Home About us Contact
|
Home About us Contact | ||
|
|
||
Simple Route (simple + route)
Selected AbstractsAllylation of Aldehyde and Imine Substrates with In Situ Generated Allylboronates , A Simple Route to Enatioenriched Homoallyl AlcoholsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2005Sara Sebelius Abstract Allylation of aldehyde and imine substrates was achieved using easily available allylacetates and diboronate reagents in the presence of catalytic amounts of palladium. This operationally simple one-pot reaction has a broad synthetic scope, as many functionalities including, acetate, carbethoxy, amido and nitro groups are tolerated. The allylation reactions proceed with excellent regio- and stereoselectivity affording the branched allylic isomer. By employment of commercially available chiral diboronates enantioenriched homoallyl alcohols (up to 53,% ee) could be obtained. The mechanistic studies revealed that the in situ generated allylboronates react directly with the aldehyde substrates, however the allylation of the sulfonylimine substrate requires palladium catalysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] A Simple Route to a Pyridinyl[2.2]paracyclophaneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2005Henning Hopf Abstract 4-Acetyl[2.2]paracyclophane (1) is converted into the nitrone 2 by treatment with N -methylhydroxylamine·hydrochloride. When 2 is reacted with (E)-1,2-dibenzoylethene (4) the pyridinyl[2.2]paracyclophane 13 is formed in a novel condensation reaction. The structures of 2 and 13, and the mechanism of formation of the latter are discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Nanoimprint Lithography on Silica Sol,Gels: A Simple Route to Sequential Patterning,ADVANCED MATERIALS, Issue 5 2009Christophe Peroz Inorganic condensing sol-gel films are promising resist materials for nanoimprint lithography. We demonstrate that sequential patterning of these materials can be performed by controlling their condensation state. As a consequence, multilevel inorganic patterns can be obtained by superimposing structures, as show here, where successive stamping of a line pattern leads to two-level square features. [source] ChemInform Abstract: A Simple Route to Synthesize New Binary Cobalt Iron Cyclotetraphosphate CoFeP4O12 Using Aqueous and Acetone Media.CHEMINFORM, Issue 5 2010Banjong Boonchom Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A Simple Route to New Phenanthro- and Phenanthroid-Fused Thiazoles by a PIFA-Mediated (Hetero)biaryl Coupling Reaction.CHEMINFORM, Issue 43 2002Isabel Moreno Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: A Simple Route to N-Arylated 2-Aminothiophenes as a New Class of Amorphous Glass Forming Molecules.CHEMINFORM, Issue 38 2001Horst Hartmann Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Simple route to ferrocenylalkyl nucleobases.APPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2009Antitumor activity in vivo Abstract Ferrocenylalkyl nucleobases (1,14) were prepared via the reaction of the ,-(hydroxy)alkyl ferrocenes FcCHR(OH) (Fc = ferrocenyl; R = H, Me, Et, Ph) with thymine, cytosine, iodo-cytosine and adenine in DMSO at 100 °C, yields being 50,80%. The antitumor activities of ferrocenylmethyl thymine (1) against solid tumor models, carcinoma 755 (Ca755) and Lewis lung carcinoma (LLC) were studied in vivo. Therapeutic synergism of antitumor activity against LLC was demonstrated in the case of combined application of compound 1 with anticancer drug cyclophosphamide. Copyright © 2009 John Wiley & Sons, Ltd. [source] PbS crystals with clover-like structure: Preparation, characterization, optical properties and influencing factorsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2004Yonghong Ni Abstract A new and simple route to synthesize Lead sulfide (PbS) crystals with the clover-like structure was described in the current paper. PbS was prepared in a simple aqueous solution employing (CH3COO)2Pb and thiourea as the initial materials under 130 W microwave irradiation. No any surfactant or template including organic polyamines with N-chelation property was needed. The phase and composition of the product were identified by X-ray powder diffraction (XRD) and X-ray photoelectron spectra (XPS). TEM observation showed that the product with the six-petal flower-shaped structures was obtained, but SEM observation confirmed the clover-like structure of the product; and the six-petal flowers were formed via the overlap of two clovers revolved 60° around the center of the flower. Some factors affected the shape of the final product were studied and the optical properties of PbS crystals with the clover-like structure were measured. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fabrication of CdSe-Nanofibers with Potential for Biomedical ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Amir Fahmi Abstract The design and synthesis of nanostructured functional hybrid biomaterials are essential for the next generation of advanced diagnostics and the treatment of disease. A simple route to fabricate semiconductor nanofibers by self-assembled, elastin-like polymer (ELP)-templated semiconductor nanoparticles is reported. Core,shell nanostructures of CdSe nanoparticles with a shell of ELPs are used as building blocks to fabricate functional one-dimensional (1D) nanostructures. The CdSe particles are generated in situ within the ELP matrix at room temperature. The ELP controls the size and the size-distribution of the CdSe nanoparticles in an aqueous medium and simultaneously directs the self-assembly of core,shell building blocks into fibril architectures. It was found that the self-assembly of core,shell building blocks into nanofibers is strongly dependent on the pH value of the medium. Results of cytotoxicity and antiproliferation of the CdSe-ELP nanofibers demonstrate that the CdSe-ELP does not exhibit any toxicity towards B14 cells. Moreover, these are found to be markedly capable of crossing the cell membrane of B14. In contrast, unmodified CdSe nanoparticles with ELPs cause a strong toxic response and reduction in the cell proliferation. This concept is valid for the fabrication of a variety of metallic and semiconductor 1D-architectures. Therefore, it is believed that these could be used not only for biomedical purposes but for application in a wide range of advanced miniaturized devices. [source] Arrays of Inorganic Nanodots and Nanowires Using Nanotemplates Based on Switchable Block Copolymer Supramolecular AssembliesADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Bhanu Nandan Abstract Here, a novel and simple route to fabricate highly dense arrays of palladium nanodots and nanowires with sub-30,nm periodicity using nanoporous templates fabricated from supramolecular assemblies of a block copolymer, polystyrene- block -poly(4-vinylpyridine) (PS- b -P4VP) and a low molecular weight additive, 2-(4,-hydroxybenzeneazo) benzoic acid (HABA) is demonstrated. The palladium nanoparticles, which are directly deposited in the nanoporous templates from an aqueous solution, selectively migrate in the pores mainly due to their preferential attraction to the P4VP block covering the pore wall. The polymer template is then removed by oxygen plasma etching or pyrolysis in air resulting in palladium nanostructures whose large scale morphology mirrors that of the original template. The method adopted in this work is general and versatile so that it could easily be extended for patterning a variety of metallic materials into dot and wire arrays. [source] Macroscopically Aligned Ionic Self-Assembled Perylene-Surfactant Complexes within a Polymer Matrix,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2008Ari Laiho Abstract Ionic self-assembled (ISA) surfactant complexes present a facile concept for self-assembly of various functional materials. However, no general scheme has been shown to allow their overall alignment beyond local polydomain-like order. Here we demonstrate that ionic complexes forming a columnar liquid-crystalline phase in bulk can be aligned within polymer blends upon shearing, taken that the matrix polymers have sufficiently high molecular weight. We use an ISA complex of N,N,-bis(ethylenetrimethylammonium)perylenediimide/bis(2-ethylhexyl) phosphate (Pery-BEHP) blended with different molecular weight polystyrenes (PS). Based on X-ray scattering studies and transmission electron microscopy the pure Pery-BEHP complex was found to form a two-dimensional oblique columnar phase where the perylene units stack within the columns. Blending the complex with PS lead to high aspect ratio Pery-BEHP aggregates with lateral dimension in the mesoscale, having internal columnar liquid-crystalline order similar to the pure Pery-BEHP complex. When the Pery-BEHP/PS blend was subjected to a shear flow field, the alignment of perylenes can be achieved but requires sufficiently high molecular weight of the polystyrene matrix. The concept also suggests a simple route for macroscopically aligned nanocomposites with conjugated columnar liquid-crystalline functional additives. [source] Comments on ,Electric-Field-Assisted Growth of Highly Uniform and Oriented Gold Nanotriangles on Conducting Glass Substrates'ADVANCED MATERIALS, Issue 13 2009Peng Diao AFM artifacts: Recent results by Sajanlal and Pradeep on the electric-field-assisted growth of highly uniform and oriented gold nanotriangles appear to provide a simple route to the size-, shape-, and orientation-controlled synthesis of nano structures. In our view, however, the triangle patterns observed in the AFM images are not real surface features but artifacts produced by a broken or contaminated AFM tip. [source] Gold Nanocages for Biomedical Applications,ADVANCED MATERIALS, Issue 20 2007E. Skrabalak Abstract Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy. [source] Rydberg states of the helium atomINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 9 2009Jia Deng Abstract Using the recently introduced maximum overlap method and Hartree,Fock Perturbation Theory (HFPT), we compute Hartree,Fock (HF) wavefunctions for triplet 1s ns states of the helium atom. Comparison with near-exact results from Nakatsuji's free ICI method reveals that HF theory provides a simple route to accurate energies of these Rydberg states, especially for large n. