排序方式: 共有29条查询结果,搜索用时 31 毫秒
1.
Diantha R. Kelman Lisa F. Szczepura Karen I. Goldberg Werner Kaminsky Anne K. Hermetet Lily J. Ackerman John K. Swearingen Douglas X. West 《Journal of Molecular Structure》2002,610(1-3):143-150
N-2-(4-picolyl)-N′-2-chlorophenylthiourea, 4PicTu2Cl, monoclinic, P21/c, a=10.068(5), b=11.715(2),
β=96.88(4)°,
and Z=4; N-2-(6-picolyl)-N′-2-chlorophenylthiourea, 6PicTu2Cl, triclinic, P-1, a=7.4250(8), b=7.5690(16), c=12.664(3) Å, =105.706(17), β=103.181(13), γ=90.063(13)°, V=665.6(2) Å3 and Z=2 and N-2-(6-picolyl)-N′-2-bromophenylthiourea, 6PicTu2Br, triclinic, P-1, a=7.512(4), b=7.535(6), c=12.575(4) Å, a=103.14(3), β=105.67(3), γ=90.28(4)°, V=665.7(2) Å3 and Z=2. The intramolecular hydrogen bonding between N′H and the pyridine nitrogen and intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen, as well as the planarity of the molecules, are affected by the position of the methyl substituent on the pyridine ring. The enthalpies of fusion and melting points of these thioureas are also affected. 1H NMR studies in CDCl3 show the NH′ hydrogen resonance considerably downfield from other resonances in their spectra. 相似文献
2.
Reduction of 2-cyanopyridine by sodium in dry MeOH in the presence of N(4)-methylthiosemicarbazide produces 2-pyridineformamide N(4)-methylthiosemicarbazone, HAm4M. Copper(II) complexes have been prepared and characterized by molar conductivities, magnetic susceptibilities and spectroscopic techniques. Coordination is via the pyridyl nitrogen, imine nitrogen and thione or thiolato sulfur, when coordinating as the neutral or anionic ligand, respectively. 相似文献
3.
Colin M. Mcgill Kristian E. Swearingen Kelly L. Drew Brian T. Rasley Thomas K. Green 《Journal of heterocyclic chemistry》2005,42(4):475-481
Naphthalene‐2,3‐dicarbaldehyde (NDA), a reagent used for the fluorescent detection of amino acids in the presence of cyanide, self‐condenses in the presence of cyanide ion and methanol at room temperature to yield a unique crystalline product 2, 15‐hydroxybenzo[g]benzo[6,7]isochromeno[4,3‐c]isochromen‐7(15H)‐one. The product is proposed to result from facile air oxidation of NDA to a methyl ester in combination with benzoin condensation. Product 2 does not to form in the absence of air. The gHMBC spectrum of 2 distinguishes it from a possible alternative isomeric condensation product. 相似文献
4.
Cobalt(II), nickel(II) and copper(II) complexes of di-2-pyridyl ketone N(4)-methyl- and N(4)-dimethylthiosemicarbazone have been prepared and characterized by physical and spectral methods. Use of different ligand-to-metal chloride molar ratios in the preparation of the complexes has produced both mononuclear and polynuclear species for the three metal ions. Crystal structures of the uncomplexed di-2-pyridyl ketone N(4)-methylthiosemicarbazone and a nickel(II) complex, di-2-pyridyl ketone N(4)-dimethylthiosemicarbazone, have been determined and aid the assignments of the i.r., n.m.r., u.v.–vis.–n.i.r. and e.s.r. spectra. 相似文献
5.
