共查询到20条相似文献,搜索用时 15 毫秒
1.
Reductive disilylation (Li+Me3SiCl−THF) of 1,3,5-cycloheptatriene led to 1,1′-bi[(S∗,S∗)-6-(trimethylsilyl)cyclohepta-2,4-dien-1-yl] (2). In the presence of TiCl4 in dichloromethane, 2 gave rise to a spherical molecule 5 resulting from an intramolecular formal [4+4] supra-supra cycloaddition. 相似文献
2.
Three new cocrystals based upon 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ) with 4,4′-bipyridine (4,4′-bipy), 1,2-bis(4-pyridyl)ethylene (bpe) and 1,3-bis(4-pyridyl)propane (bpp): [(DABTZ) (4,4′-bipy)], [(DABTZ) (bpe)] and [(DABTZ) (bpp)] have been synthesized and characterized by elemental analysis, IR-, 1H NMR-, 13C NMR spectroscopy and studied by thermal and X-ray crystallography. Self-assembly of these compounds in the solid state is likely caused by both hydrogen bonding, and π-π stacking. 相似文献
3.
The lithiation of 2,7-dihydrodinaphthoheteroepines (5) with 2.2 equiv of lithium naphthalenide in THF at −78 °C gives dianionic intermediates 8, which by reaction with different electrophiles [H2O, D2O, tBuCHO, Me2CO, Et2CO, (CH2)4CO, (CH2)5CO] at the same temperature, followed by hydrolysis, leads to unsymmetrically 2,2′-disubstituted binaphthyls 6. When the lithiation is performed with an excess of lithium in the presence of a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 10 mol %), a double reductive cleavage takes place to give dianionic intermediate 9, which by reaction with different electrophiles [H2O, Me2CO, Et2CO, (CH2)4CO, (CH2)5CO], followed by hydrolysis with water, yields symmetrically 2,2′-disubstituted binaphthyls 7. In the case of starting from (R)-5a, the reductive opening by treatment with 2.2 equiv of lithium naphthalenide followed by reaction with H2O or (CH2)5CO as electrophiles and final hydrolysis, leads to enantiomerically pure compounds (R)-6aa and (R)-6af, respectively. 相似文献
4.
Norman Lu Yan-Chou Lin Jeng-Yung Chen Tsung-Chi Chen Shih-Chieh Chen Yuh-Sheng Wen Ling-Kang Liu 《Polyhedron》2007
With the readily available fluorous alkanols RfCH2OH, a series of novel fluorous-ponytailed bpy ligands, 4,4′-bis(RfCH2OCH2)-2,2′-bpy (1a–e), were prepared and treated with [PdCl2(CH3CN)2] to result in the corresponding novel Pd complexes [PdCl2(4,4′-bis(RfCH2OCH2)-2,2′-bpy)] (2a–e) where Rf = n-C3F7 (a), HCF2(CF2)3 (b), HCF2(CF2)7 (c), n-C8F17 (d), n-C10F21 (e). The new ligands and Pd complexes were spectroscopically characterized by multi-nuclei NMR (1H, 19F and 13C), FTIR and high resolution mass (FAB). The structure for the Pd complex 2b, the first with fluorinated ponytails on bpy and not on phosphine, was also established by a single crystal X-ray diffraction study. The TGA data of both ligands and Pd complexes indicated that the Pd-complexes were resistant to higher temperatures than the corresponding ligands. The Pd catalysts derived from 2a–c showed an almost quantitative conversion and could be reused for eight runs with Heck reactions, in that the products and unspent reactants were directly removed by distillation. With the highest fluorine content in the series, Pd complex 2e was successfully applied in the Heck reaction using the fluorous biphasic catalysis strategy. 相似文献
5.
A new class of highly fluorinated aromatic poly(ether-amide)s was prepared through triphenyl phosphite-activated polycondensation of 2,2′-bis(3,4,5-trifluorophenyl)-4,4′-diaminodiphenyl ether (FPAPE) and four dicarboxylic acid comonomers. All the resulting polymers were thoroughly characterized by FT-IR, UV, and NMR spectroscopic methods. The effects of the fluorine atoms directly linked to the lateral phenyl rings as well as fluoro-containing phenyl groups attached to the macromolecular chains on some properties of the polymers were investigated by comparing with poly(ether-amide)s prepared from 4,4′-oxydianiline (4,4′-ODA) and 2,2′-diphenyl-4,4′-diaminodiphenyl ether (PAPE). The FPAPE-derived polymers exhibited excellent solubility in a variety of organic solvents. Results obtained from X-ray studies showed that the presence of the bulky fluoro-containing phenyl groups attached to the chains disrupts their structural order in a great amount, and leads to a decrease in crystallinity extent of the macromolecules. Furthermore, the highly fluorinated polymeric chains showed a significant enhancement in organo-solubility, heat-stability and Tg values when compared to their non-fluorinated counterparts. 相似文献
6.
