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1.
从酸的电子给体HO-C6H4-CHCH-C6H4-NO2(OSN)可以向碱的电子受体Me2N-C6H4-CHCH-C5H4N(DAMS)发生质子转移,质子转移后形成的相应离子与其中性分子相比,光学非线性增强.采用ZINDO-SOS,FF/PM3及CPHF/PM3三种方法对其进行了系统的理论研究.三种方法研究结果均表明,质子转移后所产生的离子和相应的中性分子相比,其第一超极化率β和第二超极化率γ-都显著增强.  相似文献   

2.
通过硼烷阴离子网-B3H8-和闭-B10H102-与一系列卤化铵反应合成出十五种新的硼烷阴离子铵盐。这些新化合物均经元素分析和红外光谱鉴定。它们的差热分析结果表明:B10H102-铵盐的热稳定性高于B3H8-铵盐;在季铵离子中导入氨基以后,化合物的热稳定性降低,并且导入的氨基愈多,化合物愈不稳定。  相似文献   

3.
Functionalized aromatic halides Ar1XY (Ar1 = C6H4, Y = OCH3, CONH2, CN, COCH3, CHO, COC6H5) undergo SRN1 reactions with sulphur anions -SR, either simple (R=C2H5, CH2C6H5) or functionalized (R = (CH2)2OH, (CH2)2CO2Et, CH2CO2Et). Products Ar1YS- formed from the fragmentation of the radical anion Ar1YSR- are related to the redox potential of the aryl moiety Ar1Y and with the energy of the bond S-R. In the heterocyclic series (Ar2 = pyridine, Ar3 = quinoline) a similar relationship appears but a competitive SN(Ar) reaction occurs for pyridine substrates bearing an electron withdrawing group. A direct synthesis of benzothiophen via SRN1 reaction and an improved synthesis of thienopyridines based on the SN(Ar) reaction are reported.  相似文献   

4.
Extended basis sets of gaussian functions were used to calculate near Hartree-Fock estimates of the electric dipole polarizabilities, , and first hyperpolarizabilities, β, of the “inorganic benzenes” B3N3H6, B3O3H3, B3P3H3 and Al3N3H6. Assuming that electron delocalization is responsible for the enhanced polarizabilities of aromatic systems, an aromaticity scale can be set up according to the trend of theoretical polarizabilities obtained in this work, i.e. (B3O3H3) < (B3N3H6 ) < (C6H6 ), which is consistent with previous calculations of the degree of delocalization in these compounds.  相似文献   

5.
The cyclomercurated ferrocenylimines containing heterocyclic ring can be prepared by the cyclomercuration of acylferrocene, followed by the condensation of the resulting product with the appropriate heterocyclic amine. This procedure provides an efficient method for the synthesis of cyclomerucurated ferrocenylimines containing heterocyclic ring which is difficultly synthesized by the traditional method, i.e. imination and then cyclomercuration. A series of these compounds were synthesized by this new method and characterized. The X-ray crystal structure of [HgCl(η5-C5H3C(CH3)=N-2-C5H3N-6-CH3) Fe(η5-C5H5)] (3d) has been determined and the reaction mechanism was proposed.  相似文献   

6.
The behaviour of tetraarylstannanes, R4Sn (R = C6H5CH2, C6H5, o-, m-, p-CH3C6H4), towards SO2 under various conditions has now been studied in detail. Compared to aliphatic tetraorganostannanes, the variability of the reaction products is much less, so that in nearly all cases only disulfinates, R2Sn(O2SR)2, are formed. The aromatic tin(IV) mono-, di- and tri-sulfinates are also obtained by metathetical reaction between the corresponding organotin halides and sodium sulfinates. A unique feature of triaryltin chlorides, R3SnCl (R = C6H5, o-, m-, p-CH3C6H4), is their disproportionation in liquid SO2 leading to disulfinates, R2Sn(O2SR)2, and dichlorides, R2SnCl2. (p-CH3C6H4)2SnCl2, under more efficient conditions, also accepts SO2 forming (p-CH3C6H4SO2)2SnCl2. The structural investigations of the newly prepared compounds are carried out on the basis of their IR and 1H NMR spectra.  相似文献   