Kim BY Swearingen CB Ho JA Romanova EV Bohn PW Sweedler JV 《Journal of the American Chemical Society》2007,129(24):7620-7626
Interfacing nanoscale elements into a microfluidic device enables a new range of fluidic manipulations. Nanocapillary array membranes (NCAMs), consisting of thin (5 microm < d < 20 microm) membranes containing arrays of nanometer diameter (10 nm < a < 500 nm) pores, are a convenient method of interfacing vertically separated microchannels in microfluidic devices that allow the external control of analyte transport between microfluidic channels. To add functionality to these nanopores beyond simple fluid transport, here we incorporate an antibody-based molecular recognition element onto the pore surface that allows selective capture, purification, and release of specific analytes from a mixture. The pores are fabricated by electroless plating of gold into the nanopores of an NCAM (Au-NCAM). An antibody is then immobilized on the Au-NCAM via gold-thiol chemistry as a thiolated fragment of antigen-binding (Fab') prepared by direct digestion of the antibody followed by reduction of the disulfide linkage on the hinge region. The successful immobilization and biological activity of the resultant Fab' through this protocol is verified on planar gold by fluorescence microscopy, scanning electron microscopy, and atomic force microscopy. Selective capture and release of human insulin is verified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The relative mass spectral peak intensities for insulin versus nonantigenic peptides increase more than 20-fold after passing through the Fab'-Au-NCAM relative to the control Au-NCAM. The affinity-tagged Au-NCAM can be incorporated into microfluidic devices to allow the concentration, capture, and characterization of analytes in complex mixtures with high specificity. 相似文献
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A Pb(ii)-specific DNAzyme has been successfully incorporated into Au-coated polycarbonate track-etched (PCTE) nanocapillary array membranes (NCAMs) by thiol-gold immobilization. Incorporation of the DNAzyme into the membrane provides a substrate-bound sensor using a novel internal control methodology for fluorescence-based detection of Pb(ii). A non-cleavable substrate strand, identical to the cleavable DNAzyme substrate strand except the RNA-base is replaced by the corresponding DNA-base, is used for ratiometric comparison of intensities. The cleavable substrate strand is labeled with fluorescein, and the non-cleavable strand is labeled with a red fluorophore (Cy5 or Alexa 546) for detection after release from the membrane surface. This internal standard based ratiometric method allows for real-time monitoring of Pb(ii)-induced cleavage, as well as standardizing variations in substrate size, solution detection volume, and monolayer density. The result is a Pb(ii)-sensing structure that can be stored in a prepared state for 30 days, regenerated after reaction, and detect Pb(ii) concentrations as low as 17 nM (3.5 ppb). 相似文献
9.
Anne K. Hermetet Lily J. Ackerman John K. Swearingen Carmina A. Presto Diantha R. Kelman James M. Giesen Karen I. Goldberg Werner Kaminsky Douglas X. West 《Journal of chemical crystallography》2002,32(1-2):17-25
Reaction of 2-amino-6-picoline with 2-, 3-, and 4-tolyl isothiocyanates produces the three N-2-(6-picolyl)-N-tolylthioureas, 6PicTu2T, 6PicTu3T, and 6PicTu4T. 6PicTu2T is mono-clinic, space group P21/n with a = 8.1700(3) Å, b = 25.5840(6) Å, c = 12.6840(5) Å, = 98.8750(16)°, and V = 2619.5(2) Å3 with Z = 8, for d
calc = 1.305 g/cm3. 6PicTu3T is monoclinic, space group C2/c with a = 23.879(3) Å, b = 6.744(3) Å, c = 17.116(10) Å, = 99.26(4)°, and V = 2720(3) Å3 with Z = 8, for d
calc = 1.257 g/cm3. 6PicTu4T is triclinic, space group P-1 with a = 8.829(6) Å, b = 8.8950(15) Å, c = 10.495(3) Å, = 68.63(3)°, = 72.19(4)°, = 63.06(4)°, and V = 681.2(5) Å3 with Z = 2, for d
calc = 1.255 g/cm3. Intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen and the planarity of the thiourea are affected by the position of substitution on the aryl ring. 1H NMR studies in CDCl3 show the NH hydrogen resonance considerably downfield from other signals in the spectrum of each thiourea. The enthalpies of fusion of the present thioureas reflect the extent of intermolecular hydrogen bonding and are compared to other heterocyclic thioureas. 相似文献
10.
Karen A. Ketcham Isabel Garcia Elena Bermejo John K. Swearingen Alfonso Castieiras Douglas X. West 《无机化学与普通化学杂志》2002,628(2):409-415
Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}2C4H4O4]·2DMSO·H2O, [Cu(HAmhexim)Cl2] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}2C4H4O4] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl2] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate. 相似文献