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1.
The Rayleigh–Taylor instability (RTI) of a ferrofluid has been the subject of recent research, because of its implications on the stability of stellar and planetary interiors. This paper analyzes the effects of rotation and magnetic field on nonlinear RTI of two superposed ferrofluids. It is considered that the system is subjected to uniform parallel rotation and normal magnetic field. Surface tension acts at the interface. The method of multiple scales is utilized to obtain the solutions and dispersion relations are obtained for the nonlinear problem of RTI of magnetic fluids. Finally the stability of the problem is discussed. 相似文献
2.
One‐Pot Synthesis of Hydrophobically Modified Iminosugar C‐Alkynylglycosides: Facile Synthesis of Polyhydroxy Tetrahydroindolizines
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Soundararasu Senthilkumar Sure Siva Prasad Amrita Das Prof. Dr. Sundarababu Baskaran 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):15914-15918
A mild and efficient one‐pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugar C‐alkynylglycosides. The generality of this methodology has been demonstrated with a wide variety of amines and copper acetylides. This one‐pot method has been exploited in the synthesis of new class of DNA cross‐linking agents, polyhydroxy 1‐vinyl‐tetrahydroindolizine derivatives. 相似文献
3.
Kaliyaperumal Thanigaimani Nuridayanti Che Khalib Suhana Arshad Madhukar Hemamalini 《Molecular Crystals and Liquid Crystals》2016,625(1):259-275
The 1:1 cocrystal of 2-amino-3-bromopyridine (2A3BP) with 4-methylbenzoic acid (4MBA) has been prepared by slow evaporation method in methanol, which was crystallized in monoclinic P21/c space group having two molecules in the asymmetric unit. The cocrystal has been characterized by single crystal X-ray analysis, FTIR, 1H NMR, 13C NMR, and Powder XRD. Theoretical investigations have been calculated by HF and density function (B3LYP) method with the 6-311+G(d,p) basis set. The vibrational frequencies together with the 1H NMR and 13C NMR chemical shifts have been calculated on the fully optimized geometry of 1. Theoretical calculations of bond parameters, harmonic vibration frequencies, and isotropic chemical shifts are in good agreement with the experimental results. Solvent-free formation of these cocrystal was confirmed by powder X-ray diffraction analysis. The crystal structure was stabilized by Npyridine—H···O = C, C = O—H···Npyridine and C—H···Br hydrogen bonding interactions. 相似文献
4.
A novel and general method has been developed for the stereoselective construction of 5-hydroxymethyl azabicyclic ring skeletons based on epoxide-initiated cationic cyclization of azides. The key cyclization reaction was systematically studied with the model compound, 3-(1-oxa-spiro[2.4]hept-4-yl)propyl azide 3a, and EtAlCl(2) was found to be an ideal choice as the catalyst. The generality of this transformation was further tested with different ring sizes, where six- and seven-membered epoxyazides 3b,c underwent smooth cyclization to give 5-hydroxymethyl azepine 4b and 5-hydroxymethyl azocine 4c, respectively, as a single detectable diastereomer. This novel methodology was elegantly applied in the stereoselective total synthesis of indolizidine alkaloids 167B and 209D. Further, the enantioselective total synthesis of natural and unnatural indolizidine alkaloids 167B and 209D was accomplished by using Sharpless asymmetric dihydroxylation as a key step. 相似文献
5.
K. Balasubramani M. Hemamalini S. Francis P. Thomas Muthiah T. Vijay T. N. Guru Row G. Bocelli A. Cantoni 《Journal of chemical crystallography》2010,40(4):316-322
Abstract
The complexes, Ba (HQS) (H2O)4 (HQS = 8-hydroxyquinoline-5-sulfonic acid) (1) and Ag (HIQS) (H2O) (Ferron = 7-iodo-8-hydroxyquinoline-5-sulfonic acid) (2) have been synthesized and characterized by X-ray diffraction analysis and spectroscopic studies. In compound 1, Ba2+ ion has a nine-coordinate monocapped antiprismatic geometry. In compound 2, Ag+ has distorted tetrahedral coordination and Ag···I interactions generate the supramolecular architectures. The complexes have been characterized by FT-IR and UV–Visible measurements. In both the structures, the inversion-related organic ligands are stacked over one another leading to three-dimensional networks. 相似文献6.
