TIGER

Journal Articles: 14 results
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 Hckel-aromatic and chiral Mbius-aromatic transition states.
Rzepa, Henry S. J. Chem. Educ. 2007, 84, 1535.
Alkanes / Cycloalkanes |
Alkenes |
Aromatic Compounds |
Mechanisms of Reactions |
Stereochemistry
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
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
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
Melting Point and Molecular Symmetry  R. J. C. Brown and R. F. C. Brown
In 1882 Thomas Carnelley observed that high molecular symmetry is associated with high melting point. The application of the rule to a number of different molecular crystals is discussed. The rule applies to different categories of crystal for different reasons, which can be explained by thermodynamic analysis.
Brown, R. J. C.; Brown, R. F. C. J. Chem. Educ. 2000, 77, 724.
Liquids |
Molecular Properties / Structure |
Phases / Phase Transitions / Diagrams |
Solids |
Thermodynamics |
Physical Properties |
Aromatic Compounds |
Crystals / Crystallography
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
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
Correction  
Correction in equation 1.
J. Chem. Educ. 1997, 74, 480.
Aromatic Compounds |
Molecular Properties / Structure
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
ESR studies and HMO calculations on benzosemiquinone radical anions: A physical chemistry experiment  Beck, Rainer; Nibler, Joseph W.
For this laboratory study, several benzosemiquinone radical anions were chosen since they are long-lived and are easily made from inexpensive source materials. The effects of molecular symmetry and of different substituents attached to the aromatic ring system are also readily seen.
Beck, Rainer; Nibler, Joseph W. J. Chem. Educ. 1989, 66, 263.
Spectroscopy |
MO Theory |
Aromatic Compounds
Synthesis of azulene, a blue hydrocarbon  Lemal, David M.; Goldman, Glenn D.
A procedure of the synthesis of this simple, beautiful, and theoretically interesting compound with many unusual properties.
Lemal, David M.; Goldman, Glenn D. J. Chem. Educ. 1988, 65, 923.
MO Theory |
Aromatic Compounds |
Diastereomers |
Synthesis
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
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
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