| Journal Articles: 22 results |
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The Aromaticity of Pericyclic Reaction Transition States Henry S. Rzepa
Presents an approach that combines two fundamental concepts in organic chemistry, chirality and aromaticity, into a simple rule for stating selection rules for pericyclic reactions in terms of achiral Hckel-aromatic and chiral Mbius-aromatic transition states.
Rzepa, Henry S. J. Chem. Educ. 2007, 84, 1535.
Alkanes / Cycloalkanes |
Alkenes |
Aromatic Compounds |
Mechanisms of Reactions |
Stereochemistry
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Quantitative Determination of the Rotameric Energy Differences of 1,2-Dihaloethanes Using Raman Spectroscopy. An Experimental Project for the Physical Chemistry Laboratory Mark D. Young, Natalia C. Borjemscaia, and Brian D. Wladkowski
The effects of structure and environment on the rotameric energy difference between gauche and trans conformations of 1,2-disubtitutedethanes are determined quantitatively through the use of Raman spectroscopy. Two 1,2-dihaloethanes (chloro- and bromo-) were analyzed in the condensed phase (pure liquid, carbon tetrachloride, and acetonitrile solutions). Since the gauche conformation of these molecules has a nonzero dipole, dissolving the compounds in solvents with increasing dielectric constant causes a stabilization of the gauche conformation, thus decreasing the absolute energy difference between the rotamers. The major factor governing the intrinsic stability is that of steric hindrance.
Young, Mark D.; Borjemscaia, Natalia C.; Wladkowski, Brian D. J. Chem. Educ. 2005, 82, 912.
Instrumental Methods |
IR Spectroscopy |
Quantitative Analysis |
Raman Spectroscopy |
Alkanes / Cycloalkanes |
Conformational Analysis |
Stereochemistry
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A Set of Hands-On Exercises on Conformational Analysis Silvina C. Pellegrinet and Ernesto G. Mata
This article describes a set of comprehensive exercises on conformational analysis that employs a hands-on approach by the use of molecular modeling kits. In addition, the exercises provide illustrations of other topics such as nomenclature, functional groups, and isomerism, and introduce some notions of chirality.
Pellegrinet, Silvina C.; Mata, Ernesto G. J. Chem. Educ. 2005, 82, 73.
Alkanes / Cycloalkanes |
Conformational Analysis |
Constitutional Isomers |
Molecular Properties / Structure |
Stereochemistry
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A Method for Drawing the Cyclohexane Ring and Its Substituents Veljko Dragojlovic
A simple method for drawing cyclohexanes.
Dragojlovic, Veljko. J. Chem. Educ. 2001, 78, 923.
Molecular Properties / Structure |
Stereochemistry |
Alkanes / Cycloalkanes
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Resolution of trans-Cyclohexane-1,2-diamine and Determination of the Enantiopurity Using Chiral Solid-Phase HPLC Techniques and Polarimetry Patrick J. Walsh, Diane K. Smith, and Chris Castello
The experiment is designed to reinforce and broaden the students' understanding of the relationship between enantiomers and diasteriomers and of diasteriomeric interactions. Additionally, it illustrates the differences in physical properties (solubility and melting range) between a racemic mixture and the same compound in highly resolved form.
Walsh, Patrick J.; Smith, Diane K.; Castello, Chris. J. Chem. Educ. 1998, 75, 1459.
Chromatography |
Synthesis |
Separation Science |
Stereochemistry |
HPLC |
Alkanes / Cycloalkanes |
Amines / Ammonium Compounds |
Chirality / Optical Activity
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A Simple Molecular Orbital Treatment of the Barrier to Internal Rotation in the Ethane Molecule Derek W. Smith
The origin of the barrier to internal rotation in the ethane molecule is explored in terms of elementary molecular orbital (MO) considerations. Emphasis is placed on the antibonding effect, i.e. the result that an antibonding MO is more destabilized than its bonding counterpart is stabilized, relative to the parent atomic orbitals (AOs). It is shown that, in the case of two equivalent AOs, this effect is approximately proportional to the square of the overlap integral.
Smith, Derek W. J. Chem. Educ. 1998, 75, 907.
