PHYSICAL METHODS IN ORGANIC CHEMISTRY
Learning outcomes of the course unit
The aim of the course is to give the students the theoretical and practical guidelines for the structural identification of organic compounds by interpretation of spectroscopic data (IR, UV, NMR e MS), highlighting the analysis of 1H- e 13C-NMR spectra.
Course contents summary
UV-Vis Spectroscopy. Infrared Spectroscopy. Nuclear Magnetic Resonance Spectroscopy (NMR). Mass Spectrometry (MS).
Introduction on the techniques for the structural investigation of organic compounds. Radiation-matter interaction. Electromagnetic spectrum, absorption and emission phenomena, ground and excited states, emission and absorption spectroscopy.
UV-Vis Spectroscopy. Electronic transitions and absorption in the UV-Vis region. Rotational, vibrational and electronic energetic levels. Molecular orbitals and electronic transitions in alkenes, polyenes, in carbonyls and α,β unsaturated carbonyls, in benzene, and in aromatic polycycle aromatics. Effects of the substituents on the electronic transitions.
Infrared Spectroscopy. Fundamental theoretical concepts. Vibrational frequency in diatomic and polyatomic molecules. Stretching and bending vibrations. Classification of the absorption bands. Interpretation of IR spectra of the most important classes of organic compounds.
Nuclear Magnetic Resonance Spectroscopy (NMR). Magnetic properties of the atomic nuclei. Nuclear spin and resonance. The vector model of NMR. The rotating frame of reference. Spin relaxation. Pulses. Longitudinal and Transverse Relaxation. Chemical shifts and couplings. Factors influencing chemical shift. Geminal and vicinal J coupling. Long range J coupling. Chemical and Magnetic Equivalence. Enantiotopicity and Diastereotopicity. First-order and second-order spectra. Spin systems with two or three coupling constants. 13C-NMR Spectroscopy. Two dimensional methods 2D NMR. (1H-1H COSY. 1H-1H NOESY. 1H-13C HETCOR)
Mass Spectrometry (MS). Introduction. Ion sources: electron impact, chemical ionizazion, FAB, Electrospray and MALDI. Mass analyzers: sector field, quadrupole, time-of-flight. Resolving power. Molecular peak, isotopic peaks, base peak. Principal fragmentations and characteristic rearrangements.
R. M. SILVERSTEIN, F. WEBSTER, " Spectrometric identification of organic compounds "
Assessment methods and criteria
Written and oral examination