7.
The compound (o-MeC6H4Me2Si)3CH has been prepared and shown to be metallated slowly by MeLi in refluxing THF to give the lithium reagent (o-MeC6H4Me2Si)3CLi. This reacts with MeI to give (o-MeC6H4Me2Si)3CMe, but not with Me2SiHCl nor with a range of other organosilicon halides.  相似文献   

8.
There is currently considerable interest in the synthesis of new material with large second-order optical nonlinearities[1-2]. Ferrocenyl derivatives that we synthesized should offer the nonlinear optical properties because they possess (-donor acceptor interactions and non-centrosymmetry. In these compounds, ferrocenyl moiety is strong donor and pyridinium moiety can provide low-lying (* acceptor orbitals. Furthermore, these ferrocenyl compounds may also be used in preparation of self-assembled monolayers (SAMs)[3] due to their long alkyl chain that can be anchored on metal oxide by carboxylic group. The synthesis of ferrocenyl derivatives is shown in Scheme 1.  相似文献   

9.
在有机合成中可用芳磺酰基作暂时性活化基团。芳磺酰基乙酸酯是具有活性亚甲基的弱酸性化合物。通常要在氢化钠、醇钠存在下才能起烷基化反应。Ono等曾报道4-甲苯磺酰基乙酸甲酯在DBu存在下进行烷基化反应,但反应时间长。近年来,相转移催化在有机反应中的应用受到重视,然而用固液相转移催化法使芳磺酰基乙酸酯起烷基化反应还未见报道。我们在K2CO3/DMF体系中,用TEBA作催化剂,研究了4-氯苯磺酰基乙酸异丙酯与不同类型卤代烃所起的烷基化反应。合成了尚未见报道的一或二烷基化产物。  相似文献   

10.
通过两步法合成铜掺杂的氧化锌纳米棒,通过X射线衍射(XRD)、扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)分光光谱等技术对系列样品进行了表征,研究并探索了铜掺杂的氧化锌纳米棒光降解染料罗丹明B(RhB)和气体乙醛的催化活性。通过对多孔Cu掺杂ZnO纳米棒光催化分解乙醛进行了评价。多孔Cu掺杂ZnO纳米棒(CZ-5)光催化剂具有最高的催化分解乙醛的能力,比其它多孔Cu掺杂ZnO纳米棒具有很高的催化活性。多孔Cu掺杂ZnO纳米棒光催化剂在室温下在可见光(435 nm)下照射16 h,5.50×10-4φ,体积分数)的乙醛气体完全降解为二氧化碳(CO2)。多孔铜掺杂的氧化锌纳米棒光催化剂的光催化性能的改善主要归因于铜和氧化锌纳米棒之间的协同作用。这种改进的光催化协同作用归因于Cu掺杂ZnO的可见光吸收的延伸和光生电子空穴对的抗重组。  相似文献   

11.
将水溶性膦/钌配合物Ru3(CO)9(TPPTS)3(TPPTS:三苯基膦三-间磺酸钠)用于以CO为还原剂的水/有机两相芳香硝基化合物选择还原为芳胺的反应,发现相转移催化剂对反应有明显的促进作用,其中以添加十六烷基三甲基溴化铵(CTAB)的效果最好.以邻氯硝基苯为底物考察了相转移催化剂浓度、NaOH浓度、反应温度、压力等对反应转化率和选择性的影响.当反应条件为120℃,4MPa,3mol/LNaOH时,反应8h,邻氯硝基苯的转化率和邻氯苯胺的选择性均可达到99.9%.而且对含有羰基、氰基的芳香硝基化合物也有很高的活性和选择性.催化剂循环3次后,邻氯硝基苯的转化率和邻氯苯胺的收率仍可达到92%.  相似文献   

12.
Owing to the lack of suitable precursor complexes and applicable synthetic methodology, few soluble divalent organosamarium compounds are known. Recently, a facile route to SmI2(THF)2 proceeding from the bulk metal powder and several organic halides has been described by Kagan & co-workers. We demonstrate herein that this material or the desolvated salt can be used directly in mathematical syntheses (as illustrated by the synthesis of insoluble Sm(C8H8) and the THF-soluble K2Sm(C8H8)2).  相似文献   

