TIGER

Journal Articles: 10 results
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
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
A Unified Approach to Electron Counting in Main-Group Clusters  John E. McGrady
A unified approach to electron counting in main-group cluster chemistry is presented, wherein the different classes, electron-rich, electron-precise, and electron-deficient, are viewed simply as different regions of a continuum defined by two variables, vertex count and valence electron count.
McGrady, John E. J. Chem. Educ. 2004, 81, 733.
Main-Group Elements |
MO Theory
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
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
Syntheses and rearrangements of cage molecules related to cubane  Jefford, Charles W.
This article looks at the synthesis of cubane, basketene, miscellaneous homocubane chemistry, snoutene, triqunacene, hypostrophene, tris-homocubane, and catalysis by transition metals.
Jefford, Charles W. J. Chem. Educ. 1976, 53, 477.
Catalysis |
Transition Elements |
Alkenes |
Synthesis |
Aromatic Compounds |
Heterocycles |
Alcohols
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
Who proposed the Dewar formula of benzene?  Sementsov, A.
The bridged formula of benzene was first proposed by two German chemists in 1868.
Sementsov, A. J. Chem. Educ. 1966, 43, 151.
Aromatic Compounds
Rules for molecular orbital structures  Meislich, Herbert
In view of the fact that molecular orbital theory makes more correct predictions and avoids the misconceptions that arise in the minds of novice students when they are exposed to resonance theory, it would be better to use M.O. theory as much as possible in teaching organic chemistry.
Meislich, Herbert J. Chem. Educ. 1963, 40, 401.
MO Theory |
Resonance Theory