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N‐(2‐Bromoethyl)‐4‐piperidino‐1,8‐naphthalimide and N‐(3‐bromopropyl)‐4‐piperidino‐1,8‐naphthalimide
Tei Tagg C. John McAdam Brian H. Robinson Jim Simpson 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o388-o391
N‐(2‐Bromoethyl)‐4‐piperidino‐1,8‐naphthalimide, C19H19BrN2O2, (I), and N‐(3‐bromopropyl)‐4‐piperidino‐1,8‐naphthalimide, C20H21BrN2O2, (II), are an homologous pair of 1,8‐naphthalimide derivatives. The naphthalimide units are planar and each piperidine substituent adopts a chair conformation. This study emphasizes the importance of π‐stacking interactions, often augmented by other contacts, in determining the crystal structures of 1,8‐naphthalimide derivatives. 相似文献
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Arca M Bencini A Berni E Caltagirone C Devillanova FA Isaia F Garau A Giorgi C Lippolis V Perra A Tei L Valtancoli B 《Inorganic chemistry》2003,42(21):6929-6939
The synthesis and characterization of three new bis([9]aneN(3)) ligands, containing respectively 2,2'-bipyridine (L(1)), 1,10-phenanthroline (L(2)), and quinoxaline (L(3)) moieties linking the two macrocyclic units, are reported. Proton binding and Cu(II), Zn(II), Cd(II), and Pb(II) coordination with L(1)-L(3) have been studied by potentiometric titrations and, for L(1) and L(2), by spectrophotometric UV-vis measurements in aqueous solutions. All ligands can give stable mono- and dinuclear complexes. In the case of L(1), trinuclear Cu(II) complexes are also formed. The stability constants and structural features of the formed complexes are strongly affected by the different architecture and binding properties of the spacers bridging the two [9]aneN(3) units. In the case of the L(1) and L(2) mononuclear complexes, the metal is coordinated by the three donors of one [9]aneN(3) moiety; in the [ML(2)](2+) complexes, however, the phenanthroline nitrogens are also involved in metal binding. Finally, in the [ML(3)](2+) complexes both macrocyclic units, at a short distance from each other, can be involved in metal coordination, giving rise to sandwich complexes. In the binuclear complexes each metal ion is generally coordinated by one [9]aneN(3) unit. In L(1), however, the dipyridine nitrogens can also act as a potential binding site for metals. The dinuclear complexes show a marked tendency to form mono-, di-, and, in some cases, trihydroxo species in aqueous solutions. The resulting M-OH functions may behave as nucleophiles in hydrolytic reactions. The hydrolysis rate of bis(p-nitrophenyl)phosphate (BNPP) was measured in aqueous solution at 308.1 K in the presence of the L(2) and L(3) dinuclear Zn(II) complexes. Both the L(2) complexes [Zn(2)L(2)(OH)(2)](2+) and [Zn(2)L(2)(OH)(3)](+) and the L(3) complex [Zn(2)L(3)(OH)(3)](+) promote BNPP hydrolysis. The [Zn(2)L(3)(OH)(3)](+) complex is ca. 2 orders of magnitude more active than the L(2) complexes, due both to the short distance between the metal centers in [Zn(2)L(3)(OH)(3)](+), which could allow a bridging interaction of the phosphate ester, and to the simultaneous presence of single-metal bound nucleophilic Zn-OH functions. These structural features are substantially corroborated by semiempirical PM3 calculations carried out on the mono-, di-, and trihydroxo species of the L(3) dizinc complex. 相似文献
54.
Tei Newman-Lehman Roberto Grana Kalyanasundaram Seshadri Forman Williams 《Proceedings of the Combustion Institute》2013,34(2):2147-2153
Knowledge of combustion of hydrocarbon fuels with nitrogen-containing oxidizers is a first step in understanding key aspects of combustion of hypergolic and gun propellants. Here an experimental and kinetic-modeling study is carried out to elucidate aspects of nonpremixed combustion of methane (CH4) and nitrous oxide (N2O), and ethane (C2H6) and N2O. Experiments are conducted, at a pressure of 1 atm, on flames stabilized between two opposing streams. One stream is a mixture of oxygen (O2), nitrogen (N2), and N2O, and the other a mixture of CH4 and N2 or C2H6 and N2. Critical conditions for extinction are measured. Kinetic-modeling studies are performed with the San Diego Mechanism. Experimental data and results of kinetic-modeling show that N2O inhibits the flame by promoting extinction. Analysis of the flame structure shows that H radicals are produced in the overall chain-branching step 3H2 + O2 ? 2H2O + 2H, in which molecular hydrogen is consumed. Hydrogen is also consumed in the overall step N2O + H2 ? N2 + H2O where stable products are formed. Inhibition of the flames by N2O is attributed to competition between these two overall steps. 相似文献
55.
Ryusuke Horiuchi Koichi Saiki Koji Adachi Kazuyoku Tei Shigeru Yamaguchi 《Optical Review》2008,15(3):136-139
A high-peak-power and high-repetition-rate fiber laser architecture is successfully demonstrated using a single-stage fiber
amplifier. Nonlinear optical effects in a fiber amplifier degrade the monochromaticity of amplified laser pulses. In general,
it is difficult for a non-monochromatic laser pulse to realize high-order harmonic generation with bulk nonlinear optical
crystals. To overcome this problem, a single-stage amplifier architecture and a gain fiber with a high cladding absorption
coefficient are employed. Furthermore, single-stage amplification enables the use of a multi-longitudinal mode electro-optically
(EO) Q-switched micro seed laser. This architecture can generate a peak power of 100 kW at 50 kHz and an average power of
10 W. A second-harmonic conversion efficiency of 51% is obtained using this architecture and a LiB3O5 (LBO) crystal. 相似文献
56.
Shamsipur M Javanbakht M Mousavi MF Ganjali MR Lippolis V Garau A Tei L 《Talanta》2001,55(6):507-1054
Three different mixed aza-thioether crowns containing a 1,10-phenanthroline sub-unit were investigated to characterize their abilities as copper(II) ion carriers in PVC-membrane electrodes. The electrode based on L1 exhibited a Nernstian response for Cu2+ ions over a wide concentration range (2×10−1 to 1×10−5 M) with a limit of detection of 8.0×10−6 M (0.5 p.p.m.). The response time of sensor is 15 s, and the membrane can be used for more than 3 months without observing any deviation. The electrode revealed comparatively good selectivities with respect to many alkali, alkaline earth, transition and heavy metal ions, and could be used in a pH range of 2.5–5.5. It was applied to the direct determination and potentiometric titration of the copper(II) ion. 相似文献
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Barge A Tei L Upadhyaya D Fedeli F Beltrami L Stefanìa R Aime S Cravotto G 《Organic & biomolecular chemistry》2008,6(7):1176-1184
Efficient routes to DOTA-monoamide ligands bearing amino, hydroxyl, aldehyde and maleimido groups are described. These functional groups, which can be spaced at will from the coordination cage, will readily react with suitable groups of targeting moieties. Bioconjugates obtained in this way can be used for diagnostic imaging and therapeutic applications. 相似文献