Covalent Bonding |
MO Theory |
Stereochemistry |
Theoretical Chemistry |
Alkanes / Cycloalkanes
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The Energy Profile for Rotation about the C-C Bond in Substituted Ethanes: A Multi-Part Experimental Computational Project for the Physical Chemistry Laboratory Luther E. Erickson and Kevin F. Morris
This paper describes a multi-part project for the physical chemistry lab that includes both experimental and computational approaches to the investigation of the energy profile for internal rotation in substituted ethanes. Experimental approaches include dipole moment determinations, high-resolution nmr spectroscopy (including coupling constant determinations from the analysis of C-13 satellites), and infrared spectral analysis, all directed toward the goal of determining the relative populations - and thereby the relative energies - of low energy rotamers of a substituted ethane as a function of substituent, temperature and solvent composition.
Erickson, Luther E.; Morris, Kevin F. J. Chem. Educ. 1998, 75, 900.
Theoretical Chemistry |
Computational Chemistry |
Stereochemistry |
Alkanes / Cycloalkanes
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A Three-Dimensional Energy Surface for the Conformational Inversion of Cyclohexane Nicholas Leventis*, Samir B. Hanna, Chariklia Sotiriou-Leventis
While it is well known that chair forms of cyclohexane can interconvert without passing through the boat conformation, the same statement frequently comprises a source of confusion regarding the location of the boat conformation on the energy surface of the conformational inversion of cyclohexane. To alleviate this problem, a novel three-dimensional energy diagram has been introduced showing explicitly how the chair forms of cyclohexane interconvert.
Leventis, Nicholas; Hanna , Samir B. ; Sotiriou-Leventis, Chariklia . J. Chem. Educ. 1997, 74, 813.
Learning Theories |
Mechanisms of Reactions |
Stereochemistry |
Alkanes / Cycloalkanes |
Conformational Analysis |
Molecular Properties / Structure
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The enumeration of isomers-With special reference to the stereoisomers of decane Whyte, J. R. C.; Clugston, M. J.
Structural isomers predicted through algorithms.
Whyte, J. R. C.; Clugston, M. J. J. Chem. Educ. 1993, 70, 874.
Alkanes / Cycloalkanes |
Stereochemistry |
Diastereomers
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An easily constructed model: The boat form of a six-membered ring composed of six distorted tetrahedral penetrating each other Yamana, Shukichi
Instructions for constructing a model of the boat form of a six-membered ring using six empty envelopes.
Yamana, Shukichi J. Chem. Educ. 1992, 69, 964.
Molecular Modeling |
Molecular Properties / Structure |
Alkanes / Cycloalkanes |
Stereochemistry
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A source of isomer-drawing assignments Kjonaas, Richard A.
A comprehensive source from which instructors can choose a wide variety of good isomer drawing examples to use as homework assignments and exam questions.
Kjonaas, Richard A. J. Chem. Educ. 1992, 69, 452.
Stereochemistry |
Alcohols |
Alkanes / Cycloalkanes |
Alkenes |
Aldehydes / Ketones |
Ethers |
Esters |
Alkynes
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Discovering stereoselectivity: Synthesis of exo- and endobrevicomin using a tunable hydride reduction: A program of organic synthesis experiments for advanced undergraduate students Richardson, David P.; Wilson, Whitney; Mattson, Rebecca J.; Powers, Dawn M.; Dolan, Brian T.
With their low molecular weights and modest structural complexity, insect pheromones have proven to be especially fruitful for advanced undergraduate organic synthesis laboratory exercises.
Richardson, David P.; Wilson, Whitney; Mattson, Rebecca J.; Powers, Dawn M.; Dolan, Brian T. J. Chem. Educ. 1991, 68, 951.
Natural Products |
Diastereomers |
Enantiomers |
Stereochemistry |
Aldehydes / Ketones |
Alcohols |
Gas Chromatography |
Alkanes / Cycloalkanes
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Drawing different views of the chair form of substituted cyclohexanes Richardson, W. S.
A set of rules to instruct students in a method for drawing chair structures of cyclohexane after rotation about the central axis.
Richardson, W. S. J. Chem. Educ. 1989, 66, 478.
