| Journal Articles: 27 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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Electronic Structure Principles and Aromaticity P. K. Chattaraj, U. Sarkar, and D. R. Roy
Electronic structure principles dictate that aromatic molecules are associated with low energy, polarizability, and electrophilicity but high hardness values, while antiaromatic molecules possess the opposite characteristics. These relationships are demonstrated through B3LYP/6-311G** calculations on benzene and cyclobutadiene.
Chattaraj, P. K.; Sarkar, U.; Roy, D. R. J. Chem. Educ. 2007, 84, 354.
Aromatic Compounds |
Molecular Properties / Structure |
Quantitative Analysis |
Theoretical Chemistry |
Alkenes |
Quantum Chemistry
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Acid-Catalyzed Isomerization of Carvone to Carvacrol Richard A. Kjonaas and Shawn P. Mattingly
Describes the acid-catalyzed isomerization of carvone (oil of spearmint) to carvacrol (oil of origanum). The experiment demonstrates several important concepts including formation of a carbocation by protonation of an alkene, rearrangement of a carbocation, deprotonation of a carbocation, acid-catalyzed enolization, and aromaticity.
Kjonaas, Richard A.; Mattingly, Shawn P. J. Chem. Educ. 2005, 82, 1813.
Aromatic Compounds |
Medicinal Chemistry |
Natural Products |
NMR Spectroscopy
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Quantitative Thermodynamic Descriptions of Aromaticity. A Computational Exercise for the Organic Chemistry Laboratory Terrence Gavin
This article describes an exercise that enables students to establish a quantitative scale of aromaticity via computer-driven quantum mechanical calculations using Spartan software. The method utilizes a group of analogous isodesmic reactions from which the energy difference between two isomeric cyclic polyenes is calculated from their optimized geometries. The energy differences found are used to characterize structures as aromatic, nonaromatic, or antiaromatic depending on the value obtained. A representative group of structures, including hydrocarbons, hydrocarbon ions, and heterocycles are studied.
Gavin, Terrence. J. Chem. Educ. 2005, 82, 953.
Aromatic Compounds |
Computational Chemistry |
Heterocycles |
Molecular Modeling |
Thermodynamics
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An Acid Hydrocarbon: A Chemical Paradox Jeffrey T. Burke
This article explores the use of paradox as a teaching and learning strategy. Specifically, students observe the acid-like paradoxical behavior of the hydrocarbon cyclopentadiene. This observation then serves as a springboard to an understanding of the non-benzenoid aromatics.
Burke, Jeffrey T. J. Chem. Educ. 2004, 81, 65.
Acids / Bases |
Aromatic Compounds
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Using Hydrocarbon Acidities To Demonstrate Principles of Organic Structure and Bonding Andrew P. Dicks
This article demonstrates the utility of hydrocarbon acidity as a teaching tool within the undergraduate classroom. Acidities of compounds containing only hydrogen and carbon vary by at least 50 orders of magnitude. Differences in acidities are rationalized by invoking principles of hybridization, resonance, induction, and aromaticity.
Dicks, Andrew P. J. Chem. Educ. 2003, 80, 1322.
Acids / Bases |
Aromatic Compounds |
Alkanes / Cycloalkanes
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A New Approach to Understanding Oxidation-Reduction of Compounds in Organic Chemistry Abdullah Menzek
Teaching oxidation-reduction in introductory organic chemistry.
Menzek, Abdullah. J. Chem. Educ. 2002, 79, 700.
Aromatic Compounds |
Oxidation / Reduction |
Oxidation State
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Isolation and Spectral Analysis of Naturally Occurring Thiarubrine A Juan Reyes, Melita Morton, Kelsey Downum, and Kevin E. O'Shea
An experiment in which students isolate (from ragweed) and characterize thiarubrine A; thiarubrines are an important class of compounds which have recently received attention because of their unusual reactivity, unique biological activity, and potential medicinal applications.