13.
Meerwein芳基化反应是在烯键上导入芳基的一种重要方法:ArN2Cl+RCH=CHZ→ArCR=CHZ+ArCHRCHClZ化合物RCH=CHZ中Z为电子取代基时,反应容易进行,Z为OAc、OR时,也可以起芳基化反应,但烯胺(Z=NR2)与芳基重氮盐作用,只得到偶联产物。烯胺与N,N-二烷基苯胺为插烯物(Vinglogs),由于氮原子上的未共电子对与π键共轭,使烯键或苯环碳原子上电子密度增加,容易起偶联反应。  相似文献   

14.
From the reaction of MeReO3 with the neutral arylamine C6H5CH2NMe2 and the aryldiamine C6H4(CH2NMe2)2−1,3, have been isolated in good yields the 1/1 adduct complex [MeReO3 · C6H5CH2NMe2], 1, and the 2/1 adduct complex [(MeReO3)2 · C6H4(CH2NMe2)2− 1,3], 2, respectively. The X-ray molecular structure of 2 shows that both rhenium centres have a trigonal bipyramidal geometry and in the axial positions of each rhenium centre are one of the NMe2 units of the aryldiamine ligand and a methyl group. The mono(ortho)-chelated arylaminorhenium trioxide complex [ReO3(C6H4CH2NMe2−2], 3, can be synthesized by a transmetallation reaction of ClReO3 with [ZnC6H4CH2NMe2−22] in a 2:1 molar ratio. In a similar way the bis(ortho)-chelated arylaminorhenium trioxide complex [ReO3C6H3(CH2NMe2)2−2,6], 4, can be synthesized by addition of a mixture of [Li2C6H3(CH2NMe2)2−2,62] and ZnCl2 to ClReO3. Complexes 3 and 4 have been isolated as white solids in 66% and 81% yields respectively. The rhenium centre in complex 4 has a bicapped tetrahedral geometry in which the monoanionic C6H3(CH2NMe2)2−2,6 ligand is pseudo-facially bonded with a characteristic N1-Re-N2 angle of 107.7(3)°, a Re-Cipso bond length of 2.112(11) Å and Re-N1 and Re-N2 bond lengths of 2.518(9) Å and 2.480(8) Å respectively.  相似文献   

15.
Reaction of YbI2 with two equivalents of cyclopentylindenyl lithium (C5H9C9H6Li) affords ytterbium(II) substituted indenyl complex (C5H9C9H6)2Yb(THF)2 (1) which shows high activity to ring-opening polymerization (ROP) of lactones. The reaction between YbI2 and cyclopentylcyclopentadienyl sodium (C5H9C5H4Na) gives complex [(C5H9C5H4)2Yb(THF)]2O2 (2) in the presence of a trace amount of O2, the molecular structure of which comprises two (C5H9C5H4)2Yb(THF) bridged by an asymmetric O2 unit. The O2 unit and ytterbium atoms define a plane that contains a Ci symmetry center.  相似文献   

16.
In order to complete the rs structure of chlorobenzene given in a preceding paper, a variety of isotopic species of this molecule were synthesized and their microwave spectra studied. This made twenty isotopic species available, enabling the determination of the geometrical parameters by a least squares method. Fitting only differences of moments of inertia either for monosubstituted species or to multiply substituted species gave the same result. They hardly differ from the ro values and agree with the rs values obtained by the Kraitchman equations. The resulting error limits were reduced, however.

The following structural parameters were obtained, C1C2 = 1.399 Å, C2C3 = 1.386 Å, C3C4 = 1.3976 Å, C1Cl = 1.7248 Å, C2H2 = 1.080 Å, C3H3 = 1.081 Å, C4H4 = 1.081 Å, C6C1C2 = 120° 16, C1C2C3 = 119°78, C2C3C4 = 120°24, C3C4C5 = 119°80, C1C2H2 = 119°45, C2C3H3 = 119°76.

