Aim of the course is the combined and comparative use of spectroscopic techniques for the structural determination of organic molecules. Infrared spectroscopy (IR), mono- (1H and 13C) and two-dimensional (homonuclear and heteronuclear) nuclear magnetic resonance spectroscopy (NMR), and mass spectrometry (MS) are discussed, to give students a basic knowledge, together with exercises for systematic analysis and interpretation of IR, NMR and MS spectra for the identification of organic compounds.
1. Hesse Meier
“Metodi spettroscopici nella chimica organica”
EdiSES
2. Robert M. Silverstein, Francis X. Webster, David J. Kiemle
“Identificazione spettrometrica di composti organici”
Casa Editrice Ambrosiana
Learning Objectives
The course objectives are to illustrate the use of spectroscopic techniques for determination of organic molecule structure.
Prerequisites
According to the teaching regulations, the exams relating to the disciplines of each year are preparatory to those of the following year.
Teaching Methods
Teaching lessons and exercises for the resolution of structures through the various discussed spectroscopies.
Slides/transparences and other related material provided by the teachers (present in the virtual classroom set up on the Moodle e-learning platform)
Lessons notes.
Teaching tools: light board, e-learning Moodle platform.
Further information
Reception hours:
Every day after appointment.
Type of Assessment
There are 5 official appeals, 2 in the January-February winter session, and 3 in the summer session, June-September. In addition, there are 2 appeals, in November and April (during periods of teaching silence). In case of failure to pass the exam, students can register for the next first useful appeal. The final exam consists of a written exam (time available 2 hours), followed by an oral exam. The written exam is aimed at ascertaining the learning process in the resolution of an unknown organic structure through the interpretation of the IR, NMR and MS spectra. Passing the written test allows admission to the oral examination.
During the oral examination the understanding of the relationship between the structure of an organic molecule and its spectroscopic properties is further evaluated, through the prediction of the characteristic absorptions in the spectroscopies treated in class, taking into account, for example, implications due to the effect of chirality, stereochemistry, symmetry, and conjugation. In any case, the student's ability to apply the topics and concepts discussed in class to understand and predict the spectroscopic characteristics of the main functional groups is verified.
The final grade takes into account the evaluation both of the written and oral test.
The exam is booked through the online booking service.
Course program
General principles of infrared spectroscopy, with particular attention to the characteristics of the various functional groups and to the nature of the substituents. The process of infrared absorption; modes of vibration and oscillation; properties of bonds and absorption. Instrumentation. Systematic examination of the spectra of the most important classes of organic compounds. Overview of quantitative analysis. Lambert-Beer Law. General principles of mass spectrometry. Generation, fragmentation and detection of ions. Instrumentation. Electron impact (EI) as the main ionization method. Overview of other ionization methods: chemical ionization (CI), FAB, FD, ESI, MALDI. Types of analyzer: quadrupole and sectors (electrostatic and magnetic). Metastable ions. The mass spectrometer as a gas chromatography detector. Examples of rearrangements (retro Diels-Alder, McLafferty). Fragmentations characteristic of the most important classes of organic compounds.
General principles of nuclear magnetic resonance spectroscopy (NMR). Nuclear spin states, nuclear magnetic moment, energy absorption and its effects. Pulse technique with Fourier transform. Rotating frame of reference. Instrumentation. Definition of chemical shift. Shielding constant, local diamagnetic effects, diamagnetic anisotropy. Proton magnetic resonance. Spin-spin coupling. Relaxation. Signal intensity. Coupling constants, chemical and magnetic equivalence. Types of proton spectra. Simplification of spectra. Decoupling methods. Effect of chirality. Overview of magnetic resonance of Carbon-13. Effect of symmetry on NMR spectra. nOe Effect. Shift reagents. Overview of two-dimensional nuclear magnetic resonance imaging.
Sustainable Development Goals 2030
The course is in line with the objectives of Quality Education (Cod. 4) and Decent Work and Economic Growth (Cod. 8).