Reyes, Juan; Morton, Melita; Downum, Kelsey; O'Shea, Kevin E. J. Chem. Educ. 2001, 78, 781.
Aromatic Compounds |
IR Spectroscopy |
Natural Products |
NMR Spectroscopy |
UV-Vis Spectroscopy |
Medicinal Chemistry
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Organic Acids without a Carboxylic Acid Functional Group G. V. Perez and Alice L. Perez
This paper presents several organic molecules that have been labeled as acids but do not contain a carboxylic acid functional group. Various chemical principles such as pKa, tautomerization, aromaticity, conformation, resonance, and induction are explored.
Perez, G. V.; Perez, Alice L. J. Chem. Educ. 2000, 77, 910.
Acids / Bases |
Molecular Properties / Structure |
Nomenclature / Units / Symbols |
Phenols |
Carboxylic Acids |
Aromatic Compounds
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Keep Going with Cyclooctatetraene! Addison Ault
This paper shows how some simple properties of cyclooctatetraene can indicate important ideas about the structure of cyclooctatetraene.
Ault, Addison. J. Chem. Educ. 2000, 77, 55.
Aromatic Compounds |
NMR Spectroscopy |
Mechanisms of Reactions |
Molecular Properties / Structure
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Comments on the Treatment of Aromaticity and Acid-Base Character of Pyridine and Pyrrole in Contemporary Organic Chemistry Textbooks Hugh J. Anderson and Ludwig Bauer
Presentations of aromaticity and acid-base character of pyridine and pyrrole in 18 contemporary organic chemistry textbooks were surveyed.
Anderson, Hugh J.; Bauer, Ludwig. J. Chem. Educ. 1999, 76, 1151.
Acids / Bases |
Aromatic Compounds
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A Simple and Convenient Method for Generation and NMR Observation of Stable Carbanions Hamid S. Kasmai
A simple and convenient method for the generation and NMR study of stable carbanions is described. The data and sample spectra illustrate that reliable and good quality NMR spectra of stable carbanions may be obtained. The experiments described provide a good opportunity for students to apply the basic principles of 1H and 13C NMR spectrometry and the interesting topic of the exchange phenomenon in NMR.
Kasmai, Hamid S. J. Chem. Educ. 1999, 76, 830.
Acids / Bases |
Reactive Intermediates |
NMR Spectroscopy |
Aromatic Compounds
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Correction
Correction in equation 1.
J. Chem. Educ. 1997, 74, 480.
Aromatic Compounds |
Molecular Properties / Structure
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Don't stop with benzene! The educational value of the cyclooctatetraene (C8H8) molecule Samet, Cindy
Educators often ignore larger molecular ring systems, suggesting to students that benzene covers all the important aspects of the chemistry of annulenes.
Samet, Cindy J. Chem. Educ. 1993, 70, 291.
Aromatic Compounds
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The misuse of the circle notation to represent aromatic rings Belloli, Robert C.
This chemistry educator has noticed confusion and erroneous conclusions resulting from the overuse and misuse of the circle notation to represent aromaticity in polycyclic aromatic hydrocarbons.
Belloli, Robert C. J. Chem. Educ. 1983, 60, 190.
Aromatic Compounds |
Molecular Properties / Structure
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Pi bonding without tears Akeroyd, F. Michael
A non-mathematical treatment of sigma-pi bonding applied to conjugation, hyperconjugation, Markovnikoff addition, aromaticity, and aromatic substitution.
Akeroyd, F. Michael J. Chem. Educ. 1982, 59, 371.
Alkenes |
Mechanisms of Reactions |
Addition Reactions |
Aromatic Compounds
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Structure-resonance theory for pericyclic transition states Herndon, William C.
The purpose of this article is to show that structure-resonance theory can be used to understand the effects of structure or substituents on the rates of thermal pericyclic reactions.
Herndon, William C. J. Chem. Educ. 1981, 58, 371.