Alkanes / Cycloalkanes |
Molecular Properties / Structure |
Stereochemistry
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C167H336 is the smallest alkane with more realizable isomers than the observed universe has "particles" Davies, Robert E.; Freyd, Peter J.
The number of stereoisomers of C167H336 that can exist, though not all at the same time, is greater than the classical figure for the number of particles in the observed universe.
Davies, Robert E.; Freyd, Peter J. J. Chem. Educ. 1989, 66, 278.
Alkanes / Cycloalkanes |
Stereochemistry
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Stereochemistry of cyclic hydrocarbons Perkins, Robert R.
The topic of stereochemistry always poses great difficulties for many students in introductory organic chemistry. The following problems can be used as a tutorial question after having introduced the various terms associated with stereochemistry. The question requires skills at the applications level in the Bloom taxonomy.
Perkins, Robert R. J. Chem. Educ. 1988, 65, 860.
Alkanes / Cycloalkanes |
Chirality / Optical Activity |
Stereochemistry |
Diastereomers |
Constitutional Isomers
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From shadows to three dimensions: Stereographic images using Dreiding models and the Macintosh Strauss, Michael J.; Gribble, Gordon
Printing stereographic images using ChemDraw.
Strauss, Michael J.; Gribble, Gordon J. Chem. Educ. 1987, 64, 850.
Alkanes / Cycloalkanes |
Stereochemistry |
Molecular Modeling |
Molecular Properties / Structure
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Identification of the stable conformer of cyclohexane by vibrational spectroscopy Garcia, M. V.; Redondo, M. I.
A laboratory experiment that uses group theory to help interpret infrared and Raman spectra of cyclohexane.
Garcia, M. V.; Redondo, M. I. J. Chem. Educ. 1985, 62, 887.
Alkanes / Cycloalkanes |
Spectroscopy |
Stereochemistry |
IR Spectroscopy |
Raman Spectroscopy |
Conformational Analysis |
Molecular Properties / Structure |
Group Theory / Symmetry
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Resolvability and the tetrahedral configuration of carbon Kauffman, George B.
A popular explanation about the tetrahedral configuration of carbon is not entirely accurate.
Kauffman, George B. J. Chem. Educ. 1983, 60, 402.
Molecular Properties / Structure |
Alkanes / Cycloalkanes |
Enantiomers |
X-ray Crystallography |
Stereochemistry |
Chirality / Optical Activity
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An easily conducted free radical substitution for organic chemistry courses Pavlis, Robert R.
The photobromination of 1,2-diphenylethane into its dibromo derivative, (2R) (3S) 1,2-dibromo-1,2-diphenylethane.
Pavlis, Robert R. J. Chem. Educ. 1982, 59, 658.
Free Radicals |
Reactions |
Molecular Properties / Structure |
Stereochemistry |
Diastereomers |
Photochemistry |
Alkanes / Cycloalkanes |
Aromatic Compounds
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Optical illusions in drawings of cyclohexane derivatives Feldman, Martin R.
An optical illusion in the representation of chair cyclohexanes.
Feldman, Martin R. J. Chem. Educ. 1979, 56, 659.
Molecular Properties / Structure |
Stereochemistry |
Enantiomers |
Diastereomers |
Alkanes / Cycloalkanes
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Computer calculation of alkane isomers Davis, Charles C.; Ebel, Michael
A FORTRAN IV computer program has been written which calculates the number of possible isomers of the saturated aliphatic hydrocarbons.
Davis, Charles C.; Ebel, Michael J. Chem. Educ. 1971, 48, 675.
Alkanes / Cycloalkanes |
Stereochemistry |
Diastereomers |
Constitutional Isomers
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The stereospecific synthesis of trans-1,4-disubstituted cyclohexanes. An organic chemistry laboratory experiment Monson, Richard S.
The authors present a synthetic experiment suitable for the introductory organic chemistry laboratory which the introductory organic chemistry laboratory which allows for the unambiguous preparation of trans-1,4-disubstituted cyclohexane derivatives from readily available starting materials.
Monson, Richard S. J. Chem. Educ. 1971, 48, 197.
Alkanes / Cycloalkanes |
Stereochemistry |
Reactions
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