Transition to an Investigative Laboratory Program in Chemistry at Birmingham-Southern College David J. A. Schedler and Laura K. Stultz Introduction • • • • National Science Foundation Grant Investigative Laboratories Development of Laboratory Projects Examples Project Goals Student Goals Improve - Problem solving and collaborative skills - Ability to apply experimental techniques to solve a chemical problem. - Ability to communicate results (written and oral) Curricular Goals - Improved laboratory experience - Better synergy between lecture and laboratory - Connections between chemistry courses Investigative Laboratories • Students discover results instead of • • • • verifying them Experimental protocols are largely student designed Work is done in collaborative groups Interpretation of results through data analysis Group discussion Project Plan Gradualism Model – stepwise presentation of new material with specific goals Instrumental techniques as common thread - Molecular Modeling - FTNMR (1H and 13C) Project based Laboratories – Reinforces concepts and skills Student involvement in laboratory design • First Semester Focuses on Techniques and Instrumentation • • • • • • Distillation Crystallization Melting point TLC GC NMR • Second Semester Focuses on Application • • • • NMR FT-IR Molecular modeling Stereochemistry and Coupling Constants • Projects should have clearly stated: • Objective • Outcome • Introduction • Theory for the instrumentation to be used • background into the chemistry involved • Experimental Procedure OH O H3C NaBH4 NaOH, H2O OH H3C trans-3-methylcyclohexan-1-ol 2.39 kcal/mol H3C cis-3-methylcyclohexan-1-ol 1.34 kcal/mol Heq OH Heq Hax Heq Heq OH Heq H3C Hax Hax Hax Hax H3C Entry Dihedral Expected Dihedral Angle(°) Expected value (Hz) Entry Dihedral Expected Dihedral Angle (°) Expected value (Hz) 1 HeqCCHeq 60 2.5 1 HaxCCHe 60 2.5 60 2.5 180 12 180 12 q 2 HeqCCHeq 60 2.5 3 HeqCCHax 60 2.5 4 HeqCCHax 60 2.5 2 q 3 Hax HaxCCHa x 4 OH HaxCCHe HaxCCHa Hax x Heq Heq Heq OH Hax Heq Hax Jax-eq Jax-ax Jax-eq H OH H3C Heq Hax Jax-eq Jax-ax Jax-eq Ψ Quintet Ψ Triplet of Ψ triplets OH OH O + O O O toluene CH3 O CH3 O Adapted from: McDaniel, Keith F.; Weekley, R. Matthew “The Diels-Alder Reaction of 2,4-Hexadien-1-ol with Maleic Anhydride: A Novel Preparation for the Undergraduate Organic Chemistry Laboratory Course” J. Chem. Educ. 1997, 74, 1465. Diels-Alder Reaction • prediction of reaction product • carry out reaction using previously learned lab techniques OH O O O OH O CH3 O Structure Determination •NMR •IR •Mechanistic explanation CH3 O O H1 H2 H4 CH3 H3 O A B H1 O OH H2 H4 O Dihedral Measured Angle A (°) CH3 Calculated Measured Calculated J Value A Angle B J Value B (Hz) (°) (Hz) H1CCH2 18.93 8.42 179.31 11.19 H2CCH3 40.36 5.61 53.33 3.64 H3CCH4 45.28 4.85 99.05 1.18 www.casper.organ.su.se/ke3690/jhh.html program calculates 3JHH values according to: C.A.G. Haasnoot, F.A.A.M. DeLeeuw and C. Altona Tetrahedron 36 (1980) 2783-2792 H3 O O OH O H1 H2 H4 CH3 H3 O O OH O A H1 CH3 H3 Measured Angle (°) Calculated J Value A (Hz) Measure J Value A (Hz) H1CCH2 18.93 8.42 8.9 H2CCH3 40.36 5.61 5.5 H3CCH4 45.28 4.85 4.6 O OH H2 H4 Dihedral O H2 H1 H3 • Electron Transfer Self Exchange Rates • Kinetic NMR experiment • Factors that affect the electron transfer rates Jameson, D.L.; Anand, R. J. Chem. Ed., 2000, 77, 88 Acknowledgements • National Science Foundation • • • • • • (Award DUE-0126478) Dr. Regina Stanton Mr. Patrick McTamney Ms. Karen Johnson Mr. Nathan Boyd Birmingham-Southern College www.bsc.edu/chemistrylabs.htm