TIGER

Other Resources: 14 results
Molecular Models of Antioxidants and Radicals  William F. Coleman
This month's featured molecules come from the paper by John M. Berger, Roshniben J. Rana, Hira Javeed, Iqra Javeed, and Sandi L. Schulien (1) describing the use of DPPH to measure antioxidant activity. DPPH was one of the featured molecules in September 2007 (2) and the basics of antioxidant activity were introduced in last month's column (3). In addition, some of the other molecules in the paper are already in the featured molecules collection (4). The remaining structures in the Figure 1 and Table 1 of the paper have been added to the collection. All structures have been optimized at the 6-311G(D,P) level. These molecules suggest a number of possible student activities, some reminiscent of previous columns and some new. (R,R,R)-α-tocopherol is one of the molecules in the mixture that goes by the name vitamin E. These molecules differ in the substituents on the benzene ring and on whether or not there are alternating double bonds in the phytyl tail. In (R,R,R)-α-tocopherol the R's refer to the three chiral carbon atoms in tail while α refers to the substituents on the ring. (R,R,R)-α-Tocopherol is the form found in nature. An interesting literature problem would be to have students learn more about the vitamin E mixture and the differing antioxidant activity of the various constituents. Additionally they could be asked to explore the difference between the word natural as used by a chemist, and "natural" as used on vitamin E supplements. Can students find regulations governing the use of the term "natural"? Can they suggest alternative legislation, and defend their ideas? If students read about vitamin C they will discover that only L-ascorbic acid is useful in the body. It would be interesting to extend the experiment described in the Berger et al. paper (1) to include D-ascorbic acid. How do the antioxidant abilities of the enantiomers, as determined by reaction with DPPH compare? Is this consistent with the behavior in the body? Why or why not? Berger et al. mention two other stable neutral radicals, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and Fremy's salt. In a reversal from the use of stable radicals to measure antioxidant properties, these two molecules have proven to be very versatile oxidation catalysts in organic synthesis, and would make a rich source of research papers for students in undergraduate organic courses.
Free Radicals |
Natural Products
Biologically Active Exceptions to the Octet Rule  Ed Vitz
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Lewis Structures |
Free Radicals |
Vitamins
Alkanes  Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Alkanes / Cycloalkanes
Cycloalkanes  Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Alkanes / Cycloalkanes
Hexane 1 (GCMP)  David M. Whisnant
Hexane 1: this is a resource in the collection "General Chemistry Multimedia Problems". Hexane, a liquid hydrocarbon with the formula C6H14, burns when ignited in the presence of oxygen. In this problem we will observe videos of this combustion reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
Alkanes / Cycloalkanes
Hexane 2 (GCMP)  David M. Whisnant
Hexane 2: this is a resource in the collection "General Chemistry Multimedia Problems". Hexane, a liquid hydrocarbon with the formula C6H14, burns when ignited in the presence of oxygen. In this problem we will observe videos of this combustion reaction. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
Alkanes / Cycloalkanes
Alkanes with Cultural Connections  Garrett Schwarzman
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Alkanes / Cycloalkanes
Organic Compounds: Hydrocarbons  Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Alkanes / Cycloalkanes
Exceptions to the Octet Rule  Ed Vitz, John W. Moore
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Lewis Structures |
Free Radicals |
Molecular Properties / Structure
Carbon Compounds  
Volume 03, issue 13 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Bioorganic Chemistry |
Alkanes / Cycloalkanes
Organic Compounds of Carbon  
Volume 04, issue 13 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Bioorganic Chemistry |
Alkanes / Cycloalkanes
Carbon and Its Organic Compounds  
Volume 05, issue 13 of a series of leaflets covering subjects of interest to students of elementary chemistry distributed in 1929 - 1932.
Bioorganic Chemistry |
Alkanes / Cycloalkanes
Alkanes in Astronomy  Robert Hetue
A section of ChemPrime, the Chemical Educations Digital Library's free General Chemistry textbook.
Alkanes / Cycloalkanes |
Astrochemistry
ChemPaths 104 F Jan 21  John W. Moore
Today in Chem 104: * Lecture: Organic Structures; Isomers * Reading: Kotz Ch. 10, Sec. 1-2; Appendix E (pp. A-17-20) Moore Ch. 3: Sec. 3-4; Ch. 8: Sec. 3, 5; App E (pp. A.26-A.30) * Practice Quiz and Homework #1 are due by 11:55 pm M Jan 24.
Alkanes / Cycloalkanes |
Constitutional Isomers