Akın Baysal Murat Aydemir Feyyaz Durap Bahattin Gümgüm Saim Özkar Leyla Tatar Yıldırım 《Polyhedron》2007
New bis(phosphinoamine) and bis(phosphinite) derivatives of 2,2′-bipyridine were prepared through a single step reaction of 3,3′-diamino-2,2′-bipyridine or 3,3′-dihydroxy-2,2′-bipyridine with diphenylchlorophosphine, respectively. Their P = E chalcogenides (E = O, S, Se) were also prepared. All the new compounds were characterized by elemental analysis, IR and NMR spectroscopies. The molecular structure of 3,3′-bis(diphenylthiophosphinite)-2,2′-bipyridine was elucidated by single-crystal X-ray crystallography. 相似文献
7.
Qiong Ji YaoZaher M.A. Judeh 《Tetrahedron》2011,67(22):4086-4092
The preparation of new chiral 1,3-diamine ligand systems based on the 1,1′-methylene-bis(1,1′,2,2′,3,3′,4,4′-octahydroisoquinoline) framework is described. Synthesis of various mono-, di-, and bridged N-alkyl derivatives are presented. Resolution of one compound, its Cu(I)Br X-ray crystallographic structure and the preliminary results on its application in the enantioselective Henry and Aldol reactions are disclosed. 相似文献
8.
One of fluorinated polyimides was synthesized from 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′-dimethyl-4,4′-diaminodiphenylmethane (DMMDA) by two-steps method, which had good solubility and hydrophilicity. 6FDA-DMMDA polyimide was dissolved in chloroform (CHCl3) and cast on a glass substrate in a humid atmosphere. It was found that 6FDA-DMMDA/CHCl3 solution was easy to form ordered porous structure at high concentration, and the reason was discussed in detail. In addition, the influences of solution concentration, the atmosphere humidity, were also tested. 相似文献
9.
Halogeno(methyl)pentafluorophenylsilanes C6F5SiMenX3−n (n=1, 2) (X=F, Cl, Br) were prepared in good yields from the corresponding phenylsilanes C6F5SiMenPh3−n by reactions with the electrophiles aHF, HCl–AlCl3, Br2–AlBr3 or AlX3 (X=Cl, Br) halogenated hydrocarbons. Additionally, reactions of C6F5SiMe3 and (C6F5)2SiMe2 with selected electrophiles were studied. 相似文献
10.
Base-catalyzed reactions of propane-1,3-dithiols with 2-chloronitrobenzene, 3,4-dichloronitrobenzene, and 2-chloro-3-nitropyridine
afforded 1,3-bis(nitroarylthio)propanes, whose thiolate-thiolate exchange with propane-1,3-dithiols gave dihydrobenzodithiepines.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 163–166, January, 2006. 相似文献
11.
A series of ferrocene-based organosilicon compounds have been prepared via hydrosilylation or double silylation of carbonyl compounds with 1,1′-bis(dimethylsilyl)ferrocene using (C2H4)Pt(PPh3)2 or Ni(PEt3)4 catalysts. In general, while the platinum catalyst (C2H4)Pt(PPh3)2 preferentially produced cyclic double-silylated products, the Ni(PEt3)4 catalyst led to the hydrosilylated ferrocene products from aldehydes or ketones. 相似文献
12.
Toshiyuki Kamei 《Tetrahedron letters》2012,53(30):3894-3896
Scandium triflate-catalyzed iodination of 2,2′-dimethoxy-1,1′-binaphthyl with 2 equiv of 1,3-diiodo-5,5-dimethylhydantoin (DIH) proceeded to give 6,6′-diiodo-2,2′-dimethoxy-1,1′-binaphtyl in 98% yield and subsequent deprotection of methyl groups provided 6,6′-diiodo-1,1′-binaphthol, which is a useful ligand or reagent for many enantioselective transformations. Use of 2 equiv of NIS in place of DIH in the presence of scandium triflate, however, did not successfully yield 6,6′-diiodo-2,2′-dimethoxy-1,1′-binaphtyl, indicating that one of two types of iodine atoms in DIH is more reactive toward the iodination than iodine in NIS. 相似文献
13.
Virginia Ruiz 《Polymer Degradation and Stability》2006,91(12):3117-3123
UV-vis bidimensional spectroelectrochemistry has been applied to the study of the electrochemical stability of conducting polymer films during p- and n-doping processes. Specifically, poly(4,4′-bis(butylthio)-2,2′-bithiophene) has been chosen as example to prove the usefulness and suitability of this multi-response technique to characterize polymer stability during p- and n-doping. It was found that oxidative doping and corresponding de-doping alone did not result in noticeable polymer film degradation. However, in experiments involving both p- and n-doping of this conducting polymer, soluble species arising from the polymer film were detected in solution for the first time, indicating a lower electrochemical stability of the film under these experimental conditions. Moreover, bidimensional spectroelectrochemistry has enabled us not only to detect the soluble degradation products, but also the potential range in which the degradation takes place. 相似文献
14.
The title product 4,4′-hexafluoroisopropylidene-2,2-bis-(phthalic acid anhydride) was prepared from hexafluoroacetone and o-xylene as the starting materials by condensation, oxidation and dehydration three-step reaction sequence. It reacted with diamines in DMF or xylene to give polyimides by condensation polymerization. Thermal and viscosity analyses show that these polyimides have lower molecular weight but excellent thermal stability. 相似文献
15.
