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- Catalysis (3)
- Alcohols (2)
- Cyclization (2)
- Cyclobutanes (2)
- Mesylates (2)
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- Molecular Structure (2)
- Organometallic Compounds (2)
- Piperidines (2)
- ABSORPTION FINE-STRUCTURE; NI-ZN NANOFERRITE; SATURATION MAGNETIZATION; REVERSE MICELLES; NANOPARTICLES; SIZE (1)
- Aldehydes (1)
- Aza Compounds (1)
- CORE-SHELL NANOPARTICLES; QUANTUM DOTS; DNA-MOLECULES; XPS; PHOTOLUMINESCENCE; NANOCRYSTALS; CANCER; CELLS; FILMS (1)
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- MAGNETIC-PROPERTIES; COBALT NANOCRYSTALS; PARTICLES; TEMPERATURE; ALLOYS; CHAINS; TIME (1)
- MAGNETIC-PROPERTIES; FECO NANOPARTICLES; PARTICLES; CO (1)
- MULTIFUNCTIONAL NANOSTRUCTURES; NANOCRYSTALS; LUMINESCENCE; LN (1)
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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Ytterbium Triflate Catalyzed Synthesis Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Their Formal [4 + 2] Cycloaddition With Imines: Stereoselective Synthesis Of Piperidines., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf
Ytterbium Triflate Catalyzed Synthesis Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Their Formal [4 + 2] Cycloaddition With Imines: Stereoselective Synthesis Of Piperidines., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf
Chemistry Publications
A new synthesis of 2-alkoxy-1,1-cyclobutane diesters and their first use in dipolar cycloadditions is reported. Both the formation of the donor-acceptor cyclobutanes and their subsequent annulation with in situ formed imines are catalyzed by Yb(OTf)(3). Cyclobutanes with carbon donor groups give piperidines with high trans stereoselectivity.
Formal [4 + 2] Cycloaddition Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Aldehydes Catalyzed By Yb(Otf)3., Mahmoud M Abd Rabo Moustafa, Andrew C Stevens, Ben P Machin, Brian L Pagenkopf
Formal [4 + 2] Cycloaddition Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Aldehydes Catalyzed By Yb(Otf)3., Mahmoud M Abd Rabo Moustafa, Andrew C Stevens, Ben P Machin, Brian L Pagenkopf
Chemistry Publications
The cycloaddition between 2-alkoxy-1,1-cyclobutane diesters and aromatic, heteroaromatic, or aliphatic aldehydes under Yb(OTf)(3) catalysis generates tetrahydropyrans in high yields with exclusive cis-stereochemistry.
Diels-Alder Chemistry Of Siloles And Their Transformation Into Cyclohex-2-Ene-1,4-Cis-Diols., Andrew C Stevens, Brian L Pagenkopf
Diels-Alder Chemistry Of Siloles And Their Transformation Into Cyclohex-2-Ene-1,4-Cis-Diols., Andrew C Stevens, Brian L Pagenkopf
Chemistry Publications
The synthesis of siloles with substitution patterns that are continuative toward natural product synthesis are described. Their reactivity in Diels-Alder chemistry was explored through thermal, Lewis acid, and high-pressure reactions. Furthermore, bicyclic adducts were oxidatively cleaved to reveal a highly functionalized cyclohexene core.
Chemical Reasoning Based On An Invariance Property: Bond And Lone Pair Pictures In Quantum Structural Formulas, Joseph D. Alia
Chemical Reasoning Based On An Invariance Property: Bond And Lone Pair Pictures In Quantum Structural Formulas, Joseph D. Alia
Chemistry Publications
Chemists use one set of orbitals when comparing to a structural formula, hybridized AOs or NBOs for example, and another for reasoning in terms of frontier orbitals, MOs usually. Chemical arguments can frequently be made in terms of energy and/or electron density without the consideration of orbitals at all. All orbital representations, orthogonal or not, within a given function space are related by linear transformation. Chemical arguments based on orbitals are really energy or electron density arguments; orbitals are linked to these observables through the use of operators. The Valency Interaction Formula, VIF, offers a system of chemical reasoning based …
Synthesis Of 5-Azaindoles Via A Cycloaddition Reaction Between Nitriles And Donor-Acceptor Cyclopropanes., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf
Synthesis Of 5-Azaindoles Via A Cycloaddition Reaction Between Nitriles And Donor-Acceptor Cyclopropanes., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf
Chemistry Publications
A new method for the synthesis of 5-azaindole derivatives is reported. A [3+2] dipolar cycloaddition between nitriles and a 3,4-cyclopropanopiperidine followed by SeO(2) oxidation affords the target compounds in moderate to excellent yields. The divergent nature and cost effectiveness of this method makes it very suitable for combinatorial applications in the pharmaceutical industry.