The structure of the ring differs significantly from C6 symmetry. The deformation can be regarded as a compression of the position C1 while the angle of C2H2 bond is also changed.  相似文献   


17.
A series of heterocyclic compounds of triazole thione substituted by tetrazole(I)were prepared using nicotinic acid as starting material through several steps.They reacted with 1-O-trifluoroacety1-2,3,5-O-tri-benxoyl-β-D-ribofuranose(Ⅱ) inanhydrous CH2Cl2 at room temperature in the presence of BF3·Et2O to give nine new nucleosides, named as 3-[5-(3-pyridyl)-tetrazol-2-yl-methylene]-4-aryl,2,4-triazole-5-(4H)-thione-2, 3, 5-O-tribenwyl-β-D-ribo-furanoside(Ⅲ)(Ar=C6H5,o-MeC6H4,m-MeC6H4,p-MeC6H4,o-MeC6H4,p-MeC6H4,p-EtOC6H3,3,4-Me2C6H4,a-C10H7).The structures and compositions were characterized by means of elemental analysis and spectroscopic methods.  相似文献   

18.
Brianna R. White  James A. Holcombe   《Talanta》2007,71(5):2015-2020
A new fluorescent peptidyl chemosensor for Cu2+ ions with fluorescence resonance energy transfer (FRET) capabilities has been synthesized via Fmoc solid-phase peptide synthesis. The metal chelating unit, which is flanked by the fluorophores tryptophan (donor) and dansyl chloride (acceptor), consists of the amino acids glycine and aspartic acid (Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly-Asp-Gly-Gly). Coordination of the Cu2+ ions to the metal chelating unit results in fluorescent quenching of both the donor and acceptor fluorophores. Although it was determined that Cu2+ binding causes no change in FRET efficiency, emission and Cu2+-induced quenching of the acceptor dye can be used to monitor the concentration of the copper ions, with a detection limit of 32 μg L−1. The sensor also demonstrated sensitivity, reversibility and selectivity towards Cu2+ in a transition metal matrix at pH 7.0.  相似文献   

19.
A predominantly localized electron pair scheme is outlined for describing the electron distribution and bonding in closo borane anions BnHn2− and related electron deficient deltahedral clusters, in which a skeletal electron pair is assigned to each vertex, one pair being regarded as delocalized just inside the roughly spherical surface on which the skeletal atoms lie. The scheme gives a clearer picture of the electron distribution than is conveyed by resonating 2- and 3-centre bonds in the polyhedron edges and faces, and allows the bond orders of the polyhedron edge links to be calculated readily. The consequence of formal removal of BH2+ units from closo species BnHn2− to generate nido species Bn−1Hn−14− and arachno species Bn−2Hn−26− is explored, and seen to allow rationalization of two features of such deltahedral-fragment clusters: (i) why a high-connectivity vertex is left vacant and (ii) why the frontier orbitals of such species concentrate electronic charge around their open faces. Moreover, in the case of D4‘h B4H46− (cf. C4H42−) and D5h B5H56− (cf. C5H5), the approach leads directly to the familiar picture for aromatic ring systems in which the highest filled, doubly degenerate π-bonding molecular orbital concentrates electronic charge in rings above and below the polygon on which the skeletal nuclei lie. It also leads to the expectation that arachno clusters with non-adjacent vacant vertices will be more stable than those with adjacent vacant vertices.  相似文献   

20.
A one flask synthesis of cis -substituted amphipathic porphyrins is reported. These porphyrins were used to study electrostatic effects on photoinduced electron transfer across the lipid bilayer-water interface. A neutral porphyrin undergoes only dynamic interfacial electron transfer reactions irrespective of charge of the acceptor, although ionic strength effects indicate a negative charge on the porphyrin donor species. A dianionic porphyrin forms an interfacial static complex with a dicationic electron acceptor, methyl viologen, at low ionic strength. The electron transfer rate within the complex is slow, 105∼ 106 s-1, which is attributed to a near orthogonal orientation between the donor and the acceptor ∼ orbitals.  相似文献   

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