Examples of Guided Inquiry
Activities for Organic Lecture and Laboratory
Dr. Jamie L. Schneider*
Department
of Chemistry, University of Wisconsin - La Crosse, 1725 State Street,
La Crosse, WIÊ
54601
Guided Inquiry
activities have the potential to create a minds-on, student-centered
environment for students. This poster will describe two activities, one
for lecture and one for the laboratory, which connect with a POGIL classroom
approach for organic chemistry. The classroom activity uses C-13 NMR data
to help students better visualize symmetry in organic molecules. This
activity is used early in the semester after students have discovered that
several structural isomers can sometimes exist for a given molecular
formula. The laboratory activity is used to create data on electrophilic
aromatic substitution reactions, specifically Friedel-Crafts alkylation of an
alkyl benzene which can then be discussed and further explored during lecture.
Both of these activities support process guided inquiry learning in the organic
classroom.
Investigations of Columnar
Photomechanically Active Rhodium(I) Complexes
Ryan W. Davis,1 James A. Brozik,1
Alexsia L. Richards,2 and William F. Wacholtz*2
1 Department of Chemistry University of New Mexico, Albuquerque, NMÊ 87131, and
2 Department of Chemistry University of
Wisconsin Oshkosh, Oshkosh, WIÊ 54901
Low dimensional
materials are compounds whose properties are dominated by physical behaviors
along primarily one axis. Crystals of the complex Rh(CO)2(3,6-DTSQ)
where Rh is rhodium and 3,6-DTSQ is 3,6-di-tert-butylsemiquinone have
been shown to bend reversibly when exposed to near IR light. This
property has been attributed in the literature to a metal to ligand charge
transfer (MLCT) transition. Theoretical calculations of this compound and an
analogous compound employing 3,6-di-tert-butylnaphthaquinone (3,6-DTNQ)
indicate that the actual excited state transition appears to be a ligand to
metal charge transfer (LMCT). Implications of this study and confirmatory
experiments employing excited state IR and time resolved IR spectroscopy will
be discussed.
An Environmentally Friendly
Solvent System for Stereoselective Enol Ether Formation
Linfeng Xie*, Eric Kiefer, Melissa Wielgosh,
Jessica Budish, and Carolyn Bernier
Department of Chemistry University of Wisconsin
Oshkosh, Oshkosh, WI 54901
Enolates are an
important reactive species in organic synthesis. Their uses via aldol
condensation types of reactions allow the construction of useful carbon-carbon
bonds. In the literature, most enolate-forming reactions have been
carried out in an oxygenated solvent such as tetrahydrofuran (THF). The
solvent presents potential environmental problems during the workup step, in
which THF dissolves in water and enters the sewer system.
We investigated the possibility of carrying out enolate-forming reactions in
solvent systems that are environmentally friendly. Specifically, a
hydrocarbon solvent system would prevent the solvent from contaminating the aqueous
phase during the product work-up. In our study several ketones have been
subject to enolization with two lithium amide bases in a mixture of
tetrahydrofuran (THF) and toluene. The resulting enol ethers were trapped
with trimethylsilyl chloride to yield the corresponding enol ethers. High
stereoselectivity of enol ethers has been achieved with as low as 5-10% of THF
in toluene. We found that a minimum amount of THF is necessary to carry
out enolization in toluene without compromising stereoselectivity and
yields. We envision that such a mixed solvent system may be applied to
other reactions requiring THF as the solvent. This finding is of
economical and environmental value for industrial scale syntheses.
ON THE MAILLARD REACTION OF
METEORITIC AMINO ACIDS
Vera M. Kolb*, Milica Bajagic, and Patrick J.
Liesch
Department of Chemistry, University of
Wisconsin-Parkside, Kenosha, WIÊ
53141-2000
We have performed the
Maillard reaction of a series of meteoritic amino acids with sugar ribose under
simulated prebiotic conditions, in the solid state at 65oC and at
the room temperature. Many meteoritic amino acids are highly reactive with
ribose, even at the room temperature. We have isolated high molecular
weight products that are insoluble in water, and have studied their structure
by the IR (infrared) and solid-state C-13 NMR (nuclear magnetic resonance)
spectroscopic methods. The functional groups and their distribution were
similar among these products, and were comparable to the previously isolated
insoluble organic materials from the Maillard reaction of the common amino
acids with ribose. In addition, there were some similarities with the insoluble
organic material that is found on Murchison meteorite. Our results
suggest that the Maillard products may contribute to the composition of the
part of the insoluble organic material that is found on Murchison. We have also
studied the reaction of sodium silicate solution with the Maillard mixtures, to
elucidate the process by which the organic compounds are preserved under
prebiotic conditions.