Annealing Temperature And Initial Iron Valence Ratio Effects On The Structural Characteristics Of Nanoscale Nickel Zinc Ferrite, S. Calvin, M. D. Schultz, L. Glowzenski, E. E. Carpenter
Annealing Temperature And Initial Iron Valence Ratio Effects On The Structural Characteristics Of Nanoscale Nickel Zinc Ferrite, S. Calvin, M. D. Schultz, L. Glowzenski, E. E. Carpenter
Chemistry Publications
Nickelzincferrite (NZFO) nanoparticles were synthesized via a reverse micelle method with a nonionic surfactant. Three different initial Fe3+/Fe2+ ratios were employed along with three different firing temperatures (200, 500, 1000 °C) to investigate the effects on the NZFO system. Extended x-rayabsorption fine structure (EXAFS) results reveal zinc loss at high annealing temperatures; at 1000 °C, the loss is nearly total for Fe3+/Fe2+ ratios other than 10:90. Annealing at 500 °C, however, appears necessary for fully incorporating the zinc and nickel into the spinel phase. The best nanoferrite was thus obtained using an initial Fe3+/Fe2+ ratio of 10:90 and a moderate …
Localized Surface Plasmon Resonance Enhanced Magneto-Optical Activity In Core-Shell Fe-Ag Nanoparticles, L. Wang, K. Yang, C. Clavero, A. J. Nelson, K. J. Carroll, E. E. Carpenter, R. A. Lukaszew
Localized Surface Plasmon Resonance Enhanced Magneto-Optical Activity In Core-Shell Fe-Ag Nanoparticles, L. Wang, K. Yang, C. Clavero, A. J. Nelson, K. J. Carroll, E. E. Carpenter, R. A. Lukaszew
Chemistry Publications
Metallic nanoparticles (NPs) are suitable platforms for miniaturized biosensing based on their optical and magneto-opticalproperties. It is possible to enhance the sensitivity of specific kinds of NPs by exploiting their optical and magneto-opticalproperties under suitable external magnetic field modulation. Here, the magneto-opticalproperties of Fe–Ag core-shell ferromagnet-noble metal NPs have been investigated as a function of the incident light frequency. For Fe–Ag NPs with a concentration ratio around 25:75, an optical absorption band centered at 3 eV due to localized surface plasmon resonance (LSPR) excitation is observed. A strong enhancement of the Faraday rotation is also observed, greatly exceeding the value …
Dual Mode Nanoparticles: Cds Coated Iron Nanoparticles, F. N. Radwan, K. J. Carroll, E. E. Carpenter
Dual Mode Nanoparticles: Cds Coated Iron Nanoparticles, F. N. Radwan, K. J. Carroll, E. E. Carpenter
Chemistry Publications
Reverse micelles can be used in a sequential fashion to make core-shell nanoparticles. Using this technique it is possible to make a magnetic quantum dot, by coating an iron core with a cadmium sulfide shell. Transmission electron microscopy indicated core-shell morphology and narrow size distribution of the obtained particles. Collectively, x-ray powder diffraction and x-ray photoelectron spectroscopy verified the presence of cadmium sulfide on the surface of the nanoparticles. Optical properties of the coated particles were demonstrated using fluorescence spectroscopy. A vibrating sample magnetometer was used to determine magnetic properties. Dual mode cadmium sulfide coatediron core-shell nanoparticles make unique candidates …
High Magnetization Aqueous Ferrofluid: A Simple One-Pot Synthesis, Kyler J. Carroll, Michael D. Schultz, Panos P. Fatouros, Everett E. Carpenter
High Magnetization Aqueous Ferrofluid: A Simple One-Pot Synthesis, Kyler J. Carroll, Michael D. Schultz, Panos P. Fatouros, Everett E. Carpenter
Chemistry Publications
A one-step polyol method was utilized to prepare a stable aqueous iron/iron oxide ferrofluid. The dried powders were characterized by x-ray diffraction, electron microscopy, x-ray absorption spectroscopy, and vibrating sample magnetometry for the determination of phase, morphology, and magnetic properties. To show its potential for imaging applications, the ferrofluid was also investigated as a magnetic resonance imaging contrast agent.