Aromatic Compounds |
Resonance Theory |
Molecular Properties / Structure
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Benzene, a familiar hazard? Smith, Roger M.
Reviews the hazards of benzene.
Smith, Roger M. J. Chem. Educ. 1980, 57, A85.
Aromatic Compounds |
Toxicology
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Where does resonance energy come from? A nonmathematical approach to the theory of aromaticity Sardella, D. J.
In confronting the central issue of why aromatic systems are aromatic, the author provides a verbal application of perturbational molecular orbital theory.
Sardella, D. J. J. Chem. Educ. 1977, 54, 217.
Aromatic Compounds |
MO Theory
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Teaching aromaticity, conjugation, and enolization Schambach, Robert A.
An understanding of the delocalization of electrons in organic compounds is central knowledge. In teaching undergraduates about aromaticity, conjugation, and enoliztion, this author has found it useful to present examples of compounds in which delocalization. Effects are sustained in the presence of potentially interfering saturated carbon atoms.
Schambach, Robert A. J. Chem. Educ. 1976, 53, 711.
Aromatic Compounds |
Reactions
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The Friedel-Crafts pathway to diarylcyclopropenones. An undergraduate organic experiment Agranat, Israel; Tapuhi, Yitzhak
The authors describe a facile entry into the cyclopropenone series which may conveniently be practiced in an undergraduate organic chemistry laboratory.
Agranat, Israel; Tapuhi, Yitzhak J. Chem. Educ. 1976, 53, 531.
Aromatic Compounds |
Reactions
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Imidazole - Versatile today, prominent tomorrow Matuszak, C. A.; Matuszak, A. J.
Imidazole chemistry has pedagogical utility for all the organic chemistry students pursing careers in the life sciences.
Matuszak, C. A.; Matuszak, A. J. J. Chem. Educ. 1976, 53, 280.
Grignard Reagents |
Aromatic Compounds |
Heterocycles |
Phenols |
Acids / Bases |
Catalysis |
Coordination Compounds |
Hydrogen Bonding
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Dewar resonance energy Baird, N. C.
In the present paper, some of the general properties of the Dewar Resonance Energy definition are developed. In particular, the DRE value for a compound is shown to be independent of the numerical values used to bond energies, and the use of DRE in judging the aromaticity of organic molecules is illustrated.
Baird, N. C. J. Chem. Educ. 1971, 48, 509.
Resonance Theory |
Aromatic Compounds |
Molecular Properties / Structure
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Teaching aromatic substitution: A molecular orbital approach Meislich, Herbert
This paper presents a way of teaching aromatic substitution using the concepts of alternate polarity and electron delocalization through extended pi-bonding.
Meislich, Herbert J. Chem. Educ. 1967, 44, 153.
Aromatic Compounds |
MO Theory |
Nucleophilic Substitution |
Covalent Bonding |
Molecular Properties / Structure
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The contributions of Fritz Arndt to resonance theory Campaigne, E.
Examines the contribution of Fritz Arndt to resonance theory and his work regarding the nature of bonds in pyrone ring systems.
Campaigne, E. J. Chem. Educ. 1959, 36, 336.
Resonance Theory |
Aromatic Compounds |
Covalent Bonding
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Representation of polycyclic aromatic compounds Bieber, Theodore I.
Reviews the representation of polycyclic aromatic compounds and the matter of pi-electron sharing by adjacent sextets.
Bieber, Theodore I. J. Chem. Educ. 1958, 35, 235.
Aromatic Compounds |
Nomenclature / Units / Symbols |
Molecular Properties / Structure
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The organization of subject matter in elementary organic chemistry MacKenzie, Charles A.
Describes a curricular approach in which aliphatic and aromatic compounds are treated simultaneously rather than separately.
MacKenzie, Charles A. J. Chem. Educ. 1953, 30, 243.
Aromatic Compounds |
Alkanes / Cycloalkanes
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