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Direct functionalization of polyisobutylene by living initiation with ,-methylstyrene epoxideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2002J. Song Abstract This article describes the synthesis and characterization of polyisobutylene (PIB) carrying one primary hydroxyl head group and a tertiary chloride end group, [PhC(CH3)(CH2OH),PIB,CH2C(CH3)2Cl] prepared with direct functionalization via initiation. The polymerization of isobutylene was initiated with the ,-methylstyrene epoxide/titanium tetrachloride system. Living conditions were obtained from ,75 to ,50 °C (198,223 K). Low molecular weight samples (number-average molecular weight , 4000 g/mol) were prepared under suitable conditions and characterized by Fourier transform infrared and 1H NMR spectroscopy. The presence of primary hydroxyl head groups in PIB was verified by both methods. Quantitative Fourier transform infrared with 2-phenyl-1-propanol calibration and 1H NMR performed on both the hydroxyl-functionalized PIB and its reaction product with trimethylchlorosilane showed that each polymer chain carried one primary hydroxyl head group. The synthetic methodology presented here is an effective and simple route for the direct functionalization of PIB. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1005,1015, 2002 [source] Noble Metal Decoration and Alignment of Carbon Nanotubes in Carboxymethyl CelluloseMACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2008Mallikarjuna N. Nadagouda Abstract A facile microwave method (MW) is described that accomplishes alignment and decoration of noble metals on carbon nanotubes (CNT) wrapped with carboxymethyl cellulose (CMC). Carbon nanotubes such as single- and multi-walled, and Buckminsterfullerene (C-60) are well dispersed using the sodium salt of CMC under sonication. Addition of respective noble metal salts then generates noble metal-decorated CNT composites at room temperature. However, aligned nanocomposites of CNTs could only be generated by exposing the above nanocomposites to MW irradiation. The CNT composites are characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray mapping, transmission electron microscopy, and UV-visible spectroscopy. The general preparative procedure is versatile and provides a simple route to manufacturing useful metal-coated CNT nanocomposites. [source] Characterization of the DNA-assisted purification of single-walled carbon nanotubesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2007G. Sánchez-Pomales Abstract Carbon nanotubes (CNTs) possess outstanding structural, mechanical, and electronic properties. Nevertheless, to achieve their full potential, many problems still need to be solved, including the development of an easy purification procedure, the design of functionalization chemistries that result in increased solubility of the CNTs without altering their properties, and the development of a simple route for the attachment of aligned CNTs on solid substrates. DNA offers a solution to the previous challenges. Recently, DNA-functionalized single-walled carbon nanotubes (SWNTs) have been prepared by our group and attached on gold by the self-assembling technique [1, 2]. We therefore decided to perform an in-depth study of the DNA-assisted functionalization of SWNTs, which leads to their purification. The results showed a decrease in the SWNTs impurities after functionalization with DNA and demonstrated that the method used is a straightforward and time-effective route for the purification of SWNTs at room temperature. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A Simple Approach to the Solution of the Diffusion Equation at the Microcylinder Electrode,an Inspiration from the Film ProjectorCHEMPHYSCHEM, Issue 14 2009Yi-Min Fang 16 frames per second: A new and simple route for the solution of diffusion equation at three types of electrode (see picture) is based on a time-dependent diffusion layer approximation and time-dependent boundary conditions, without employing the traditional Laplace transform. [source] | ||||||||||||||||||||||||||||