the bulk of the groups at nitrogen, e.g., from CH3 to (CH3)2CH to (CH3)3Si, increases the rotational barriers about the PN bond; however, changing R from (CH3)3C to [(CH3)3Si]2CH increases the barrier, which is a reversal of the trend earlier observed. It is suggested that these very bulky silylated groups represent limiting cases of steric interference. 相似文献
18.
The reaction of the Si8O208? silicate anion with X(CH3)2SiCl (X?H or CH3) has been studied to develop a cost‐effective procedure for synthesizing Si8O20[Si(CH3)2X]8 in high yield. Use of hexane as solvent and adjustment of the reaction temperature to ca 20 °C were found to be effective in promoting the reaction, by which Si8O20[Si(CH3)2X]8 could be produced in good yield employing 24 mol of X(CH3)2SiCl per mole of Si8O208?. It was also demonstrated that the yield of Si8O20[Si(CH3)2X]8 depends on the amount of solvent, suggesting that the amount is an important factor when scaling up the reaction to produce a large quantity of Si8O20[Si(CH3)2X]8. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
19.
Deeb Taher 《Transition Metal Chemistry》2009,34(6):641-645
The heterotrimetallic complex 1,1′-[Fc(SeRuCp(PPh3)2)2] is accessible by the reaction of 1,1′-[Fc(SeLi)2·2THF] (Fc = Fe(η5-C5H4)2, THF = Tetrahydrofuran) with two equivalents of CpRu(PPh3)2Cl in high yield. Complex 1,1′-[Fc(SeLi)2·2THF] can be prepared by treatment of 1,1′-[Fc(SeSiMe3)2] with two equivalents of n-BuLi in THF solution. 1,1′-[Fc(SeRuCp(PPh3)2)2] is converted to 1,1′-[Fc(SeRuCpCO(PPh3))2] under CO atmosphere in THF solution. The complexes 1,1′-[Fc(SeRuCp(PP))2] [PP = Ph2P(CH2)PPh2 (dppm), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH=CH)2PPh2 (dppee), Ph2P(CH2)3PPh2 (dppp)] are obtained in a one-pot reaction of CpRu(PPh3)2Cl and 1,1′-[Fc(SeLi)2·2THF] with the chelating bisphosphine ligand. 相似文献
20.
E. Yu. Ladilina T. S. Lyubova V. V. Semenov O. V. Kuznetsova A. I. Kirillov V. I. Faerman A. Yu. Dolgonosova M. A. Baten’kin M. A. Lopatin 《Russian Chemical Bulletin》2010,59(3):590-597
Perfluoroadipic bis(trialkoxysilylpropyl)amide was synthesized as a mixture of five compounds with the general formula (EtO)
n
(MeO)3-n
Si(CH2)3NHC(O)(CF2)4C(O)NH(CH2)3-Si(OMe)
n
(OEt)3-n
(1, n = 1, 2). Hydrolysis of this product by a specified amount of water (1: 4) gave oligomers EtO[(HO)(EtO)Si(CH2)3NH(O)C(CF2)4C(O)NH(CH2)3Si(OEt)2O]nH (
n
= 7–9). From oligomer solutions, transparent glassy thermally stable films were obtained. The film material was studied by
IR spectroscopy, atomic force microscopy, transmission electron microscopy, and powder X-ray diffraction. Compound 1 and oligomers
can efficiently solvate lanthanide diketonate complexes. They displace water from the metal coordination sphere, and this
water is then spent for hydrolysis of trialkoxysilyl groups. The luminescence intensity of matrix films based on the oligomers
depends on the concentration of lanthanide complexes and is very low at 7nexc = 330 nm, whereas the luminescence intensity of the Eu3+ cation is very high. 相似文献