93779 - Spectroscopic Identification of Organic Compounds

Learning outcomes

In this course, the student will learn “hands-on” how to apply the most up-to-date spectroscopic and chirooptical techniques (ECD and VCD), combined with QM calculations, to the structural and stereochemical assignment of complex organic molecules of natural origin as well as coming from multistep syntheses. Methodologies include also advanced NMR experiments, such as dynamic NMR, analysis of enantiomeric mixtures, and study of the interactions of organic molecules (drugs) with large biomolecules (i.e. proteins). The student will also learn how to observe reaction intermediates generated in catalytic processes. During the laboratory part the student will have access to the instrumentation and will learn how to experimentally acquire the spectroscopic data needed for the complete assignment of organic molecules

Course contents

Conformational analysis by NMR

NOE NMR
Variable temperature NMR
Relative configuration of stereogenic centers via NOE

Optical methods

Circular electronic dichroism - basis of theory and instrumentation
Excitonic coupling and absolute configuration
Vibrational circular dichroism

Conformational analysis by QM methods

Conformational analysis by QM methods

1. Overwiew of QM methods for conformational analysys
2. DFT fundamentals
3. Conformational analysis by DFT methods.
4. Ground state search and evaluation of relative energies.
5. Transition state for conformational analysis, atropisomers barrier evaluation
6. Calculations of observables: NMR chemical shifts and coupling constants
7. Calculations of excited states: TD-DFT simulations for absolute configuration
8. Optical activity calculation
9. Vibrational circular dichroism

Case studies by synergic combination of the above techniques for relative and absolute configuration of organic and natural molecules.

Laboratory:

1. NOE and variable temperature NMR
2. Acquisition of ECD spectra
3. Setup of calculations for AC determination.

Readings/Bibliography

Some relevant literature and review articles will be made avaialable from the teacher.

for deeper knowledge the following text book may be consulted:

NMR: High-Resolution NMR Techniques in Organic Chemistry, T.D.W. Claridge, ISBN ‎ 978-0080999869

Optical Methods: COmprehensive Chiroptical Spectroscopy, vol. 1 and 2; N.Berova, P.L. Polavarapu, K.Nakanishi, R.W.Woody. ISBN 978-0-470-64135-4

DFT calculations: Computational Organic Chemistry, 2nd Edition, S.M.Bachrach. ISBN: 978-1-118-29192-4

 

Teaching methods

Powerpoint Slides will be made available from the teacher at the beginning of the course.

Assessment methods

Final exam is based on a critical reading of a research article taken from the literature, with discussion.

Teaching tools

Powerpoint slides and experimental work on NMR and ECD spectrometers.

Office hours

See the website of Andrea Mazzanti