[reaction: see text] A novel and general method for the stereoselective construction of 5-hydroxymethyl azabicyclic ring skeletons based on epoxide initiated electrophilic cyclization of azides has been developed and applied in the synthesis of (+/-)-indolizidine 167B and 209D with an overall yield of 16.5% and 17.8%, respectively. The efficiency of this methodology is further exemplified in the synthesis of azepine skeleton via tandem cation-olefin-azide cyclization. 相似文献
7.
In the present study, we report the crystal structures of two organic salts, namely 2,4-diamino-5-(3′,4′,5′-trimethoxybenzyl)pyrimidinium
(TMP) barbiturate monohydrate (TMPBAR) (I), 2-amino-4,6-dimethylpyrimidinium (AMPY) barbiturate trihydrate (AMPYBAR) (II).
In both complexes, one ring nitrogen of TMP and AMPY are protonated as a result of proton transfer from the−CH2 group of barbituric acid. In compound (I), the TMP cation and barbiturate anion are paired through twoN−H···O and one N−H···N
hydrogen bonds. This pair further self-organizes through N−H···O hydrogen bonds to generate an array of six hydrogen bonds.
These arrays are further cross-linked by N−H···O hydrogen bonds forming a sheet-like structure. The water molecule is also
embedded in the sheet via O−H···O and C−H···O hydrogen bonds, forming a rosette-like supramolecular motif. TMP cations are
also bridged by alternating water molecules via C−H···O and O−H···N hydrogen bonds. In compound (II), the symmetrical barbiturate
anions self-organize on both sides through N−H···O hydrogen bonds generating a supramolecular chain. These chains are cross-linked
by the three water molecules. A pair of barbiturate anions and two water molecules constitute an array of four hydrogen bonds
(DADA quadruple array). These arrays are cross-linked by another water molecule. 2-Amino-4,6-dimethylpyrimidine cations are
paired through N−H···N hydrogen bonds. These pairs are bridged by three water molecules generating a supramolecular ribbon.
The barbiturate chains and base pairs are arranged in an alternate manner via N−H···O and O−H···O hydrogen bonds to generate
a 3-D network. 相似文献
8.
Madhukar Hemamalini Packianathan Thomas Muthiah Urszula Rychlewska Agnieszka Plutecka 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):o95-o97
In the title compound, C6H10N3+·HSO4−, the asymmetric unit consists of a hydrogen sulfate anion and a 2‐amino‐4,6‐dimethylpyrimidinium cation. The hydrogen sulfate anions self‐assemble through O—H⋯O hydrogen bonds, forming supramolecular chains along the b axis, while the organic cations form base pairs via N—H⋯N hydrogen bonds. The aminopyrimidinium cations join to the sulfate anions via a pair of hydrogen bonds donated from the pyrimidinium protonation site and from the exo amine group cis to the protonated site. 相似文献
9.
Annamalai Subashini Madhukar Hemamalini P. Thomas Muthiah Gabriele Bocelli Andrea Cantoni 《Journal of chemical crystallography》2009,39(2):112-116
Abstract The structure of the title compound (C17H15N3O4S)2 the schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was elucidated by H1, C13 NMR, UV–VIS and IR spectroscopic techniques. The X-ray structure was determined in order to establish the conformation of
the molecule. The compound crystallizes in the triclinic space group P-1, with a = 11.419(1), b = 11.426(0), c = 13.316(1) ?, α = 71.94(2), β = 89.79(1), γ = 89.14(2)° and Z = 4. Two benzene rings and azomethine group are practically coplanar, as a result of intramolecular hydrogen bonds involving
the hydroxy O atom and azomethine N atom. The component species further interact via N–H···N and C–H···O hydrogen bonds and
π–π stacking interactions.
Index Abstract The title compound (C17H15N3O4S)2, Schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was synthesized by the condensation of 4-amino-N-(5-methyl-3-isoxazolyl) benzene sulfonamide (SMZ) and 2-hydroxy benzaldehyde (SA). Its structure was confirmed by single
crystal X-ray diffraction analysis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Antibodies and antigen binding fragments thereof were photochemically immobilized on surface-modified silicon chips of 5 × 5 mm size. Silicon surface-grafted diazirines and benzophenones formed covalent bonds with the immunoreagents on light activation. Photolithographic immobilization of monoclonal antibodies in aqueous media was achieved on silicon chips by activating surface-grafted benzophenones. The presence of bovine serum albumin during irradiation reduced nonspecific adsorption of the immunoreagents and retained the immunoactivity of the photoimmobilized molecules. 相似文献