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L-脯氨酸对离子液体介质中的不对称Michael反应催化性能研究 总被引:1,自引:0,他引:1
研究了L-脯氨酸对离子液体介质中醛(酮)与β-硝基烯烃的不对称Michael加成反应的催化性能, 利用X射线单晶衍射对Michael产物结构进行了表征. 结果表明, 反应在遵循胺催化机理的同时, 烯胺是从Re面对β-硝基烯烃进行加成, 产物的优势结构为(1R,2S)的syn型. 脯氨酸在离子液体1-正己基-3-甲基咪唑氯盐中显示良好的催化性能, 室温反应3~5 h, 得到89%以上收率的Michael产物, 其ee值最高70%. 脯氨酸与离子液体形成的催化体系具有良好的重复使用性能, 可至少稳定地重复使用6次. 相似文献
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以BrΦnsted酸性离子液体[HSO3-bpy][HSO4]为催化剂, 将吲哚或取代吲哚与α,β-不饱和酮在乙腈中于80 ℃下反应3 h, 以92%~98%的产率制备了一系列的β-吲哚酮. 该方法简便易行且产率高. 催化剂离子液体对环境友好, 并可循环使用. 相似文献
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离子液体介质中钌纳米粒子催化苯乙酮及其衍生物的不对称加氢反应 总被引:1,自引:0,他引:1
采用水溶性三(间-磺酸钠苯基)膦(TPPTS)作稳定剂, 在离子液体1-丁基-3-甲基-咪唑四氟硼酸盐([BMIM]BF4)或1-丁基-3-甲基-咪唑对甲基苯磺酸盐([BMIM][p-CH3C6H4SO3])介质中用氢气还原RuCl3·3H2O, 得到钌纳米粒子. 将此钌纳米粒子与(1S, 2S)-1,2-二苯基乙二胺(简称(1S, 2S)-DPEN)、KOH在离子液体/异丙醇介质中原位生成一种不对称加氢催化剂, 用于催化苯乙酮及其衍生物的不对称加氢反应. 实验结果表明, 离子液体介质中的纳米钌催化剂体系具有良好的催化活性和对映选择性. 在优化反应条件下, 催化苯乙酮获得了100%的转化率和79.1%的对映选择性. 并且产物经正己烷萃取后, 含有钌纳米粒子的离子液体可以循环使用. 相似文献
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A. Leineweber 《Journal of solid state chemistry》2003,176(1):198-202
A re-interpretation and re-evaluation of single-crystal X-ray diffraction data of a previously reported ‘(NH4)2(NH3)[Ni(NH3)2Cl4]’ (J. Solid State Chem. 162 (2001) 254) give a new formula (NH4)2−2z[Ni(NH3)2]z[Ni(NH3)2Cl4] with z=0.152. This new formula results from defects in an idealized ‘(NH4)2[Ni(NH3)2Cl4]’ basic structure, where two adjacent NH4+ cations are replaced by one Ni(NH3)22+ unit. Cl− anions from the basic structure complete the coordination sphere of the new Ni2+ to [Ni(NH3)2Cl4]2−. 相似文献
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C.J. Antony M. Junaid Bushiri Hema Tresa Varghese C. Yohannan Panicker Michel Fleck 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,73(5):942-945
Raman and FTIR spectra of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO42− tetrahedra with distinct S–O bonds. The distortion of the sulphate tetrahedra is attributed to Zn–O–S–O–Zn bridging in the structure as well as hydrogen bonding. The CN3 group is planar which is expressed in the twofold symmetry along the C–N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH2)3]2 and HC(NH2)3 are computed using Gaussian 03 with HF/6-31G* as basis set. 相似文献
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Mg Kα X-ray photoelectron (ESCA) spectra of the Co 2p levels have been obtained in trans- and cis-[Co(NH3)4Cl2]Cl isomers. It is observed that these compounds slowly decompose under X-ray irradiation. A procedure is employed to record real spectra for both the trans and cis isomers without any significant complication by the decomposition products. Three satellites are observed in both spectra at binding energies ≈ 4.8 eV, ≈ 9.3 eV, and ≈ 16.5 eV greater than that of the Co 2p peak. These isomers are distinguished from one another by the sizable difference in the relative intensity of the first satellite to the main peak. The first two satellites are assigned to ligand to Co 3d shake-up transitions by use of symmetry arguments based on molecular orbital theory, while the origin of the third satellite is less certain. The implication of the results is discussed. 相似文献
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Cyclohexane solutions of [W(Cp)(CO)3]2 and [Mo(Cp)(CO)3]2 exhibit weak bimodal emission spectra when excited With 354 nm picosecond pulses, but do not luminesce when pumped at 530 nm. Picosecond lifetimes characterize the short-wavelength, emission bands, which may originate from metal-cyclopentadienyl CT excited states. 相似文献
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Double complex salts (DCSs) [Co(NH3)6][Fe(CN)6] (I) and [Co(NH3)6]2[Cu(C2O4)2]3 (II) and complex [Co(NH3)6]2(C2O4)3·4H2O (III) are synthesized and investigated by single crystal XRD, crystal optics, and elemental analysis. The crystalline phases of
I, II, and III (R-3, P21/c, and Pnnm space groups respectively) have the following crystallographic characteristics: a = 10.9804(2) ?, b = 10.9804(2) ?, c = 10.8224(3) ?, V = 1130.03(4) ?3, Z = 3, d
x = 1.65 g/cm3 (I); a = 9.6370(2) ?, b = 10.2452(2) ?, c = 13.2108(3) ?, V = 1932.90(9) ?3, Z = 2, d
x= 1.97 g/cm3 (II), and a = 11.7658(3) ?, b = 11.7254(3) ?, c = 14.1913(4) ?, V = 1304.34(5) ?3, Z = 2, d
x = 1.68 g/cm3 (III). This paper investigates the products of DCS thermolysis in a hydrogen atmosphere: the intermetallic compound CoFe with
