1. The Methanolysis of Substituted Methyl Benzoates: Students are asked to synthesize C14 labeled methyl esters of several aromatic acids and to study their methanolysis. While ester synthesis is straightforward this synthesis requires some thought and trial experimentation since it must be done on a small scale in order to conserve expensive C14 labeled methanol. Student follow the methanolysis using a scintillation counter. Each student group works on a different ester synthesis. We then summarize the class results and students correlate them using a linear free energy relationship.
2. A Study of the Relationship Between Structure and Acidity: Go to the literature and find routes for the synthesis of the following compounds. The P represents a phenyl group.
Alkylate the product with any alkylating agent that your group chooses. Consider the problem of C versus O alkylation. Teams which choose the easier synthesis of Dimedone, the first molecule, should do both C and O alkylation. Purify all products and use instrumental methods to confirm your product identification. Prepare a report on this phase of the project.
Compare the pKa and ketone/enone ratios of these two cyclic diones to 1,4-pentane-dione (acetylacetone). Use two different ethanol/water ratios and compare your values to literature values for acetylacetone. Determine the ketone/enone ratios in at least two solvents and compare those values to that for the acyclic ketone in the same solvents. In your report for this phase of the project address the differences found.
3. TiO2 Catalyzed Formation of Amino Acids in a Primitive Earth Atmosphere: When methane, ammonia, and water are irradiated with near ultraviolet light in the presence of platinized TiO2, amino acids are formed. Prepare platinized TiO2, a semi-conductor, using the literature procedure. Set up a vessel containing water and the catalyst and slowly flow methane and ammonia through it while irradiating with near ultraviolet light. This irradiation should go for several days. Work up the resulting solution and analyze it using TLC, or HPLC, or GC-MS. Note that you must prepare appropriate derivatives for any of the three analyses. The experiment may be extended by adding possible labeled intermediates and looking for the label in the amino acid products. In your oral presentation include an explanation of how semi-conductors work and what the possible mechanisms of initiation of the chemistry are.
4. Synthesis, Spectroscopy, and Photochemistry of Ru(II) Complexes: Go to the literature to find out how to synthesize ruthenium complexes with the formula RuL3+, where L is either bipyridyl ligand or 1-10 phenanthroline. Establish purity using either spectroscopy or electrochemistry using literature procedures. When excited these Ru complexes luminesce. You may determine the lifetime of this luminescence using our nitrogen dye laser. Alternately you may use a fluorimeter to study luminescence as a function of quencher concentration. Discuss the photophysics of these processes in both your oral presentation and your written report.
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