Annealing Of Amorphous Fexco100-X Nanoparticles Synthesized By A Modified Aqueous Reduction Using Nabh4, Kyler J. Carroll, Daniel M. Hudgins, L. W. Brown Iii, S. D. Yoon, D. Heiman, V. G. Harris, Everett E. Carpenter
Annealing Of Amorphous Fexco100-X Nanoparticles Synthesized By A Modified Aqueous Reduction Using Nabh4, Kyler J. Carroll, Daniel M. Hudgins, L. W. Brown Iii, S. D. Yoon, D. Heiman, V. G. Harris, Everett E. Carpenter
Chemistry Publications
FexCo100−x nanoparticles were synthesized by aqueous reduction in iron (II) sulfate and cobalt (II) sulfate using sodium borohydride and sodium citrate. The initial concentrations of iron and cobalt were varied while maintaining an overall metal concentration of 4.60 mM. Increasing the cobalt content from 0 to 100 at. % decreased the magnetization saturation from 152 to 48 emu/g, as determined by room temperature vibrating sample magnetometry. Annealing the samples at 450 and 600 °C showed an increase in crystallite size. Powder x-ray diffraction and transmission electron microscopy was performed to determine the phases and morphology of the materials.
Nonclassical Crystallization Of Amorphous Iron Nanoparticles By Radio Frequency Methods, Kyler J. Carroll, J. A. Pitts, Kai Zhang, A. K. Pradhan, E. E. Carpenter
Nonclassical Crystallization Of Amorphous Iron Nanoparticles By Radio Frequency Methods, Kyler J. Carroll, J. A. Pitts, Kai Zhang, A. K. Pradhan, E. E. Carpenter
Chemistry Publications
Amorphousironnanoparticles were synthesized using an aqueous reduction in iron(II) sulfate with sodium borohydride and sodium citrate. Various radio frequency (rf) exposure times were investigated in order to determine trends in nonclassical crystallization. RF times from 15 to 300 s revealed an increase in crystallite size from 5 to 60 nm, as determined by powde rx-ray diffraction. Also, solvent optimization revealed that ethanol produced the largest trends for increasing crystallite size without total oxidation of the samples. Magnetic characterization by room temperature vibrating sample magnetometry and high resolution transmission microscopy was performed to verify magnetic properties and particle morphology.
Spectrally Tunable Magnetic Nanoparticles Designed For Distribution/Recollection Applications, Nicholas B. Mcdowall, James R. Wilkins, Kyler J. Carroll, Jarrod D. Edwards, Jean D. Nelson, Everett E. Carpenter, Garry P. Glaspell
Spectrally Tunable Magnetic Nanoparticles Designed For Distribution/Recollection Applications, Nicholas B. Mcdowall, James R. Wilkins, Kyler J. Carroll, Jarrod D. Edwards, Jean D. Nelson, Everett E. Carpenter, Garry P. Glaspell
Chemistry Publications
The comprehensive goal of this research is the synthesis and characterization of nanomaterials that are spectrally tunable in terms of their electromagnetic signal, are robust, magnetic (allowing their piloted movement), and have the potential to be functionalized for the detection of CBRNE threats. Various chemical methods were utilized for synthesis of magnetic (iron) and luminescent rare earth (RE) components, and their mixtures. Effects of integrating an iron core into RE luminescent lattices (excited by UV, emit in the VIS) were investigated. The determination of the optimum balances between magnetic and luminescent components such that the magnetism was maximized while maintaining …