the bcc parameter a = 2.852 ? for I and a heterogeneous mixture of Co and Cu in the decomposition of II. The coordinated CN− and C2O42− groups then turn into NH3, hydrocarbons, and CO2. The dominant hydrocarbon is methane. 相似文献
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The temperature dependence measurements of 35Cl NQR frequencies and 1H NMR spin-lattice relaxation time T1 were carried out for guanidinium tetrachloro-aurate(III), -platinate(II), and -palladate(II). The gold(III) complex showed four NQR lines at various temperatures between 77 and 344 K, while the platinum-(II) and palladium(II) complexes gave two NQR lines in the temperature ranges 77–169 K and 77–220 K, respectively. An unusual phase transition was located at 363 K for the gold(III) complex. The high-temperature phase was easily supercooled. All the complexes studied yielded a T1 minimum attributable to the reorientation of the planar cation about its C3 axis. The motional parameters were evaluated. The Zeeman-quadrupole cross relaxation between protons and chlorine nuclei was observed for the platinum(II) and palladium(II) complexes at various temperatures below room temperature, while it was also detected for the high-temperature phase of the gold(III) complex. 相似文献
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A. I. Smolentsev A. I. Gubanov A. V. Zadesenets P. E. Plyusnin I. A. Baidina S. V. Korenev 《Journal of Structural Chemistry》2010,51(4):709-713
This contribution presents the results of a single crystal X-ray diffraction study of three ammine complexes of bivalent platinum
and palladium: [Pt(NH3)4](N03)2, [Pd(NH3)4](N03)2 and [Pd(NH3)4]F2H2O. The first two compounds are isostructural; metal atoms are located on inversion centers, all other atoms are in general
positions. A three-dimensional framework is built from planar-square complex cations and nitrate ions joined by N-H...O hydrogen
bonds. In [Pd(NH3)4]F2H2O, palladium atoms, as in the previous cases, are located on inversion centers, while oxygen atoms of water molecules are
on the two-fold symmetry axis. A network of strong N-H...F and O-H...F hydrogen bonds linking the cations, anions, and crystallization
water molecules is present in the structure. 相似文献
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The title compound was synthesized by reaction of Cu(ClO4)2, picolinic acid and carbamide in C2H5OH/CH3CN solution, and characterized by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a=14.0481(8), b=9.0130(5), c=18.626(1)?, V=2358.3(2)?3, Z=4, Dx=1.771g·cm-3, μ=1.235mm-1 and F(000)=1276. The final R factor is 0.0440 for 1434 observed reflections. The X-ray analysis revealed that the copper(Ⅱ) atom is coordinated by two picolinic ligands in the equatorial plane, while the two oxygen atoms of perchlorate occupy the axial positions of octahedron with lengthened Cu-O distances, resulting in a 4+2 elongated octahedral environment. In the compound, there also exist two protonated carbamide cations for charge balance. CCDC: 195354. 相似文献
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S. I. Pechenyuk D. P. Domonov D. L. Rogachev A. T. Belyavskii 《Russian Journal of Inorganic Chemistry》2007,52(7):1033-1038
The thermolysis of complexes [Co(NH3)6][Fe(CN)6] and [Co(NH3
6]4[Fe(CN)6]3 under an air or hydrogen atmosphere at 200, 350, and 500°C is studied. The composition and properties of thermolysis products
are determined. The oxidative thermolysis yields mixtures of oxides of the central metals; the reductive thermolysis yields
intermetallic compounds CoFe. The density of the complexes and the specific surface area of the intermetallic compounds are
measured. Average particle sizes are calculated. The morphology and dispersion of the powders are dictated by the shape and
density of the crystals of the precursor double salts and the thermolysis temperature. The thermolysis chemism in the oxidative
and reductive atmospheres is discussed in the context of the nature of the complex anion.
Original Russian Text ? S.I. Pechenyuk, D.P. Domonov, D.L. Rogachev, A.T. Belyavskii, 2007, published in Zhurnal Neorganicheskoi
Khimii, 2007, Vol. 52, No. 7, pp. 1110–1115. 相似文献
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在离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIm][BF4])中以HAuCl4·3H2O为主盐、通过添加5,5-二甲基乙内酰脲(DMH)和胞嘧啶可得到色泽光亮、厚度达1.5 μm的金镀层,沉积过程中阴极电流效率可达到100%。SEM和XRD测试结果表明,DMH和胞嘧啶具有细化晶粒、平整镀层的作用。电化学测试结果表明,DMH可分别与Au3+、Au+形成配合物[Au(DMH)4]-、[Au(DMH)2]-,抑制了还原过程的表面转化步骤,从而增加了阴极极化,起到光亮镀层、细化晶粒的作用;胞嘧啶可在金核表面吸附,从而可以进一步光亮镀层、细化晶粒,与DMH有协同作用。循环伏安测试研究了镀液的电化学行为,研究表明在此体系中Au3+的还原为两步还原过程,分别为Au3+→ Au+和Au+→ Au。此外DMH和胞嘧啶的添加不会带来副反应。 相似文献