Eleven new complexes of the form cis-[RuII(bpy)2(LA)]4+ (bpy = 2,2′-bipyridyl; LA = a pyridinium-substituted bpy derivative) have been prepared and isolated as their PF6− salts. Characterisation involved various techniques including 1H NMR spectroscopy and MALDI mass spectrometry. The UV-Vis spectra show intense intraligand π → π∗ absorptions and metal-to-ligand charge-transfer (MLCT) bands with two distinct maxima in the visible region. Small shifts in the MLCT bands correlate with the electron-withdrawing strength of the ligand LA. Cyclic voltammograms show quasi-reversible or reversible RuIII/II oxidation waves, and two or more ligand-based reductions with varying degrees of reversibility. The variations in the redox potentials correlate with changes in the structure of LA, and also with the MLCT energies. Differential pulse voltammetry allows the first reduction process for two of the complex salts to be resolved into two peaks. Single-crystal X-ray structures have been solved for three of the new complex salts and also for a pro-ligand salt. Two carboxylate-functionalised compounds have been tested as photosensitizers on TiO2-coated electrodes, but show only negligible efficiencies, in accord with expectations. 相似文献
16.
Martin Pomerantz 《Tetrahedron letters》2003,44(8):1563-1565
Ab initio calculations have shown that when carbonyl groups are incorporated into the 3- and 3′-positions of bithiophenes, as part of five-membered rings, the bithiophene system is planar. This is due to electrostatic attraction between the carbonyl oxygen and the sulfur atom in the adjacent ring. In the analogous systems containing a CH2 group in place of the carbonyl, or containing six-membered rather than five-membered rings, the bithiophenes are twisted. This has implications for preparing planar polythiophenes. 相似文献
17.
G. Bator W. Sawka-DobrowolskaL. Sobczyk M. OwczarekA. Pawlukoj? E. GrechJ. Nowicka-Scheibe 《Chemical physics》2012,392(1):114-121
In crystalline state 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) forms with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP) the hydrogen bonded chains along the b-axis. From one side of the CLA molecule the proton transfer takes place and the hydrogen bond length is very short (2.615 Å). A continuous infrared absorption is observed for dtBBP·CLA in the wavenumber range between 3100 and 800 cm−1 also indicating the strong hydrogen bonds. The DSC measurements show a weak, close to continuous, phase transition at 414 K. The complex dielectric permittivity for a single crystal sample was measured in the temperature range 100-440 K and at frequencies between 200 Hz and 2 MHz. The dielectric response is a combination of semiconducting properties and a relaxation process most probably connected with the proton dynamics in the hydrogen bonds. The mechanism of the structural phase transition is discussed. 相似文献
18.
Vasily V. Bashilov Pavel V. Petrovskii Mara Sada Gianni Zotti 《Journal of organometallic chemistry》2005,690(19):4330-4336
η2-Fullerene (C60 and C70) palladium optically active complexes with the axially chiral enantiomeric ligand of bithienyl series, [(−)tetraMe-BITIOP], have been synthesized and investigated by 31P-{1H} NMR, electronic spectroscopy, CD spectroscopy, cyclic voltammetry and by single crystal X-ray diffraction. 相似文献
19.
Various phenols, methoxy aromatic compounds, 3- and 4-hydroxycoumarins and enols smoothly condense with 2-hydroxy-2,2′-biindan-1,1′,3,3′-tetrone 1 in an acid medium producing 2-aryl/alkyl-2,2′-biindan-1,1′,3,3′-tetrones in high yields. The adducts of resorcinol, 1,3,5-trihydroxybenzene and α- and β-naphthols of 1 preferably remain in the intramolecular hemi-ketal form, confirmed by X-ray diffraction studies. On the other hand para and meta substituted phenols condense with 1 in an acid medium to produce 6 or 7 substituted 2′,4-spiro(1′,3′-indanedion)-indeno[3,2-b]chromenes in good yields. 相似文献
20.
Kazem D. Safa Farnaz Behmagham Khatereh Ghorbanpour 《Journal of organometallic chemistry》2011,696(9):1840-1844
The magnesium bromide-diethyl etherate-catalyzed ring-opening of (3-(naphthalen-2-yl)-2,2-bis(trimethylsilyl)oxiran 2 with thiophenols affords (1-trimethylsilylvinyl)sulfides 3 and the (1-bromovinyl)silane 4. Nucleophilic attack occurs regioselectively at the position α- to silicon. The compound 2 has been converted into the (1-trimethylsilylvinyl)amide 5 with an excess of acetonitrile and into the (1-trimethylsilylvinyl)acetate 6 with acetic acid/acetic anhydride. These reactions proceed with catalytic amounts of boron trifluoride-diethylether. Treatment of 2 with acetic acid alone gives naphthaldehyde. The epoxide 2 reacts also with MgBr2·OEt2, MeLi/CuI, HX (XBr or Cl) and LiAlH4 with nucleophilic attack at the bis(trimethylsilyl)-substituted carbon. 相似文献